png.h 130 KB
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547 1548 1549 1550 1551 1552 1553 1554 1555 1556 1557 1558 1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 1578 1579 1580 1581 1582 1583 1584 1585 1586 1587 1588 1589 1590 1591 1592 1593 1594 1595 1596 1597 1598 1599 1600 1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611 1612 1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 1623 1624 1625 1626 1627 1628 1629 1630 1631 1632 1633 1634 1635 1636 1637 1638 1639 1640 1641 1642 1643 1644 1645 1646 1647 1648 1649 1650 1651 1652 1653 1654 1655 1656 1657 1658 1659 1660 1661 1662 1663 1664 1665 1666 1667 1668 1669 1670 1671 1672 1673 1674 1675 1676 1677 1678 1679 1680 1681 1682 1683 1684 1685 1686 1687 1688 1689 1690 1691 1692 1693 1694 1695 1696 1697 1698 1699 1700 1701 1702 1703 1704 1705 1706 1707 1708 1709 1710 1711 1712 1713 1714 1715 1716 1717 1718 1719 1720 1721 1722 1723 1724 1725 1726 1727 1728 1729 1730 1731 1732 1733 1734 1735 1736 1737 1738 1739 1740 1741 1742 1743 1744 1745 1746 1747 1748 1749 1750 1751 1752 1753 1754 1755 1756 1757 1758 1759 1760 1761 1762 1763 1764 1765 1766 1767 1768 1769 1770 1771 1772 1773 1774 1775 1776 1777 1778 1779 1780 1781 1782 1783 1784 1785 1786 1787 1788 1789 1790 1791 1792 1793 1794 1795 1796 1797 1798 1799 1800 1801 1802 1803 1804 1805 1806 1807 1808 1809 1810 1811 1812 1813 1814 1815 1816 1817 1818 1819 1820 1821 1822 1823 1824 1825 1826 1827 1828 1829 1830 1831 1832 1833 1834 1835 1836 1837 1838 1839 1840 1841 1842 1843 1844 1845 1846 1847 1848 1849 1850 1851 1852 1853 1854 1855 1856 1857 1858 1859 1860 1861 1862 1863 1864 1865 1866 1867 1868 1869 1870 1871 1872 1873 1874 1875 1876 1877 1878 1879 1880 1881 1882 1883 1884 1885 1886 1887 1888 1889 1890 1891 1892 1893 1894 1895 1896 1897 1898 1899 1900 1901 1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 1926 1927 1928 1929 1930 1931 1932 1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043 2044 2045 2046 2047 2048 2049 2050 2051 2052 2053 2054 2055 2056 2057 2058 2059 2060 2061 2062 2063 2064 2065 2066 2067 2068 2069 2070 2071 2072 2073 2074 2075 2076 2077 2078 2079 2080 2081 2082 2083 2084 2085 2086 2087 2088 2089 2090 2091 2092 2093 2094 2095 2096 2097 2098 2099 2100 2101 2102 2103 2104 2105 2106 2107 2108 2109 2110 2111 2112 2113 2114 2115 2116 2117 2118 2119 2120 2121 2122 2123 2124 2125 2126 2127 2128 2129 2130 2131 2132 2133 2134 2135 2136 2137 2138 2139 2140 2141 2142 2143 2144 2145 2146 2147 2148 2149 2150 2151 2152 2153 2154 2155 2156 2157 2158 2159 2160 2161 2162 2163 2164 2165 2166 2167 2168 2169 2170 2171 2172 2173 2174 2175 2176 2177 2178 2179 2180 2181 2182 2183 2184 2185 2186 2187 2188 2189 2190 2191 2192 2193 2194 2195 2196 2197 2198 2199 2200 2201 2202 2203 2204 2205 2206 2207 2208 2209 2210 2211 2212 2213 2214 2215 2216 2217 2218 2219 2220 2221 2222 2223 2224 2225 2226 2227 2228 2229 2230 2231 2232 2233 2234 2235 2236 2237 2238 2239 2240 2241 2242 2243 2244 2245 2246 2247 2248 2249 2250 2251 2252 2253 2254 2255 2256 2257 2258 2259 2260 2261 2262 2263 2264 2265 2266 2267 2268 2269 2270 2271 2272 2273 2274 2275 2276 2277 2278 2279 2280 2281 2282 2283 2284 2285 2286 2287 2288 2289 2290 2291 2292 2293 2294 2295 2296 2297 2298 2299 2300 2301 2302 2303 2304 2305 2306 2307 2308 2309 2310 2311 2312 2313 2314 2315 2316 2317 2318 2319 2320 2321 2322 2323 2324 2325 2326 2327 2328 2329 2330 2331 2332 2333 2334 2335 2336 2337 2338 2339 2340 2341 2342 2343 2344 2345 2346 2347 2348 2349 2350 2351 2352 2353 2354 2355 2356 2357 2358 2359 2360 2361 2362 2363 2364 2365 2366 2367 2368 2369 2370 2371 2372 2373 2374 2375 2376 2377 2378 2379 2380 2381 2382 2383 2384 2385 2386 2387 2388 2389 2390 2391 2392 2393 2394 2395 2396 2397 2398 2399 2400 2401 2402 2403 2404 2405 2406 2407 2408 2409 2410 2411 2412 2413 2414 2415 2416 2417 2418 2419 2420 2421 2422 2423 2424 2425 2426 2427 2428 2429 2430 2431 2432 2433 2434 2435 2436 2437 2438 2439 2440 2441 2442 2443 2444 2445 2446 2447 2448 2449 2450 2451 2452 2453 2454 2455 2456 2457 2458 2459 2460 2461 2462 2463 2464 2465 2466 2467 2468 2469 2470 2471 2472 2473 2474 2475 2476 2477 2478 2479 2480 2481 2482 2483 2484 2485 2486 2487 2488 2489 2490 2491 2492 2493 2494 2495 2496 2497 2498 2499 2500 2501 2502 2503 2504 2505 2506 2507 2508 2509 2510 2511 2512 2513 2514 2515 2516 2517 2518 2519 2520 2521 2522 2523 2524 2525 2526 2527 2528 2529 2530 2531 2532 2533 2534 2535 2536 2537 2538 2539 2540 2541 2542 2543 2544 2545 2546 2547 2548 2549 2550 2551 2552 2553 2554 2555 2556 2557 2558 2559 2560 2561 2562 2563 2564 2565 2566 2567 2568 2569 2570 2571 2572 2573 2574 2575 2576 2577 2578 2579 2580 2581 2582 2583 2584 2585 2586 2587 2588 2589 2590 2591 2592 2593 2594 2595 2596 2597 2598 2599 2600 2601 2602 2603 2604 2605 2606 2607 2608 2609 2610 2611 2612 2613 2614 2615 2616 2617 2618 2619 2620 2621 2622 2623 2624 2625 2626 2627 2628 2629 2630 2631 2632 2633 2634 2635 2636 2637 2638 2639 2640 2641 2642 2643 2644 2645 2646 2647 2648 2649 2650 2651 2652 2653 2654 2655 2656 2657 2658 2659 2660 2661 2662 2663 2664 2665 2666 2667 2668 2669 2670 2671 2672 2673 2674 2675 2676 2677 2678 2679 2680 2681 2682 2683 2684 2685 2686 2687 2688 2689 2690 2691 2692 2693 2694 2695 2696 2697 2698 2699 2700 2701 2702 2703 2704 2705 2706 2707 2708 2709 2710 2711 2712 2713 2714 2715 2716 2717 2718 2719 2720 2721 2722 2723 2724 2725 2726 2727 2728 2729 2730 2731 2732 2733 2734 2735 2736 2737 2738 2739 2740 2741 2742 2743 2744 2745 2746 2747 2748 2749 2750 2751 2752 2753 2754 2755 2756 2757 2758 2759 2760 2761 2762 2763 2764 2765 2766 2767 2768 2769 2770 2771 2772 2773 2774 2775 2776 2777 2778 2779 2780 2781 2782 2783 2784 2785 2786 2787 2788 2789 2790 2791 2792 2793 2794 2795 2796 2797 2798 2799 2800 2801 2802 2803 2804 2805 2806 2807 2808 2809 2810 2811 2812 2813 2814 2815 2816 2817 2818 2819 2820 2821 2822 2823 2824 2825 2826 2827 2828 2829 2830 2831 2832 2833 2834 2835 2836 2837 2838 2839 2840 2841 2842 2843 2844 2845 2846 2847 2848 2849 2850 2851 2852 2853 2854 2855 2856 2857 2858 2859 2860 2861 2862 2863 2864 2865 2866 2867 2868 2869 2870 2871 2872 2873 2874 2875 2876 2877 2878 2879 2880 2881 2882 2883 2884 2885 2886 2887 2888 2889 2890 2891 2892 2893 2894 2895 2896 2897 2898 2899 2900 2901 2902 2903 2904 2905 2906 2907 2908 2909 2910 2911 2912 2913 2914 2915 2916 2917 2918 2919 2920 2921 2922 2923 2924 2925 2926 2927 2928 2929 2930 2931 2932 2933 2934 2935 2936 2937 2938 2939 2940 2941 2942 2943 2944 2945 2946 2947 2948 2949 2950 2951 2952 2953 2954 2955 2956 2957 2958 2959 2960 2961 2962 2963 2964 2965 2966 2967 2968 2969 2970 2971 2972 2973 2974 2975 2976 2977 2978 2979 2980 2981 2982 2983 2984 2985 2986 2987 2988 2989 2990 2991 2992 2993 2994 2995 2996 2997 2998 2999 3000 3001 3002 3003 3004 3005 3006 3007 3008 3009 3010 3011 3012 3013 3014 3015 3016 3017 3018 3019 3020 3021 3022 3023 3024 3025 3026 3027 3028 3029 3030 3031 3032 3033 3034 3035 3036 3037 3038 3039 3040 3041 3042 3043 3044 3045 3046 3047 3048 3049 3050 3051 3052 3053 3054 3055 3056 3057 3058 3059 3060 3061 3062 3063 3064 3065 3066 3067 3068 3069 3070 3071 3072 3073 3074 3075 3076 3077 3078 3079 3080 3081 3082 3083 3084 3085 3086 3087 3088 3089 3090 3091 3092 3093 3094 3095 3096 3097 3098 3099 3100 3101 3102 3103 3104 3105 3106 3107 3108 3109 3110 3111 3112 3113 3114 3115 3116 3117 3118 3119 3120 3121 3122 3123 3124 3125 3126 3127 3128 3129 3130 3131 3132 3133 3134 3135 3136 3137 3138 3139 3140 3141 3142 3143 3144 3145 3146 3147 3148 3149 3150 3151 3152 3153 3154 3155 3156 3157 3158 3159 3160 3161 3162 3163 3164 3165 3166 3167 3168 3169 3170 3171 3172 3173 3174 3175 3176 3177 3178 3179 3180 3181 3182 3183 3184 3185 3186 3187 3188 3189 3190 3191 3192 3193 3194 3195 3196 3197 3198 3199 3200

/* png.h - header file for PNG reference library
 *
 * libpng version 1.2.1 - December 12, 2001
 * Copyright (c) 1998-2001 Glenn Randers-Pehrson
 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
 *
 * Authors and maintainers:
 *  libpng versions 0.71, May 1995, through 0.88, January 1996: Guy Schalnat
 *  libpng versions 0.89c, June 1996, through 0.96, May 1997: Andreas Dilger
 *  libpng versions 0.97, January 1998, through 1.2.1 - December 12, 2001: Glenn
 *  See also "Contributing Authors", below.
 *
 * Note about libpng version numbers:
 *
 *    Due to various miscommunications, unforeseen code incompatibilities
 *    and occasional factors outside the authors' control, version numbering
 *    on the library has not always been consistent and straightforward.
 *    The following table summarizes matters since version 0.89c, which was
 *    the first widely used release:
 *
 *    source                 png.h  png.h  shared-lib
 *    version                string   int  version
 *    -------                ------ -----  ----------
 *    0.89c "1.0 beta 3"     0.89      89  1.0.89
 *    0.90  "1.0 beta 4"     0.90      90  0.90  [should have been 2.0.90]
 *    0.95  "1.0 beta 5"     0.95      95  0.95  [should have been 2.0.95]
 *    0.96  "1.0 beta 6"     0.96      96  0.96  [should have been 2.0.96]
 *    0.97b "1.00.97 beta 7" 1.00.97   97  1.0.1 [should have been 2.0.97]
 *    0.97c                  0.97      97  2.0.97
 *    0.98                   0.98      98  2.0.98
 *    0.99                   0.99      98  2.0.99
 *    0.99a-m                0.99      99  2.0.99
 *    1.00                   1.00     100  2.1.0 [100 should be 10000]
 *    1.0.0      (from here on, the   100  2.1.0 [100 should be 10000]
 *    1.0.1       png.h string is   10001  2.1.0
 *    1.0.1a-e    identical to the  10002  from here on, the shared library
 *    1.0.2       source version)   10002  is 2.V where V is the source code
 *    1.0.2a-b                      10003  version, except as noted.
 *    1.0.3                         10003
 *    1.0.3a-d                      10004
 *    1.0.4                         10004
 *    1.0.4a-f                      10005
 *    1.0.5 (+ 2 patches)           10005
 *    1.0.5a-d                      10006
 *    1.0.5e-r                      10100 (not source compatible)
 *    1.0.5s-v                      10006 (not binary compatible)
 *    1.0.6 (+ 3 patches)           10006 (still binary incompatible)
 *    1.0.6d-f                      10007 (still binary incompatible)
 *    1.0.6g                        10007
 *    1.0.6h                        10007  10.6h (testing xy.z so-numbering)
 *    1.0.6i                        10007  10.6i
 *    1.0.6j                        10007  2.1.0.6j (incompatible with 1.0.0)
 *    1.0.7beta11-14        DLLNUM  10007  2.1.0.7beta11-14 (binary compatible)
 *    1.0.7beta15-18           1    10007  2.1.0.7beta15-18 (binary compatible)
 *    1.0.7rc1-2               1    10007  2.1.0.7rc1-2 (binary compatible)
 *    1.0.7                    1    10007  (still compatible)
 *    1.0.8beta1-4             1    10008  2.1.0.8beta1-4
 *    1.0.8rc1                 1    10008  2.1.0.8rc1
 *    1.0.8                    1    10008  2.1.0.8
 *    1.0.9beta1-6             1    10009  2.1.0.9beta1-6
 *    1.0.9rc1                 1    10009  2.1.0.9rc1
 *    1.0.9beta7-10            1    10009  2.1.0.9beta7-10
 *    1.0.9rc2                 1    10009  2.1.0.9rc2
 *    1.0.9                    1    10009  2.1.0.9
 *    1.0.10beta1              1    10010  2.1.0.10beta1
 *    1.0.10rc1                1    10010  2.1.0.10rc1
 *    1.0.10                   1    10010  2.1.0.10
 *    1.0.11beta1-3            1    10011  2.1.0.11beta1-3
 *    1.0.11rc1                1    10011  2.1.0.11rc1
 *    1.0.11                   1    10011  2.1.0.11
 *    1.0.12beta1-2            2    10012  2.1.0.12beta1-2
 *    1.0.12rc1                2    10012  2.1.0.12rc1
 *    1.0.12                   2    10012  2.1.0.12
 *    1.1.0a-f                 -    10100  2.1.1.0a-f (branch abandoned)
 *    1.2.0beta1-2             2    10200  2.1.2.0beta1-2
 *    1.2.0beta3-5             3    10200  3.1.2.0beta3-5
 *    1.2.0rc1                 3    10200  3.1.2.0rc1
 *    1.2.0                    3    10200  3.1.2.0
 *    1.2.1beta1-4             3    10201  3.1.2.1beta1-4
 *    1.2.1rc1-2               3    10201  3.1.2.1rc1-2
 *    1.2.1                    3    10201  3.1.2.1
 *
 *    Henceforth the source version will match the shared-library major
 *    and minor numbers; the shared-library major version number will be
 *    used for changes in backward compatibility, as it is intended.  The
 *    PNG_LIBPNG_VER macro, which is not used within libpng but is available
 *    for applications, is an unsigned integer of the form xyyzz corresponding
 *    to the source version x.y.z (leading zeros in y and z).  Beta versions
 *    were given the previous public release number plus a letter, until
 *    version 1.0.6j; from then on they were given the upcoming public
 *    release number plus "betaNN" or "rcN".
 *
 *    Binary incompatibility exists only when applications make direct access
 *    to the info_ptr or png_ptr members through png.h, and the compiled
 *    application is loaded with a different version of the library.
 *
 *    DLLNUM will change each time there are forward or backward changes
 *    in binary compatibility (e.g., when a new feature is added).
 *
 * See libpng.txt or libpng.3 for more information.  The PNG specification
 * is available as RFC 2083 <ftp://ftp.uu.net/graphics/png/documents/>
 * and as a W3C Recommendation <http://www.w3.org/TR/REC.png.html>
 */

/*
 * COPYRIGHT NOTICE, DISCLAIMER, and LICENSE:
 *
 * If you modify libpng you may insert additional notices immediately following
 * this sentence.
 *
 * libpng versions 1.0.7, July 1, 2000, through  1.2.1, December 12, 2001, are
 * Copyright (c) 2000, 2001 Glenn Randers-Pehrson, and are
 * distributed according to the same disclaimer and license as libpng-1.0.6
 * with the following individuals added to the list of Contributing Authors
 *
 *    Simon-Pierre Cadieux
 *    Eric S. Raymond
 *    Gilles Vollant
 *
 * and with the following additions to the disclaimer:
 *
 *    There is no warranty against interference with your enjoyment of the
 *    library or against infringement.  There is no warranty that our
 *    efforts or the library will fulfill any of your particular purposes
 *    or needs.  This library is provided with all faults, and the entire
 *    risk of satisfactory quality, performance, accuracy, and effort is with
 *    the user.
 *
 * libpng versions 0.97, January 1998, through 1.0.6, March 20, 2000, are
 * Copyright (c) 1998, 1999, 2000 Glenn Randers-Pehrson
 * Distributed according to the same disclaimer and license as libpng-0.96,
 * with the following individuals added to the list of Contributing Authors:
 *
 *    Tom Lane
 *    Glenn Randers-Pehrson
 *    Willem van Schaik
 *
 * libpng versions 0.89, June 1996, through 0.96, May 1997, are
 * Copyright (c) 1996, 1997 Andreas Dilger
 * Distributed according to the same disclaimer and license as libpng-0.88,
 * with the following individuals added to the list of Contributing Authors:
 *
 *    John Bowler
 *    Kevin Bracey
 *    Sam Bushell
 *    Magnus Holmgren
 *    Greg Roelofs
 *    Tom Tanner
 *
 * libpng versions 0.5, May 1995, through 0.88, January 1996, are
 * Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
 *
 * For the purposes of this copyright and license, "Contributing Authors"
 * is defined as the following set of individuals:
 *
 *    Andreas Dilger
 *    Dave Martindale
 *    Guy Eric Schalnat
 *    Paul Schmidt
 *    Tim Wegner
 *
 * The PNG Reference Library is supplied "AS IS".  The Contributing Authors
 * and Group 42, Inc. disclaim all warranties, expressed or implied,
 * including, without limitation, the warranties of merchantability and of
 * fitness for any purpose.  The Contributing Authors and Group 42, Inc.
 * assume no liability for direct, indirect, incidental, special, exemplary,
 * or consequential damages, which may result from the use of the PNG
 * Reference Library, even if advised of the possibility of such damage.
 *
 * Permission is hereby granted to use, copy, modify, and distribute this
 * source code, or portions hereof, for any purpose, without fee, subject
 * to the following restrictions:
 *
 * 1. The origin of this source code must not be misrepresented.
 *
 * 2. Altered versions must be plainly marked as such and
 * must not be misrepresented as being the original source.
 *
 * 3. This Copyright notice may not be removed or altered from
 *    any source or altered source distribution.
 *
 * The Contributing Authors and Group 42, Inc. specifically permit, without
 * fee, and encourage the use of this source code as a component to
 * supporting the PNG file format in commercial products.  If you use this
 * source code in a product, acknowledgment is not required but would be
 * appreciated.
 */

/*
 * A "png_get_copyright" function is available, for convenient use in "about"
 * boxes and the like:
 *
 * printf("%s",png_get_copyright(NULL));
 *
 * Also, the PNG logo (in PNG format, of course) is supplied in the
 * files "pngbar.png" and "pngbar.jpg (88x31) and "pngnow.png" (98x31).
 */

/*
 * Libpng is OSI Certified Open Source Software.  OSI Certified is a
 * certification mark of the Open Source Initiative.
 */

/*
 * The contributing authors would like to thank all those who helped
 * with testing, bug fixes, and patience.  This wouldn't have been
 * possible without all of you.
 *
 * Thanks to Frank J. T. Wojcik for helping with the documentation.
 */

/*
 * Y2K compliance in libpng:
 * =========================
 *
 *    December 12, 2001
 *
 *    Since the PNG Development group is an ad-hoc body, we can't make
 *    an official declaration.
 *
 *    This is your unofficial assurance that libpng from version 0.71 and
 *    upward through 1.2.1 are Y2K compliant.  It is my belief that earlier
 *    versions were also Y2K compliant.
 *
 *    Libpng only has three year fields.  One is a 2-byte unsigned integer
 *    that will hold years up to 65535.  The other two hold the date in text
 *    format, and will hold years up to 9999.
 *
 *    The integer is
 *        "png_uint_16 year" in png_time_struct.
 *
 *    The strings are
 *        "png_charp time_buffer" in png_struct and
 *        "near_time_buffer", which is a local character string in png.c.
 *
 *    There are seven time-related functions:
 *        png.c: png_convert_to_rfc_1123() in png.c
 *          (formerly png_convert_to_rfc_1152() in error)
 *        png_convert_from_struct_tm() in pngwrite.c, called in pngwrite.c
 *        png_convert_from_time_t() in pngwrite.c
 *        png_get_tIME() in pngget.c
 *        png_handle_tIME() in pngrutil.c, called in pngread.c
 *        png_set_tIME() in pngset.c
 *        png_write_tIME() in pngwutil.c, called in pngwrite.c
 *
 *    All handle dates properly in a Y2K environment.  The
 *    png_convert_from_time_t() function calls gmtime() to convert from system
 *    clock time, which returns (year - 1900), which we properly convert to
 *    the full 4-digit year.  There is a possibility that applications using
 *    libpng are not passing 4-digit years into the png_convert_to_rfc_1123()
 *    function, or that they are incorrectly passing only a 2-digit year
 *    instead of "year - 1900" into the png_convert_from_struct_tm() function,
 *    but this is not under our control.  The libpng documentation has always
 *    stated that it works with 4-digit years, and the APIs have been
 *    documented as such.
 *
 *    The tIME chunk itself is also Y2K compliant.  It uses a 2-byte unsigned
 *    integer to hold the year, and can hold years as large as 65535.
 *
 *    zlib, upon which libpng depends, is also Y2K compliant.  It contains
 *    no date-related code.
 *
 *       Glenn Randers-Pehrson
 *       libpng maintainer
 *       PNG Development Group
 */

#ifndef PNG_H
#define PNG_H

/* This is not the place to learn how to use libpng.  The file libpng.txt
 * describes how to use libpng, and the file example.c summarizes it
 * with some code on which to build.  This file is useful for looking
 * at the actual function definitions and structure components.
 */

/* Version information for png.h - this should match the version in png.c */
#define PNG_LIBPNG_VER_STRING "1.2.1"

#define PNG_LIBPNG_VER_SONUM   3
#define PNG_LIBPNG_VER_DLLNUM  %DLLNUM%

/* These should match the first 3 components of PNG_LIBPNG_VER_STRING: */
#define PNG_LIBPNG_VER_MAJOR   1
#define PNG_LIBPNG_VER_MINOR   2
#define PNG_LIBPNG_VER_RELEASE 1
/* This should match the numeric part of the final component of
 * PNG_LIBPNG_VER_STRING, omitting any leading zero: */

#define PNG_LIBPNG_VER_BUILD  0

#define PNG_LIBPNG_BUILD_ALPHA    1
#define PNG_LIBPNG_BUILD_BETA     2
#define PNG_LIBPNG_BUILD_RC       3
#define PNG_LIBPNG_BUILD_STABLE   4
#define PNG_LIBPNG_BUILD_TYPEMASK 7
#define PNG_LIBPNG_BUILD_PATCH    8 /* Can be OR'ed with STABLE only */
#define PNG_LIBPNG_BUILD_TYPE 4

/* Careful here.  At one time, Guy wanted to use 082, but that would be octal.
 * We must not include leading zeros.
 * Versions 0.7 through 1.0.0 were in the range 0 to 100 here (only
 * version 1.0.0 was mis-numbered 100 instead of 10000).  From
 * version 1.0.1 it's    xxyyzz, where x=major, y=minor, z=release */
#define PNG_LIBPNG_VER 10201 /* 1.2.1 */

#ifndef PNG_VERSION_INFO_ONLY

/* include the compression library's header */
#include "zlib.h"

/* include all user configurable info, including optional assembler routines */
#include "pngconf.h"

/* Inhibit C++ name-mangling for libpng functions but not for system calls. */
#ifdef __cplusplus
extern "C" {
#endif /* __cplusplus */

/* This file is arranged in several sections.  The first section contains
 * structure and type definitions.  The second section contains the external
 * library functions, while the third has the internal library functions,
 * which applications aren't expected to use directly.
 */

#ifndef PNG_NO_TYPECAST_NULL
#define int_p_NULL                (int *)NULL
#define png_bytep_NULL            (png_bytep)NULL
#define png_bytepp_NULL           (png_bytepp)NULL
#define png_doublep_NULL          (png_doublep)NULL
#define png_error_ptr_NULL        (png_error_ptr)NULL
#define png_flush_ptr_NULL        (png_flush_ptr)NULL
#define png_free_ptr_NULL         (png_free_ptr)NULL
#define png_infopp_NULL           (png_infopp)NULL
#define png_malloc_ptr_NULL       (png_malloc_ptr)NULL
#define png_read_status_ptr_NULL  (png_read_status_ptr)NULL
#define png_rw_ptr_NULL           (png_rw_ptr)NULL
#define png_structp_NULL          (png_structp)NULL
#define png_uint_16p_NULL         (png_uint_16p)NULL
#define png_voidp_NULL            (png_voidp)NULL
#define png_write_status_ptr_NULL (png_write_status_ptr)NULL
#else
#define int_p_NULL                NULL
#define png_bytep_NULL            NULL
#define png_bytepp_NULL           NULL
#define png_doublep_NULL          NULL
#define png_error_ptr_NULL        NULL
#define png_flush_ptr_NULL        NULL
#define png_free_ptr_NULL         NULL
#define png_infopp_NULL           NULL
#define png_malloc_ptr_NULL       NULL
#define png_read_status_ptr_NULL  NULL
#define png_rw_ptr_NULL           NULL
#define png_structp_NULL          NULL
#define png_uint_16p_NULL         NULL
#define png_voidp_NULL            NULL
#define png_write_status_ptr_NULL NULL
#endif

/* variables declared in png.c - only it needs to define PNG_NO_EXTERN */
#if !defined(PNG_NO_EXTERN) || defined(PNG_ALWAYS_EXTERN)
/* Version information for C files, stored in png.c.  This had better match
 * the version above.
 */
#ifdef PNG_USE_GLOBAL_ARRAYS
PNG_EXPORT_VAR (const char) png_libpng_ver[18];
  /* need room for 99.99.99beta99z*/
#else
#define png_libpng_ver png_get_header_ver(NULL)
#endif

#ifdef PNG_USE_GLOBAL_ARRAYS
/* This was removed in version 1.0.5c */
/* Structures to facilitate easy interlacing.  See png.c for more details */
PNG_EXPORT_VAR (const int FARDATA) png_pass_start[7];
PNG_EXPORT_VAR (const int FARDATA) png_pass_inc[7];
PNG_EXPORT_VAR (const int FARDATA) png_pass_ystart[7];
PNG_EXPORT_VAR (const int FARDATA) png_pass_yinc[7];
PNG_EXPORT_VAR (const int FARDATA) png_pass_mask[7];
PNG_EXPORT_VAR (const int FARDATA) png_pass_dsp_mask[7];
#ifdef PNG_HAVE_ASSEMBLER_COMBINE_ROW
PNG_EXPORT_VAR (const int FARDATA) png_pass_width[7];
#endif
/* This isn't currently used.  If you need it, see png.c for more details.
PNG_EXPORT_VAR (const int FARDATA) png_pass_height[7];
*/
#endif

#endif /* PNG_NO_EXTERN */

/* Three color definitions.  The order of the red, green, and blue, (and the
 * exact size) is not important, although the size of the fields need to
 * be png_byte or png_uint_16 (as defined below).
 */
typedef struct png_color_struct
{
   png_byte red;
   png_byte green;
   png_byte blue;
} png_color;
typedef png_color FAR * png_colorp;
typedef png_color FAR * FAR * png_colorpp;

typedef struct png_color_16_struct
{
   png_byte index;    /* used for palette files */
   png_uint_16 red;   /* for use in red green blue files */
   png_uint_16 green;
   png_uint_16 blue;
   png_uint_16 gray;  /* for use in grayscale files */
} png_color_16;
typedef png_color_16 FAR * png_color_16p;
typedef png_color_16 FAR * FAR * png_color_16pp;

typedef struct png_color_8_struct
{
   png_byte red;   /* for use in red green blue files */
   png_byte green;
   png_byte blue;
   png_byte gray;  /* for use in grayscale files */
   png_byte alpha; /* for alpha channel files */
} png_color_8;
typedef png_color_8 FAR * png_color_8p;
typedef png_color_8 FAR * FAR * png_color_8pp;

/*
 * The following two structures are used for the in-core representation
 * of sPLT chunks.
 */
typedef struct png_sPLT_entry_struct
{
   png_uint_16 red;
   png_uint_16 green;
   png_uint_16 blue;
   png_uint_16 alpha;
   png_uint_16 frequency;
} png_sPLT_entry;
typedef png_sPLT_entry FAR * png_sPLT_entryp;
typedef png_sPLT_entry FAR * FAR * png_sPLT_entrypp;

/*  When the depth of the sPLT palette is 8 bits, the color and alpha samples
 *  occupy the LSB of their respective members, and the MSB of each member
 *  is zero-filled.  The frequency member always occupies the full 16 bits.
 */

typedef struct png_sPLT_struct
{
   png_charp name;           /* palette name */
   png_byte depth;           /* depth of palette samples */
   png_sPLT_entryp entries;  /* palette entries */
   png_int_32 nentries;      /* number of palette entries */
} png_sPLT_t;
typedef png_sPLT_t FAR * png_sPLT_tp;
typedef png_sPLT_t FAR * FAR * png_sPLT_tpp;

#ifdef PNG_TEXT_SUPPORTED
/* png_text holds the contents of a text/ztxt/itxt chunk in a PNG file,
 * and whether that contents is compressed or not.  The "key" field
 * points to a regular zero-terminated C string.  The "text", "lang", and
 * "lang_key" fields can be regular C strings, empty strings, or NULL pointers.
 * However, the * structure returned by png_get_text() will always contain
 * regular zero-terminated C strings (possibly empty), never NULL pointers,
 * so they can be safely used in printf() and other string-handling functions.
 */
typedef struct png_text_struct
{
   int  compression;       /* compression value:
                             -1: tEXt, none
                              0: zTXt, deflate
                              1: iTXt, none
                              2: iTXt, deflate  */
   png_charp key;          /* keyword, 1-79 character description of "text" */
   png_charp text;         /* comment, may be an empty string (ie "")
                              or a NULL pointer */
   png_size_t text_length; /* length of the text string */
#ifdef PNG_iTXt_SUPPORTED
   png_size_t itxt_length; /* length of the itxt string */
   png_charp lang;         /* language code, 0-79 characters
                              or a NULL pointer */
   png_charp lang_key;     /* keyword translated UTF-8 string, 0 or more
                              chars or a NULL pointer */
#endif
} png_text;
typedef png_text FAR * png_textp;
typedef png_text FAR * FAR * png_textpp;
#endif

/* Supported compression types for text in PNG files (tEXt, and zTXt).
 * The values of the PNG_TEXT_COMPRESSION_ defines should NOT be changed. */
#define PNG_TEXT_COMPRESSION_NONE_WR -3
#define PNG_TEXT_COMPRESSION_zTXt_WR -2
#define PNG_TEXT_COMPRESSION_NONE    -1
#define PNG_TEXT_COMPRESSION_zTXt     0
#define PNG_ITXT_COMPRESSION_NONE     1
#define PNG_ITXT_COMPRESSION_zTXt     2
#define PNG_TEXT_COMPRESSION_LAST     3  /* Not a valid value */

/* png_time is a way to hold the time in an machine independent way.
 * Two conversions are provided, both from time_t and struct tm.  There
 * is no portable way to convert to either of these structures, as far
 * as I know.  If you know of a portable way, send it to me.  As a side
 * note - PNG has always been Year 2000 compliant!
 */
typedef struct png_time_struct
{
   png_uint_16 year; /* full year, as in, 1995 */
   png_byte month;   /* month of year, 1 - 12 */
   png_byte day;     /* day of month, 1 - 31 */
   png_byte hour;    /* hour of day, 0 - 23 */
   png_byte minute;  /* minute of hour, 0 - 59 */
   png_byte second;  /* second of minute, 0 - 60 (for leap seconds) */
} png_time;
typedef png_time FAR * png_timep;
typedef png_time FAR * FAR * png_timepp;

#if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
/* png_unknown_chunk is a structure to hold queued chunks for which there is
 * no specific support.  The idea is that we can use this to queue
 * up private chunks for output even though the library doesn't actually
 * know about their semantics.
 */
typedef struct png_unknown_chunk_t
{
    png_byte name[5];
    png_byte *data;
    png_size_t size;

    /* libpng-using applications should NOT directly modify this byte. */
    png_byte location; /* mode of operation at read time */
}
png_unknown_chunk;
typedef png_unknown_chunk FAR * png_unknown_chunkp;
typedef png_unknown_chunk FAR * FAR * png_unknown_chunkpp;
#endif

/* png_info is a structure that holds the information in a PNG file so
 * that the application can find out the characteristics of the image.
 * If you are reading the file, this structure will tell you what is
 * in the PNG file.  If you are writing the file, fill in the information
 * you want to put into the PNG file, then call png_write_info().
 * The names chosen should be very close to the PNG specification, so
 * consult that document for information about the meaning of each field.
 *
 * With libpng < 0.95, it was only possible to directly set and read the
 * the values in the png_info_struct, which meant that the contents and
 * order of the values had to remain fixed.  With libpng 0.95 and later,
 * however, there are now functions that abstract the contents of
 * png_info_struct from the application, so this makes it easier to use
 * libpng with dynamic libraries, and even makes it possible to use
 * libraries that don't have all of the libpng ancillary chunk-handing
 * functionality.
 *
 * In any case, the order of the parameters in png_info_struct should NOT
 * be changed for as long as possible to keep compatibility with applications
 * that use the old direct-access method with png_info_struct.
 *
 * The following members may have allocated storage attached that should be
 * cleaned up before the structure is discarded: palette, trans, text,
 * pcal_purpose, pcal_units, pcal_params, hist, iccp_name, iccp_profile,
 * splt_palettes, scal_unit, row_pointers, and unknowns.   By default, these
 * are automatically freed when the info structure is deallocated, if they were
 * allocated internally by libpng.  This behavior can be changed by means
 * of the png_data_freer() function.
 *
 * More allocation details: all the chunk-reading functions that
 * change these members go through the corresponding png_set_*
 * functions.  A function to clear these members is available: see
 * png_free_data().  The png_set_* functions do not depend on being
 * able to point info structure members to any of the storage they are
 * passed (they make their own copies), EXCEPT that the png_set_text
 * functions use the same storage passed to them in the text_ptr or
 * itxt_ptr structure argument, and the png_set_rows and png_set_unknowns
 * functions do not make their own copies.
 */
typedef struct png_info_struct
{
   /* the following are necessary for every PNG file */
   png_uint_32 width;       /* width of image in pixels (from IHDR) */
   png_uint_32 height;      /* height of image in pixels (from IHDR) */
   png_uint_32 valid;       /* valid chunk data (see PNG_INFO_ below) */
   png_uint_32 rowbytes;    /* bytes needed to hold an untransformed row */
   png_colorp palette;      /* array of color values (valid & PNG_INFO_PLTE) */
   png_uint_16 num_palette; /* number of color entries in "palette" (PLTE) */
   png_uint_16 num_trans;   /* number of transparent palette color (tRNS) */
   png_byte bit_depth;      /* 1, 2, 4, 8, or 16 bits/channel (from IHDR) */
   png_byte color_type;     /* see PNG_COLOR_TYPE_ below (from IHDR) */
   /* The following three should have been named *_method not *_type */
   png_byte compression_type; /* must be PNG_COMPRESSION_TYPE_BASE (IHDR) */
   png_byte filter_type;    /* must be PNG_FILTER_TYPE_BASE (from IHDR) */
   png_byte interlace_type; /* One of PNG_INTERLACE_NONE, PNG_INTERLACE_ADAM7 */

   /* The following is informational only on read, and not used on writes. */
   png_byte channels;       /* number of data channels per pixel (1, 2, 3, 4)*/
   png_byte pixel_depth;    /* number of bits per pixel */
   png_byte spare_byte;     /* to align the data, and for future use */
   png_byte signature[8];   /* magic bytes read by libpng from start of file */

   /* The rest of the data is optional.  If you are reading, check the
    * valid field to see if the information in these are valid.  If you
    * are writing, set the valid field to those chunks you want written,
    * and initialize the appropriate fields below.
    */

#if defined(PNG_gAMA_SUPPORTED) && defined(PNG_FLOATING_POINT_SUPPORTED)
   /* The gAMA chunk describes the gamma characteristics of the system
    * on which the image was created, normally in the range [1.0, 2.5].
    * Data is valid if (valid & PNG_INFO_gAMA) is non-zero.
    */
   float gamma; /* gamma value of image, if (valid & PNG_INFO_gAMA) */
#endif

#if defined(PNG_sRGB_SUPPORTED)
    /* GR-P, 0.96a */
    /* Data valid if (valid & PNG_INFO_sRGB) non-zero. */
   png_byte srgb_intent; /* sRGB rendering intent [0, 1, 2, or 3] */
#endif

#if defined(PNG_TEXT_SUPPORTED)
   /* The tEXt, and zTXt chunks contain human-readable textual data in
    * uncompressed, compressed, and optionally compressed forms, respectively.
    * The data in "text" is an array of pointers to uncompressed,
    * null-terminated C strings. Each chunk has a keyword that describes the
    * textual data contained in that chunk.  Keywords are not required to be
    * unique, and the text string may be empty.  Any number of text chunks may
    * be in an image.
    */
   int num_text; /* number of comments read/to write */
   int max_text; /* current size of text array */
   png_textp text; /* array of comments read/to write */
#endif /* PNG_TEXT_SUPPORTED */

#if defined(PNG_tIME_SUPPORTED)
   /* The tIME chunk holds the last time the displayed image data was
    * modified.  See the png_time struct for the contents of this struct.
    */
   png_time mod_time;
#endif

#if defined(PNG_sBIT_SUPPORTED)
   /* The sBIT chunk specifies the number of significant high-order bits
    * in the pixel data.  Values are in the range [1, bit_depth], and are
    * only specified for the channels in the pixel data.  The contents of
    * the low-order bits is not specified.  Data is valid if
    * (valid & PNG_INFO_sBIT) is non-zero.
    */
   png_color_8 sig_bit; /* significant bits in color channels */
#endif

#if defined(PNG_tRNS_SUPPORTED) || defined(PNG_READ_EXPAND_SUPPORTED) || \
defined(PNG_READ_BACKGROUND_SUPPORTED)
   /* The tRNS chunk supplies transparency data for paletted images and
    * other image types that don't need a full alpha channel.  There are
    * "num_trans" transparency values for a paletted image, stored in the
    * same order as the palette colors, starting from index 0.  Values
    * for the data are in the range [0, 255], ranging from fully transparent
    * to fully opaque, respectively.  For non-paletted images, there is a
    * single color specified that should be treated as fully transparent.
    * Data is valid if (valid & PNG_INFO_tRNS) is non-zero.
    */
   png_bytep trans; /* transparent values for paletted image */
   png_color_16 trans_values; /* transparent color for non-palette image */
#endif

#if defined(PNG_bKGD_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
   /* The bKGD chunk gives the suggested image background color if the
    * display program does not have its own background color and the image
    * is needs to composited onto a background before display.  The colors
    * in "background" are normally in the same color space/depth as the
    * pixel data.  Data is valid if (valid & PNG_INFO_bKGD) is non-zero.
    */
   png_color_16 background;
#endif

#if defined(PNG_oFFs_SUPPORTED)
   /* The oFFs chunk gives the offset in "offset_unit_type" units rightwards
    * and downwards from the top-left corner of the display, page, or other
    * application-specific co-ordinate space.  See the PNG_OFFSET_ defines
    * below for the unit types.  Valid if (valid & PNG_INFO_oFFs) non-zero.
    */
   png_int_32 x_offset; /* x offset on page */
   png_int_32 y_offset; /* y offset on page */
   png_byte offset_unit_type; /* offset units type */
#endif

#if defined(PNG_pHYs_SUPPORTED)
   /* The pHYs chunk gives the physical pixel density of the image for
    * display or printing in "phys_unit_type" units (see PNG_RESOLUTION_
    * defines below).  Data is valid if (valid & PNG_INFO_pHYs) is non-zero.
    */
   png_uint_32 x_pixels_per_unit; /* horizontal pixel density */
   png_uint_32 y_pixels_per_unit; /* vertical pixel density */
   png_byte phys_unit_type; /* resolution type (see PNG_RESOLUTION_ below) */
#endif

#if defined(PNG_hIST_SUPPORTED)
   /* The hIST chunk contains the relative frequency or importance of the
    * various palette entries, so that a viewer can intelligently select a
    * reduced-color palette, if required.  Data is an array of "num_palette"
    * values in the range [0,65535]. Data valid if (valid & PNG_INFO_hIST)
    * is non-zero.
    */
   png_uint_16p hist;
#endif

#ifdef PNG_cHRM_SUPPORTED
   /* The cHRM chunk describes the CIE color characteristics of the monitor
    * on which the PNG was created.  This data allows the viewer to do gamut
    * mapping of the input image to ensure that the viewer sees the same
    * colors in the image as the creator.  Values are in the range
    * [0.0, 0.8].  Data valid if (valid & PNG_INFO_cHRM) non-zero.
    */
#ifdef PNG_FLOATING_POINT_SUPPORTED
   float x_white;
   float y_white;
   float x_red;
   float y_red;
   float x_green;
   float y_green;
   float x_blue;
   float y_blue;
#endif
#endif

#if defined(PNG_pCAL_SUPPORTED)
   /* The pCAL chunk describes a transformation between the stored pixel
    * values and original physical data values used to create the image.
    * The integer range [0, 2^bit_depth - 1] maps to the floating-point
    * range given by [pcal_X0, pcal_X1], and are further transformed by a
    * (possibly non-linear) transformation function given by "pcal_type"
    * and "pcal_params" into "pcal_units".  Please see the PNG_EQUATION_
    * defines below, and the PNG-Group's PNG extensions document for a
    * complete description of the transformations and how they should be
    * implemented, and for a description of the ASCII parameter strings.
    * Data values are valid if (valid & PNG_INFO_pCAL) non-zero.
    */
   png_charp pcal_purpose;  /* pCAL chunk description string */
   png_int_32 pcal_X0;      /* minimum value */
   png_int_32 pcal_X1;      /* maximum value */
   png_charp pcal_units;    /* Latin-1 string giving physical units */
   png_charpp pcal_params;  /* ASCII strings containing parameter values */
   png_byte pcal_type;      /* equation type (see PNG_EQUATION_ below) */
   png_byte pcal_nparams;   /* number of parameters given in pcal_params */
#endif

/* New members added in libpng-1.0.6 */
#ifdef PNG_FREE_ME_SUPPORTED
   png_uint_32 free_me;     /* flags items libpng is responsible for freeing */
#endif

#if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
   /* storage for unknown chunks that the library doesn't recognize. */
   png_unknown_chunkp unknown_chunks;
   png_size_t unknown_chunks_num;
#endif

#if defined(PNG_iCCP_SUPPORTED)
   /* iCCP chunk data. */
   png_charp iccp_name;     /* profile name */
   png_charp iccp_profile;  /* International Color Consortium profile data */
                            /* Note to maintainer: should be png_bytep */
   png_uint_32 iccp_proflen;  /* ICC profile data length */
   png_byte iccp_compression; /* Always zero */
#endif

#if defined(PNG_sPLT_SUPPORTED)
   /* data on sPLT chunks (there may be more than one). */
   png_sPLT_tp splt_palettes;
   png_uint_32 splt_palettes_num;
#endif

#if defined(PNG_sCAL_SUPPORTED)
   /* The sCAL chunk describes the actual physical dimensions of the
    * subject matter of the graphic.  The chunk contains a unit specification
    * a byte value, and two ASCII strings representing floating-point
    * values.  The values are width and height corresponsing to one pixel
    * in the image.  This external representation is converted to double
    * here.  Data values are valid if (valid & PNG_INFO_sCAL) is non-zero.
    */
   png_byte scal_unit;         /* unit of physical scale */
#ifdef PNG_FLOATING_POINT_SUPPORTED
   double scal_pixel_width;    /* width of one pixel */
   double scal_pixel_height;   /* height of one pixel */
#endif
#ifdef PNG_FIXED_POINT_SUPPORTED
   png_charp scal_s_width;     /* string containing height */
   png_charp scal_s_height;    /* string containing width */
#endif
#endif

#if defined(PNG_INFO_IMAGE_SUPPORTED)
   /* Memory has been allocated if (valid & PNG_ALLOCATED_INFO_ROWS) non-zero */
   /* Data valid if (valid & PNG_INFO_IDAT) non-zero */
   png_bytepp row_pointers;        /* the image bits */
#endif

#if defined(PNG_FIXED_POINT_SUPPORTED) && defined(PNG_gAMA_SUPPORTED)
   png_fixed_point int_gamma; /* gamma of image, if (valid & PNG_INFO_gAMA) */
#endif

#if defined(PNG_cHRM_SUPPORTED) && defined(PNG_FIXED_POINT_SUPPORTED)
   png_fixed_point int_x_white;
   png_fixed_point int_y_white;
   png_fixed_point int_x_red;
   png_fixed_point int_y_red;
   png_fixed_point int_x_green;
   png_fixed_point int_y_green;
   png_fixed_point int_x_blue;
   png_fixed_point int_y_blue;
#endif

} png_info;

typedef png_info FAR * png_infop;
typedef png_info FAR * FAR * png_infopp;

/* Maximum positive integer used in PNG is (2^31)-1 */
#define PNG_MAX_UINT ((png_uint_32)0x7fffffffL)

/* These describe the color_type field in png_info. */
/* color type masks */
#define PNG_COLOR_MASK_PALETTE    1
#define PNG_COLOR_MASK_COLOR      2
#define PNG_COLOR_MASK_ALPHA      4

/* color types.  Note that not all combinations are legal */
#define PNG_COLOR_TYPE_GRAY 0
#define PNG_COLOR_TYPE_PALETTE  (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_PALETTE)
#define PNG_COLOR_TYPE_RGB        (PNG_COLOR_MASK_COLOR)
#define PNG_COLOR_TYPE_RGB_ALPHA  (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_ALPHA)
#define PNG_COLOR_TYPE_GRAY_ALPHA (PNG_COLOR_MASK_ALPHA)
/* aliases */
#define PNG_COLOR_TYPE_RGBA  PNG_COLOR_TYPE_RGB_ALPHA
#define PNG_COLOR_TYPE_GA  PNG_COLOR_TYPE_GRAY_ALPHA

/* This is for compression type. PNG 1.0-1.2 only define the single type. */
#define PNG_COMPRESSION_TYPE_BASE 0 /* Deflate method 8, 32K window */
#define PNG_COMPRESSION_TYPE_DEFAULT PNG_COMPRESSION_TYPE_BASE

/* This is for filter type. PNG 1.0-1.2 only define the single type. */
#define PNG_FILTER_TYPE_BASE      0 /* Single row per-byte filtering */
#define PNG_INTRAPIXEL_DIFFERENCING 64 /* Used only in MNG datastreams */
#define PNG_FILTER_TYPE_DEFAULT   PNG_FILTER_TYPE_BASE

/* These are for the interlacing type.  These values should NOT be changed. */
#define PNG_INTERLACE_NONE        0 /* Non-interlaced image */
#define PNG_INTERLACE_ADAM7       1 /* Adam7 interlacing */
#define PNG_INTERLACE_LAST        2 /* Not a valid value */

/* These are for the oFFs chunk.  These values should NOT be changed. */
#define PNG_OFFSET_PIXEL          0 /* Offset in pixels */
#define PNG_OFFSET_MICROMETER     1 /* Offset in micrometers (1/10^6 meter) */
#define PNG_OFFSET_LAST           2 /* Not a valid value */

/* These are for the pCAL chunk.  These values should NOT be changed. */
#define PNG_EQUATION_LINEAR       0 /* Linear transformation */
#define PNG_EQUATION_BASE_E       1 /* Exponential base e transform */
#define PNG_EQUATION_ARBITRARY    2 /* Arbitrary base exponential transform */
#define PNG_EQUATION_HYPERBOLIC   3 /* Hyperbolic sine transformation */
#define PNG_EQUATION_LAST         4 /* Not a valid value */

/* These are for the sCAL chunk.  These values should NOT be changed. */
#define PNG_SCALE_UNKNOWN         0 /* unknown unit (image scale) */
#define PNG_SCALE_METER           1 /* meters per pixel */
#define PNG_SCALE_RADIAN          2 /* radians per pixel */
#define PNG_SCALE_LAST            3 /* Not a valid value */

/* These are for the pHYs chunk.  These values should NOT be changed. */
#define PNG_RESOLUTION_UNKNOWN    0 /* pixels/unknown unit (aspect ratio) */
#define PNG_RESOLUTION_METER      1 /* pixels/meter */
#define PNG_RESOLUTION_LAST       2 /* Not a valid value */

/* These are for the sRGB chunk.  These values should NOT be changed. */
#define PNG_sRGB_INTENT_PERCEPTUAL 0
#define PNG_sRGB_INTENT_RELATIVE   1
#define PNG_sRGB_INTENT_SATURATION 2
#define PNG_sRGB_INTENT_ABSOLUTE   3
#define PNG_sRGB_INTENT_LAST       4 /* Not a valid value */

/* This is for text chunks */
#define PNG_KEYWORD_MAX_LENGTH     79

/* Maximum number of entries in PLTE/sPLT/tRNS arrays */
#define PNG_MAX_PALETTE_LENGTH	   256

/* These determine if an ancillary chunk's data has been successfully read
 * from the PNG header, or if the application has filled in the corresponding
 * data in the info_struct to be written into the output file.  The values
 * of the PNG_INFO_<chunk> defines should NOT be changed.
 */
#define PNG_INFO_gAMA 0x0001
#define PNG_INFO_sBIT 0x0002
#define PNG_INFO_cHRM 0x0004
#define PNG_INFO_PLTE 0x0008
#define PNG_INFO_tRNS 0x0010
#define PNG_INFO_bKGD 0x0020
#define PNG_INFO_hIST 0x0040
#define PNG_INFO_pHYs 0x0080
#define PNG_INFO_oFFs 0x0100
#define PNG_INFO_tIME 0x0200
#define PNG_INFO_pCAL 0x0400
#define PNG_INFO_sRGB 0x0800   /* GR-P, 0.96a */
#define PNG_INFO_iCCP 0x1000   /* ESR, 1.0.6 */
#define PNG_INFO_sPLT 0x2000   /* ESR, 1.0.6 */
#define PNG_INFO_sCAL 0x4000   /* ESR, 1.0.6 */
#define PNG_INFO_IDAT 0x8000L  /* ESR, 1.0.6 */

/* This is used for the transformation routines, as some of them
 * change these values for the row.  It also should enable using
 * the routines for other purposes.
 */
typedef struct png_row_info_struct
{
   png_uint_32 width; /* width of row */
   png_uint_32 rowbytes; /* number of bytes in row */
   png_byte color_type; /* color type of row */
   png_byte bit_depth; /* bit depth of row */
   png_byte channels; /* number of channels (1, 2, 3, or 4) */
   png_byte pixel_depth; /* bits per pixel (depth * channels) */
} png_row_info;

typedef png_row_info FAR * png_row_infop;
typedef png_row_info FAR * FAR * png_row_infopp;

/* These are the function types for the I/O functions and for the functions
 * that allow the user to override the default I/O functions with his or her
 * own.  The png_error_ptr type should match that of user-supplied warning
 * and error functions, while the png_rw_ptr type should match that of the
 * user read/write data functions.
 */
typedef struct png_struct_def png_struct;
typedef png_struct FAR * png_structp;

typedef void (PNGAPI *png_error_ptr) PNGARG((png_structp, png_const_charp));
typedef void (PNGAPI *png_rw_ptr) PNGARG((png_structp, png_bytep, png_size_t));
typedef void (PNGAPI *png_flush_ptr) PNGARG((png_structp));
typedef void (PNGAPI *png_read_status_ptr) PNGARG((png_structp, png_uint_32,
   int));
typedef void (PNGAPI *png_write_status_ptr) PNGARG((png_structp, png_uint_32,
   int));

#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
typedef void (PNGAPI *png_progressive_info_ptr) PNGARG((png_structp, png_infop));
typedef void (PNGAPI *png_progressive_end_ptr) PNGARG((png_structp, png_infop));
typedef void (PNGAPI *png_progressive_row_ptr) PNGARG((png_structp, png_bytep,
   png_uint_32, int));
#endif

#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
    defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED) || \
    defined(PNG_LEGACY_SUPPORTED)
typedef void (PNGAPI *png_user_transform_ptr) PNGARG((png_structp,
    png_row_infop, png_bytep));
#endif

#if defined(PNG_USER_CHUNKS_SUPPORTED)
typedef int (PNGAPI *png_user_chunk_ptr) PNGARG((png_structp, png_unknown_chunkp));
#endif
#if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
typedef void (PNGAPI *png_unknown_chunk_ptr) PNGARG((png_structp));
#endif

/* Transform masks for the high-level interface */
#define PNG_TRANSFORM_IDENTITY       0x0000    /* read and write */
#define PNG_TRANSFORM_STRIP_16       0x0001    /* read only */
#define PNG_TRANSFORM_STRIP_ALPHA    0x0002    /* read only */
#define PNG_TRANSFORM_PACKING        0x0004    /* read and write */
#define PNG_TRANSFORM_PACKSWAP       0x0008    /* read and write */
#define PNG_TRANSFORM_EXPAND         0x0010    /* read only */
#define PNG_TRANSFORM_INVERT_MONO    0x0020    /* read and write */
#define PNG_TRANSFORM_SHIFT          0x0040    /* read and write */
#define PNG_TRANSFORM_BGR            0x0080    /* read and write */
#define PNG_TRANSFORM_SWAP_ALPHA     0x0100    /* read and write */
#define PNG_TRANSFORM_SWAP_ENDIAN    0x0200    /* read and write */
#define PNG_TRANSFORM_INVERT_ALPHA   0x0400    /* read and write */
#define PNG_TRANSFORM_STRIP_FILLER   0x0800    /* WRITE only */

/* Flags for MNG supported features */
#define PNG_FLAG_MNG_EMPTY_PLTE     0x01
#define PNG_FLAG_MNG_FILTER_64      0x04
#define PNG_ALL_MNG_FEATURES        0x05

typedef png_voidp (*png_malloc_ptr) PNGARG((png_structp, png_size_t));
typedef void (*png_free_ptr) PNGARG((png_structp, png_voidp));

/* The structure that holds the information to read and write PNG files.
 * The only people who need to care about what is inside of this are the
 * people who will be modifying the library for their own special needs.
 * It should NOT be accessed directly by an application, except to store
 * the jmp_buf.
 */

struct png_struct_def
{
#ifdef PNG_SETJMP_SUPPORTED
   jmp_buf jmpbuf;            /* used in png_error */
#endif
   png_error_ptr error_fn;    /* function for printing errors and aborting */
   png_error_ptr warning_fn;  /* function for printing warnings */
   png_voidp error_ptr;       /* user supplied struct for error functions */
   png_rw_ptr write_data_fn;  /* function for writing output data */
   png_rw_ptr read_data_fn;   /* function for reading input data */
   png_voidp io_ptr;          /* ptr to application struct for I/O functions*/

#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED)
   png_user_transform_ptr read_user_transform_fn; /* user read transform */
#endif

#if defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
   png_user_transform_ptr write_user_transform_fn; /* user write transform */
#endif

/* These were added in libpng-1.0.2 */
#if defined(PNG_USER_TRANSFORM_PTR_SUPPORTED)
#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
    defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
   png_voidp user_transform_ptr; /* user supplied struct for user transform */
   png_byte user_transform_depth;    /* bit depth of user transformed pixels */
   png_byte user_transform_channels; /* channels in user transformed pixels */
#endif
#endif

   png_uint_32 mode;          /* tells us where we are in the PNG file */
   png_uint_32 flags;         /* flags indicating various things to libpng */
   png_uint_32 transformations; /* which transformations to perform */

   z_stream zstream;          /* pointer to decompression structure (below) */
   png_bytep zbuf;            /* buffer for zlib */
   png_size_t zbuf_size;      /* size of zbuf */
   int zlib_level;            /* holds zlib compression level */
   int zlib_method;           /* holds zlib compression method */
   int zlib_window_bits;      /* holds zlib compression window bits */
   int zlib_mem_level;        /* holds zlib compression memory level */
   int zlib_strategy;         /* holds zlib compression strategy */

   png_uint_32 width;         /* width of image in pixels */
   png_uint_32 height;        /* height of image in pixels */
   png_uint_32 num_rows;      /* number of rows in current pass */
   png_uint_32 usr_width;     /* width of row at start of write */
   png_uint_32 rowbytes;      /* size of row in bytes */
   png_uint_32 irowbytes;     /* size of current interlaced row in bytes */
   png_uint_32 iwidth;        /* width of current interlaced row in pixels */
   png_uint_32 row_number;    /* current row in interlace pass */
   png_bytep prev_row;        /* buffer to save previous (unfiltered) row */
   png_bytep row_buf;         /* buffer to save current (unfiltered) row */
   png_bytep sub_row;         /* buffer to save "sub" row when filtering */
   png_bytep up_row;          /* buffer to save "up" row when filtering */
   png_bytep avg_row;         /* buffer to save "avg" row when filtering */
   png_bytep paeth_row;       /* buffer to save "Paeth" row when filtering */
   png_row_info row_info;     /* used for transformation routines */

   png_uint_32 idat_size;     /* current IDAT size for read */
   png_uint_32 crc;           /* current chunk CRC value */
   png_colorp palette;        /* palette from the input file */
   png_uint_16 num_palette;   /* number of color entries in palette */
   png_uint_16 num_trans;     /* number of transparency values */
   png_byte chunk_name[5];    /* null-terminated name of current chunk */
   png_byte compression;      /* file compression type (always 0) */
   png_byte filter;           /* file filter type (always 0) */
   png_byte interlaced;       /* PNG_INTERLACE_NONE, PNG_INTERLACE_ADAM7 */
   png_byte pass;             /* current interlace pass (0 - 6) */
   png_byte do_filter;        /* row filter flags (see PNG_FILTER_ below ) */
   png_byte color_type;       /* color type of file */
   png_byte bit_depth;        /* bit depth of file */
   png_byte usr_bit_depth;    /* bit depth of users row */
   png_byte pixel_depth;      /* number of bits per pixel */
   png_byte channels;         /* number of channels in file */
   png_byte usr_channels;     /* channels at start of write */
   png_byte sig_bytes;        /* magic bytes read/written from start of file */

#if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED)
#ifdef PNG_LEGACY_SUPPORTED
   png_byte filler;           /* filler byte for pixel expansion */
#else
   png_uint_16 filler;           /* filler bytes for pixel expansion */
#endif
#endif

#if defined(PNG_bKGD_SUPPORTED)
   png_byte background_gamma_type;
#  ifdef PNG_FLOATING_POINT_SUPPORTED
   float background_gamma;
#  endif
   png_color_16 background;   /* background color in screen gamma space */
#if defined(PNG_READ_GAMMA_SUPPORTED)
   png_color_16 background_1; /* background normalized to gamma 1.0 */
#endif
#endif /* PNG_bKGD_SUPPORTED */

#if defined(PNG_WRITE_FLUSH_SUPPORTED)
   png_flush_ptr output_flush_fn;/* Function for flushing output */
   png_uint_32 flush_dist;    /* how many rows apart to flush, 0 - no flush */
   png_uint_32 flush_rows;    /* number of rows written since last flush */
#endif

#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
   int gamma_shift;      /* number of "insignificant" bits 16-bit gamma */
#ifdef PNG_FLOATING_POINT_SUPPORTED
   float gamma;          /* file gamma value */
   float screen_gamma;   /* screen gamma value (display_exponent) */
#endif
#endif

#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
   png_bytep gamma_table;     /* gamma table for 8-bit depth files */
   png_bytep gamma_from_1;    /* converts from 1.0 to screen */
   png_bytep gamma_to_1;      /* converts from file to 1.0 */
   png_uint_16pp gamma_16_table; /* gamma table for 16-bit depth files */
   png_uint_16pp gamma_16_from_1; /* converts from 1.0 to screen */
   png_uint_16pp gamma_16_to_1; /* converts from file to 1.0 */
#endif

#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_sBIT_SUPPORTED)
   png_color_8 sig_bit;       /* significant bits in each available channel */
#endif

#if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED)
   png_color_8 shift;         /* shift for significant bit tranformation */
#endif

#if defined(PNG_tRNS_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) \
 || defined(PNG_READ_EXPAND_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
   png_bytep trans;           /* transparency values for paletted files */
   png_color_16 trans_values; /* transparency values for non-paletted files */
#endif

   png_read_status_ptr read_row_fn;   /* called after each row is decoded */
   png_write_status_ptr write_row_fn; /* called after each row is encoded */
#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
   png_progressive_info_ptr info_fn; /* called after header data fully read */
   png_progressive_row_ptr row_fn;   /* called after each prog. row is decoded */
   png_progressive_end_ptr end_fn;   /* called after image is complete */
   png_bytep save_buffer_ptr;        /* current location in save_buffer */
   png_bytep save_buffer;            /* buffer for previously read data */
   png_bytep current_buffer_ptr;     /* current location in current_buffer */
   png_bytep current_buffer;         /* buffer for recently used data */
   png_uint_32 push_length;          /* size of current input chunk */
   png_uint_32 skip_length;          /* bytes to skip in input data */
   png_size_t save_buffer_size;      /* amount of data now in save_buffer */
   png_size_t save_buffer_max;       /* total size of save_buffer */
   png_size_t buffer_size;           /* total amount of available input data */
   png_size_t current_buffer_size;   /* amount of data now in current_buffer */
   int process_mode;                 /* what push library is currently doing */
   int cur_palette;                  /* current push library palette index */

#  if defined(PNG_TEXT_SUPPORTED)
     png_size_t current_text_size;   /* current size of text input data */
     png_size_t current_text_left;   /* how much text left to read in input */
     png_charp current_text;         /* current text chunk buffer */
     png_charp current_text_ptr;     /* current location in current_text */
#  endif /* PNG_PROGRESSIVE_READ_SUPPORTED && PNG_TEXT_SUPPORTED */

#endif /* PNG_PROGRESSIVE_READ_SUPPORTED */

#if defined(__TURBOC__) && !defined(_Windows) && !defined(__FLAT__)
/* for the Borland special 64K segment handler */
   png_bytepp offset_table_ptr;
   png_bytep offset_table;
   png_uint_16 offset_table_number;
   png_uint_16 offset_table_count;
   png_uint_16 offset_table_count_free;
#endif

#if defined(PNG_READ_DITHER_SUPPORTED)
   png_bytep palette_lookup;         /* lookup table for dithering */
   png_bytep dither_index;           /* index translation for palette files */
#endif

#if defined(PNG_READ_DITHER_SUPPORTED) || defined(PNG_hIST_SUPPORTED)
   png_uint_16p hist;                /* histogram */
#endif

#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
   png_byte heuristic_method;        /* heuristic for row filter selection */
   png_byte num_prev_filters;        /* number of weights for previous rows */
   png_bytep prev_filters;           /* filter type(s) of previous row(s) */
   png_uint_16p filter_weights;      /* weight(s) for previous line(s) */
   png_uint_16p inv_filter_weights;  /* 1/weight(s) for previous line(s) */
   png_uint_16p filter_costs;        /* relative filter calculation cost */
   png_uint_16p inv_filter_costs;    /* 1/relative filter calculation cost */
#endif

#if defined(PNG_TIME_RFC1123_SUPPORTED)
   png_charp time_buffer;            /* String to hold RFC 1123 time text */
#endif

/* New members added in libpng-1.0.6 */

#ifdef PNG_FREE_ME_SUPPORTED
   png_uint_32 free_me;       /* flags items libpng is responsible for freeing */
#endif

#if defined(PNG_USER_CHUNKS_SUPPORTED)
   png_voidp user_chunk_ptr;
   png_user_chunk_ptr read_user_chunk_fn; /* user read chunk handler */
#endif

#if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
   int num_chunk_list;
   png_bytep chunk_list;
#endif

/* New members added in libpng-1.0.3 */
#if defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
   png_byte rgb_to_gray_status;
   /* These were changed from png_byte in libpng-1.0.6 */
   png_uint_16 rgb_to_gray_red_coeff;
   png_uint_16 rgb_to_gray_green_coeff;
   png_uint_16 rgb_to_gray_blue_coeff;
#endif

/* New member added in libpng-1.0.4 (renamed in 1.0.9) */
#if defined(PNG_MNG_FEATURES_SUPPORTED) || \
    defined(PNG_READ_EMPTY_PLTE_SUPPORTED) || \
    defined(PNG_WRITE_EMPTY_PLTE_SUPPORTED)
/* changed from png_byte to png_uint_32 at version 1.2.0 */
   png_uint_32 mng_features_permitted;
#endif

/* New member added in libpng-1.0.7 */
#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
   png_fixed_point int_gamma;
#endif

/* New member added in libpng-1.0.9, ifdef'ed out in 1.0.12, enabled in 1.2.0 */
#if defined(PNG_MNG_FEATURES_SUPPORTED)
   png_byte filter_type;
#endif

#if defined(PNG_DEBUG) && defined(PNG_USE_PNGGCCRD)
/* New member added in libpng-1.0.10, ifdef'ed out in 1.2.0 */
   png_uint_32 row_buf_size;
#endif

/* New members added in libpng-1.2.0 */
#if defined(PNG_ASSEMBLER_CODE_SUPPORTED)
   png_byte     mmx_bitdepth_threshold;
   png_uint_32  mmx_rowbytes_threshold;
   png_uint_32  asm_flags;
#endif

/* New members added in libpng-1.0.2 but first enabled by default in 1.2.0 */
#ifdef PNG_USER_MEM_SUPPORTED
   png_voidp mem_ptr;                /* user supplied struct for mem functions */
   png_malloc_ptr malloc_fn;         /* function for allocating memory */
   png_free_ptr free_fn;             /* function for freeing memory */
#endif

   png_bytep big_row_buf;         /* buffer to save current (unfiltered) row */

};


/* This prevents a compiler error in png_get_copyright() in png.c if png.c
   and png.h are both at version 1.2.1
 */
typedef png_structp version_1_2_1;

typedef png_struct FAR * FAR * png_structpp;

/* Here are the function definitions most commonly used.  This is not
 * the place to find out how to use libpng.  See libpng.txt for the
 * full explanation, see example.c for the summary.  This just provides
 * a simple one line description of the use of each function.
 */

/* Returns the version number of the library */
extern PNG_EXPORT(png_uint_32,png_access_version_number) PNGARG((void));

/* Tell lib we have already handled the first <num_bytes> magic bytes.
 * Handling more than 8 bytes from the beginning of the file is an error.
 */
extern PNG_EXPORT(void,png_set_sig_bytes) PNGARG((png_structp png_ptr,
   int num_bytes));

/* Check sig[start] through sig[start + num_to_check - 1] to see if it's a
 * PNG file.  Returns zero if the supplied bytes match the 8-byte PNG
 * signature, and non-zero otherwise.  Having num_to_check == 0 or
 * start > 7 will always fail (ie return non-zero).
 */
extern PNG_EXPORT(int,png_sig_cmp) PNGARG((png_bytep sig, png_size_t start,
   png_size_t num_to_check));

/* Simple signature checking function.  This is the same as calling
 * png_check_sig(sig, n) := !png_sig_cmp(sig, 0, n).
 */
extern PNG_EXPORT(int,png_check_sig) PNGARG((png_bytep sig, int num));

/* Allocate and initialize png_ptr struct for reading, and any other memory. */
extern PNG_EXPORT(png_structp,png_create_read_struct)
   PNGARG((png_const_charp user_png_ver, png_voidp error_ptr,
   png_error_ptr error_fn, png_error_ptr warn_fn));

/* Allocate and initialize png_ptr struct for writing, and any other memory */
extern PNG_EXPORT(png_structp,png_create_write_struct)
   PNGARG((png_const_charp user_png_ver, png_voidp error_ptr,
   png_error_ptr error_fn, png_error_ptr warn_fn));

extern PNG_EXPORT(png_uint_32,png_get_compression_buffer_size)
   PNGARG((png_structp png_ptr));

extern PNG_EXPORT(void,png_set_compression_buffer_size)
   PNGARG((png_structp png_ptr, png_uint_32 size));

/* Reset the compression stream */
extern PNG_EXPORT(int,png_reset_zstream) PNGARG((png_structp png_ptr));

/* New functions added in libpng-1.0.2 (not enabled by default until 1.2.0) */
#ifdef PNG_USER_MEM_SUPPORTED
extern PNG_EXPORT(png_structp,png_create_read_struct_2)
   PNGARG((png_const_charp user_png_ver, png_voidp error_ptr,
   png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr,
   png_malloc_ptr malloc_fn, png_free_ptr free_fn));
extern PNG_EXPORT(png_structp,png_create_write_struct_2)
   PNGARG((png_const_charp user_png_ver, png_voidp error_ptr,
   png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr,
   png_malloc_ptr malloc_fn, png_free_ptr free_fn));
#endif

/* Write a PNG chunk - size, type, (optional) data, CRC. */
extern PNG_EXPORT(void,png_write_chunk) PNGARG((png_structp png_ptr,
   png_bytep chunk_name, png_bytep data, png_size_t length));

/* Write the start of a PNG chunk - length and chunk name. */
extern PNG_EXPORT(void,png_write_chunk_start) PNGARG((png_structp png_ptr,
   png_bytep chunk_name, png_uint_32 length));

/* Write the data of a PNG chunk started with png_write_chunk_start(). */
extern PNG_EXPORT(void,png_write_chunk_data) PNGARG((png_structp png_ptr,
   png_bytep data, png_size_t length));

/* Finish a chunk started with png_write_chunk_start() (includes CRC). */
extern PNG_EXPORT(void,png_write_chunk_end) PNGARG((png_structp png_ptr));

/* Allocate and initialize the info structure */
extern PNG_EXPORT(png_infop,png_create_info_struct)
   PNGARG((png_structp png_ptr));

/* Initialize the info structure (old interface - DEPRECATED) */
extern PNG_EXPORT(void,png_info_init) PNGARG((png_infop info_ptr));
#define png_info_init(info_ptr) png_info_init_3(&info_ptr, sizeof(png_info));
extern PNG_EXPORT(void,png_info_init_3) PNGARG((png_infopp info_ptr,
    png_size_t png_info_struct_size));

/* Writes all the PNG information before the image. */
extern PNG_EXPORT(void,png_write_info_before_PLTE) PNGARG((png_structp png_ptr,
   png_infop info_ptr));
extern PNG_EXPORT(void,png_write_info) PNGARG((png_structp png_ptr,
   png_infop info_ptr));

/* read the information before the actual image data. */
extern PNG_EXPORT(void,png_read_info) PNGARG((png_structp png_ptr,
   png_infop info_ptr));

#if defined(PNG_TIME_RFC1123_SUPPORTED)
extern PNG_EXPORT(png_charp,png_convert_to_rfc1123)
   PNGARG((png_structp png_ptr, png_timep ptime));
#endif

#if !defined(_WIN32_WCE)
/* "time.h" functions are not supported on WindowsCE */
#if defined(PNG_WRITE_tIME_SUPPORTED)
/* convert from a struct tm to png_time */
extern PNG_EXPORT(void,png_convert_from_struct_tm) PNGARG((png_timep ptime,
   struct tm FAR * ttime));

/* convert from time_t to png_time.  Uses gmtime() */
extern PNG_EXPORT(void,png_convert_from_time_t) PNGARG((png_timep ptime,
   time_t ttime));
#endif /* PNG_WRITE_tIME_SUPPORTED */
#endif /* _WIN32_WCE */

#if defined(PNG_READ_EXPAND_SUPPORTED)
/* Expand data to 24-bit RGB, or 8-bit grayscale, with alpha if available. */
extern PNG_EXPORT(void,png_set_expand) PNGARG((png_structp png_ptr));
extern PNG_EXPORT(void,png_set_gray_1_2_4_to_8) PNGARG((png_structp png_ptr));
extern PNG_EXPORT(void,png_set_palette_to_rgb) PNGARG((png_structp png_ptr));
extern PNG_EXPORT(void,png_set_tRNS_to_alpha) PNGARG((png_structp png_ptr));
#endif

#if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
/* Use blue, green, red order for pixels. */
extern PNG_EXPORT(void,png_set_bgr) PNGARG((png_structp png_ptr));
#endif

#if defined(PNG_READ_GRAY_TO_RGB_SUPPORTED)
/* Expand the grayscale to 24-bit RGB if necessary. */
extern PNG_EXPORT(void,png_set_gray_to_rgb) PNGARG((png_structp png_ptr));
#endif

#if defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
/* Reduce RGB to grayscale. */
#ifdef PNG_FLOATING_POINT_SUPPORTED
extern PNG_EXPORT(void,png_set_rgb_to_gray) PNGARG((png_structp png_ptr,
   int error_action, double red, double green ));
#endif
extern PNG_EXPORT(void,png_set_rgb_to_gray_fixed) PNGARG((png_structp png_ptr,
   int error_action, png_fixed_point red, png_fixed_point green ));
extern PNG_EXPORT(png_byte,png_get_rgb_to_gray_status) PNGARG((png_structp
   png_ptr));
#endif

extern PNG_EXPORT(void,png_build_grayscale_palette) PNGARG((int bit_depth,
   png_colorp palette));

#if defined(PNG_READ_STRIP_ALPHA_SUPPORTED)
extern PNG_EXPORT(void,png_set_strip_alpha) PNGARG((png_structp png_ptr));
#endif

#if defined(PNG_READ_SWAP_ALPHA_SUPPORTED) || \
    defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED)
extern PNG_EXPORT(void,png_set_swap_alpha) PNGARG((png_structp png_ptr));
#endif

#if defined(PNG_READ_INVERT_ALPHA_SUPPORTED) || \
    defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED)
extern PNG_EXPORT(void,png_set_invert_alpha) PNGARG((png_structp png_ptr));
#endif

#if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED)
/* Add a filler byte to 24-bit RGB images. */
extern PNG_EXPORT(void,png_set_filler) PNGARG((png_structp png_ptr,
   png_uint_32 filler, int flags));
/* The values of the PNG_FILLER_ defines should NOT be changed */
#define PNG_FILLER_BEFORE 0
#define PNG_FILLER_AFTER 1
#endif /* PNG_READ_FILLER_SUPPORTED || PNG_WRITE_FILLER_SUPPORTED */

#if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
/* Swap bytes in 16-bit depth files. */
extern PNG_EXPORT(void,png_set_swap) PNGARG((png_structp png_ptr));
#endif

#if defined(PNG_READ_PACK_SUPPORTED) || defined(PNG_WRITE_PACK_SUPPORTED)
/* Use 1 byte per pixel in 1, 2, or 4-bit depth files. */
extern PNG_EXPORT(void,png_set_packing) PNGARG((png_structp png_ptr));
#endif

#if defined(PNG_READ_PACKSWAP_SUPPORTED) || defined(PNG_WRITE_PACKSWAP_SUPPORTED)
/* Swap packing order of pixels in bytes. */
extern PNG_EXPORT(void,png_set_packswap) PNGARG((png_structp png_ptr));
#endif

#if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED)
/* Converts files to legal bit depths. */
extern PNG_EXPORT(void,png_set_shift) PNGARG((png_structp png_ptr,
   png_color_8p true_bits));
#endif

#if defined(PNG_READ_INTERLACING_SUPPORTED) || \
    defined(PNG_WRITE_INTERLACING_SUPPORTED)
/* Have the code handle the interlacing.  Returns the number of passes. */
extern PNG_EXPORT(int,png_set_interlace_handling) PNGARG((png_structp png_ptr));
#endif

#if defined(PNG_READ_INVERT_SUPPORTED) || defined(PNG_WRITE_INVERT_SUPPORTED)
/* Invert monochrome files */
extern PNG_EXPORT(void,png_set_invert_mono) PNGARG((png_structp png_ptr));
#endif

#if defined(PNG_READ_BACKGROUND_SUPPORTED)
/* Handle alpha and tRNS by replacing with a background color. */
#ifdef PNG_FLOATING_POINT_SUPPORTED
extern PNG_EXPORT(void,png_set_background) PNGARG((png_structp png_ptr,
   png_color_16p background_color, int background_gamma_code,
   int need_expand, double background_gamma));
#endif
#define PNG_BACKGROUND_GAMMA_UNKNOWN 0
#define PNG_BACKGROUND_GAMMA_SCREEN  1
#define PNG_BACKGROUND_GAMMA_FILE    2
#define PNG_BACKGROUND_GAMMA_UNIQUE  3
#endif

#if defined(PNG_READ_16_TO_8_SUPPORTED)
/* strip the second byte of information from a 16-bit depth file. */
extern PNG_EXPORT(void,png_set_strip_16) PNGARG((png_structp png_ptr));
#endif

#if defined(PNG_READ_DITHER_SUPPORTED)
/* Turn on dithering, and reduce the palette to the number of colors available. */
extern PNG_EXPORT(void,png_set_dither) PNGARG((png_structp png_ptr,
   png_colorp palette, int num_palette, int maximum_colors,
   png_uint_16p histogram, int full_dither));
#endif

#if defined(PNG_READ_GAMMA_SUPPORTED)
/* Handle gamma correction. Screen_gamma=(display_exponent) */
#ifdef PNG_FLOATING_POINT_SUPPORTED
extern PNG_EXPORT(void,png_set_gamma) PNGARG((png_structp png_ptr,
   double screen_gamma, double default_file_gamma));
#endif
#endif

#if defined(PNG_READ_EMPTY_PLTE_SUPPORTED) || \
    defined(PNG_WRITE_EMPTY_PLTE_SUPPORTED)
/* Permit or disallow empty PLTE (0: not permitted, 1: permitted) */
/* Deprecated and will be removed.  Use png_permit_mng_features() instead. */
extern PNG_EXPORT(void,png_permit_empty_plte) PNGARG((png_structp png_ptr,
   int empty_plte_permitted));
#endif

#if defined(PNG_WRITE_FLUSH_SUPPORTED)
/* Set how many lines between output flushes - 0 for no flushing */
extern PNG_EXPORT(void,png_set_flush) PNGARG((png_structp png_ptr, int nrows));
/* Flush the current PNG output buffer */
extern PNG_EXPORT(void,png_write_flush) PNGARG((png_structp png_ptr));
#endif

/* optional update palette with requested transformations */
extern PNG_EXPORT(void,png_start_read_image) PNGARG((png_structp png_ptr));

/* optional call to update the users info structure */
extern PNG_EXPORT(void,png_read_update_info) PNGARG((png_structp png_ptr,
   png_infop info_ptr));

/* read a one or more rows of image data.*/
extern PNG_EXPORT(void,png_read_rows) PNGARG((png_structp png_ptr,
   png_bytepp row, png_bytepp display_row, png_uint_32 num_rows));

/* read a row of data.*/
extern PNG_EXPORT(void,png_read_row) PNGARG((png_structp png_ptr,
   png_bytep row,
   png_bytep display_row));

/* read the whole image into memory at once. */
extern PNG_EXPORT(void,png_read_image) PNGARG((png_structp png_ptr,
   png_bytepp image));

/* write a row of image data */
extern PNG_EXPORT(void,png_write_row) PNGARG((png_structp png_ptr,
   png_bytep row));

/* write a few rows of image data */
extern PNG_EXPORT(void,png_write_rows) PNGARG((png_structp png_ptr,
   png_bytepp row, png_uint_32 num_rows));

/* write the image data */
extern PNG_EXPORT(void,png_write_image) PNGARG((png_structp png_ptr,
   png_bytepp image));

/* writes the end of the PNG file. */
extern PNG_EXPORT(void,png_write_end) PNGARG((png_structp png_ptr,
   png_infop info_ptr));

/* read the end of the PNG file. */
extern PNG_EXPORT(void,png_read_end) PNGARG((png_structp png_ptr,
   png_infop info_ptr));

/* free any memory associated with the png_info_struct */
extern PNG_EXPORT(void,png_destroy_info_struct) PNGARG((png_structp png_ptr,
   png_infopp info_ptr_ptr));

/* free any memory associated with the png_struct and the png_info_structs */
extern PNG_EXPORT(void,png_destroy_read_struct) PNGARG((png_structpp
   png_ptr_ptr, png_infopp info_ptr_ptr, png_infopp end_info_ptr_ptr));

/* free all memory used by the read (old method - NOT DLL EXPORTED) */
extern void png_read_destroy PNGARG((png_structp png_ptr, png_infop info_ptr,
   png_infop end_info_ptr));

/* free any memory associated with the png_struct and the png_info_structs */
extern PNG_EXPORT(void,png_destroy_write_struct)
   PNGARG((png_structpp png_ptr_ptr, png_infopp info_ptr_ptr));

/* free any memory used in info_ptr struct (old method - NOT DLL EXPORTED) */
extern void png_write_destroy_info PNGARG((png_infop info_ptr));

/* free any memory used in png_ptr struct (old method - NOT DLL EXPORTED) */
extern void png_write_destroy PNGARG((png_structp png_ptr));

/* set the libpng method of handling chunk CRC errors */
extern PNG_EXPORT(void,png_set_crc_action) PNGARG((png_structp png_ptr,
   int crit_action, int ancil_action));

/* Values for png_set_crc_action() to say how to handle CRC errors in
 * ancillary and critical chunks, and whether to use the data contained
 * therein.  Note that it is impossible to "discard" data in a critical
 * chunk.  For versions prior to 0.90, the action was always error/quit,
 * whereas in version 0.90 and later, the action for CRC errors in ancillary
 * chunks is warn/discard.  These values should NOT be changed.
 *
 *      value                       action:critical     action:ancillary
 */
#define PNG_CRC_DEFAULT       0  /* error/quit          warn/discard data */
#define PNG_CRC_ERROR_QUIT    1  /* error/quit          error/quit        */
#define PNG_CRC_WARN_DISCARD  2  /* (INVALID)           warn/discard data */
#define PNG_CRC_WARN_USE      3  /* warn/use data       warn/use data     */
#define PNG_CRC_QUIET_USE     4  /* quiet/use data      quiet/use data    */
#define PNG_CRC_NO_CHANGE     5  /* use current value   use current value */

/* These functions give the user control over the scan-line filtering in
 * libpng and the compression methods used by zlib.  These functions are
 * mainly useful for testing, as the defaults should work with most users.
 * Those users who are tight on memory or want faster performance at the
 * expense of compression can modify them.  See the compression library
 * header file (zlib.h) for an explination of the compression functions.
 */

/* set the filtering method(s) used by libpng.  Currently, the only valid
 * value for "method" is 0.
 */
extern PNG_EXPORT(void,png_set_filter) PNGARG((png_structp png_ptr, int method,
   int filters));

/* Flags for png_set_filter() to say which filters to use.  The flags
 * are chosen so that they don't conflict with real filter types
 * below, in case they are supplied instead of the #defined constants.
 * These values should NOT be changed.
 */
#define PNG_NO_FILTERS     0x00
#define PNG_FILTER_NONE    0x08
#define PNG_FILTER_SUB     0x10
#define PNG_FILTER_UP      0x20
#define PNG_FILTER_AVG     0x40
#define PNG_FILTER_PAETH   0x80
#define PNG_ALL_FILTERS (PNG_FILTER_NONE | PNG_FILTER_SUB | PNG_FILTER_UP | \
                         PNG_FILTER_AVG | PNG_FILTER_PAETH)

/* Filter values (not flags) - used in pngwrite.c, pngwutil.c for now.
 * These defines should NOT be changed.
 */
#define PNG_FILTER_VALUE_NONE  0
#define PNG_FILTER_VALUE_SUB   1
#define PNG_FILTER_VALUE_UP    2
#define PNG_FILTER_VALUE_AVG   3
#define PNG_FILTER_VALUE_PAETH 4
#define PNG_FILTER_VALUE_LAST  5

#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED) /* EXPERIMENTAL */
/* The "heuristic_method" is given by one of the PNG_FILTER_HEURISTIC_
 * defines, either the default (minimum-sum-of-absolute-differences), or
 * the experimental method (weighted-minimum-sum-of-absolute-differences).
 *
 * Weights are factors >= 1.0, indicating how important it is to keep the
 * filter type consistent between rows.  Larger numbers mean the current
 * filter is that many times as likely to be the same as the "num_weights"
 * previous filters.  This is cumulative for each previous row with a weight.
 * There needs to be "num_weights" values in "filter_weights", or it can be
 * NULL if the weights aren't being specified.  Weights have no influence on
 * the selection of the first row filter.  Well chosen weights can (in theory)
 * improve the compression for a given image.
 *
 * Costs are factors >= 1.0 indicating the relative decoding costs of a
 * filter type.  Higher costs indicate more decoding expense, and are
 * therefore less likely to be selected over a filter with lower computational
 * costs.  There needs to be a value in "filter_costs" for each valid filter
 * type (given by PNG_FILTER_VALUE_LAST), or it can be NULL if you aren't
 * setting the costs.  Costs try to improve the speed of decompression without
 * unduly increasing the compressed image size.
 *
 * A negative weight or cost indicates the default value is to be used, and
 * values in the range [0.0, 1.0) indicate the value is to remain unchanged.
 * The default values for both weights and costs are currently 1.0, but may
 * change if good general weighting/cost heuristics can be found.  If both
 * the weights and costs are set to 1.0, this degenerates the WEIGHTED method
 * to the UNWEIGHTED method, but with added encoding time/computation.
 */
#ifdef PNG_FLOATING_POINT_SUPPORTED
extern PNG_EXPORT(void,png_set_filter_heuristics) PNGARG((png_structp png_ptr,
   int heuristic_method, int num_weights, png_doublep filter_weights,
   png_doublep filter_costs));
#endif
#endif /*  PNG_WRITE_WEIGHTED_FILTER_SUPPORTED */

/* Heuristic used for row filter selection.  These defines should NOT be
 * changed.
 */
#define PNG_FILTER_HEURISTIC_DEFAULT    0  /* Currently "UNWEIGHTED" */
#define PNG_FILTER_HEURISTIC_UNWEIGHTED 1  /* Used by libpng < 0.95 */
#define PNG_FILTER_HEURISTIC_WEIGHTED   2  /* Experimental feature */
#define PNG_FILTER_HEURISTIC_LAST       3  /* Not a valid value */

/* Set the library compression level.  Currently, valid values range from
 * 0 - 9, corresponding directly to the zlib compression levels 0 - 9
 * (0 - no compression, 9 - "maximal" compression).  Note that tests have
 * shown that zlib compression levels 3-6 usually perform as well as level 9
 * for PNG images, and do considerably fewer caclulations.  In the future,
 * these values may not correspond directly to the zlib compression levels.
 */
extern PNG_EXPORT(void,png_set_compression_level) PNGARG((png_structp png_ptr,
   int level));

extern PNG_EXPORT(void,png_set_compression_mem_level)
   PNGARG((png_structp png_ptr, int mem_level));

extern PNG_EXPORT(void,png_set_compression_strategy)
   PNGARG((png_structp png_ptr, int strategy));

extern PNG_EXPORT(void,png_set_compression_window_bits)
   PNGARG((png_structp png_ptr, int window_bits));

extern PNG_EXPORT(void,png_set_compression_method) PNGARG((png_structp png_ptr,
   int method));

/* These next functions are called for input/output, memory, and error
 * handling.  They are in the file pngrio.c, pngwio.c, and pngerror.c,
 * and call standard C I/O routines such as fread(), fwrite(), and
 * fprintf().  These functions can be made to use other I/O routines
 * at run time for those applications that need to handle I/O in a
 * different manner by calling png_set_???_fn().  See libpng.txt for
 * more information.
 */

#if !defined(PNG_NO_STDIO)
/* Initialize the input/output for the PNG file to the default functions. */
extern PNG_EXPORT(void,png_init_io) PNGARG((png_structp png_ptr, png_FILE_p fp));
#endif

/* Replace the (error and abort), and warning functions with user
 * supplied functions.  If no messages are to be printed you must still
 * write and use replacement functions. The replacement error_fn should
 * still do a longjmp to the last setjmp location if you are using this
 * method of error handling.  If error_fn or warning_fn is NULL, the
 * default function will be used.
 */

extern PNG_EXPORT(void,png_set_error_fn) PNGARG((png_structp png_ptr,
   png_voidp error_ptr, png_error_ptr error_fn, png_error_ptr warning_fn));

/* Return the user pointer associated with the error functions */
extern PNG_EXPORT(png_voidp,png_get_error_ptr) PNGARG((png_structp png_ptr));

/* Replace the default data output functions with a user supplied one(s).
 * If buffered output is not used, then output_flush_fn can be set to NULL.
 * If PNG_WRITE_FLUSH_SUPPORTED is not defined at libpng compile time
 * output_flush_fn will be ignored (and thus can be NULL).
 */
extern PNG_EXPORT(void,png_set_write_fn) PNGARG((png_structp png_ptr,
   png_voidp io_ptr, png_rw_ptr write_data_fn, png_flush_ptr output_flush_fn));

/* Replace the default data input function with a user supplied one. */
extern PNG_EXPORT(void,png_set_read_fn) PNGARG((png_structp png_ptr,
   png_voidp io_ptr, png_rw_ptr read_data_fn));

/* Return the user pointer associated with the I/O functions */
extern PNG_EXPORT(png_voidp,png_get_io_ptr) PNGARG((png_structp png_ptr));

extern PNG_EXPORT(void,png_set_read_status_fn) PNGARG((png_structp png_ptr,
   png_read_status_ptr read_row_fn));

extern PNG_EXPORT(void,png_set_write_status_fn) PNGARG((png_structp png_ptr,
   png_write_status_ptr write_row_fn));

#ifdef PNG_USER_MEM_SUPPORTED
/* Replace the default memory allocation functions with user supplied one(s). */
extern PNG_EXPORT(void,png_set_mem_fn) PNGARG((png_structp png_ptr,
   png_voidp mem_ptr, png_malloc_ptr malloc_fn, png_free_ptr free_fn));
/* Return the user pointer associated with the memory functions */
extern PNG_EXPORT(png_voidp,png_get_mem_ptr) PNGARG((png_structp png_ptr));
#endif

#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
    defined(PNG_LEGACY_SUPPORTED)
extern PNG_EXPORT(void,png_set_read_user_transform_fn) PNGARG((png_structp
   png_ptr, png_user_transform_ptr read_user_transform_fn));
#endif

#if defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED) || \
    defined(PNG_LEGACY_SUPPORTED)
extern PNG_EXPORT(void,png_set_write_user_transform_fn) PNGARG((png_structp
   png_ptr, png_user_transform_ptr write_user_transform_fn));
#endif

#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
    defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED) || \
    defined(PNG_LEGACY_SUPPORTED)
extern PNG_EXPORT(void,png_set_user_transform_info) PNGARG((png_structp
   png_ptr, png_voidp user_transform_ptr, int user_transform_depth,
   int user_transform_channels));
/* Return the user pointer associated with the user transform functions */
extern PNG_EXPORT(png_voidp,png_get_user_transform_ptr)
   PNGARG((png_structp png_ptr));
#endif

#ifdef PNG_USER_CHUNKS_SUPPORTED
extern PNG_EXPORT(void,png_set_read_user_chunk_fn) PNGARG((png_structp png_ptr,
   png_voidp user_chunk_ptr, png_user_chunk_ptr read_user_chunk_fn));
extern PNG_EXPORT(png_voidp,png_get_user_chunk_ptr) PNGARG((png_structp
   png_ptr));
#endif

#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
/* Sets the function callbacks for the push reader, and a pointer to a
 * user-defined structure available to the callback functions.
 */
extern PNG_EXPORT(void,png_set_progressive_read_fn) PNGARG((png_structp png_ptr,
   png_voidp progressive_ptr,
   png_progressive_info_ptr info_fn, png_progressive_row_ptr row_fn,
   png_progressive_end_ptr end_fn));

/* returns the user pointer associated with the push read functions */
extern PNG_EXPORT(png_voidp,png_get_progressive_ptr)
   PNGARG((png_structp png_ptr));

/* function to be called when data becomes available */
extern PNG_EXPORT(void,png_process_data) PNGARG((png_structp png_ptr,
   png_infop info_ptr, png_bytep buffer, png_size_t buffer_size));

/* function that combines rows.  Not very much different than the
 * png_combine_row() call.  Is this even used?????
 */
extern PNG_EXPORT(void,png_progressive_combine_row) PNGARG((png_structp png_ptr,
   png_bytep old_row, png_bytep new_row));
#endif /* PNG_PROGRESSIVE_READ_SUPPORTED */

extern PNG_EXPORT(png_voidp,png_malloc) PNGARG((png_structp png_ptr,
   png_uint_32 size));

/* frees a pointer allocated by png_malloc() */
extern PNG_EXPORT(void,png_free) PNGARG((png_structp png_ptr, png_voidp ptr));

/* Free data that was allocated internally */
extern PNG_EXPORT(void,png_free_data) PNGARG((png_structp png_ptr,
   png_infop info_ptr, png_uint_32 free_me, int num));
#ifdef PNG_FREE_ME_SUPPORTED
/* Reassign responsibility for freeing existing data, whether allocated
 * by libpng or by the application */
extern PNG_EXPORT(void,png_data_freer) PNGARG((png_structp png_ptr,
   png_infop info_ptr, int freer, png_uint_32 mask));
#endif
/* assignments for png_data_freer */
#define PNG_DESTROY_WILL_FREE_DATA 1
#define PNG_SET_WILL_FREE_DATA 1
#define PNG_USER_WILL_FREE_DATA 2
/* Flags for png_ptr->free_me and info_ptr->free_me */
#define PNG_FREE_HIST 0x0008
#define PNG_FREE_ICCP 0x0010
#define PNG_FREE_SPLT 0x0020
#define PNG_FREE_ROWS 0x0040
#define PNG_FREE_PCAL 0x0080
#define PNG_FREE_SCAL 0x0100
#define PNG_FREE_UNKN 0x0200
#define PNG_FREE_LIST 0x0400
#define PNG_FREE_PLTE 0x1000
#define PNG_FREE_TRNS 0x2000
#define PNG_FREE_TEXT 0x4000
#define PNG_FREE_ALL  0x7fff
#define PNG_FREE_MUL  0x4220 /* PNG_FREE_SPLT|PNG_FREE_TEXT|PNG_FREE_UNKN */

#ifdef PNG_USER_MEM_SUPPORTED
extern PNG_EXPORT(png_voidp,png_malloc_default) PNGARG((png_structp png_ptr,
   png_uint_32 size));
extern PNG_EXPORT(void,png_free_default) PNGARG((png_structp png_ptr,
   png_voidp ptr));
#endif

extern PNG_EXPORT(png_voidp,png_memcpy_check) PNGARG((png_structp png_ptr,
   png_voidp s1, png_voidp s2, png_uint_32 size));

extern PNG_EXPORT(png_voidp,png_memset_check) PNGARG((png_structp png_ptr,
   png_voidp s1, int value, png_uint_32 size));

#if defined(USE_FAR_KEYWORD)  /* memory model conversion function */
extern void *png_far_to_near PNGARG((png_structp png_ptr,png_voidp ptr,
   int check));
#endif /* USE_FAR_KEYWORD */

/* Fatal error in PNG image of libpng - can't continue */
extern PNG_EXPORT(void,png_error) PNGARG((png_structp png_ptr,
   png_const_charp error));

/* The same, but the chunk name is prepended to the error string. */
extern PNG_EXPORT(void,png_chunk_error) PNGARG((png_structp png_ptr,
   png_const_charp error));

/* Non-fatal error in libpng.  Can continue, but may have a problem. */
extern PNG_EXPORT(void,png_warning) PNGARG((png_structp png_ptr,
   png_const_charp message));

/* Non-fatal error in libpng, chunk name is prepended to message. */
extern PNG_EXPORT(void,png_chunk_warning) PNGARG((png_structp png_ptr,
   png_const_charp message));

/* The png_set_<chunk> functions are for storing values in the png_info_struct.
 * Similarly, the png_get_<chunk> calls are used to read values from the
 * png_info_struct, either storing the parameters in the passed variables, or
 * setting pointers into the png_info_struct where the data is stored.  The
 * png_get_<chunk> functions return a non-zero value if the data was available
 * in info_ptr, or return zero and do not change any of the parameters if the
 * data was not available.
 *
 * These functions should be used instead of directly accessing png_info
 * to avoid problems with future changes in the size and internal layout of
 * png_info_struct.
 */
/* Returns "flag" if chunk data is valid in info_ptr. */
extern PNG_EXPORT(png_uint_32,png_get_valid) PNGARG((png_structp png_ptr,
png_infop info_ptr, png_uint_32 flag));

/* Returns number of bytes needed to hold a transformed row. */
extern PNG_EXPORT(png_uint_32,png_get_rowbytes) PNGARG((png_structp png_ptr,
png_infop info_ptr));

#if defined(PNG_INFO_IMAGE_SUPPORTED)
/* Returns row_pointers, which is an array of pointers to scanlines that was
returned from png_read_png(). */
extern PNG_EXPORT(png_bytepp,png_get_rows) PNGARG((png_structp png_ptr,
png_infop info_ptr));
/* Set row_pointers, which is an array of pointers to scanlines for use
by png_write_png(). */
extern PNG_EXPORT(void,png_set_rows) PNGARG((png_structp png_ptr,
   png_infop info_ptr, png_bytepp row_pointers));
#endif

/* Returns number of color channels in image. */
extern PNG_EXPORT(png_byte,png_get_channels) PNGARG((png_structp png_ptr,
png_infop info_ptr));

#ifdef PNG_EASY_ACCESS_SUPPORTED
/* Returns image width in pixels. */
extern PNG_EXPORT(png_uint_32, png_get_image_width) PNGARG((png_structp
png_ptr, png_infop info_ptr));

/* Returns image height in pixels. */
extern PNG_EXPORT(png_uint_32, png_get_image_height) PNGARG((png_structp
png_ptr, png_infop info_ptr));

/* Returns image bit_depth. */
extern PNG_EXPORT(png_byte, png_get_bit_depth) PNGARG((png_structp
png_ptr, png_infop info_ptr));

/* Returns image color_type. */
extern PNG_EXPORT(png_byte, png_get_color_type) PNGARG((png_structp
png_ptr, png_infop info_ptr));

/* Returns image filter_type. */
extern PNG_EXPORT(png_byte, png_get_filter_type) PNGARG((png_structp
png_ptr, png_infop info_ptr));

/* Returns image interlace_type. */
extern PNG_EXPORT(png_byte, png_get_interlace_type) PNGARG((png_structp
png_ptr, png_infop info_ptr));

/* Returns image compression_type. */
extern PNG_EXPORT(png_byte, png_get_compression_type) PNGARG((png_structp
png_ptr, png_infop info_ptr));

/* Returns image resolution in pixels per meter, from pHYs chunk data. */
extern PNG_EXPORT(png_uint_32, png_get_pixels_per_meter) PNGARG((png_structp
png_ptr, png_infop info_ptr));
extern PNG_EXPORT(png_uint_32, png_get_x_pixels_per_meter) PNGARG((png_structp
png_ptr, png_infop info_ptr));
extern PNG_EXPORT(png_uint_32, png_get_y_pixels_per_meter) PNGARG((png_structp
png_ptr, png_infop info_ptr));

/* Returns pixel aspect ratio, computed from pHYs chunk data.  */
#ifdef PNG_FLOATING_POINT_SUPPORTED
extern PNG_EXPORT(float, png_get_pixel_aspect_ratio) PNGARG((png_structp
png_ptr, png_infop info_ptr));
#endif

/* Returns image x, y offset in pixels or microns, from oFFs chunk data. */
extern PNG_EXPORT(png_int_32, png_get_x_offset_pixels) PNGARG((png_structp
png_ptr, png_infop info_ptr));
extern PNG_EXPORT(png_int_32, png_get_y_offset_pixels) PNGARG((png_structp
png_ptr, png_infop info_ptr));
extern PNG_EXPORT(png_int_32, png_get_x_offset_microns) PNGARG((png_structp
png_ptr, png_infop info_ptr));
extern PNG_EXPORT(png_int_32, png_get_y_offset_microns) PNGARG((png_structp
png_ptr, png_infop info_ptr));

#endif /* PNG_EASY_ACCESS_SUPPORTED */

/* Returns pointer to signature string read from PNG header */
extern PNG_EXPORT(png_bytep,png_get_signature) PNGARG((png_structp png_ptr,
png_infop info_ptr));

#if defined(PNG_bKGD_SUPPORTED)
extern PNG_EXPORT(png_uint_32,png_get_bKGD) PNGARG((png_structp png_ptr,
   png_infop info_ptr, png_color_16p *background));
#endif

#if defined(PNG_bKGD_SUPPORTED)
extern PNG_EXPORT(void,png_set_bKGD) PNGARG((png_structp png_ptr,
   png_infop info_ptr, png_color_16p background));
#endif

#if defined(PNG_cHRM_SUPPORTED)
#ifdef PNG_FLOATING_POINT_SUPPORTED
extern PNG_EXPORT(png_uint_32,png_get_cHRM) PNGARG((png_structp png_ptr,
   png_infop info_ptr, double *white_x, double *white_y, double *red_x,
   double *red_y, double *green_x, double *green_y, double *blue_x,
   double *blue_y));
#endif
#ifdef PNG_FIXED_POINT_SUPPORTED
extern PNG_EXPORT(png_uint_32,png_get_cHRM_fixed) PNGARG((png_structp png_ptr,
   png_infop info_ptr, png_fixed_point *int_white_x, png_fixed_point
   *int_white_y, png_fixed_point *int_red_x, png_fixed_point *int_red_y,
   png_fixed_point *int_green_x, png_fixed_point *int_green_y, png_fixed_point
   *int_blue_x, png_fixed_point *int_blue_y));
#endif
#endif

#if defined(PNG_cHRM_SUPPORTED)
#ifdef PNG_FLOATING_POINT_SUPPORTED
extern PNG_EXPORT(void,png_set_cHRM) PNGARG((png_structp png_ptr,
   png_infop info_ptr, double white_x, double white_y, double red_x,
   double red_y, double green_x, double green_y, double blue_x, double blue_y));
#endif
#ifdef PNG_FIXED_POINT_SUPPORTED
extern PNG_EXPORT(void,png_set_cHRM_fixed) PNGARG((png_structp png_ptr,
   png_infop info_ptr, png_fixed_point int_white_x, png_fixed_point int_white_y,
   png_fixed_point int_red_x, png_fixed_point int_red_y, png_fixed_point
   int_green_x, png_fixed_point int_green_y, png_fixed_point int_blue_x,
   png_fixed_point int_blue_y));
#endif
#endif

#if defined(PNG_gAMA_SUPPORTED)
#ifdef PNG_FLOATING_POINT_SUPPORTED
extern PNG_EXPORT(png_uint_32,png_get_gAMA) PNGARG((png_structp png_ptr,
   png_infop info_ptr, double *file_gamma));
#endif
extern PNG_EXPORT(png_uint_32,png_get_gAMA_fixed) PNGARG((png_structp png_ptr,
   png_infop info_ptr, png_fixed_point *int_file_gamma));
#endif

#if defined(PNG_gAMA_SUPPORTED)
#ifdef PNG_FLOATING_POINT_SUPPORTED
extern PNG_EXPORT(void,png_set_gAMA) PNGARG((png_structp png_ptr,
   png_infop info_ptr, double file_gamma));
#endif
extern PNG_EXPORT(void,png_set_gAMA_fixed) PNGARG((png_structp png_ptr,
   png_infop info_ptr, png_fixed_point int_file_gamma));
#endif

#if defined(PNG_hIST_SUPPORTED)
extern PNG_EXPORT(png_uint_32,png_get_hIST) PNGARG((png_structp png_ptr,
   png_infop info_ptr, png_uint_16p *hist));
#endif

#if defined(PNG_hIST_SUPPORTED)
extern PNG_EXPORT(void,png_set_hIST) PNGARG((png_structp png_ptr,
   png_infop info_ptr, png_uint_16p hist));
#endif

extern PNG_EXPORT(png_uint_32,png_get_IHDR) PNGARG((png_structp png_ptr,
   png_infop info_ptr, png_uint_32 *width, png_uint_32 *height,
   int *bit_depth, int *color_type, int *interlace_method,
   int *compression_method, int *filter_method));

extern PNG_EXPORT(void,png_set_IHDR) PNGARG((png_structp png_ptr,
   png_infop info_ptr, png_uint_32 width, png_uint_32 height, int bit_depth,
   int color_type, int interlace_method, int compression_method,
   int filter_method));

#if defined(PNG_oFFs_SUPPORTED)
extern PNG_EXPORT(png_uint_32,png_get_oFFs) PNGARG((png_structp png_ptr,
   png_infop info_ptr, png_int_32 *offset_x, png_int_32 *offset_y,
   int *unit_type));
#endif

#if defined(PNG_oFFs_SUPPORTED)
extern PNG_EXPORT(void,png_set_oFFs) PNGARG((png_structp png_ptr,
   png_infop info_ptr, png_int_32 offset_x, png_int_32 offset_y,
   int unit_type));
#endif

#if defined(PNG_pCAL_SUPPORTED)
extern PNG_EXPORT(png_uint_32,png_get_pCAL) PNGARG((png_structp png_ptr,
   png_infop info_ptr, png_charp *purpose, png_int_32 *X0, png_int_32 *X1,
   int *type, int *nparams, png_charp *units, png_charpp *params));
#endif

#if defined(PNG_pCAL_SUPPORTED)
extern PNG_EXPORT(void,png_set_pCAL) PNGARG((png_structp png_ptr,
   png_infop info_ptr, png_charp purpose, png_int_32 X0, png_int_32 X1,
   int type, int nparams, png_charp units, png_charpp params));
#endif

#if defined(PNG_pHYs_SUPPORTED)
extern PNG_EXPORT(png_uint_32,png_get_pHYs) PNGARG((png_structp png_ptr,
   png_infop info_ptr, png_uint_32 *res_x, png_uint_32 *res_y, int *unit_type));
#endif

#if defined(PNG_pHYs_SUPPORTED)
extern PNG_EXPORT(void,png_set_pHYs) PNGARG((png_structp png_ptr,
   png_infop info_ptr, png_uint_32 res_x, png_uint_32 res_y, int unit_type));
#endif

extern PNG_EXPORT(png_uint_32,png_get_PLTE) PNGARG((png_structp png_ptr,
   png_infop info_ptr, png_colorp *palette, int *num_palette));

extern PNG_EXPORT(void,png_set_PLTE) PNGARG((png_structp png_ptr,
   png_infop info_ptr, png_colorp palette, int num_palette));

#if defined(PNG_sBIT_SUPPORTED)
extern PNG_EXPORT(png_uint_32,png_get_sBIT) PNGARG((png_structp png_ptr,
   png_infop info_ptr, png_color_8p *sig_bit));
#endif

#if defined(PNG_sBIT_SUPPORTED)
extern PNG_EXPORT(void,png_set_sBIT) PNGARG((png_structp png_ptr,
   png_infop info_ptr, png_color_8p sig_bit));
#endif

#if defined(PNG_sRGB_SUPPORTED)
extern PNG_EXPORT(png_uint_32,png_get_sRGB) PNGARG((png_structp png_ptr,
   png_infop info_ptr, int *intent));
#endif

#if defined(PNG_sRGB_SUPPORTED)
extern PNG_EXPORT(void,png_set_sRGB) PNGARG((png_structp png_ptr,
   png_infop info_ptr, int intent));
extern PNG_EXPORT(void,png_set_sRGB_gAMA_and_cHRM) PNGARG((png_structp png_ptr,
   png_infop info_ptr, int intent));
#endif

#if defined(PNG_iCCP_SUPPORTED)
extern PNG_EXPORT(png_uint_32,png_get_iCCP) PNGARG((png_structp png_ptr,
   png_infop info_ptr, png_charpp name, int *compression_type,
   png_charpp profile, png_uint_32 *proflen));
   /* Note to maintainer: profile should be png_bytepp */
#endif

#if defined(PNG_iCCP_SUPPORTED)
extern PNG_EXPORT(void,png_set_iCCP) PNGARG((png_structp png_ptr,
   png_infop info_ptr, png_charp name, int compression_type,
   png_charp profile, png_uint_32 proflen));
   /* Note to maintainer: profile should be png_bytep */
#endif

#if defined(PNG_sPLT_SUPPORTED)
extern PNG_EXPORT(png_uint_32,png_get_sPLT) PNGARG((png_structp png_ptr,
   png_infop info_ptr, png_sPLT_tpp entries));
#endif

#if defined(PNG_sPLT_SUPPORTED)
extern PNG_EXPORT(void,png_set_sPLT) PNGARG((png_structp png_ptr,
   png_infop info_ptr, png_sPLT_tp entries, int nentries));
#endif

#if defined(PNG_TEXT_SUPPORTED)
/* png_get_text also returns the number of text chunks in *num_text */
extern PNG_EXPORT(png_uint_32,png_get_text) PNGARG((png_structp png_ptr,
   png_infop info_ptr, png_textp *text_ptr, int *num_text));
#endif

/*
 *  Note while png_set_text() will accept a structure whose text,
 *  language, and  translated keywords are NULL pointers, the structure
 *  returned by png_get_text will always contain regular
 *  zero-terminated C strings.  They might be empty strings but
 *  they will never be NULL pointers.
 */

#if defined(PNG_TEXT_SUPPORTED)
extern PNG_EXPORT(void,png_set_text) PNGARG((png_structp png_ptr,
   png_infop info_ptr, png_textp text_ptr, int num_text));
#endif

#if defined(PNG_tIME_SUPPORTED)
extern PNG_EXPORT(png_uint_32,png_get_tIME) PNGARG((png_structp png_ptr,
   png_infop info_ptr, png_timep *mod_time));
#endif

#if defined(PNG_tIME_SUPPORTED)
extern PNG_EXPORT(void,png_set_tIME) PNGARG((png_structp png_ptr,
   png_infop info_ptr, png_timep mod_time));
#endif

#if defined(PNG_tRNS_SUPPORTED)
extern PNG_EXPORT(png_uint_32,png_get_tRNS) PNGARG((png_structp png_ptr,
   png_infop info_ptr, png_bytep *trans, int *num_trans,
   png_color_16p *trans_values));
#endif

#if defined(PNG_tRNS_SUPPORTED)
extern PNG_EXPORT(void,png_set_tRNS) PNGARG((png_structp png_ptr,
   png_infop info_ptr, png_bytep trans, int num_trans,
   png_color_16p trans_values));
#endif

#if defined(PNG_tRNS_SUPPORTED)
#endif

#if defined(PNG_sCAL_SUPPORTED)
#ifdef PNG_FLOATING_POINT_SUPPORTED
extern PNG_EXPORT(png_uint_32,png_get_sCAL) PNGARG((png_structp png_ptr,
   png_infop info_ptr, int *unit, double *width, double *height));
#else
#ifdef PNG_FIXED_POINT_SUPPORTED
extern PNG_EXPORT(png_uint_32,png_get_sCAL_s) PNGARG((png_structp png_ptr,
   png_infop info_ptr, int *unit, png_charpp swidth, png_charpp sheight));
#endif
#endif
#endif /* PNG_sCAL_SUPPORTED */

#if defined(PNG_sCAL_SUPPORTED)
#ifdef PNG_FLOATING_POINT_SUPPORTED
extern PNG_EXPORT(void,png_set_sCAL) PNGARG((png_structp png_ptr,
   png_infop info_ptr, int unit, double width, double height));
#endif
#ifdef PNG_FIXED_POINT_SUPPORTED
extern PNG_EXPORT(void,png_set_sCAL_s) PNGARG((png_structp png_ptr,
   png_infop info_ptr, int unit, png_charp swidth, png_charp sheight));
#endif
#endif /* PNG_sCAL_SUPPORTED || PNG_WRITE_sCAL_SUPPORTED */

#if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
/* provide a list of chunks and how they are to be handled, if the built-in
   handling or default unknown chunk handling is not desired.  Any chunks not
   listed will be handled in the default manner.  The IHDR and IEND chunks
   must not be listed.
      keep = 0: follow default behavour
           = 1: do not keep
           = 2: keep only if safe-to-copy
           = 3: keep even if unsafe-to-copy
*/
extern PNG_EXPORT(void, png_set_keep_unknown_chunks) PNGARG((png_structp
   png_ptr, int keep, png_bytep chunk_list, int num_chunks));
extern PNG_EXPORT(void, png_set_unknown_chunks) PNGARG((png_structp png_ptr,
   png_infop info_ptr, png_unknown_chunkp unknowns, int num_unknowns));
extern PNG_EXPORT(void, png_set_unknown_chunk_location)
   PNGARG((png_structp png_ptr, png_infop info_ptr, int chunk, int location));
extern PNG_EXPORT(png_uint_32,png_get_unknown_chunks) PNGARG((png_structp
   png_ptr, png_infop info_ptr, png_unknown_chunkpp entries));
#endif

/* Png_free_data() will turn off the "valid" flag for anything it frees.
   If you need to turn it off for a chunk that your application has freed,
   you can use png_set_invalid(png_ptr, info_ptr, PNG_INFO_CHNK); */
extern PNG_EXPORT(void, png_set_invalid) PNGARG((png_structp png_ptr,
   png_infop info_ptr, int mask));

#if defined(PNG_INFO_IMAGE_SUPPORTED)
/* The "params" pointer is currently not used and is for future expansion. */
extern PNG_EXPORT(void, png_read_png) PNGARG((png_structp png_ptr,
                        png_infop info_ptr,
                        int transforms,
                        png_voidp params));
extern PNG_EXPORT(void, png_write_png) PNGARG((png_structp png_ptr,
                        png_infop info_ptr,
                        int transforms,
                        png_voidp params));
#endif

/* Define PNG_DEBUG at compile time for debugging information.  Higher
 * numbers for PNG_DEBUG mean more debugging information.  This has
 * only been added since version 0.95 so it is not implemented throughout
 * libpng yet, but more support will be added as needed.
 */
#ifdef PNG_DEBUG
#if (PNG_DEBUG > 0)
#if !defined(PNG_DEBUG_FILE) && defined(_MSC_VER)
#include <crtdbg.h>
#if (PNG_DEBUG > 1)
#define png_debug(l,m)  _RPT0(_CRT_WARN,m)
#define png_debug1(l,m,p1)  _RPT1(_CRT_WARN,m,p1)
#define png_debug2(l,m,p1,p2) _RPT2(_CRT_WARN,m,p1,p2)
#endif
#else /* PNG_DEBUG_FILE || !_MSC_VER */
#ifndef PNG_DEBUG_FILE
#define PNG_DEBUG_FILE stderr
#endif /* PNG_DEBUG_FILE */
#if (PNG_DEBUG > 1)
#define png_debug(l,m) \
{ \
     int num_tabs=l; \
     fprintf(PNG_DEBUG_FILE,"%s"m,(num_tabs==1 ? "\t" : \
       (num_tabs==2 ? "\t\t":(num_tabs>2 ? "\t\t\t":"")))); \
}
#define png_debug1(l,m,p1) \
{ \
     int num_tabs=l; \
     fprintf(PNG_DEBUG_FILE,"%s"m,(num_tabs==1 ? "\t" : \
       (num_tabs==2 ? "\t\t":(num_tabs>2 ? "\t\t\t":""))),p1); \
}
#define png_debug2(l,m,p1,p2) \
{ \
     int num_tabs=l; \
     fprintf(PNG_DEBUG_FILE,"%s"m,(num_tabs==1 ? "\t" : \
       (num_tabs==2 ? "\t\t":(num_tabs>2 ? "\t\t\t":""))),p1,p2); \
}
#endif /* (PNG_DEBUG > 1) */
#endif /* _MSC_VER */
#endif /* (PNG_DEBUG > 0) */
#endif /* PNG_DEBUG */
#ifndef png_debug
#define png_debug(l, m)
#endif
#ifndef png_debug1
#define png_debug1(l, m, p1)
#endif
#ifndef png_debug2
#define png_debug2(l, m, p1, p2)
#endif

extern PNG_EXPORT(png_bytep,png_sig_bytes) PNGARG((void));

extern PNG_EXPORT(png_charp,png_get_copyright) PNGARG((png_structp png_ptr));
extern PNG_EXPORT(png_charp,png_get_header_ver) PNGARG((png_structp png_ptr));
extern PNG_EXPORT(png_charp,png_get_header_version) PNGARG((png_structp png_ptr));
extern PNG_EXPORT(png_charp,png_get_libpng_ver) PNGARG((png_structp png_ptr));

#ifdef PNG_MNG_FEATURES_SUPPORTED
extern PNG_EXPORT(png_uint_32,png_permit_mng_features) PNGARG((png_structp
   png_ptr, png_uint_32 mng_features_permitted));
#endif

/* Added to version 1.2.0 */
#if defined(PNG_ASSEMBLER_CODE_SUPPORTED)
#define PNG_ASM_FLAG_MMX_SUPPORT_COMPILED  0x01		/* not user-settable */
#define PNG_ASM_FLAG_MMX_SUPPORT_IN_CPU    0x02		/* not user-settable */
#define PNG_ASM_FLAG_MMX_READ_COMBINE_ROW  0x04
#define PNG_ASM_FLAG_MMX_READ_INTERLACE    0x08
#define PNG_ASM_FLAG_MMX_READ_FILTER_SUB   0x10
#define PNG_ASM_FLAG_MMX_READ_FILTER_UP    0x20
#define PNG_ASM_FLAG_MMX_READ_FILTER_AVG   0x40
#define PNG_ASM_FLAG_MMX_READ_FILTER_PAETH 0x80
#define PNG_ASM_FLAGS_INITIALIZED          0x80000000	/* not user-settable */

#define PNG_MMX_READ_FLAGS ( PNG_ASM_FLAG_MMX_READ_COMBINE_ROW  \
                           | PNG_ASM_FLAG_MMX_READ_INTERLACE    \
                           | PNG_ASM_FLAG_MMX_READ_FILTER_SUB   \
                           | PNG_ASM_FLAG_MMX_READ_FILTER_UP    \
                           | PNG_ASM_FLAG_MMX_READ_FILTER_AVG   \
                           | PNG_ASM_FLAG_MMX_READ_FILTER_PAETH )
#define PNG_MMX_WRITE_FLAGS ( 0 )

#define PNG_MMX_FLAGS ( PNG_ASM_FLAG_MMX_SUPPORT_COMPILED \
                      | PNG_ASM_FLAG_MMX_SUPPORT_IN_CPU   \
                      | PNG_MMX_READ_FLAGS                \
                      | PNG_MMX_WRITE_FLAGS )

#define PNG_SELECT_READ   1
#define PNG_SELECT_WRITE  2


/* pngget.c */
extern PNG_EXPORT(png_uint_32,png_get_mmx_flagmask)
   PNGARG((int flag_select, int *compilerID));

/* pngget.c */
extern PNG_EXPORT(png_uint_32,png_get_asm_flagmask)
   PNGARG((int flag_select));

/* pngget.c */
extern PNG_EXPORT(png_uint_32,png_get_asm_flags)
   PNGARG((png_structp png_ptr));

/* pngget.c */
extern PNG_EXPORT(png_byte,png_get_mmx_bitdepth_threshold)
   PNGARG((png_structp png_ptr));

/* pngget.c */
extern PNG_EXPORT(png_uint_32,png_get_mmx_rowbytes_threshold)
   PNGARG((png_structp png_ptr));

/* pngset.c */
extern PNG_EXPORT(void,png_set_asm_flags)
   PNGARG((png_structp png_ptr, png_uint_32 asm_flags));

/* pngset.c */
extern PNG_EXPORT(void,png_set_mmx_thresholds)
   PNGARG((png_structp png_ptr, png_byte mmx_bitdepth_threshold,
   png_uint_32 mmx_rowbytes_threshold));

#endif /* PNG_ASSEMBLER_CODE_SUPPORTED */

/* png.c, pnggccrd.c, or pngvcrd.c */
extern PNG_EXPORT(int,png_mmx_support) PNGARG((void));

/* Strip the prepended error numbers ("#nnn ") from error and warning
 * messages before passing them to the error or warning handler. */
#ifdef PNG_ERROR_NUMBERS_SUPPORTED
extern PNG_EXPORT(void,png_set_strip_error_numbers) PNGARG((png_structp
   png_ptr, png_uint_32 strip_mode));
#endif

/* Maintainer: Put new public prototypes here ^, in libpng.3, and project defs */

#define PNG_HEADER_VERSION_STRING \
   " libpng version 1.2.1 - December 12, 2001 (header)\n"

#ifdef PNG_READ_COMPOSITE_NODIV_SUPPORTED
/* With these routines we avoid an integer divide, which will be slower on
 * most machines.  However, it does take more operations than the corresponding
 * divide method, so it may be slower on a few RISC systems.  There are two
 * shifts (by 8 or 16 bits) and an addition, versus a single integer divide.
 *
 * Note that the rounding factors are NOT supposed to be the same!  128 and
 * 32768 are correct for the NODIV code; 127 and 32767 are correct for the
 * standard method.
 *
 * [Optimized code by Greg Roelofs and Mark Adler...blame us for bugs. :-) ]
 */

 /* fg and bg should be in `gamma 1.0' space; alpha is the opacity          */

#  define png_composite(composite, fg, alpha, bg)                            \
     { png_uint_16 temp = (png_uint_16)((png_uint_16)(fg) * (png_uint_16)(alpha) \
                        +        (png_uint_16)(bg)*(png_uint_16)(255 -       \
                        (png_uint_16)(alpha)) + (png_uint_16)128);           \
       (composite) = (png_byte)((temp + (temp >> 8)) >> 8); }

#  define png_composite_16(composite, fg, alpha, bg)                         \
     { png_uint_32 temp = (png_uint_32)((png_uint_32)(fg) * (png_uint_32)(alpha) \
                        + (png_uint_32)(bg)*(png_uint_32)(65535L -           \
                        (png_uint_32)(alpha)) + (png_uint_32)32768L);        \
       (composite) = (png_uint_16)((temp + (temp >> 16)) >> 16); }

#else  /* standard method using integer division */

#  define png_composite(composite, fg, alpha, bg)                            \
     (composite) = (png_byte)(((png_uint_16)(fg) * (png_uint_16)(alpha) +    \
       (png_uint_16)(bg) * (png_uint_16)(255 - (png_uint_16)(alpha)) +       \
       (png_uint_16)127) / 255)

#  define png_composite_16(composite, fg, alpha, bg)                         \
     (composite) = (png_uint_16)(((png_uint_32)(fg) * (png_uint_32)(alpha) + \
       (png_uint_32)(bg)*(png_uint_32)(65535L - (png_uint_32)(alpha)) +      \
       (png_uint_32)32767) / (png_uint_32)65535L)

#endif /* PNG_READ_COMPOSITE_NODIV_SUPPORTED */

/* These next functions are used internally in the code.  They generally
 * shouldn't be used unless you are writing code to add or replace some
 * functionality in libpng.  More information about most functions can
 * be found in the files where the functions are located.
 */

#if defined(PNG_INTERNAL)

/* Various modes of operation.  Note that after an init, mode is set to
 * zero automatically when the structure is created.
 */
#define PNG_HAVE_IHDR               0x01
#define PNG_HAVE_PLTE               0x02
#define PNG_HAVE_IDAT               0x04
#define PNG_AFTER_IDAT              0x08
#define PNG_HAVE_IEND               0x10
#define PNG_HAVE_gAMA               0x20
#define PNG_HAVE_cHRM               0x40
#define PNG_HAVE_sRGB               0x80
#define PNG_HAVE_CHUNK_HEADER      0x100
#define PNG_WROTE_tIME             0x200
#define PNG_WROTE_INFO_BEFORE_PLTE 0x400
#define PNG_BACKGROUND_IS_GRAY     0x800
#define PNG_HAVE_PNG_SIGNATURE    0x1000

/* flags for the transformations the PNG library does on the image data */
#define PNG_BGR                0x0001
#define PNG_INTERLACE          0x0002
#define PNG_PACK               0x0004
#define PNG_SHIFT              0x0008
#define PNG_SWAP_BYTES         0x0010
#define PNG_INVERT_MONO        0x0020
#define PNG_DITHER             0x0040
#define PNG_BACKGROUND         0x0080
#define PNG_BACKGROUND_EXPAND  0x0100
                          /*   0x0200 unused */
#define PNG_16_TO_8            0x0400
#define PNG_RGBA               0x0800
#define PNG_EXPAND             0x1000
#define PNG_GAMMA              0x2000
#define PNG_GRAY_TO_RGB        0x4000
#define PNG_FILLER             0x8000L
#define PNG_PACKSWAP          0x10000L
#define PNG_SWAP_ALPHA        0x20000L
#define PNG_STRIP_ALPHA       0x40000L
#define PNG_INVERT_ALPHA      0x80000L
#define PNG_USER_TRANSFORM   0x100000L
#define PNG_RGB_TO_GRAY_ERR  0x200000L
#define PNG_RGB_TO_GRAY_WARN 0x400000L
#define PNG_RGB_TO_GRAY      0x600000L  /* two bits, RGB_TO_GRAY_ERR|WARN */

/* flags for png_create_struct */
#define PNG_STRUCT_PNG   0x0001
#define PNG_STRUCT_INFO  0x0002

/* Scaling factor for filter heuristic weighting calculations */
#define PNG_WEIGHT_SHIFT 8
#define PNG_WEIGHT_FACTOR (1<<(PNG_WEIGHT_SHIFT))
#define PNG_COST_SHIFT 3
#define PNG_COST_FACTOR (1<<(PNG_COST_SHIFT))

/* flags for the png_ptr->flags rather than declaring a byte for each one */
#define PNG_FLAG_ZLIB_CUSTOM_STRATEGY     0x0001
#define PNG_FLAG_ZLIB_CUSTOM_LEVEL        0x0002
#define PNG_FLAG_ZLIB_CUSTOM_MEM_LEVEL    0x0004
#define PNG_FLAG_ZLIB_CUSTOM_WINDOW_BITS  0x0008
#define PNG_FLAG_ZLIB_CUSTOM_METHOD       0x0010
#define PNG_FLAG_ZLIB_FINISHED            0x0020
#define PNG_FLAG_ROW_INIT                 0x0040
#define PNG_FLAG_FILLER_AFTER             0x0080
#define PNG_FLAG_CRC_ANCILLARY_USE        0x0100
#define PNG_FLAG_CRC_ANCILLARY_NOWARN     0x0200
#define PNG_FLAG_CRC_CRITICAL_USE         0x0400
#define PNG_FLAG_CRC_CRITICAL_IGNORE      0x0800
#define PNG_FLAG_FREE_PLTE                0x1000
#define PNG_FLAG_FREE_TRNS                0x2000
#define PNG_FLAG_FREE_HIST                0x4000
#define PNG_FLAG_KEEP_UNKNOWN_CHUNKS      0x8000L
#define PNG_FLAG_KEEP_UNSAFE_CHUNKS       0x10000L
#define PNG_FLAG_LIBRARY_MISMATCH         0x20000L
#define PNG_FLAG_STRIP_ERROR_NUMBERS      0x40000L
#define PNG_FLAG_STRIP_ERROR_TEXT         0x80000L

/* For use in png_set_keep_unknown, png_handle_as_unknown */
#define HANDLE_CHUNK_AS_DEFAULT   0
#define HANDLE_CHUNK_NEVER        1
#define HANDLE_CHUNK_IF_SAFE      2
#define HANDLE_CHUNK_ALWAYS       3

#define PNG_FLAG_CRC_ANCILLARY_MASK (PNG_FLAG_CRC_ANCILLARY_USE | \
                                     PNG_FLAG_CRC_ANCILLARY_NOWARN)

#define PNG_FLAG_CRC_CRITICAL_MASK  (PNG_FLAG_CRC_CRITICAL_USE | \
                                     PNG_FLAG_CRC_CRITICAL_IGNORE)

#define PNG_FLAG_CRC_MASK           (PNG_FLAG_CRC_ANCILLARY_MASK | \
                                     PNG_FLAG_CRC_CRITICAL_MASK)

/* save typing and make code easier to understand */
#define PNG_COLOR_DIST(c1, c2) (abs((int)((c1).red) - (int)((c2).red)) + \
   abs((int)((c1).green) - (int)((c2).green)) + \
   abs((int)((c1).blue) - (int)((c2).blue)))

/* variables declared in png.c - only it needs to define PNG_NO_EXTERN */
#if !defined(PNG_NO_EXTERN) || defined(PNG_ALWAYS_EXTERN)
/* place to hold the signature string for a PNG file. */
#ifdef PNG_USE_GLOBAL_ARRAYS
   PNG_EXPORT_VAR (const png_byte FARDATA) png_sig[8];
#else
#define png_sig png_sig_bytes(NULL)
#endif
#endif /* PNG_NO_EXTERN */

/* Constant strings for known chunk types.  If you need to add a chunk,
 * define the name here, and add an invocation of the macro in png.c and
 * wherever it's needed.
 */
#define PNG_IHDR const png_byte png_IHDR[5] = { 73,  72,  68,  82, '\0'}
#define PNG_IDAT const png_byte png_IDAT[5] = { 73,  68,  65,  84, '\0'}
#define PNG_IEND const png_byte png_IEND[5] = { 73,  69,  78,  68, '\0'}
#define PNG_PLTE const png_byte png_PLTE[5] = { 80,  76,  84,  69, '\0'}
#define PNG_bKGD const png_byte png_bKGD[5] = { 98,  75,  71,  68, '\0'}
#define PNG_cHRM const png_byte png_cHRM[5] = { 99,  72,  82,  77, '\0'}
#define PNG_gAMA const png_byte png_gAMA[5] = {103,  65,  77,  65, '\0'}
#define PNG_hIST const png_byte png_hIST[5] = {104,  73,  83,  84, '\0'}
#define PNG_iCCP const png_byte png_iCCP[5] = {105,  67,  67,  80, '\0'}
#define PNG_iTXt const png_byte png_iTXt[5] = {105,  84,  88, 116, '\0'}
#define PNG_oFFs const png_byte png_oFFs[5] = {111,  70,  70, 115, '\0'}
#define PNG_pCAL const png_byte png_pCAL[5] = {112,  67,  65,  76, '\0'}
#define PNG_sCAL const png_byte png_sCAL[5] = {115,  67,  65,  76, '\0'}
#define PNG_pHYs const png_byte png_pHYs[5] = {112,  72,  89, 115, '\0'}
#define PNG_sBIT const png_byte png_sBIT[5] = {115,  66,  73,  84, '\0'}
#define PNG_sPLT const png_byte png_sPLT[5] = {115,  80,  76,  84, '\0'}
#define PNG_sRGB const png_byte png_sRGB[5] = {115,  82,  71,  66, '\0'}
#define PNG_tEXt const png_byte png_tEXt[5] = {116,  69,  88, 116, '\0'}
#define PNG_tIME const png_byte png_tIME[5] = {116,  73,  77,  69, '\0'}
#define PNG_tRNS const png_byte png_tRNS[5] = {116,  82,  78,  83, '\0'}
#define PNG_zTXt const png_byte png_zTXt[5] = {122,  84,  88, 116, '\0'}

#ifdef PNG_USE_GLOBAL_ARRAYS
PNG_EXPORT_VAR (const png_byte FARDATA) png_IHDR[5];
PNG_EXPORT_VAR (const png_byte FARDATA) png_IDAT[5];
PNG_EXPORT_VAR (const png_byte FARDATA) png_IEND[5];
PNG_EXPORT_VAR (const png_byte FARDATA) png_PLTE[5];
PNG_EXPORT_VAR (const png_byte FARDATA) png_bKGD[5];
PNG_EXPORT_VAR (const png_byte FARDATA) png_cHRM[5];
PNG_EXPORT_VAR (const png_byte FARDATA) png_gAMA[5];
PNG_EXPORT_VAR (const png_byte FARDATA) png_hIST[5];
PNG_EXPORT_VAR (const png_byte FARDATA) png_iCCP[5];
PNG_EXPORT_VAR (const png_byte FARDATA) png_iTXt[5];
PNG_EXPORT_VAR (const png_byte FARDATA) png_oFFs[5];
PNG_EXPORT_VAR (const png_byte FARDATA) png_pCAL[5];
PNG_EXPORT_VAR (const png_byte FARDATA) png_sCAL[5];
PNG_EXPORT_VAR (const png_byte FARDATA) png_pHYs[5];
PNG_EXPORT_VAR (const png_byte FARDATA) png_sBIT[5];
PNG_EXPORT_VAR (const png_byte FARDATA) png_sPLT[5];
PNG_EXPORT_VAR (const png_byte FARDATA) png_sRGB[5];
PNG_EXPORT_VAR (const png_byte FARDATA) png_tEXt[5];
PNG_EXPORT_VAR (const png_byte FARDATA) png_tIME[5];
PNG_EXPORT_VAR (const png_byte FARDATA) png_tRNS[5];
PNG_EXPORT_VAR (const png_byte FARDATA) png_zTXt[5];
#endif /* PNG_USE_GLOBAL_ARRAYS */


/* Inline macros to do direct reads of bytes from the input buffer.  These
 * require that you are using an architecture that uses PNG byte ordering
 * (MSB first) and supports unaligned data storage.  I think that PowerPC
 * in big-endian mode and 680x0 are the only ones that will support this.
 * The x86 line of processors definitely do not.  The png_get_int_32()
 * routine also assumes we are using two's complement format for negative
 * values, which is almost certainly true.
 */
#if defined(PNG_READ_BIG_ENDIAN_SUPPORTED)
#  if defined(PNG_pCAL_SUPPORTED) || defined(PNG_oFFs_SUPPORTED)
#    define png_get_int_32(buf) ( *((png_int_32p) (buf)))
#  endif
#  define png_get_uint_32(buf) ( *((png_uint_32p) (buf)))
#  define png_get_uint_16(buf) ( *((png_uint_16p) (buf)))
#else
#  if defined(PNG_pCAL_SUPPORTED) || defined(PNG_oFFs_SUPPORTED)
PNG_EXTERN png_int_32 png_get_int_32 PNGARG((png_bytep buf));
#  endif
PNG_EXTERN png_uint_32 png_get_uint_32 PNGARG((png_bytep buf));
PNG_EXTERN png_uint_16 png_get_uint_16 PNGARG((png_bytep buf));
#endif /* !PNG_READ_BIG_ENDIAN_SUPPORTED */

/* Initialize png_ptr struct for reading, and allocate any other memory.
 * (old interface - DEPRECATED - use png_create_read_struct instead).
 */
extern PNG_EXPORT(void,png_read_init) PNGARG((png_structp png_ptr));
#define png_read_init(png_ptr) png_read_init_3(&png_ptr, \
    PNG_LIBPNG_VER_STRING,  sizeof(png_struct));
extern PNG_EXPORT(void,png_read_init_3) PNGARG((png_structpp ptr_ptr,
    png_const_charp user_png_ver, png_size_t png_struct_size));
extern PNG_EXPORT(void,png_read_init_2) PNGARG((png_structp png_ptr,
    png_const_charp user_png_ver, png_size_t png_struct_size, png_size_t
    png_info_size));

/* Initialize png_ptr struct for writing, and allocate any other memory.
 * (old interface - DEPRECATED - use png_create_write_struct instead).
 */
extern PNG_EXPORT(void,png_write_init) PNGARG((png_structp png_ptr));
#define png_write_init(png_ptr) png_write_init_3(&png_ptr, \
    PNG_LIBPNG_VER_STRING, sizeof(png_struct));
extern PNG_EXPORT(void,png_write_init_3) PNGARG((png_structpp ptr_ptr,
    png_const_charp user_png_ver, png_size_t png_struct_size));
extern PNG_EXPORT(void,png_write_init_2) PNGARG((png_structp png_ptr,
    png_const_charp user_png_ver, png_size_t png_struct_size, png_size_t
    png_info_size));

/* Allocate memory for an internal libpng struct */
PNG_EXTERN png_voidp png_create_struct PNGARG((int type));

/* Free memory from internal libpng struct */
PNG_EXTERN void png_destroy_struct PNGARG((png_voidp struct_ptr));

PNG_EXTERN png_voidp png_create_struct_2 PNGARG((int type, png_malloc_ptr
  malloc_fn, png_voidp mem_ptr));
PNG_EXTERN void png_destroy_struct_2 PNGARG((png_voidp struct_ptr,
   png_free_ptr free_fn, png_voidp mem_ptr));

/* Free any memory that info_ptr points to and reset struct. */
PNG_EXTERN void png_info_destroy PNGARG((png_structp png_ptr,
   png_infop info_ptr));

/* Function to allocate memory for zlib. */
PNG_EXTERN voidpf png_zalloc PNGARG((voidpf png_ptr, uInt items, uInt size));

/* Function to free memory for zlib */
PNG_EXTERN void png_zfree PNGARG((voidpf png_ptr, voidpf ptr));

/* Reset the CRC variable */
PNG_EXTERN void png_reset_crc PNGARG((png_structp png_ptr));

/* Write the "data" buffer to whatever output you are using. */
PNG_EXTERN void png_write_data PNGARG((png_structp png_ptr, png_bytep data,
   png_size_t length));

/* Read data from whatever input you are using into the "data" buffer */
PNG_EXTERN void png_read_data PNGARG((png_structp png_ptr, png_bytep data,
   png_size_t length));

/* Read bytes into buf, and update png_ptr->crc */
PNG_EXTERN void png_crc_read PNGARG((png_structp png_ptr, png_bytep buf,
   png_size_t length));

/* Decompress data in a chunk that uses compression */
#if defined(PNG_zTXt_SUPPORTED) || defined(PNG_iTXt_SUPPORTED) || \
    defined(PNG_iCCP_SUPPORTED) || defined(PNG_sPLT_SUPPORTED)
PNG_EXTERN png_charp png_decompress_chunk PNGARG((png_structp png_ptr,
   int comp_type, png_charp chunkdata, png_size_t chunklength,
   png_size_t prefix_length, png_size_t *data_length));
#endif

/* Read "skip" bytes, read the file crc, and (optionally) verify png_ptr->crc */
PNG_EXTERN int png_crc_finish PNGARG((png_structp png_ptr, png_uint_32 skip));

/* Read the CRC from the file and compare it to the libpng calculated CRC */
PNG_EXTERN int png_crc_error PNGARG((png_structp png_ptr));

/* Calculate the CRC over a section of data.  Note that we are only
 * passing a maximum of 64K on systems that have this as a memory limit,
 * since this is the maximum buffer size we can specify.
 */
PNG_EXTERN void png_calculate_crc PNGARG((png_structp png_ptr, png_bytep ptr,
   png_size_t length));

#if defined(PNG_WRITE_FLUSH_SUPPORTED)
PNG_EXTERN void png_flush PNGARG((png_structp png_ptr));
#endif

/* Place a 32-bit number into a buffer in PNG byte order (big-endian).
 * The only currently known PNG chunks that use signed numbers are
 * the ancillary extension chunks, oFFs and pCAL.
 */
PNG_EXTERN void png_save_uint_32 PNGARG((png_bytep buf, png_uint_32 i));

#if defined(PNG_WRITE_pCAL_SUPPORTED) || defined(PNG_WRITE_oFFs_SUPPORTED)
PNG_EXTERN void png_save_int_32 PNGARG((png_bytep buf, png_int_32 i));
#endif

/* Place a 16-bit number into a buffer in PNG byte order.
 * The parameter is declared unsigned int, not png_uint_16,
 * just to avoid potential problems on pre-ANSI C compilers.
 */
PNG_EXTERN void png_save_uint_16 PNGARG((png_bytep buf, unsigned int i));

/* simple function to write the signature */
PNG_EXTERN void png_write_sig PNGARG((png_structp png_ptr));

/* write various chunks */

/* Write the IHDR chunk, and update the png_struct with the necessary
 * information.
 */
PNG_EXTERN void png_write_IHDR PNGARG((png_structp png_ptr, png_uint_32 width,
   png_uint_32 height,
   int bit_depth, int color_type, int compression_method, int filter_method,
   int interlace_method));

PNG_EXTERN void png_write_PLTE PNGARG((png_structp png_ptr, png_colorp palette,
   png_uint_32 num_pal));

PNG_EXTERN void png_write_IDAT PNGARG((png_structp png_ptr, png_bytep data,
   png_size_t length));

PNG_EXTERN void png_write_IEND PNGARG((png_structp png_ptr));

#if defined(PNG_WRITE_gAMA_SUPPORTED)
#ifdef PNG_FLOATING_POINT_SUPPORTED
PNG_EXTERN void png_write_gAMA PNGARG((png_structp png_ptr, double file_gamma));
#endif
#ifdef PNG_FIXED_POINT_SUPPORTED
PNG_EXTERN void png_write_gAMA_fixed PNGARG((png_structp png_ptr, png_fixed_point
    file_gamma));
#endif
#endif

#if defined(PNG_WRITE_sBIT_SUPPORTED)
PNG_EXTERN void png_write_sBIT PNGARG((png_structp png_ptr, png_color_8p sbit,
   int color_type));
#endif

#if defined(PNG_WRITE_cHRM_SUPPORTED)
#ifdef PNG_FLOATING_POINT_SUPPORTED
PNG_EXTERN void png_write_cHRM PNGARG((png_structp png_ptr,
   double white_x, double white_y,
   double red_x, double red_y, double green_x, double green_y,
   double blue_x, double blue_y));
#endif
#ifdef PNG_FIXED_POINT_SUPPORTED
PNG_EXTERN void png_write_cHRM_fixed PNGARG((png_structp png_ptr,
   png_fixed_point int_white_x, png_fixed_point int_white_y,
   png_fixed_point int_red_x, png_fixed_point int_red_y, png_fixed_point
   int_green_x, png_fixed_point int_green_y, png_fixed_point int_blue_x,
   png_fixed_point int_blue_y));
#endif
#endif

#if defined(PNG_WRITE_sRGB_SUPPORTED)
PNG_EXTERN void png_write_sRGB PNGARG((png_structp png_ptr,
   int intent));
#endif

#if defined(PNG_WRITE_iCCP_SUPPORTED)
PNG_EXTERN void png_write_iCCP PNGARG((png_structp png_ptr,
   png_charp name, int compression_type,
   png_charp profile, int proflen));
   /* Note to maintainer: profile should be png_bytep */
#endif

#if defined(PNG_WRITE_sPLT_SUPPORTED)
PNG_EXTERN void png_write_sPLT PNGARG((png_structp png_ptr,
   png_sPLT_tp palette));
#endif

#if defined(PNG_WRITE_tRNS_SUPPORTED)
PNG_EXTERN void png_write_tRNS PNGARG((png_structp png_ptr, png_bytep trans,
   png_color_16p values, int number, int color_type));
#endif

#if defined(PNG_WRITE_bKGD_SUPPORTED)
PNG_EXTERN void png_write_bKGD PNGARG((png_structp png_ptr,
   png_color_16p values, int color_type));
#endif

#if defined(PNG_WRITE_hIST_SUPPORTED)
PNG_EXTERN void png_write_hIST PNGARG((png_structp png_ptr, png_uint_16p hist,
   int num_hist));
#endif

#if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_pCAL_SUPPORTED) || \
    defined(PNG_WRITE_iCCP_SUPPORTED) || defined(PNG_WRITE_sPLT_SUPPORTED)
PNG_EXTERN png_size_t png_check_keyword PNGARG((png_structp png_ptr,
   png_charp key, png_charpp new_key));
#endif

#if defined(PNG_WRITE_tEXt_SUPPORTED)
PNG_EXTERN void png_write_tEXt PNGARG((png_structp png_ptr, png_charp key,
   png_charp text, png_size_t text_len));
#endif

#if defined(PNG_WRITE_zTXt_SUPPORTED)
PNG_EXTERN void png_write_zTXt PNGARG((png_structp png_ptr, png_charp key,
   png_charp text, png_size_t text_len, int compression));
#endif

#if defined(PNG_WRITE_iTXt_SUPPORTED)
PNG_EXTERN void png_write_iTXt PNGARG((png_structp png_ptr,
   int compression, png_charp key, png_charp lang, png_charp lang_key,
   png_charp text));
#endif

#if defined(PNG_WRITE_oFFs_SUPPORTED)
PNG_EXTERN void png_write_oFFs PNGARG((png_structp png_ptr,
   png_int_32 x_offset, png_int_32 y_offset, int unit_type));
#endif

#if defined(PNG_WRITE_pCAL_SUPPORTED)
PNG_EXTERN void png_write_pCAL PNGARG((png_structp png_ptr, png_charp purpose,
   png_int_32 X0, png_int_32 X1, int type, int nparams,
   png_charp units, png_charpp params));
#endif

#if defined(PNG_WRITE_pHYs_SUPPORTED)
PNG_EXTERN void png_write_pHYs PNGARG((png_structp png_ptr,
   png_uint_32 x_pixels_per_unit, png_uint_32 y_pixels_per_unit,
   int unit_type));
#endif

#if defined(PNG_WRITE_tIME_SUPPORTED)
PNG_EXTERN void png_write_tIME PNGARG((png_structp png_ptr,
   png_timep mod_time));
#endif

#if defined(PNG_WRITE_sCAL_SUPPORTED)
#if defined(PNG_FLOATING_POINT_SUPPORTED) && !defined(PNG_NO_STDIO)
PNG_EXTERN void png_write_sCAL PNGARG((png_structp png_ptr,
   int unit, double width, double height));
#else
#ifdef PNG_FIXED_POINT_SUPPORTED
PNG_EXTERN void png_write_sCAL_s PNGARG((png_structp png_ptr,
   int unit, png_charp width, png_charp height));
#endif
#endif
#endif

/* Called when finished processing a row of data */
PNG_EXTERN void png_write_finish_row PNGARG((png_structp png_ptr));

/* Internal use only.   Called before first row of data */
PNG_EXTERN void png_write_start_row PNGARG((png_structp png_ptr));

#if defined(PNG_READ_GAMMA_SUPPORTED)
PNG_EXTERN void png_build_gamma_table PNGARG((png_structp png_ptr));
#endif

/* combine a row of data, dealing with alpha, etc. if requested */
PNG_EXTERN void png_combine_row PNGARG((png_structp png_ptr, png_bytep row,
   int mask));

#if defined(PNG_READ_INTERLACING_SUPPORTED)
/* expand an interlaced row */
/* OLD pre-1.0.9 interface:
PNG_EXTERN void png_do_read_interlace PNGARG((png_row_infop row_info,
   png_bytep row, int pass, png_uint_32 transformations));
 */
PNG_EXTERN void png_do_read_interlace PNGARG((png_structp png_ptr));
#endif

/* GRR TO DO (2.0 or whenever):  simplify other internal calling interfaces */

#if defined(PNG_WRITE_INTERLACING_SUPPORTED)
/* grab pixels out of a row for an interlaced pass */
PNG_EXTERN void png_do_write_interlace PNGARG((png_row_infop row_info,
   png_bytep row, int pass));
#endif

/* unfilter a row */
PNG_EXTERN void png_read_filter_row PNGARG((png_structp png_ptr,
   png_row_infop row_info, png_bytep row, png_bytep prev_row, int filter));

/* Choose the best filter to use and filter the row data */
PNG_EXTERN void png_write_find_filter PNGARG((png_structp png_ptr,
   png_row_infop row_info));

/* Write out the filtered row. */
PNG_EXTERN void png_write_filtered_row PNGARG((png_structp png_ptr,
   png_bytep filtered_row));
/* finish a row while reading, dealing with interlacing passes, etc. */
PNG_EXTERN void png_read_finish_row PNGARG((png_structp png_ptr));

/* initialize the row buffers, etc. */
PNG_EXTERN void png_read_start_row PNGARG((png_structp png_ptr));
/* optional call to update the users info structure */
PNG_EXTERN void png_read_transform_info PNGARG((png_structp png_ptr,
   png_infop info_ptr));

/* these are the functions that do the transformations */
#if defined(PNG_READ_FILLER_SUPPORTED)
PNG_EXTERN void png_do_read_filler PNGARG((png_row_infop row_info,
   png_bytep row, png_uint_32 filler, png_uint_32 flags));
#endif

#if defined(PNG_READ_SWAP_ALPHA_SUPPORTED)
PNG_EXTERN void png_do_read_swap_alpha PNGARG((png_row_infop row_info,
   png_bytep row));
#endif

#if defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED)
PNG_EXTERN void png_do_write_swap_alpha PNGARG((png_row_infop row_info,
   png_bytep row));
#endif

#if defined(PNG_READ_INVERT_ALPHA_SUPPORTED)
PNG_EXTERN void png_do_read_invert_alpha PNGARG((png_row_infop row_info,
   png_bytep row));
#endif

#if defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED)
PNG_EXTERN void png_do_write_invert_alpha PNGARG((png_row_infop row_info,
   png_bytep row));
#endif

#if defined(PNG_WRITE_FILLER_SUPPORTED) || \
    defined(PNG_READ_STRIP_ALPHA_SUPPORTED)
PNG_EXTERN void png_do_strip_filler PNGARG((png_row_infop row_info,
   png_bytep row, png_uint_32 flags));
#endif

#if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
PNG_EXTERN void png_do_swap PNGARG((png_row_infop row_info, png_bytep row));
#endif

#if defined(PNG_READ_PACKSWAP_SUPPORTED) || defined(PNG_WRITE_PACKSWAP_SUPPORTED)
PNG_EXTERN void png_do_packswap PNGARG((png_row_infop row_info, png_bytep row));
#endif

#if defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
PNG_EXTERN int png_do_rgb_to_gray PNGARG((png_structp png_ptr, png_row_infop
   row_info, png_bytep row));
#endif

#if defined(PNG_READ_GRAY_TO_RGB_SUPPORTED)
PNG_EXTERN void png_do_gray_to_rgb PNGARG((png_row_infop row_info,
   png_bytep row));
#endif

#if defined(PNG_READ_PACK_SUPPORTED)
PNG_EXTERN void png_do_unpack PNGARG((png_row_infop row_info, png_bytep row));
#endif

#if defined(PNG_READ_SHIFT_SUPPORTED)
PNG_EXTERN void png_do_unshift PNGARG((png_row_infop row_info, png_bytep row,
   png_color_8p sig_bits));
#endif

#if defined(PNG_READ_INVERT_SUPPORTED) || defined(PNG_WRITE_INVERT_SUPPORTED)
PNG_EXTERN void png_do_invert PNGARG((png_row_infop row_info, png_bytep row));
#endif

#if defined(PNG_READ_16_TO_8_SUPPORTED)
PNG_EXTERN void png_do_chop PNGARG((png_row_infop row_info, png_bytep row));
#endif

#if defined(PNG_READ_DITHER_SUPPORTED)
PNG_EXTERN void png_do_dither PNGARG((png_row_infop row_info,
   png_bytep row, png_bytep palette_lookup, png_bytep dither_lookup));

#  if defined(PNG_CORRECT_PALETTE_SUPPORTED)
PNG_EXTERN void png_correct_palette PNGARG((png_structp png_ptr,
   png_colorp palette, int num_palette));
#  endif
#endif

#if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
PNG_EXTERN void png_do_bgr PNGARG((png_row_infop row_info, png_bytep row));
#endif

#if defined(PNG_WRITE_PACK_SUPPORTED)
PNG_EXTERN void png_do_pack PNGARG((png_row_infop row_info,
   png_bytep row, png_uint_32 bit_depth));
#endif

#if defined(PNG_WRITE_SHIFT_SUPPORTED)
PNG_EXTERN void png_do_shift PNGARG((png_row_infop row_info, png_bytep row,
   png_color_8p bit_depth));
#endif

#if defined(PNG_READ_BACKGROUND_SUPPORTED)
#if defined(PNG_READ_GAMMA_SUPPORTED)
PNG_EXTERN void png_do_background PNGARG((png_row_infop row_info, png_bytep row,
   png_color_16p trans_values, png_color_16p background,
   png_color_16p background_1,
   png_bytep gamma_table, png_bytep gamma_from_1, png_bytep gamma_to_1,
   png_uint_16pp gamma_16, png_uint_16pp gamma_16_from_1,
   png_uint_16pp gamma_16_to_1, int gamma_shift));
#else
PNG_EXTERN void png_do_background PNGARG((png_row_infop row_info, png_bytep row,
   png_color_16p trans_values, png_color_16p background));
#endif
#endif

#if defined(PNG_READ_GAMMA_SUPPORTED)
PNG_EXTERN void png_do_gamma PNGARG((png_row_infop row_info, png_bytep row,
   png_bytep gamma_table, png_uint_16pp gamma_16_table,
   int gamma_shift));
#endif

#if defined(PNG_READ_EXPAND_SUPPORTED)
PNG_EXTERN void png_do_expand_palette PNGARG((png_row_infop row_info,
   png_bytep row, png_colorp palette, png_bytep trans, int num_trans));
PNG_EXTERN void png_do_expand PNGARG((png_row_infop row_info,
   png_bytep row, png_color_16p trans_value));
#endif

/* The following decodes the appropriate chunks, and does error correction,
 * then calls the appropriate callback for the chunk if it is valid.
 */

/* decode the IHDR chunk */
PNG_EXTERN void png_handle_IHDR PNGARG((png_structp png_ptr, png_infop info_ptr,
   png_uint_32 length));
PNG_EXTERN void png_handle_PLTE PNGARG((png_structp png_ptr, png_infop info_ptr,
   png_uint_32 length));
PNG_EXTERN void png_handle_IEND PNGARG((png_structp png_ptr, png_infop info_ptr,
   png_uint_32 length));

#if defined(PNG_READ_bKGD_SUPPORTED)
PNG_EXTERN void png_handle_bKGD PNGARG((png_structp png_ptr, png_infop info_ptr,
   png_uint_32 length));
#endif

#if defined(PNG_READ_cHRM_SUPPORTED)
PNG_EXTERN void png_handle_cHRM PNGARG((png_structp png_ptr, png_infop info_ptr,
   png_uint_32 length));
#endif

#if defined(PNG_READ_gAMA_SUPPORTED)
PNG_EXTERN void png_handle_gAMA PNGARG((png_structp png_ptr, png_infop info_ptr,
   png_uint_32 length));
#endif

#if defined(PNG_READ_hIST_SUPPORTED)
PNG_EXTERN void png_handle_hIST PNGARG((png_structp png_ptr, png_infop info_ptr,
   png_uint_32 length));
#endif

#if defined(PNG_READ_iCCP_SUPPORTED)
extern void png_handle_iCCP PNGARG((png_structp png_ptr, png_infop info_ptr,
   png_uint_32 length));
#endif /* PNG_READ_iCCP_SUPPORTED */

#if defined(PNG_READ_iTXt_SUPPORTED)
PNG_EXTERN void png_handle_iTXt PNGARG((png_structp png_ptr, png_infop info_ptr,
   png_uint_32 length));
#endif

#if defined(PNG_READ_oFFs_SUPPORTED)
PNG_EXTERN void png_handle_oFFs PNGARG((png_structp png_ptr, png_infop info_ptr,
   png_uint_32 length));
#endif

#if defined(PNG_READ_pCAL_SUPPORTED)
PNG_EXTERN void png_handle_pCAL PNGARG((png_structp png_ptr, png_infop info_ptr,
   png_uint_32 length));
#endif

#if defined(PNG_READ_pHYs_SUPPORTED)
PNG_EXTERN void png_handle_pHYs PNGARG((png_structp png_ptr, png_infop info_ptr,
   png_uint_32 length));
#endif

#if defined(PNG_READ_sBIT_SUPPORTED)
PNG_EXTERN void png_handle_sBIT PNGARG((png_structp png_ptr, png_infop info_ptr,
   png_uint_32 length));
#endif

#if defined(PNG_READ_sCAL_SUPPORTED)
PNG_EXTERN void png_handle_sCAL PNGARG((png_structp png_ptr, png_infop info_ptr,
   png_uint_32 length));
#endif

#if defined(PNG_READ_sPLT_SUPPORTED)
extern void png_handle_sPLT PNGARG((png_structp png_ptr, png_infop info_ptr,
   png_uint_32 length));
#endif /* PNG_READ_sPLT_SUPPORTED */

#if defined(PNG_READ_sRGB_SUPPORTED)
PNG_EXTERN void png_handle_sRGB PNGARG((png_structp png_ptr, png_infop info_ptr,
   png_uint_32 length));
#endif

#if defined(PNG_READ_tEXt_SUPPORTED)
PNG_EXTERN void png_handle_tEXt PNGARG((png_structp png_ptr, png_infop info_ptr,
   png_uint_32 length));
#endif

#if defined(PNG_READ_tIME_SUPPORTED)
PNG_EXTERN void png_handle_tIME PNGARG((png_structp png_ptr, png_infop info_ptr,
   png_uint_32 length));
#endif

#if defined(PNG_READ_tRNS_SUPPORTED)
PNG_EXTERN void png_handle_tRNS PNGARG((png_structp png_ptr, png_infop info_ptr,
   png_uint_32 length));
#endif

#if defined(PNG_READ_zTXt_SUPPORTED)
PNG_EXTERN void png_handle_zTXt PNGARG((png_structp png_ptr, png_infop info_ptr,
   png_uint_32 length));
#endif

#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
PNG_EXTERN int png_handle_as_unknown PNGARG((png_structp png_ptr, png_bytep
   chunk_name));
#endif

PNG_EXTERN void png_handle_unknown PNGARG((png_structp png_ptr,
   png_infop info_ptr, png_uint_32 length));

PNG_EXTERN void png_check_chunk_name PNGARG((png_structp png_ptr,
   png_bytep chunk_name));

/* handle the transformations for reading and writing */
PNG_EXTERN void png_do_read_transformations PNGARG((png_structp png_ptr));
PNG_EXTERN void png_do_write_transformations PNGARG((png_structp png_ptr));

PNG_EXTERN void png_init_read_transformations PNGARG((png_structp png_ptr));

#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
PNG_EXTERN void png_push_read_chunk PNGARG((png_structp png_ptr,
   png_infop info_ptr));
PNG_EXTERN void png_push_read_sig PNGARG((png_structp png_ptr,
   png_infop info_ptr));
PNG_EXTERN void png_push_check_crc PNGARG((png_structp png_ptr));
PNG_EXTERN void png_push_crc_skip PNGARG((png_structp png_ptr,
   png_uint_32 length));
PNG_EXTERN void png_push_crc_finish PNGARG((png_structp png_ptr));
PNG_EXTERN void png_push_fill_buffer PNGARG((png_structp png_ptr,
   png_bytep buffer, png_size_t length));
PNG_EXTERN void png_push_save_buffer PNGARG((png_structp png_ptr));
PNG_EXTERN void png_push_restore_buffer PNGARG((png_structp png_ptr,
   png_bytep buffer, png_size_t buffer_length));
PNG_EXTERN void png_push_read_IDAT PNGARG((png_structp png_ptr));
PNG_EXTERN void png_process_IDAT_data PNGARG((png_structp png_ptr,
   png_bytep buffer, png_size_t buffer_length));
PNG_EXTERN void png_push_process_row PNGARG((png_structp png_ptr));
PNG_EXTERN void png_push_handle_unknown PNGARG((png_structp png_ptr,
   png_infop info_ptr, png_uint_32 length));
PNG_EXTERN void png_push_have_info PNGARG((png_structp png_ptr,
   png_infop info_ptr));
PNG_EXTERN void png_push_have_end PNGARG((png_structp png_ptr,
   png_infop info_ptr));
PNG_EXTERN void png_push_have_row PNGARG((png_structp png_ptr, png_bytep row));
PNG_EXTERN void png_push_read_end PNGARG((png_structp png_ptr,
   png_infop info_ptr));
PNG_EXTERN void png_process_some_data PNGARG((png_structp png_ptr,
   png_infop info_ptr));
PNG_EXTERN void png_read_push_finish_row PNGARG((png_structp png_ptr));
#if defined(PNG_READ_tEXt_SUPPORTED)
PNG_EXTERN void png_push_handle_tEXt PNGARG((png_structp png_ptr,
   png_infop info_ptr, png_uint_32 length));
PNG_EXTERN void png_push_read_tEXt PNGARG((png_structp png_ptr,
   png_infop info_ptr));
#endif
#if defined(PNG_READ_zTXt_SUPPORTED)
PNG_EXTERN void png_push_handle_zTXt PNGARG((png_structp png_ptr,
   png_infop info_ptr, png_uint_32 length));
PNG_EXTERN void png_push_read_zTXt PNGARG((png_structp png_ptr,
   png_infop info_ptr));
#endif
#if defined(PNG_READ_iTXt_SUPPORTED)
PNG_EXTERN void png_push_handle_iTXt PNGARG((png_structp png_ptr,
   png_infop info_ptr, png_uint_32 length));
PNG_EXTERN void png_push_read_iTXt PNGARG((png_structp png_ptr,
   png_infop info_ptr));
#endif

#endif /* PNG_PROGRESSIVE_READ_SUPPORTED */

#ifdef PNG_MNG_FEATURES_SUPPORTED
PNG_EXTERN void png_do_read_intrapixel PNGARG((png_row_infop row_info,
   png_bytep row));
PNG_EXTERN void png_do_write_intrapixel PNGARG((png_row_infop row_info,
   png_bytep row));
#endif

#if defined(PNG_ASSEMBLER_CODE_SUPPORTED)
/* png.c */ /* PRIVATE */
PNG_EXTERN void png_init_mmx_flags PNGARG((png_structp png_ptr));
#endif
/* Maintainer: Put new private prototypes here ^ and in libpngpf.3 */

#endif /* PNG_INTERNAL */

#ifdef __cplusplus
}
#endif

#endif /* PNG_VERSION_INFO_ONLY */
/* do not put anything past this line */
#endif /* PNG_H */