Worked on 100m

src/main/java/com/elphel/imagej/orthomosaic/ComboMatch.java

@@ -1161,6 +1161,7 @@ adjusted affines[1] for a pair: 1694564291_293695/1694564778_589341
 					return null;
 				}
 				int pair = 0;
+				boolean flip_pair = false;
 				if (fp.npoints > 2)  { // select pair
 					int [][] pairs = new int [fp.npoints/2][2];
 					for (int j = 0; j < pairs.length; j++) {
@@ -1174,19 +1175,22 @@ adjusted affines[1] for a pair: 1694564291_293695/1694564778_589341
 
 					GenericJTabbedDialog gds = new GenericJTabbedDialog("Select image pair from the image",1200,400);
 					gds.addChoice("Image pair in the marked image:", choices, choices[choices.length-1]);
+					gds.addCheckbox    ("Flip order", false, "Match first to second.");
 					gds.showDialog();
 					if (gds.wasCanceled()) return null;
 					pair= gds.getNextChoiceIndex();
+					flip_pair = gds.getNextBoolean();
 				}
 				
 				
 				double [][] points_xy= new double [2][2];
 				int [] pair_slices = new int[2];
-				for (int n = 0; n < points_xy.length; n++) {
+				for (int nn = 0; nn < points_xy.length; nn++) {
+					int n= flip_pair? (points_xy.length-nn-1) : nn;
 					int p = 2 * pair + n; // fp.npoints-2+n;
-					points_xy[n][0] = fp.xpoints[p];
-					points_xy[n][1] = fp.ypoints[p];
-					pair_slices[n] = pRoi.getPointPosition(p); // works
+					points_xy[nn][0] = fp.xpoints[p];
+					points_xy[nn][1] = fp.ypoints[p];
+					pair_slices[nn] = pRoi.getPointPosition(p); // works
 				}
 				PairwiseOrthoMatch match= new PairwiseOrthoMatch();
 				match.affine = new double[][] {