Hunted down hardcoded pixel size thresholds for drawing

Dynamic contrast for netname and pin numbers ('halo' text)
Handle netname drawing even on diagonal tracks

common/drawtxt.cpp

@@ -561,6 +561,38 @@ void DrawGraphicText( EDA_DRAW_PANEL* aPanel,
     }
 }
 
+void DrawGraphicHaloText( EDA_DRAW_PANEL * aPanel,
+                          wxDC * aDC,
+                          const wxPoint &aPos,
+                          enum EDA_COLOR_T aBgColor,
+                          enum EDA_COLOR_T aColor1,
+                          enum EDA_COLOR_T aColor2,
+                          const wxString &aText,
+                          int aOrient,
+                          const wxSize &aSize,
+                          enum EDA_TEXT_HJUSTIFY_T aH_justify,
+                          enum EDA_TEXT_VJUSTIFY_T aV_justify,
+                          int aWidth,
+                          bool aItalic,
+                          bool aBold,
+                          void (*aCallback)( int x0, int y0, int xf, int yf ),
+                          PLOTTER * aPlotter )
+{
+    // Swap color if contrast would be better
+    if( ColorIsLight( aBgColor ) ) {
+        EDA_COLOR_T c = aColor1;
+        aColor1 = aColor2;
+        aColor2 = c;
+    }
+
+    DrawGraphicText( aPanel, aDC, aPos, aColor1, aText, aOrient, aSize, 
+                     aH_justify, aV_justify, aWidth, aItalic, aBold, 
+                     aCallback, aPlotter );
+    
+    DrawGraphicText( aPanel, aDC, aPos, aColor2, aText, aOrient, aSize, 
+                     aH_justify, aV_justify, aWidth / 4, aItalic, aBold, 
+                     aCallback, aPlotter );
+}
 
 /**
  * Function PlotGraphicText

common/gr_basic.cpp

@@ -1512,6 +1512,14 @@ EDA_COLOR_T ColorByName( const wxChar *aName )
     return UNSPECIFIED_COLOR;
 }
 
+bool ColorIsLight( EDA_COLOR_T aColor )
+{
+    const StructColors &c = g_ColorRefs[ColorGetBase( aColor )];
+    int r = c.m_Red;
+    int g = c.m_Green;
+    int b = c.m_Blue;
+    return ((r * r) + (g * g) + (b * b)) > (128 * 128 * 3);
+}
 
 EDA_COLOR_T ColorFindNearest( const wxColour &aColor )
 {

include/colors.h

@@ -139,6 +139,12 @@ EDA_COLOR_T ColorByName( const wxChar *aName );
 /// Find the nearest color match
 EDA_COLOR_T ColorFindNearest( const wxColour &aColor );
 
+/**
+ * Check if a color is light i.e. if black would be more readable than
+ * white on it
+ */
+bool ColorIsLight( EDA_COLOR_T aColor );
+
 inline const wxChar *ColorGetName( EDA_COLOR_T aColor )
 {
     EDA_COLOR_T base = ColorGetBase( aColor );

include/drawtxt.h

@@ -88,4 +88,27 @@ void DrawGraphicText( EDA_DRAW_PANEL * aPanel,
                       PLOTTER * aPlotter = NULL );
 
 
+/**
+ * Draw graphic text with a border, so that it can be read on different
+ * backgrounds. See DrawGraphicText for most of the parameters.
+ * If aBgColor is a dark color text is drawn in aColor2 with aColor1
+ * border; otherwise colors are swapped.
+ */
+void DrawGraphicHaloText( EDA_DRAW_PANEL * aPanel,
+                          wxDC * aDC,
+                          const wxPoint &aPos,
+                          enum EDA_COLOR_T aBgColor,
+                          enum EDA_COLOR_T aColor1,
+                          enum EDA_COLOR_T aColor2,
+                          const wxString &aText,
+                          int aOrient,
+                          const wxSize &aSize,
+                          enum EDA_TEXT_HJUSTIFY_T aH_justify,
+                          enum EDA_TEXT_VJUSTIFY_T aV_justify,
+                          int aWidth,
+                          bool aItalic,
+                          bool aBold,
+                          void (*aCallback)( int x0, int y0, int xf, int yf ) = NULL,
+                          PLOTTER * aPlotter = NULL );
+
 #endif /* __INCLUDE__DRAWTXT_H__ */

pcbnew/class_dimension.cpp

@@ -350,7 +350,7 @@ void DIMENSION::Draw( EDA_DRAW_PANEL* panel, wxDC* DC, GR_DRAWMODE mode_color,
     typeaff = DisplayOpt.DisplayDrawItems;
     width   = m_Width;
 
-    if( DC->LogicalToDeviceXRel( width ) < 2 )
+    if( DC->LogicalToDeviceXRel( width ) <= MIN_DRAW_WIDTH )
         typeaff = LINE;
 
     switch( typeaff )

pcbnew/class_drawsegment.cpp

@@ -209,7 +209,7 @@ void DRAWSEGMENT::Draw( EDA_DRAW_PANEL* panel, wxDC* DC, GR_DRAWMODE draw_mode,
     if( m_Flags & FORCE_SKETCH )
         mode = SKETCH;
 
-    if( l_trace < DC->DeviceToLogicalXRel( MIN_DRAW_WIDTH ) )
+    if( DC->LogicalToDeviceXRel( l_trace ) <= MIN_DRAW_WIDTH )
         mode = LINE;
 
     switch( m_Shape )

pcbnew/class_edge_mod.cpp

@@ -146,7 +146,7 @@ void EDGE_MODULE::Draw( EDA_DRAW_PANEL* panel, wxDC* DC, GR_DRAWMODE draw_mode,
             typeaff = SKETCH;
     }
 
-    if( DC->LogicalToDeviceXRel( m_Width ) < MIN_DRAW_WIDTH )
+    if( DC->LogicalToDeviceXRel( m_Width ) <= MIN_DRAW_WIDTH )
         typeaff = LINE;
 
     switch( type_trace )

pcbnew/class_mire.cpp

@@ -115,7 +115,7 @@ void PCB_TARGET::Draw( EDA_DRAW_PANEL* panel, wxDC* DC, GR_DRAWMODE mode_color,
     typeaff = DisplayOpt.DisplayDrawItems;
     width   = m_Width;
 
-    if( DC->LogicalToDeviceXRel( width ) < 2 )
+    if( DC->LogicalToDeviceXRel( width ) <= MIN_DRAW_WIDTH )
         typeaff = LINE;
 
     radius = m_Size / 3;

pcbnew/class_pad_draw_functions.cpp

@@ -433,7 +433,7 @@ void D_PAD::DrawShape( EDA_RECT* aClipBox, wxDC* aDC, PAD_DRAWINFO& aDrawInfo )
         switch( m_DrillShape )
         {
         case PAD_CIRCLE:
-            if( aDC->LogicalToDeviceXRel( hole ) > 1 )
+            if( aDC->LogicalToDeviceXRel( hole ) > MIN_DRAW_WIDTH )
                 GRFilledCircle( aClipBox, aDC, holepos.x, holepos.y, hole, 0,
                                 aDrawInfo.m_Color, hole_color );
             break;
@@ -487,6 +487,11 @@ void D_PAD::DrawShape( EDA_RECT* aClipBox, wxDC* aDC, PAD_DRAWINFO& aDrawInfo )
                     holepos.x - dx0, holepos.y + dx0, 0, nc_color );
     }
 
+    if( aDrawInfo.m_DrawMode != GR_XOR )
+        GRSetDrawMode( aDC, GR_COPY );
+    else
+        GRSetDrawMode( aDC, GR_XOR );
+
     // Draw the pad number
     if( !aDrawInfo.m_Display_padnum && !aDrawInfo.m_Display_netname )
         return;
@@ -542,15 +547,17 @@ void D_PAD::DrawShape( EDA_RECT* aClipBox, wxDC* aDC, PAD_DRAWINFO& aDrawInfo )
         numpad_len = std::max( numpad_len, MIN_CHAR_COUNT );
 
         tsize = std::min( AreaSize.y, AreaSize.x / numpad_len );
-        #define CHAR_SIZE_MIN 5
 
-        if( aDC->LogicalToDeviceXRel( tsize ) >= CHAR_SIZE_MIN ) // Not drawable when size too small.
+        if( aDC->LogicalToDeviceXRel( tsize ) >= MIN_TEXT_SIZE ) // Not drawable when size too small.
         {
             // tsize reserve room for marges and segments thickness
-            tsize = (int) ( tsize * 0.8 );
-            DrawGraphicText( aDrawInfo.m_DrawPanel, aDC, tpos, WHITE, buffer, t_angle,
-                             wxSize( tsize, tsize ), GR_TEXT_HJUSTIFY_CENTER,
-                             GR_TEXT_VJUSTIFY_CENTER, tsize / 7, false, false );
+            tsize = ( tsize * 8 ) / 10;
+            DrawGraphicHaloText( aDrawInfo.m_DrawPanel, aDC, tpos, 
+                                 aDrawInfo.m_Color, BLACK, WHITE, 
+                                 buffer, t_angle,
+                                 wxSize( tsize , tsize ), GR_TEXT_HJUSTIFY_CENTER,
+                                 GR_TEXT_VJUSTIFY_CENTER, tsize / 7, false, false );
+
         }
     }
 
@@ -561,7 +568,7 @@ void D_PAD::DrawShape( EDA_RECT* aClipBox, wxDC* aDC, PAD_DRAWINFO& aDrawInfo )
     shortname_len = std::max( shortname_len, MIN_CHAR_COUNT );
     tsize = std::min( AreaSize.y, AreaSize.x / shortname_len );
 
-    if( aDC->LogicalToDeviceXRel( tsize ) >= CHAR_SIZE_MIN )  // Not drawable in size too small.
+    if( aDC->LogicalToDeviceXRel( tsize ) >= MIN_TEXT_SIZE )  // Not drawable in size too small.
     {
         tpos = tpos0;
 
@@ -571,10 +578,12 @@ void D_PAD::DrawShape( EDA_RECT* aClipBox, wxDC* aDC, PAD_DRAWINFO& aDrawInfo )
         RotatePoint( &tpos, shape_pos, angle );
 
         // tsize reserve room for marges and segments thickness
-        tsize = (int) ( tsize * 0.8 );
-        DrawGraphicText( aDrawInfo.m_DrawPanel, aDC, tpos, WHITE, m_ShortNetname, t_angle,
-                         wxSize( tsize, tsize ), GR_TEXT_HJUSTIFY_CENTER,
-                         GR_TEXT_VJUSTIFY_CENTER, tsize / 7, false, false );
+        tsize = ( tsize * 8 ) / 10;
+        DrawGraphicHaloText( aDrawInfo.m_DrawPanel, aDC, tpos, 
+                             aDrawInfo.m_Color, BLACK, WHITE, 
+                             m_ShortNetname, t_angle,
+                             wxSize( tsize, tsize ), GR_TEXT_HJUSTIFY_CENTER,
+                             GR_TEXT_VJUSTIFY_CENTER, tsize / 7, false, false );
     }
 }
 

pcbnew/class_text_mod.cpp

@@ -275,7 +275,7 @@ void TEXTE_MODULE::Draw( EDA_DRAW_PANEL* panel, wxDC* DC, GR_DRAWMODE draw_mode,
     PCB_BASE_FRAME* frame = (PCB_BASE_FRAME*) panel->GetParent();
     int width = m_Thickness;
     if( ( frame->m_DisplayModText == LINE )
-        || ( DC->LogicalToDeviceXRel( width ) < MIN_DRAW_WIDTH ) )
+        || ( DC->LogicalToDeviceXRel( width ) <= MIN_DRAW_WIDTH ) )
         width = 0;
     else if( frame->m_DisplayModText == SKETCH )
         width = -width;

pcbnew/class_track.h

@@ -50,6 +50,7 @@ class MSG_PANEL_ITEM;
 
 #define UNDEFINED_DRILL_DIAMETER  -1       //< Undefined via drill diameter.
 
+#define MIN_VIA_DRAW_SIZE          4       /// Minimum size in pixel for full drawing
 
 /**
  * Function GetTrace