[freetype2-demos] master 840a3953 2/2: [ftmulti] Enable fill rule flag testing.

[Werner Lemberg]

branch: master
commit 840a39535c338715a9f4b12ae231b66a204a4e6f
Author: Alexei Podtelezhnikov <apodtele@gmail.com>
Commit: Alexei Podtelezhnikov <apodtele@gmail.com>

    [ftmulti] Enable fill rule flag testing.
    
    Variation fonts often relay on overlapping contours. To reveal them,
    we enable turning the even-odd fill rule on and off. This flag is
    always off in FreeType by default but supported by the anti-aliased
    renderer.
    
    * src/ftmulti.c (Process_Event): Reassign F3 to fill rule toggle,
    assign Tab to anti-aliasing toggle.
    (Render_Glyph): Tinker with the fill rule flags before rendering.
---
 src/ftmulti.c | 51 +++++++++++++++++++++++++++++++--------------------
 1 file changed, 31 insertions(+), 20 deletions(-)

diff --git a/src/ftmulti.c b/src/ftmulti.c
index 2193118b..67f1e4b3 100644
--- a/src/ftmulti.c
+++ b/src/ftmulti.c
@@ -94,6 +94,7 @@
   static int  hinted    = 1;         /* is glyph hinting active?    */
   static int  grouping  = 1;         /* is axis grouping active?    */
   static int  antialias = 1;         /* is anti-aliasing active?    */
+  static int  fillrule  = 0x0;       /* flip fill flags or not?     */
   static int  overlaps  = 0x0;       /* flip overlap flags or not?  */
   static int  Num;                   /* current first glyph index   */
 
@@ -320,8 +321,9 @@
     if ( glyph->format != FT_GLYPH_FORMAT_BITMAP )
     {
       /* overlap flags mitigate AA rendering artifacts in overlaps */
-      /* by oversampling, toggle the flag to test the effect       */
-      glyph->outline.flags ^= overlaps;
+      /* by oversampling; even-odd fill rule reveals the overlaps; */
+      /* toggle these flag to test the effects                     */
+      glyph->outline.flags ^= overlaps | fillrule;
 
       error = FT_Render_Glyph( glyph, antialias ? FT_RENDER_MODE_NORMAL
                                                 : FT_RENDER_MODE_MONO );
@@ -540,13 +542,15 @@
     grLn();
     grWriteln( "F1, ?       display this help screen" );
     grWriteln( "q, ESC      quit ftmulti" );
+    grLn();
     grWriteln( "F2          toggle axis grouping" );
-    grWriteln( "F3          toggle outline hinting" );
+    grWriteln( "F3          toggle fill rule flags" );
     grWriteln( "F4          toggle overlap flags" );
-    grWriteln( "F5          toggle anti-aliasing" );
+    grWriteln( "F5          toggle outline hinting" );
     grWriteln( "F6          cycle through hinting engines (if available)" );
     grLn();
-    grWriteln( "space       toggle rendering mode" );
+    grWriteln( "Tab         toggle anti-aliasing" );
+    grWriteln( "Space       toggle rendering mode" );
     grLn();
     grWriteln( ", .         previous/next font" );
     grLn();
@@ -613,6 +617,10 @@
       Help();
       break;
 
+    case grKEY( ',' ):
+    case grKEY( '.' ):
+      return (int)event.key;
+
     /* mode keys */
 
     case grKeyF2:
@@ -622,10 +630,11 @@
       set_up_axes();
       break;
 
-    case grKeyF5:
-      antialias  = !antialias;
-      new_header = antialias ? "anti-aliasing is now on"
-                             : "anti-aliasing is now off";
+    case grKeyF3:
+      fillrule  ^= FT_OUTLINE_EVEN_ODD_FILL;
+      new_header = fillrule
+                     ? "fill rule flags are flipped"
+                     : "fill rule flags are unchanged";
       break;
 
     case grKeyF4:
@@ -635,22 +644,12 @@
                      : "overlap flags are unchanged";
       break;
 
-    case grKEY( ',' ):
-    case grKEY( '.' ):
-      return (int)event.key;
-
-    case grKeyF3:
+    case grKeyF5:
       hinted     = !hinted;
       new_header = hinted ? "glyph hinting is now active"
                           : "glyph hinting is now ignored";
       break;
 
-    case grKEY( ' ' ):
-      render_mode ^= 1;
-      new_header   = render_mode ? "rendering all glyphs in font"
-                                 : "rendering test text string";
-      break;
-
     case grKeyF6:
       if ( !strcmp( font_format, "CFF" ) )
         FTDemo_Event_Cff_Hinting_Engine_Change( library,
@@ -668,6 +667,18 @@
         tt_interpreter_version_change();
       break;
 
+    case grKeyTab:
+      antialias  = !antialias;
+      new_header = antialias ? "anti-aliasing is now on"
+                             : "anti-aliasing is now off";
+      break;
+
+    case grKEY( ' ' ):
+      render_mode ^= 1;
+      new_header   = render_mode ? "rendering all glyphs in font"
+                                 : "rendering test text string";
+      break;
+
     /* MM-related keys */
 
     case grKEY( '+' ):