[freetype2-demos] master b786a43: [graph] Fix color management bugs including `ftmulti'.

[Alexei Podtelezhnikov]

branch: master
commit b786a4313ca0cae72e35fbec531bac9ac0ceca08
Author: Alexei Podtelezhnikov <apodtele@gmail.com>
Commit: Alexei Podtelezhnikov <apodtele@gmail.com>

    [graph] Fix color management bugs including `ftmulti'.
    
    * graph/gblblit.c (grSetTargetPenBrush): New function to manage color
    and other parameters required for direct rendering.
    (grBlitGlyphToSurface): Use it here to decode color only.
    * src/ftcommon.h (FTDemo_Sketch_Glyph_Color): Use it here in full.
    * graph/graph.h: Update docs.
---
 ChangeLog       |  10 ++++++
 graph/gblblit.c | 102 ++++++++++++++++++++++++++++++++++++--------------------
 graph/graph.h   |  23 +++++++++++++
 src/ftcommon.c  |  30 +----------------
 4 files changed, 100 insertions(+), 65 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index f4ed6c9..4f48686 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,13 @@
+2020-06-04  Alexei Podtelezhnikov  <apodtele@gmail.com>
+
+       [graph] Fix color management bugs including `ftmulti'.
+
+       * graph/gblblit.c (grSetTargetPenBrush): New function to manage color
+       and other parameters required for direct rendering.
+       (grBlitGlyphToSurface): Use it here to decode color only.
+       * src/ftcommon.h (FTDemo_Sketch_Glyph_Color): Use it here in full.
+       * graph/graph.h: Update docs.
+
 2020-06-01  Alexei Podtelezhnikov  <apodtele@gmail.com>
 
        [ftgrid,ftstring,ftview] Avoid uninitialized `event.type'.
diff --git a/graph/gblblit.c b/graph/gblblit.c
index b5e30f7..a03821a 100644
--- a/graph/gblblit.c
+++ b/graph/gblblit.c
@@ -61,6 +61,8 @@
 
 #define  GRGB_TO_GRAY8(r,g,b)  ( (unsigned char)( ( 2*(r) + 7*(g) + (b) ) / 10 
) )
 
+#define  GGRAY8_TO_RGB24(p)    GRGB_PACK(p,p,p)
+
 #define  GRGB24_TO_GRAY8(p)   ( (unsigned char)( ( 2*( ((p) >> 16) & 0xFF ) +  
       \
                                                    7*( ((p) >>  8) & 0xFF ) +  
       \
                                                      ( ((p))       & 0xFF ) ) 
/ 10 ) )
@@ -345,6 +347,67 @@ gblender_blit_init( GBlenderBlit           blit,
 }
 
 
+GBLENDER_APIDEF( void )
+grSetTargetGamma( grBitmap*  target,
+                  double     gamma )
+{
+  grSurface*  surface = (grSurface*)target;
+
+
+  gblender_init( surface->gblender, gamma );
+}
+
+
+GBLENDER_APIDEF( void )
+grSetTargetPenBrush( grBitmap*  target,
+                     int        x,
+                     int        y,
+                     grColor    color )
+{
+  grSurface*  surface = (grSurface*)target;
+
+
+  surface->origin = target->buffer;
+  if ( target->pitch < 0 )
+    surface->origin += ( y - target->rows ) * target->pitch;
+  else
+    surface->origin += ( y - 1 ) * target->pitch;
+
+  switch ( target->mode )
+  {
+  case gr_pixel_mode_gray:
+    surface->origin    += x;
+    surface->gray_spans = _gblender_spans_gray8;
+    surface->gcolor     = GGRAY8_TO_RGB24( color.value );
+    break;
+  case gr_pixel_mode_rgb565:
+    surface->origin    += x * 2;
+    surface->gray_spans = _gblender_spans_rgb565;
+    surface->gcolor     = GRGB565_TO_RGB24( color.value );
+    break;
+  case gr_pixel_mode_rgb24:
+    surface->origin    += x * 3;
+    surface->gray_spans = _gblender_spans_rgb24;
+    surface->gcolor     = GRGB_PACK( color.chroma[0],
+                                     color.chroma[1],
+                                     color.chroma[2] );
+    break;
+  case gr_pixel_mode_rgb32:
+    surface->origin    += x * 4;
+    surface->gray_spans = _gblender_spans_rgb32;
+    surface->gcolor     = GRGB_PACK( color.chroma[0],
+                                     color.chroma[1],
+                                     color.chroma[2] );
+    break;
+  default:
+    (void)_gblender_spans_bgr565;  /* unused */
+    surface->origin     = NULL;
+    surface->gray_spans = (grSpanFunc)NULL;
+    surface->gcolor     = 0;
+  }
+}
+
+
 GBLENDER_APIDEF( int )
 grBlitGlyphToSurface( grSurface*  surface,
                       grBitmap*   glyph,
@@ -353,7 +416,6 @@ grBlitGlyphToSurface( grSurface*  surface,
                       grColor     color )
 {
   GBlenderBlitRec       gblit[1];
-  GBlenderPixel         gcolor;
 
 
   /* check arguments */
@@ -377,41 +439,9 @@ grBlitGlyphToSurface( grSurface*  surface,
     return -1;
   }
 
-  gcolor = ((GBlenderPixel)color.chroma[0] << 16) |
-           ((GBlenderPixel)color.chroma[1] << 8 ) |
-           ((GBlenderPixel)color.chroma[2]      ) ;
+  /* this is not a direct mode but we need to decode color */
+  grSetTargetPenBrush( (grBitmap*)surface, 0, 0, color );
 
-  gblender_blit_run( gblit, gcolor );
+  gblender_blit_run( gblit, surface->gcolor );
   return 1;
 }
-
-
-GBLENDER_APIDEF( void )
-grSetTargetGamma( grBitmap*  target,
-                  double     gamma )
-{
-  grSurface*  surface = (grSurface*)target;
-
-
-  gblender_init( surface->gblender, gamma );
-
-  /* not related to gamma but needs to be set */
-  switch ( target->mode )
-  {
-  case gr_pixel_mode_gray:
-    surface->gray_spans = _gblender_spans_gray8;
-    break;
-  case gr_pixel_mode_rgb32:
-    surface->gray_spans = _gblender_spans_rgb32;
-    break;
-  case gr_pixel_mode_rgb24:
-    surface->gray_spans = _gblender_spans_rgb24;
-    break;
-  case gr_pixel_mode_rgb565:
-    surface->gray_spans = _gblender_spans_rgb565;
-    break;
-  default:
-    (void)_gblender_spans_bgr565;  /* unused */
-    surface->gray_spans = (grSpanFunc)0;
-  }
-}
diff --git a/graph/graph.h b/graph/graph.h
index 357bfb1..ce681a3 100644
--- a/graph/graph.h
+++ b/graph/graph.h
@@ -667,6 +667,7 @@
   *    blit glyphs
   *
   * <Input>
+  *    target     :: handle to target bitmap/surface
   *    gamma      :: gamma value. <= 0 to select sRGB transfer function
   *
   **********************************************************************/
@@ -674,6 +675,28 @@
   extern
   void  grSetTargetGamma( grBitmap*  target, double  gamma_value );
 
+
+ /**********************************************************************
+  *
+  * <Function>
+  *    grSetTargetPenBrush
+  *
+  * <Description>
+  *    set the pen position and brush color as required for direct mode.
+  *
+  * <Input>
+  *    target     :: handle to target bitmap/surface
+  *    x, y       :: pen position
+  *    color      :: color as defined by grFindColor
+  *
+  **********************************************************************/
+
+  extern
+  void  grSetTargetPenBrush( grBitmap*  target,
+                             int        x,
+                             int        y,
+                             grColor    color );
+
 /* */
 
 #endif /* GRAPH_H_ */
diff --git a/src/ftcommon.c b/src/ftcommon.c
index 8f01264..48c0d9b 100644
--- a/src/ftcommon.c
+++ b/src/ftcommon.c
@@ -1771,7 +1771,6 @@
   {
     grSurface*        surface = (grSurface*)display->surface;
     grBitmap*         target = display->bitmap;
-    unsigned char*    origin;
     FT_Outline*       outline;
     FT_Raster_Params  params;
 
@@ -1779,35 +1778,8 @@
     if ( glyph->format != FT_GLYPH_FORMAT_OUTLINE )
       return FT_Err_Ok;
 
-    origin = target->buffer;
-    if ( target->pitch < 0 )
-      origin += ( y - target->rows ) * target->pitch;
-    else
-      origin += ( y - 1 ) * target->pitch;
-
-    switch ( target->mode )
-    {
-    case gr_pixel_mode_gray:
-      origin += x;
-      break;
-    case gr_pixel_mode_rgb565:
-      origin += x * 2;
-      break;
-    case gr_pixel_mode_rgb24:
-      origin += x * 3;
-      break;
-    case gr_pixel_mode_rgb32:
-      origin += x * 4;
-      break;
-    default:
-      fprintf( stderr, "Unsupported target\n" );
-      return FT_Err_Ok;
-    }
+    grSetTargetPenBrush( target, x, y, color );
 
-    surface->origin = origin;
-    surface->gcolor = ((GBlenderPixel)color.chroma[0] << 16) |
-                      ((GBlenderPixel)color.chroma[1] << 8 ) |
-                      ((GBlenderPixel)color.chroma[2]      ) ;
     outline = &((FT_OutlineGlyph)glyph)->outline;
 
     params.source        = outline;