Merge pull request #4044 from harfbuzz/custom-palette

Custom palette

docs/harfbuzz-sections.txt

@@ -225,6 +225,8 @@ hb_draw_state_t
 
 <SECTION>
 <FILE>hb-paint</FILE>
+HB_PAINT_PALETTE_INDEX_CUSTOM
+
 hb_paint_funcs_t
 hb_paint_funcs_create
 hb_paint_funcs_get_empty
@@ -270,6 +272,8 @@ hb_paint_push_group_func_t
 hb_paint_funcs_set_push_group_func
 hb_paint_pop_group_func_t
 hb_paint_funcs_set_pop_group_func
+hb_paint_custom_palette_color_func_t
+hb_paint_funcs_set_custom_palette_color_func
 
 hb_paint_push_transform
 hb_paint_pop_transform
@@ -283,6 +287,7 @@ hb_paint_radial_gradient
 hb_paint_sweep_gradient
 hb_paint_push_group
 hb_paint_pop_group
+hb_paint_custom_palette_color
 </SECTION>
 
 <SECTION>

src/OT/Color/COLR/COLR.hh

@@ -67,7 +67,7 @@ public:
   hb_paint_funcs_t *funcs;
   void *data;
   hb_font_t *font;
-  unsigned int palette;
+  unsigned int palette_index;
   hb_color_t foreground;
   VarStoreInstancer &instancer;
   int depth_left = HB_MAX_NESTING_LEVEL;
@@ -84,7 +84,7 @@ public:
     funcs (funcs_),
     data (data_),
     font (font_),
-    palette (palette_),
+    palette_index (palette_),
     foreground (foreground_),
     instancer (instancer_)
   { }
@@ -97,10 +97,16 @@ public:
 
     if (color_index != 0xffff)
     {
-      unsigned int clen = 1;
+      if (palette_index != HB_PAINT_PALETTE_INDEX_CUSTOM)
-      hb_face_t *face = hb_font_get_face (font);
+      {
+	unsigned int clen = 1;
+	hb_face_t *face = hb_font_get_face (font);
+
+	hb_ot_color_palette_get_colors (face, palette_index, color_index, &clen, &color);
+      }
+      else
+	color = funcs->custom_palette_color (data, color_index);
 
-      hb_ot_color_palette_get_colors (face, palette, color_index, &clen, &color);
       *is_foreground = false;
     }
 
@@ -2033,12 +2039,12 @@ struct COLR
   }
 
   bool
-  paint_glyph (hb_font_t *font, hb_codepoint_t glyph, hb_paint_funcs_t *funcs, void *data, unsigned int palette, hb_color_t foreground, bool clip = true) const
+  paint_glyph (hb_font_t *font, hb_codepoint_t glyph, hb_paint_funcs_t *funcs, void *data, unsigned int palette_index, hb_color_t foreground, bool clip = true) const
   {
     VarStoreInstancer instancer (this+varStore,
 	                         this+varIdxMap,
 	                         hb_array (font->coords, font->num_coords));
-    hb_paint_context_t c (this, funcs, data, font, palette, foreground, instancer);
+    hb_paint_context_t c (this, funcs, data, font, palette_index, foreground, instancer);
 
     if (version == 1)
     {
@@ -2071,7 +2077,7 @@ struct COLR
 
 	    paint_glyph (font, glyph,
 			 extents_funcs, &extents_data,
-			 palette, foreground,
+			 palette_index, foreground,
 			 false);
 
 	    hb_extents_t extents = extents_data.get_extents ();

src/hb-font.cc

@@ -1429,7 +1429,7 @@ hb_font_draw_glyph (hb_font_t *font,
  * @glyph: The glyph ID
  * @pfuncs: #hb_paint_funcs_t to paint with
  * @paint_data: User data to pass to paint callbacks
- * @palette: The index of the font's color palette to use
+ * @palette_index: The index of the font's color palette to use
  * @foreground: The foreground color, unpremultipled
  *
  * Paints the glyph.
@@ -1439,8 +1439,9 @@ hb_font_draw_glyph (hb_font_t *font,
  * to them.
  *
  * If the font has color palettes (see hb_ot_color_has_palettes()),
- * then @palette selects the palette to use. If the font doesn't
+ * then @palette_index selects the palette to use. If the font only
- * have palettes, passing 0 is fine.
+ * has one palette, this will be 0.  Use %HB_PAINT_PALETTE_INDEX_CUSTOM
+ * for custom palette.
  *
  * Since: REPLACEME
  */
@@ -1448,10 +1449,10 @@ void
 hb_font_paint_glyph (hb_font_t *font,
                      hb_codepoint_t glyph,
                      hb_paint_funcs_t *pfuncs, void *paint_data,
-                     unsigned int palette,
+                     unsigned int palette_index,
                      hb_color_t foreground)
 {
-  font->paint_glyph (glyph, pfuncs, paint_data, palette, foreground);
+  font->paint_glyph (glyph, pfuncs, paint_data, palette_index, foreground);
 }
 
 /* A bit higher-level, and with fallback */

src/hb-font.h

@@ -531,7 +531,7 @@ typedef void (*hb_font_draw_glyph_func_t) (hb_font_t *font, void *font_data,
  * @glyph: The glyph ID to query
  * @paint_funcs: The paint functions to use
  * @paint_data: The data accompanying the paint functions
- * @palette: The color palette to use
+ * @palette_index: The color palette to use
  * @foreground: The foreground color
  * @user_data: User data pointer passed by the caller
  *
@@ -542,7 +542,7 @@ typedef void (*hb_font_draw_glyph_func_t) (hb_font_t *font, void *font_data,
 typedef void (*hb_font_paint_glyph_func_t) (hb_font_t *font, void *font_data,
                                             hb_codepoint_t glyph,
                                             hb_paint_funcs_t *paint_funcs, void *paint_data,
-                                            unsigned int palette,
+                                            unsigned int palette_index,
                                             hb_color_t foreground,
                                             void *user_data);
 
@@ -950,7 +950,7 @@ HB_EXTERN void
 hb_font_paint_glyph (hb_font_t *font,
                      hb_codepoint_t glyph,
                      hb_paint_funcs_t *pfuncs, void *paint_data,
-                     unsigned int palette,
+                     unsigned int palette_index,
                      hb_color_t foreground);
 
 /* high-level funcs, with fallback */

src/hb-ft-colr.hh

@@ -83,10 +83,11 @@ struct hb_ft_paint_context_t
 			 hb_font_t *font,
 			 hb_paint_funcs_t *paint_funcs, void *paint_data,
 			 FT_Color *palette,
+			 unsigned palette_index,
 			 hb_color_t foreground) :
     ft_font (ft_font), font(font),
     funcs (paint_funcs), data (paint_data),
-    palette (palette), foreground (foreground) {}
+    palette (palette), palette_index (palette_index), foreground (foreground) {}
 
   void recurse (FT_OpaquePaint paint)
   {
@@ -102,6 +103,7 @@ struct hb_ft_paint_context_t
   hb_paint_funcs_t *funcs;
   void *data;
   FT_Color *palette;
+  unsigned palette_index;
   hb_color_t foreground;
   int depth_left = HB_MAX_NESTING_LEVEL;
   int edge_count = HB_COLRV1_MAX_EDGE_COUNT;
@@ -154,11 +156,22 @@ _hb_ft_color_line_get_color_stops (hb_color_line_t *color_line,
 				       (hb_color_get_alpha (c->foreground) * stop.color.alpha) >> 14);
       else
       {
-	FT_Color ft_color = c->palette[stop.color.palette_index];
+        if (c->palette_index == HB_PAINT_PALETTE_INDEX_CUSTOM)
-	color_stops->color = HB_COLOR (ft_color.blue,
+	{
-				       ft_color.green,
+	  hb_color_t color = c->funcs->custom_palette_color (c->data, stop.color.palette_index);
-				       ft_color.red,
+	  color_stops->color = HB_COLOR (hb_color_get_blue (color),
-				       (ft_color.alpha * stop.color.alpha) >> 14);
+					 hb_color_get_green (color),
+					 hb_color_get_red (color),
+					 (hb_color_get_alpha (color) * stop.color.alpha) >> 14);
+	}
+	else
+	{
+	  FT_Color ft_color = c->palette[stop.color.palette_index];
+	  color_stops->color = HB_COLOR (ft_color.blue,
+					 ft_color.green,
+					 ft_color.red,
+					 (ft_color.alpha * stop.color.alpha) >> 14);
+	}
       }
 
       color_stops++;
@@ -224,11 +237,22 @@ _hb_ft_paint (hb_ft_paint_context_t *c,
 			  (hb_color_get_alpha (c->foreground) * paint.u.solid.color.alpha) >> 14);
       else
       {
-	FT_Color ft_color = c->palette[paint.u.solid.color.palette_index];
+        if (c->palette_index == HB_PAINT_PALETTE_INDEX_CUSTOM)
-	color = HB_COLOR (ft_color.blue,
+	{
-			  ft_color.green,
+	  color = c->funcs->custom_palette_color (c->data, paint.u.solid.color.palette_index);
-			  ft_color.red,
+	  color = HB_COLOR (hb_color_get_blue (color),
-			  (ft_color.alpha * paint.u.solid.color.alpha) >> 14);
+			    hb_color_get_green (color),
+			    hb_color_get_red (color),
+			    (hb_color_get_alpha (color) * paint.u.solid.color.alpha) >> 14);
+	}
+	else
+	{
+	  FT_Color ft_color = c->palette[paint.u.solid.color.palette_index];
+	  color = HB_COLOR (ft_color.blue,
+			    ft_color.green,
+			    ft_color.red,
+			    (ft_color.alpha * paint.u.solid.color.alpha) >> 14);
+	}
       }
       c->funcs->color (c->data, is_foreground, color);
     }
@@ -450,7 +474,7 @@ hb_ft_paint_glyph_colr (hb_font_t *font,
   {
     hb_ft_paint_context_t c (ft_font, font,
 			     paint_funcs, paint_data,
-			     palette, foreground);
+			     palette, palette_index, foreground);
 
     bool is_bounded = true;
     FT_ClipBox clip_box;
@@ -473,7 +497,7 @@ hb_ft_paint_glyph_colr (hb_font_t *font,
       hb_paint_extents_context_t extents_data;
       hb_ft_paint_context_t ce (ft_font, font,
 			        extents_funcs, &extents_data,
-			        palette, foreground);
+			        palette, palette_index, foreground);
       ce.funcs->push_root_transform (ce.data, font);
       ce.recurse (paint);
       ce.funcs->pop_transform (ce.data);

src/hb-paint.cc

@@ -117,6 +117,11 @@ hb_paint_pop_group_nil (hb_paint_funcs_t *funcs, void *paint_data,
                         hb_paint_composite_mode_t mode,
                         void *user_data) {}
 
+static hb_color_t
+hb_paint_custom_palette_color_nil (hb_paint_funcs_t *funcs, void *paint_data,
+                                   unsigned int color_index,
+                                   void *user_data) { return HB_COLOR(0,0,0,0); }
+
 static bool
 _hb_paint_funcs_set_preamble (hb_paint_funcs_t  *funcs,
                              bool                func_is_null,
@@ -673,5 +678,23 @@ hb_paint_pop_group (hb_paint_funcs_t *funcs, void *paint_data,
   funcs->pop_group (paint_data, mode);
 }
 
+/**
+ * hb_paint_custom_palette_color:
+ * @funcs: paint functions
+ * @paint_data: associated data passed by the caller
+ * @color_index: color index
+ *
+ * Gets the custom palette color for @color_index.
+ *
+ * Return value: the custom color
+ *
+ * Since: REPLACEME
+ */
+hb_color_t
+hb_paint_custom_palette_color (hb_paint_funcs_t *funcs, void *paint_data,
+                               unsigned int color_index)
+{
+  return funcs->custom_palette_color (paint_data, color_index);
+}
 
 #endif

src/hb-paint.h

@@ -33,6 +33,18 @@
 
 HB_BEGIN_DECLS
 
+
+/**
+ * HB_PAINT_PALETTE_INDEX_CUSTOM
+ *
+ * A palette index signifying that custom colors are in use.
+ * Such colors are fetched from the client using the
+ * custom-palette-color callback of the paint functions.
+ *
+ * Since: REPLACEME
+ **/
+#define HB_PAINT_PALETTE_INDEX_CUSTOM 0xFFFFFFFF
+
 /**
  * hb_paint_funcs_t:
  *
@@ -655,6 +667,25 @@ typedef void (*hb_paint_pop_group_func_t) (hb_paint_funcs_t *funcs,
                                            hb_paint_composite_mode_t mode,
                                            void *user_data);
 
+/**
+ * hb_paint_custom_palette_color_func_t:
+ * @funcs: paint functions object
+ * @paint_data: The data accompanying the paint functions in hb_font_paint_glyph()
+ * @color_index: the color index
+ * @user_data: User data pointer passed to hb_paint_funcs_set_pop_group_func()
+ *
+ * A virtual method for the #hb_paint_funcs_t to fetch a color from the custom
+ * color palette.
+ *
+ * Return value: the color
+ * Since: REPLACEME
+ */
+typedef hb_color_t (*hb_paint_custom_palette_color_func_t) (hb_paint_funcs_t *funcs,
+                                                            void *paint_data,
+                                                            unsigned int color_index,
+                                                            void *user_data);
+
+
 /**
  * hb_paint_funcs_set_push_transform_func:
  * @funcs: A paint functions struct
@@ -859,6 +890,22 @@ hb_paint_funcs_set_pop_group_func (hb_paint_funcs_t          *funcs,
                                    void                       *user_data,
                                    hb_destroy_func_t           destroy);
 
+/**
+ * hb_paint_funcs_set_custom_palette_color_func:
+ * @funcs: A paint functions struct
+ * @func: (closure user_data) (destroy destroy) (scope notified): The custom-palette-color callback
+ * @user_data: Data to pass to @func
+ * @destroy: (nullable): Function to call when @user_data is no longer needed
+ *
+ * Sets the custom-palette-color callback on the paint functions struct.
+ *
+ * Since: REPLACEME
+ */
+HB_EXTERN void
+hb_paint_funcs_set_custom_palette_color_func (hb_paint_funcs_t                     *funcs,
+                                              hb_paint_custom_palette_color_func_t  func,
+                                              void                                 *user_data,
+                                              hb_destroy_func_t                     destroy);
 /*
  * Manual API
  */
@@ -927,6 +974,10 @@ HB_EXTERN void
 hb_paint_pop_group (hb_paint_funcs_t *funcs, void *paint_data,
                     hb_paint_composite_mode_t mode);
 
+HB_EXTERN hb_color_t
+hb_paint_custom_palette_color (hb_paint_funcs_t *funcs, void *paint_data,
+                               unsigned int color_index);
+
 HB_END_DECLS
 
 #endif  /* HB_PAINT_H */

src/hb-paint.hh

@@ -42,6 +42,7 @@
   HB_PAINT_FUNC_IMPLEMENT (sweep_gradient) \
   HB_PAINT_FUNC_IMPLEMENT (push_group) \
   HB_PAINT_FUNC_IMPLEMENT (pop_group) \
+  HB_PAINT_FUNC_IMPLEMENT (custom_palette_color) \
   /* ^--- Add new callbacks here */
 
 struct hb_paint_funcs_t
@@ -137,6 +138,11 @@ struct hb_paint_funcs_t
   { func.pop_group (this, paint_data,
                     mode,
                     !user_data ? nullptr : user_data->pop_group); }
+  hb_color_t custom_palette_color (void *paint_data,
+                             unsigned int color_index)
+  { return func.custom_palette_color (this, paint_data,
+                                      color_index,
+                                      !user_data ? nullptr : user_data->custom_palette_color); }
 
 
   /* Internal specializations. */