[paint] Docs

docs/harfbuzz-sections.txt

@@ -225,8 +225,6 @@ 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

src/hb-paint.cc

@@ -684,10 +684,11 @@ hb_paint_pop_group (hb_paint_funcs_t *funcs, void *paint_data,
  * @funcs: paint functions
  * @paint_data: associated data passed by the caller
  * @color_index: color index
+ * @color: (out): fetched color
  *
  * Gets the custom palette color for @color_index.
  *
- * Return value: the custom color
+ * Return value: `true` if found, `false` otherwise
  *
  * Since: REPLACEME
  */

src/hb-paint.h

@@ -661,12 +661,14 @@ typedef void (*hb_paint_pop_group_func_t) (hb_paint_funcs_t *funcs,
  * @funcs: paint functions object
  * @paint_data: The data accompanying the paint functions in hb_font_paint_glyph()
  * @color_index: the color index
+ * @color: (out): fetched color
  * @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
+ * Return value: `true` if found, `false` otherwise
+ *
  * Since: REPLACEME
  */
 typedef hb_bool_t (*hb_paint_custom_palette_color_func_t) (hb_paint_funcs_t *funcs,