[paint] Change the image callback

Instead of passing the glyph ID, give
it the image blob, a mimetype, and
glyph extents (if available).

Update all callers.

src/hb-ot-color-cbdt-table.hh

@@ -939,11 +939,15 @@ struct CBDT
 
     bool paint_glyph (hb_font_t *font, hb_codepoint_t glyph, hb_paint_funcs_t *funcs, void *data) const
     {
+      hb_glyph_extents_t extents;
       hb_blob_t *blob = reference_png (font, glyph);
       if (unlikely (blob == hb_blob_get_empty ()))
         return false;
 
-      funcs->image (data, glyph);
+      if (unlikely (!get_extents (font, glyph, &extents)))
+        return false;
+
+      funcs->image (data, blob, "image/png", &extents);
 
       hb_blob_destroy (blob);
       return true;

src/hb-ot-color-sbix-table.hh

@@ -240,11 +240,15 @@ struct sbix
       int x_offset = 0, y_offset = 0;
       unsigned int strike_ppem = 0;
       hb_blob_t *blob = reference_png (font, glyph, &x_offset, &y_offset, &strike_ppem);
+      hb_glyph_extents_t extents;
 
       if (blob == hb_blob_get_empty ())
         return false;
 
-      funcs->image (data, glyph);
+      if (!get_extents (font, glyph, &extents))
+        return false;
+
+      funcs->image (data, blob, "image/png", &extents);
 
       hb_blob_destroy (blob);
       return true;

src/hb-ot-color-svg-table.hh

@@ -103,7 +103,7 @@ struct SVG
       if (blob == hb_blob_get_empty ())
         return false;
 
-      funcs->image (data, glyph);
+      funcs->image (data, blob, "image/svg+xml", nullptr);
 
       hb_blob_destroy (blob);
       return true;

src/hb-paint.cc

@@ -70,7 +70,9 @@ hb_paint_color_nil (hb_paint_funcs_t *funcs, void *paint_data,
 
 static void
 hb_paint_image_nil (hb_paint_funcs_t *funcs, void *paint_data,
-                    hb_codepoint_t glyph,
+                    hb_blob_t *image,
+                    const char *mimetype,
+                    hb_glyph_extents_t *extents,
                     void *user_data) {}
 
 static void
@@ -344,9 +346,11 @@ hb_paint_color (hb_paint_funcs_t *funcs, void *paint_data,
 
 void
 hb_paint_image (hb_paint_funcs_t *funcs, void *paint_data,
-                hb_codepoint_t glyph)
+                hb_blob_t *image,
+                const char *mimetype,
+                hb_glyph_extents_t *extents)
 {
-  funcs->image (paint_data, glyph);
+  funcs->image (paint_data, image, mimetype, extents);
 }
 
 void

src/hb-paint.h

@@ -30,6 +30,7 @@
 #define HB_PAINT_H
 
 #include "hb.h"
+#include "hb-font.h"
 
 HB_BEGIN_DECLS
 
@@ -225,20 +226,27 @@ typedef void (*hb_paint_color_func_t) (hb_paint_funcs_t *funcs,
  * hb_paint_image_func_t:
  * @funcs: paint functions object
  * @paint_data: The data accompanying the paint functions
- * @glyph: the glyph ID
+ * @image: the image data
+ * @mimetype: the mime type for the image data
+ * @extents: (nullable): glyph extents
  * @user_data: user data passed to the hb_font_paint_glyph() call
  *
  * A virtual method for the #hb_paint_funcs_t to paint the
  * glyph image.
  *
  * This method is intended for glyphs with image blobs in the CBDT,
- * sbix or SVG tables.
+ * sbix or SVG tables. The @mimetype identifies the kind of data
+ * that is contained in @image. Possible values include "image/png"
+ * and "image/svg+xml". The glyph extents are provided if available,
+ * and should be used to position the image.
  *
  * Since: REPLACEME
  */
 typedef void (*hb_paint_image_func_t) (hb_paint_funcs_t *funcs,
                                        void *paint_data,
-                                       hb_codepoint_t glyph,
+                                       hb_blob_t *image,
+                                       const char *mimetype,
+                                       hb_glyph_extents_t *extents,
                                        void *user_data);
 
 /**
@@ -684,7 +692,9 @@ hb_paint_color (hb_paint_funcs_t *funcs, void *paint_data,
 
 HB_EXTERN void
 hb_paint_image (hb_paint_funcs_t *funcs, void *paint_data,
-                hb_codepoint_t glyph);
+                hb_blob_t *image,
+                const char *mimetype,
+                hb_glyph_extents_t *extents);
 
 HB_EXTERN void
 hb_paint_linear_gradient (hb_paint_funcs_t *funcs, void *paint_data,

src/hb-paint.hh

@@ -94,9 +94,11 @@ struct hb_paint_funcs_t
                 color_index, alpha,
                 !user_data ? nullptr : user_data->color); }
   void image (void *paint_data,
-              hb_codepoint_t glyph)
+              hb_blob_t *image,
+              const char *mimetype,
+              hb_glyph_extents_t *extents)
   { func.image (this, paint_data,
-                glyph,
+                image, mimetype, extents,
                 !user_data ? nullptr : user_data->image); }
   void linear_gradient (void *paint_data,
                         hb_color_line_t *color_line,

util/hb-test.c

@@ -324,7 +324,9 @@ read_blob (void *closure,
 static void
 paint_image (hb_paint_funcs_t *funcs,
              void *paint_data,
-             hb_codepoint_t glyph,
+             hb_blob_t *blob,
+             const char *mimetype,
+             hb_glyph_extents_t *extents,
              void *user_data)
 {
   paint_data_t *data = user_data;
@@ -332,17 +334,19 @@ paint_image (hb_paint_funcs_t *funcs,
   cairo_surface_t *surface;
   cairo_pattern_t *pattern;
   cairo_matrix_t m;
-  hb_glyph_extents_t extents;
 
-  hb_font_get_glyph_extents (data->font, glyph, &extents);
-  r.blob = hb_ot_color_glyph_reference_png (data->font, glyph);
+  if (strcmp (mimetype, "image/png") != 0)
+    return;
+
+  r.blob = blob;
   r.offset = 0;
   surface = cairo_image_surface_create_from_png_stream (read_blob, &r);
-  hb_blob_destroy (r.blob);
 
   pattern = cairo_pattern_create_for_surface (surface);
   cairo_matrix_init_scale (&m, 1, -1);
-  cairo_matrix_translate (&m, extents.x_bearing, - extents.y_bearing);
+  cairo_matrix_translate (&m,
+                          extents ? extents->x_bearing : 0,
+                          extents ? - extents->y_bearing : 0);
   cairo_pattern_set_matrix (pattern, &m);
   cairo_set_source (data->cr, pattern);