[sfnt] Add 'COLR' v1 API to retrieve color layers (#59703).
* src/sfnt/ttcolr.c (tt_face_get_paint_layers): New function to get
the layers of a `PaintColrLayers` table in the font, using an
`FT_LayerIterator` from an `FT_PaintColrLayers` object retrieved via
`tt_face_get_paint`.
* src/sfnt/ttcolr.h: Updated.
diff --git a/ChangeLog b/ChangeLog
index 9ac91c4..481a558 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,16 @@
2020-12-16 Dominik Röttsches <drott@chromium.org>
+ [sfnt] Add 'COLR' v1 API to retrieve color layers (#59703).
+
+ * src/sfnt/ttcolr.c (tt_face_get_paint_layers): New function to get
+ the layers of a `PaintColrLayers` table in the font, using an
+ `FT_LayerIterator` from an `FT_PaintColrLayers` object retrieved via
+ `tt_face_get_paint`.
+
+ * src/sfnt/ttcolr.h: Updated.
+
+2020-12-16 Dominik Röttsches <drott@chromium.org>
+
[sfnt] Add 'COLR' v1 API to iterate color stops (#59703).
* src/sfnt/ttcolr.c (tt_face_get_colorline_stops): New function to
diff --git a/src/sfnt/ttcolr.c b/src/sfnt/ttcolr.c
index 1e97d87..a39773d 100644
--- a/src/sfnt/ttcolr.c
+++ b/src/sfnt/ttcolr.c
@@ -693,6 +693,58 @@
}
+ FT_LOCAL_DEF( FT_Bool )
+ tt_face_get_paint_layers( TT_Face face,
+ FT_LayerIterator* iterator,
+ FT_OpaquePaint* opaque_paint )
+ {
+ FT_Byte* p = NULL;
+ FT_Byte* p_first_layer = NULL;
+ FT_UInt32 paint_offset;
+
+ Colr* colr;
+
+
+ if ( iterator->layer == iterator->num_layers )
+ return 0;
+
+ colr = (Colr*)face->colr;
+ if ( !colr )
+ return 0;
+
+ /*
+ * We have an iterator pointing at a paint offset as part of the
+ * `paintOffset` array in `LayerV1List`.
+ */
+ p = iterator->p;
+
+ /*
+ * Do a cursor sanity check of the iterator. Counting backwards from
+ * where it stands, we need to end up at a position after the beginning
+ * of the `LayerV1List` table and not after the end of the
+ * `LayerV1List`.
+ */
+ p_first_layer = p -
+ iterator->layer * LAYER_V1_LIST_PAINT_OFFSET_SIZE -
+ LAYER_V1_LIST_NUM_LAYERS_SIZE;
+ if ( p_first_layer < (FT_Byte*)colr->layers_v1 )
+ return 0;
+ if ( p_first_layer >= (FT_Byte*)(
+ colr->layers_v1 + LAYER_V1_LIST_NUM_LAYERS_SIZE +
+ colr->num_layers_v1 * LAYER_V1_LIST_PAINT_OFFSET_SIZE ) )
+ return 0;
+
+ paint_offset = FT_NEXT_ULONG( p );
+ opaque_paint->p = (FT_Byte*)( colr->layers_v1 + paint_offset );
+
+ iterator->p = p;
+
+ iterator->layer++;
+
+ return 1;
+ }
+
+
FT_LOCAL_DEF ( FT_Bool )
tt_face_get_colorline_stops( TT_Face face,
FT_ColorStop* color_stop,
diff --git a/src/sfnt/ttcolr.h b/src/sfnt/ttcolr.h
index 77690f6..4a65cb8 100644
--- a/src/sfnt/ttcolr.h
+++ b/src/sfnt/ttcolr.h
@@ -47,6 +47,11 @@
FT_UInt base_glyph,
FT_OpaquePaint* paint );
+ FT_LOCAL ( FT_Bool )
+ tt_face_get_paint_layers( TT_Face face,
+ FT_LayerIterator* iterator,
+ FT_OpaquePaint* paint );
+
FT_LOCAL( FT_Bool )
tt_face_get_colorline_stops( TT_Face face,
FT_ColorStop* color_stop,
