BUGGY: Add surface_backend->acquire_source_image_transformed

This is an initial attempt at addressing the recently noticed
fallback-resolution bug. It isn't working correctly yet.

I'm just committing so that behdad can see what I'm up to.

src/cairo-meta-surface.c

@@ -182,17 +182,26 @@ _cairo_meta_surface_finish (void *abstract_surface)
 }
 
 static cairo_status_t
-_cairo_meta_surface_acquire_source_image (void			 *abstract_surface,
-					  cairo_image_surface_t	**image_out,
-					  void			**image_extra)
+_cairo_meta_surface_acquire_source_image_transformed (
+    void			 *abstract_surface,
+    cairo_matrix_t		 *device_transform,
+    cairo_image_surface_t	**image_out,
+    void			**image_extra)
 {
     cairo_status_t status;
     cairo_meta_surface_t *surface = abstract_surface;
     cairo_surface_t *image;
+    double width = surface->width_pixels;
+    double height = surface->height_pixels;
+
+    cairo_matrix_transform_distance (device_transform, &width, &height);
 
     image = _cairo_image_surface_create_with_content (surface->content,
-						      surface->width_pixels,
-						      surface->height_pixels);
+						      ceil (width),
+						      ceil (height));
+
+    _cairo_surface_set_device_scale (image,
+				     device_transform->xx, device_transform->yy);
 
     status = _cairo_meta_surface_replay (&surface->base, image);
     if (status) {
@@ -206,6 +215,19 @@ _cairo_meta_surface_acquire_source_image (void			 *abstract_surface,
     return status;
 }
 
+static cairo_status_t
+_cairo_meta_surface_acquire_source_image (void			 *abstract_surface,
+					  cairo_image_surface_t	**image_out,
+					  void			**image_extra)
+{
+    cairo_matrix_t identity;
+
+    cairo_matrix_init_identity (&identity);
+
+    return _cairo_meta_surface_acquire_source_image_transformed (
+	abstract_surface, &identity, image_out, image_extra);
+}
+
 static void
 _cairo_meta_surface_release_source_image (void			*abstract_surface,
 					  cairo_image_surface_t	*image,
@@ -629,7 +651,13 @@ static const cairo_surface_backend_t cairo_meta_surface_backend = {
     _cairo_meta_surface_fill,
     _cairo_meta_surface_show_glyphs,
 
-    _cairo_meta_surface_snapshot
+    _cairo_meta_surface_snapshot,
+
+    NULL, /* is_similar */
+    NULL, /* reset */
+    NULL, /* fill_stroke */
+
+    _cairo_meta_surface_acquire_source_image_transformed
 };
 
 static cairo_path_fixed_t *

src/cairo-pattern.c

@@ -1702,9 +1702,12 @@ _cairo_pattern_acquire_surface_for_surface (cairo_surface_pattern_t   *pattern,
     {
 	cairo_image_surface_t *image;
 
-	status = _cairo_surface_acquire_source_image (pattern->surface,
-						      &image,
-						      &attr->extra);
+	status = _cairo_surface_acquire_source_image_transformed (
+	    pattern->surface,
+	    &dst->device_transform,
+	    &image,
+	    &attr->extra);
+
 	if (status)
 	    return status;
 

src/cairo-surface.c

@@ -968,6 +968,26 @@ _cairo_surface_acquire_source_image (cairo_surface_t         *surface,
 						    image_out, image_extra));
 }
 
+cairo_status_t
+_cairo_surface_acquire_source_image_transformed (cairo_surface_t	 *surface,
+						 cairo_matrix_t		 *device_transform,
+						 cairo_image_surface_t  **image_out,
+						 void                   **image_extra)
+{
+    assert (!surface->finished);
+
+    if (surface->status)
+	return surface->status;
+
+    if (surface->backend->acquire_source_image_transformed == NULL)
+	return _cairo_surface_acquire_source_image (surface,
+						    image_out, image_extra);
+
+    return _cairo_surface_set_error (surface,
+	    surface->backend->acquire_source_image_transformed (
+		surface, device_transform, image_out, image_extra));
+}
+
 /**
  * _cairo_surface_release_source_image:
  * @surface: a #cairo_surface_t

src/cairoint.h

@@ -738,6 +738,12 @@ struct _cairo_surface_backend {
 				 cairo_matrix_t		*stroke_ctm_inverse,
 				 double			 stroke_tolerance,
 				 cairo_antialias_t	 stroke_antialias);
+
+    cairo_warn cairo_status_t
+    (*acquire_source_image_transformed)	(void                    *abstract_surface,
+					 cairo_matrix_t		 *device_trasnform,
+					 cairo_image_surface_t  **image_out,
+					 void                   **image_extra);
 };
 
 #include "cairo-surface-private.h"
@@ -1721,6 +1727,12 @@ _cairo_surface_acquire_source_image (cairo_surface_t         *surface,
 				     cairo_image_surface_t  **image_out,
 				     void                   **image_extra);
 
+cairo_private cairo_status_t
+_cairo_surface_acquire_source_image_transformed (cairo_surface_t         *surface,
+						 cairo_matrix_t		 *device_trasnform,
+						 cairo_image_surface_t  **image_out,
+						 void                   **image_extra);
+
 cairo_private void
 _cairo_surface_release_source_image (cairo_surface_t        *surface,
 				     cairo_image_surface_t  *image,