Fix bug 7268: Fix coordinate space for _cairo_surface_get_extents

Previously this function was attempting to return values in surface
space, (but even then it was doing it wrong). However, all callers
actually expect values in backend space. Fixing this cleans up bug
7268 quite nicely.

1 files changed, 13 insertions, 18 deletions

diff --git a/src/cairo-surface.c b/src/cairo-surface.c
index dd4514706..0aafa7366 100644
--- a/src/cairo-surface.c
+++ b/src/cairo-surface.c
@@ -1649,37 +1649,32 @@ _cairo_surface_set_clip (cairo_surface_t *surface, cairo_clip_t *clip)
  * possibly be recorded, in otherwords, it is the maximum extent of
  * potentially usable coordinates.
  *
- * For simple pixel-based surfaces, it can be a close bound on the
- * retained pixel region.
- *
  * For vector surfaces, (PDF, PS, SVG and meta-surfaces), the surface
  * might be conceived as unbounded, but we force the user to provide a
- * maximum size at the time of surface_create.
+ * maximum size at the time of surface_create. So get_extents uses
+ * that size.
+ *
+ * NOTE: The coordinates returned are in "backend" space rather than
+ * "surface" space. That is, they are relative to the true (0,0)
+ * origin rather than the device_transform origin. This might seem a
+ * bit inconsistent with other cairo_surface interfaces, but all
+ * current callers are within the surface layer where backend space is
+ * desired.
+ *
+ * This behavior would have to be changed is we ever exported a public
+ * variant of this function.
  */
-
 cairo_status_t
 _cairo_surface_get_extents (cairo_surface_t         *surface,
 			    cairo_rectangle_int16_t *rectangle)
 {
-    cairo_status_t status;
-
     if (surface->status)
 	return surface->status;
 
     if (surface->finished)
 	return CAIRO_STATUS_SURFACE_FINISHED;
 
-    status = surface->backend->get_extents (surface, rectangle);
-
-    /* XXX: FRAGILE: This code is currently ignoring any scaling in
-     * the device_transform. This will almost certainly need to be
-     * changed for device_transform scaling will work. */
-    rectangle->x = rectangle->x + surface->device_transform.x0;
-    rectangle->y = rectangle->y + surface->device_transform.y0;
-    rectangle->width = rectangle->width - surface->device_transform.x0;
-    rectangle->height = rectangle->height - surface->device_transform.y0;
-
-    return status;
+    return surface->backend->get_extents (surface, rectangle);
 }
 
 cairo_status_t