test: Fix surface-pattern-scale-down-extend

This test creates a similar surface using cairo_push_group () and
assumes its size will be w x h. This is not true when testing similar
surfaces with "cairo-test-suite -a", because they are bigger than the
actual ROI, which corresponds to the rectangle (0,0) - (w,h).

Clipping to the ROI guarantees that the surface created by
cairo_push_group () always has the same size.

Fixes surface-pattern-scale-down-extend.

1 files changed, 13 insertions, 0 deletions

diff --git a/test/surface-pattern-scale-down-extend.c b/test/surface-pattern-scale-down-extend.c
index 80338611b..191ab927f 100644
--- a/test/surface-pattern-scale-down-extend.c
+++ b/test/surface-pattern-scale-down-extend.c
@@ -39,6 +39,17 @@ draw_with_extend (cairo_t *cr, int w, int h, cairo_extend_t extend)
     cairo_set_source_rgb (cr, 1,1,1);
     cairo_paint (cr);
 
+    cairo_save (cr);
+
+    /* When the destination surface is created by cairo-test-suite to
+     * test device-offset, it is bigger than w x h. This test expects
+     * the group to have a size which is exactly w x h, so it must
+     * clip to the this rectangle to guarantee that the group will
+     * have the correct size.
+     */
+    cairo_rectangle (cr, 0, 0, w, h);
+    cairo_clip (cr);
+
     cairo_push_group_with_content (cr, CAIRO_CONTENT_COLOR); {
         /* A two by two checkerboard with black, red and yellow
          * cells. */
@@ -52,6 +63,8 @@ draw_with_extend (cairo_t *cr, int w, int h, cairo_extend_t extend)
     pattern = cairo_pop_group (cr);
     cairo_pattern_set_extend(pattern, extend);
 
+    cairo_restore (cr);
+
     cairo_scale (cr, 0.5, 0.5);
     cairo_set_source (cr, pattern);
     cairo_paint (cr);