[test] Use poppler_page_render with a transparent surface

Instead of using an opaque surface filled in white, use a transparent
surface and fill it in white by using CAIRO_OPERATOR_DEST_OVER after
rendering.

1 files changed, 5 insertions, 4 deletions

diff --git a/test/any2ppm.c b/test/any2ppm.c
index 4800b545..31dd0eb4 100644
--- a/test/any2ppm.c
+++ b/test/any2ppm.c
@@ -332,15 +332,16 @@ _poppler_render_page (const char *filename,
 
     poppler_page_get_size (page, &width, &height);
 
-    surface = cairo_image_surface_create (CAIRO_FORMAT_RGB24, width, height);
+    surface = cairo_image_surface_create (CAIRO_FORMAT_ARGB32, width, height);
     cr = cairo_create (surface);
 
-    cairo_set_source_rgb (cr, 1., 1., 1.);
-    cairo_paint (cr);
-
     poppler_page_render (page, cr);
     g_object_unref (page);
 
+    cairo_set_operator (cr, CAIRO_OPERATOR_DEST_OVER);
+    cairo_set_source_rgb (cr, 1., 1., 1.);
+    cairo_paint (cr);
+
     status = cairo_status (cr);
     cairo_destroy (cr);