[eog] Improve the rendering of scaled images

[Claudio Saavedra <csaavedra src gnome org>]

commit 2be68aaee33e3e6732e512a22d9ee5b681e95cc5
Author: Claudio Saavedra <csaavedra igalia com>
Date:   Wed Aug 25 12:32:31 2010 +0300

    Improve the rendering of scaled images
    
    Not using CAIRO_CONTENT_ALPHA added a black border to images, when
    painted scaled. Also, a extend mode of CAIRO_EXTEND_PAD, clipped to
    the image rectangle, prevents the image borders to be drawn blending
    out with the background.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=626795

 src/eog-scroll-view.c |   12 +++++-------
 1 files changed, 5 insertions(+), 7 deletions(-)
---
diff --git a/src/eog-scroll-view.c b/src/eog-scroll-view.c
index 67f434f..bb886d3 100644
--- a/src/eog-scroll-view.c
+++ b/src/eog-scroll-view.c
@@ -194,13 +194,8 @@ create_surface_from_pixbuf (EogScrollView *view, GdkPixbuf *pixbuf)
 	cairo_format_t format;
 	cairo_content_t content;
 
-	if (gdk_pixbuf_get_has_alpha (pixbuf)) {
-		format = CAIRO_FORMAT_ARGB32;
-		content = CAIRO_CONTENT_COLOR | CAIRO_CONTENT_ALPHA;
-	} else {
-		format = CAIRO_FORMAT_RGB24;
-		content = CAIRO_CONTENT_COLOR;
-	}
+	format = CAIRO_FORMAT_ARGB32;
+	content = CAIRO_CONTENT_COLOR | CAIRO_CONTENT_ALPHA;
 	surface = gdk_window_create_similar_surface (gtk_widget_get_window (view->priv->display),
 						     content,
 						     gdk_pixbuf_get_width (pixbuf),
@@ -1892,8 +1887,11 @@ display_expose_event (GtkWidget *widget, GdkEventExpose *event, gpointer data)
 	} else
 #endif /* HAVE_RSVG */
 	{
+		cairo_rectangle (cr, xofs, yofs, scaled_width, scaled_height);
+		cairo_clip (cr);
 		cairo_scale (cr, priv->zoom, priv->zoom);
 		cairo_set_source_surface (cr, priv->surface, xofs/priv->zoom, yofs/priv->zoom);
+		cairo_pattern_set_extend (cairo_get_source (cr), CAIRO_EXTEND_PAD);
 		if ((is_zoomed_in (view) && priv->interp_type_in == CAIRO_FILTER_NEAREST) ||
 		    (is_zoomed_out (view) && priv->interp_type_out == CAIRO_FILTER_NEAREST))
 			cairo_pattern_set_filter (cairo_get_source (cr), CAIRO_FILTER_NEAREST);