Switch to nearest neighbor filtering when image is larger than original

(bzr r9508.1.12)

3 files changed, 20 insertions, 0 deletions

diff --git a/src/display/cairo-utils.cpp b/src/display/cairo-utils.cpp
index 8aaf838ed..bb401dc87 100644
--- a/src/display/cairo-utils.cpp
+++ b/src/display/cairo-utils.cpp
@@ -315,6 +315,20 @@ ink_cairo_pattern_set_matrix(cairo_pattern_t *cp, Geom::Matrix const &m)
     cairo_pattern_set_matrix(cp, &cm);
 }
 
+void
+ink_cairo_set_source_argb32_pixbuf(cairo_t *ct, GdkPixbuf *pb, double x, double y)
+{
+    guchar *data = gdk_pixbuf_get_pixels(pb);
+    int w = gdk_pixbuf_get_width(pb);
+    int h = gdk_pixbuf_get_height(pb);
+    int stride = gdk_pixbuf_get_rowstride(pb);
+
+    cairo_surface_t *pbs = cairo_image_surface_create_for_data(
+        data, CAIRO_FORMAT_ARGB32, w, h, stride);
+    cairo_set_source_surface(ct, pbs, x, y);
+    cairo_surface_destroy(pbs);
+}
+
 // taken from Cairo sources
 static inline guint32 premul_alpha(guint32 color, guint32 alpha)
 {
diff --git a/src/display/cairo-utils.h b/src/display/cairo-utils.h
index 882742d5f..096dc6046 100644
--- a/src/display/cairo-utils.h
+++ b/src/display/cairo-utils.h
@@ -82,6 +82,7 @@ void ink_cairo_set_source_color(cairo_t *ct, SPColor const &color, double opacit
 void ink_cairo_set_source_rgba32(cairo_t *ct, guint32 rgba);
 void ink_cairo_transform(cairo_t *ct, Geom::Matrix const &m);
 void ink_cairo_pattern_set_matrix(cairo_pattern_t *cp, Geom::Matrix const &m);
+void ink_cairo_set_source_argb32_pixbuf(cairo_t *ct, GdkPixbuf *pb, double x, double y);
 
 void convert_pixels_pixbuf_to_argb32(guchar *data, int w, int h, int rs);
 void convert_pixels_argb32_to_pixbuf(guchar *data, int w, int h, int rs);
diff --git a/src/display/nr-arena-image.cpp b/src/display/nr-arena-image.cpp
index f198b176b..325cff65a 100644
--- a/src/display/nr-arena-image.cpp
+++ b/src/display/nr-arena-image.cpp
@@ -197,6 +197,11 @@ nr_arena_image_render( cairo_t *ct, NRArenaItem *item, NRRectL *area, NRPixBlock
         cairo_pattern_t *p = cairo_get_source(ct);
         ink_cairo_pattern_set_matrix(p, image->grid2px);
 
+        Geom::Matrix total = item->ctm * image->grid2px.inverse();
+        if (total.expansionX() > 1.0 || total.expansionY() > 1.0) {
+            cairo_pattern_set_filter(p, CAIRO_FILTER_NEAREST);
+        }
+
         cairo_paint_with_alpha(ct, ((double) item->opacity) / 255.0);
         cairo_restore(ct);