1 files changed, 17 insertions, 3 deletions

diff --git a/src/image.c b/src/image.c
index e7e0a93313b..e236b389210 100644
--- a/src/image.c
+++ b/src/image.c
@@ -259,6 +259,8 @@ cr_put_image_to_cr_data (struct image *img)
           cairo_matrix_t matrix;
           cairo_pattern_get_matrix (img->cr_data, &matrix);
           cairo_pattern_set_matrix (pattern, &matrix);
+          cairo_pattern_set_filter
+            (pattern, cairo_pattern_get_filter (img->cr_data));
           cairo_pattern_destroy (img->cr_data);
         }
       cairo_surface_destroy (surface);
@@ -2114,6 +2116,15 @@ image_set_transform (struct frame *f, struct image *img)
   double rotation = 0.0;
   compute_image_rotation (img, &rotation);
 
+# if defined USE_CAIRO || defined HAVE_XRENDER || defined HAVE_NS
+  /* We want scale up operations to use a nearest neighbour filter to
+     show real pixels instead of munging them, but scale down
+     operations to use a blended filter, to avoid aliasing and the like.
+
+     TODO: implement for Windows.  */
+  bool scale_down = (width < img->width) || (height < img->height);
+# endif
+
   /* Perform scale transformation.  */
 
   matrix3x3 matrix
@@ -2225,11 +2236,14 @@ image_set_transform (struct frame *f, struct image *img)
   /* Under NS the transform is applied to the drawing surface at
      drawing time, so store it for later.  */
   ns_image_set_transform (img->pixmap, matrix);
+  ns_image_set_smoothing (img->pixmap, scale_down);
 # elif defined USE_CAIRO
   cairo_matrix_t cr_matrix = {matrix[0][0], matrix[0][1], matrix[1][0],
                               matrix[1][1], matrix[2][0], matrix[2][1]};
   cairo_pattern_t *pattern = cairo_pattern_create_rgb (0, 0, 0);
   cairo_pattern_set_matrix (pattern, &cr_matrix);
+  cairo_pattern_set_filter (pattern, scale_down
+                            ? CAIRO_FILTER_BEST : CAIRO_FILTER_NEAREST);
   /* Dummy solid color pattern just to record pattern matrix.  */
   img->cr_data = pattern;
 # elif defined (HAVE_XRENDER)
@@ -2246,14 +2260,14 @@ image_set_transform (struct frame *f, struct image *img)
              XDoubleToFixed (matrix[1][2]),
              XDoubleToFixed (matrix[2][2])}}};
 
-      XRenderSetPictureFilter (FRAME_X_DISPLAY (f), img->picture, FilterBest,
-                               0, 0);
+      XRenderSetPictureFilter (FRAME_X_DISPLAY (f), img->picture,
+                               scale_down ? FilterBest : FilterNearest, 0, 0);
       XRenderSetPictureTransform (FRAME_X_DISPLAY (f), img->picture, &tmat);
 
       if (img->mask_picture)
         {
           XRenderSetPictureFilter (FRAME_X_DISPLAY (f), img->mask_picture,
-                                   FilterBest, 0, 0);
+                                   scale_down ? FilterBest : FilterNearest, 0, 0);
           XRenderSetPictureTransform (FRAME_X_DISPLAY (f), img->mask_picture,
                                       &tmat);
         }