Implement box filter

1 files changed, 32 insertions, 1 deletions

diff --git a/downscaling.c b/downscaling.c
index 1d96fe6..2dadb09 100644
--- a/downscaling.c
+++ b/downscaling.c
@@ -313,7 +313,38 @@ set_lanczos (pixman_image_t *image, int w, int h, double scale)
 static void
 set_box (pixman_image_t *image, int w, int h, double scale)
 {
-    g_error ("Box filter is not implemented yet");
+    if (scale < 1.0)
+    {
+	int size = (1.0 / scale + 0.5);
+	int n_params = size * size + 2;
+	pixman_fixed_16_16_t *params = g_malloc (n_params * sizeof (pixman_fixed_16_16_t));
+	int i, j;
+	
+	params[0] = size << 16;
+	params[1] = size << 16;
+
+	g_print ("size of box: %d\n", size);
+	
+	for (i = 0; i < size; ++i)
+	{
+	    for (j = 0; j < size; ++j)
+	    {
+		int idx = i * size + j + 2;
+
+		g_assert (idx < n_params);
+
+		params[idx] = _cairo_fixed_16_16_from_double (1.0 / (size * size));
+	    }
+	}
+	
+	pixman_image_set_filter (image, PIXMAN_FILTER_CONVOLUTION, params, n_params);
+	
+	g_free (params);
+    }
+    else
+    {
+	pixman_image_set_filter (image, PIXMAN_FILTER_NEAREST, NULL, 0);
+    }
 }
 
 static void