Optimize window blur calculation.

cairo-util.c

@@ -101,13 +101,13 @@ buffer_create_from_cairo_surface(int fd, cairo_surface_t *surface)
 }
 
 void
-blur_surface(cairo_surface_t *surface)
+blur_surface(cairo_surface_t *surface, int margin)
 {
 	cairo_surface_t *tmp;
 	int32_t width, height, stride, x, y, z, w;
 	uint8_t *src, *dst;
 	uint32_t *s, *d, a, p;
-	int i, j, k, size = 23, half;
+	int i, j, k, size = 17, half;
 	uint8_t kernel[100];
 	double f;
 
@@ -131,6 +131,9 @@ blur_surface(cairo_surface_t *surface)
 		s = (uint32_t *) (src + i * stride);
 		d = (uint32_t *) (dst + i * stride);
 		for (j = 0; j < width; j++) {
+			if (margin < j && j < width - margin &&
+			    margin < i && i < height - margin)
+				continue;
 			x = 0;
 			y = 0;
 			z = 0;
@@ -153,6 +156,9 @@ blur_surface(cairo_surface_t *surface)
 		s = (uint32_t *) (dst + i * stride);
 		d = (uint32_t *) (src + i * stride);
 		for (j = 0; j < width; j++) {
+			if (margin <= j && j < width - margin &&
+			    margin <= i && i < height - margin)
+				continue;
 			x = 0;
 			y = 0;
 			z = 0;

cairo-util.h

@@ -19,6 +19,6 @@ struct buffer *
 buffer_create_from_cairo_surface(int fd, cairo_surface_t *surface);
 
 void
-blur_surface(cairo_surface_t *surface);
+blur_surface(cairo_surface_t *surface, int margin);
 
 #endif

pointer.c

@@ -48,7 +48,7 @@ draw_pointer(int width, int height)
 	cairo_set_source_rgb(cr, 0, 0, 0);
 	cairo_stroke_preserve(cr);
 	cairo_fill(cr);
-	blur_surface(surface);
+	blur_surface(surface, INT_MAX);
 
 	pointer_path(cr, hotspot_x, hotspot_y);
 	cairo_stroke_preserve(cr);

window.c

@@ -89,7 +89,7 @@ draw_window(void *data)
 	rounded_rect(cr, 1, 1, window->width - 1, window->height - 1, radius);
 	cairo_stroke_preserve(cr);
 	cairo_fill(cr);
-	blur_surface(surface);
+	blur_surface(surface, 16 + radius);
 
 	cairo_translate(cr, -5, -3);
 	cairo_set_line_width (cr, border);
@@ -148,7 +148,6 @@ draw_window(void *data)
 	cairo_stroke_preserve(cr);
 	cairo_set_source_rgb(cr, 1, 1, 1);
 	cairo_fill(cr);
-
 	cairo_destroy(cr);
 
 	if (window->buffer != NULL)