2 * Copyright © 2008 Kristian Høgsberg
4 * Permission to use, copy, modify, distribute, and sell this software and its
5 * documentation for any purpose is hereby granted without fee, provided that
6 * the above copyright notice appear in all copies and that both that copyright
7 * notice and this permission notice appear in supporting documentation, and
8 * that the name of the copyright holders not be used in advertising or
9 * publicity pertaining to distribution of the software without specific,
10 * written prior permission. The copyright holders make no representations
11 * about the suitability of this software for any purpose. It is provided "as
12 * is" without express or implied warranty.
14 * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
15 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
16 * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
17 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
18 * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
19 * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
29 #include "cairo-util.h"
31 #define ARRAY_LENGTH(a) (sizeof (a) / sizeof (a)[0])
34 blur_surface(cairo_surface_t *surface, int margin)
37 int32_t width, height, stride, x, y, z, w;
39 uint32_t *s, *d, a, p;
40 int i, j, k, size, half;
44 size = ARRAY_LENGTH(kernel);
45 width = cairo_image_surface_get_width(surface);
46 height = cairo_image_surface_get_height(surface);
47 stride = cairo_image_surface_get_stride(surface);
48 src = cairo_image_surface_get_data(surface);
50 tmp = cairo_image_surface_create(CAIRO_FORMAT_RGB24, width, height);
51 dst = cairo_image_surface_get_data(tmp);
55 for (i = 0; i < size; i++) {
57 kernel[i] = exp(- f * f / 30.0) * 80;
61 for (i = 0; i < height; i++) {
62 s = (uint32_t *) (src + i * stride);
63 d = (uint32_t *) (dst + i * stride);
64 for (j = 0; j < width; j++) {
65 if (margin < j && j < width - margin) {
74 for (k = 0; k < size; k++) {
75 if (j - half + k < 0 || j - half + k >= width)
79 x += (p >> 24) * kernel[k];
80 y += ((p >> 16) & 0xff) * kernel[k];
81 z += ((p >> 8) & 0xff) * kernel[k];
82 w += (p & 0xff) * kernel[k];
84 d[j] = (x / a << 24) | (y / a << 16) | (z / a << 8) | w / a;
88 for (i = 0; i < height; i++) {
89 s = (uint32_t *) (dst + i * stride);
90 d = (uint32_t *) (src + i * stride);
91 for (j = 0; j < width; j++) {
92 if (margin <= i && i < height - margin) {
101 for (k = 0; k < size; k++) {
102 if (i - half + k < 0 || i - half + k >= height)
104 s = (uint32_t *) (dst + (i - half + k) * stride);
107 x += (p >> 24) * kernel[k];
108 y += ((p >> 16) & 0xff) * kernel[k];
109 z += ((p >> 8) & 0xff) * kernel[k];
110 w += (p & 0xff) * kernel[k];
112 d[j] = (x / a << 24) | (y / a << 16) | (z / a << 8) | w / a;
116 cairo_surface_destroy(tmp);