1 /* GdkPixbuf library - convert X drawable information to RGB
3 * Copyright (C) 1999 Michael Zucchi
5 * Authors: Michael Zucchi <zucchi@zedzone.mmc.com.au>
6 * Cody Russell <bratsche@dfw.net>
7 * Federico Mena-Quintero <federico@gimp.org>
9 * This library is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU Lesser General Public
11 * License as published by the Free Software Foundation; either
12 * version 2 of the License, or (at your option) any later version.
14 * This library is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 * Lesser General Public License for more details.
19 * You should have received a copy of the GNU Lesser General Public
20 * License along with this library; if not, write to the
21 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
22 * Boston, MA 02111-1307, USA.
27 #include "gdkpixbuf.h"
30 #include "gdkwindow.h"
31 #include "gdkinternals.h"
33 #include <gdk-pixbuf/gdk-pixbuf.h>
37 * @Short_description: Functions for obtaining pixbufs
40 * Pixbufs are client-side images. For details on how to create
41 * and manipulate pixbufs, see the #GdkPixbuf API documentation.
43 * The functions described here allow to obtain pixbufs from
44 * #GdkWindows and cairo surfaces.
49 * gdk_pixbuf_get_from_window:
50 * @window: Source window
51 * @src_x: Source X coordinate within @window
52 * @src_y: Source Y coordinate within @window
53 * @width: Width in pixels of region to get
54 * @height: Height in pixels of region to get
56 * Transfers image data from a #GdkWindow and converts it to an RGB(A)
57 * representation inside a #GdkPixbuf. In other words, copies
58 * image data from a server-side drawable to a client-side RGB(A) buffer.
59 * This allows you to efficiently read individual pixels on the client side.
61 * This function will create an RGB pixbuf with 8 bits per channel with
62 * the same size specified by the @width and @height arguments. The pixbuf
63 * will contain an alpha channel if the @window contains one.
65 * If the window is off the screen, then there is no image data in the
66 * obscured/offscreen regions to be placed in the pixbuf. The contents of
67 * portions of the pixbuf corresponding to the offscreen region are undefined.
69 * If the window you're obtaining data from is partially obscured by
70 * other windows, then the contents of the pixbuf areas corresponding
71 * to the obscured regions are undefined.
73 * If the window is not mapped (typically because it's iconified/minimized
74 * or not on the current workspace), then %NULL will be returned.
76 * If memory can't be allocated for the return value, %NULL will be returned
79 * (In short, there are several ways this function can fail, and if it fails
80 * it returns %NULL; so check the return value.)
82 * Return value: (transfer full): A newly-created pixbuf with a reference
83 * count of 1, or %NULL on error
86 gdk_pixbuf_get_from_window (GdkWindow *src,
92 cairo_surface_t *surface;
95 g_return_val_if_fail (GDK_IS_WINDOW (src), NULL);
96 g_return_val_if_fail (gdk_window_is_viewable (src), NULL);
98 surface = _gdk_window_ref_cairo_surface (src);
99 dest = gdk_pixbuf_get_from_surface (surface,
102 cairo_surface_destroy (surface);
107 static cairo_format_t
108 gdk_cairo_format_for_content (cairo_content_t content)
112 case CAIRO_CONTENT_COLOR:
113 return CAIRO_FORMAT_RGB24;
114 case CAIRO_CONTENT_ALPHA:
115 return CAIRO_FORMAT_A8;
116 case CAIRO_CONTENT_COLOR_ALPHA:
118 return CAIRO_FORMAT_ARGB32;
122 static cairo_surface_t *
123 gdk_cairo_surface_coerce_to_image (cairo_surface_t *surface,
124 cairo_content_t content,
130 cairo_surface_t *copy;
133 copy = cairo_image_surface_create (gdk_cairo_format_for_content (content),
137 cr = cairo_create (copy);
138 cairo_set_operator (cr, CAIRO_OPERATOR_SOURCE);
139 cairo_set_source_surface (cr, surface, -src_x, -src_y);
147 convert_alpha (guchar *dest_data,
158 src_data += src_stride * src_y + src_x * 4;
160 for (y = 0; y < height; y++) {
161 guint32 *src = (guint32 *) src_data;
163 for (x = 0; x < width; x++) {
164 guint alpha = src[x] >> 24;
168 dest_data[x * 4 + 0] = 0;
169 dest_data[x * 4 + 1] = 0;
170 dest_data[x * 4 + 2] = 0;
174 dest_data[x * 4 + 0] = (((src[x] & 0xff0000) >> 16) * 255 + alpha / 2) / alpha;
175 dest_data[x * 4 + 1] = (((src[x] & 0x00ff00) >> 8) * 255 + alpha / 2) / alpha;
176 dest_data[x * 4 + 2] = (((src[x] & 0x0000ff) >> 0) * 255 + alpha / 2) / alpha;
178 dest_data[x * 4 + 3] = alpha;
181 src_data += src_stride;
182 dest_data += dest_stride;
187 convert_no_alpha (guchar *dest_data,
198 src_data += src_stride * src_y + src_x * 4;
200 for (y = 0; y < height; y++) {
201 guint32 *src = (guint32 *) src_data;
203 for (x = 0; x < width; x++) {
204 dest_data[x * 3 + 0] = src[x] >> 16;
205 dest_data[x * 3 + 1] = src[x] >> 8;
206 dest_data[x * 3 + 2] = src[x];
209 src_data += src_stride;
210 dest_data += dest_stride;
215 * gdk_pixbuf_get_from_surface:
216 * @surface: surface to copy from
217 * @src_x: Source X coordinate within @surface
218 * @src_y: Source Y coordinate within @surface
219 * @width: Width in pixels of region to get
220 * @height: Height in pixels of region to get
222 * Transfers image data from a #cairo_surface_t and converts it to an RGB(A)
223 * representation inside a #GdkPixbuf. This allows you to efficiently read
224 * individual pixels from cairo surfaces. For #GdkWindows, use
225 * gdk_pixbuf_get_from_window() instead.
227 * This function will create an RGB pixbuf with 8 bits per channel.
228 * The pixbuf will contain an alpha channel if the @surface contains one.
230 * Return value: (transfer full): A newly-created pixbuf with a reference
231 * count of 1, or %NULL on error
234 gdk_pixbuf_get_from_surface (cairo_surface_t *surface,
240 cairo_content_t content;
243 /* General sanity checks */
244 g_return_val_if_fail (surface != NULL, NULL);
245 g_return_val_if_fail (width > 0 && height > 0, NULL);
247 content = cairo_surface_get_content (surface) | CAIRO_CONTENT_COLOR;
248 dest = gdk_pixbuf_new (GDK_COLORSPACE_RGB,
249 !!(content & CAIRO_CONTENT_ALPHA),
253 surface = gdk_cairo_surface_coerce_to_image (surface, content,
256 cairo_surface_flush (surface);
257 if (cairo_surface_status (surface) || dest == NULL)
259 cairo_surface_destroy (surface);
263 if (gdk_pixbuf_get_has_alpha (dest))
264 convert_alpha (gdk_pixbuf_get_pixels (dest),
265 gdk_pixbuf_get_rowstride (dest),
266 cairo_image_surface_get_data (surface),
267 cairo_image_surface_get_stride (surface),
271 convert_no_alpha (gdk_pixbuf_get_pixels (dest),
272 gdk_pixbuf_get_rowstride (dest),
273 cairo_image_surface_get_data (surface),
274 cairo_image_surface_get_stride (surface),
278 cairo_surface_destroy (surface);