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, see <http://www.gnu.org/licenses/>.
25 #include "gdkpixbuf.h"
28 #include "gdkwindow.h"
29 #include "gdkinternals.h"
31 #include <gdk-pixbuf/gdk-pixbuf.h>
35 * @Short_description: Functions for obtaining pixbufs
38 * Pixbufs are client-side images. For details on how to create
39 * and manipulate pixbufs, see the #GdkPixbuf API documentation.
41 * The functions described here allow to obtain pixbufs from
42 * #GdkWindows and cairo surfaces.
47 * gdk_pixbuf_get_from_window:
48 * @window: Source window
49 * @src_x: Source X coordinate within @window
50 * @src_y: Source Y coordinate within @window
51 * @width: Width in pixels of region to get
52 * @height: Height in pixels of region to get
54 * Transfers image data from a #GdkWindow and converts it to an RGB(A)
55 * representation inside a #GdkPixbuf. In other words, copies
56 * image data from a server-side drawable to a client-side RGB(A) buffer.
57 * This allows you to efficiently read individual pixels on the client side.
59 * This function will create an RGB pixbuf with 8 bits per channel with
60 * the same size specified by the @width and @height arguments. The pixbuf
61 * will contain an alpha channel if the @window contains one.
63 * If the window is off the screen, then there is no image data in the
64 * obscured/offscreen regions to be placed in the pixbuf. The contents of
65 * portions of the pixbuf corresponding to the offscreen region are undefined.
67 * If the window you're obtaining data from is partially obscured by
68 * other windows, then the contents of the pixbuf areas corresponding
69 * to the obscured regions are undefined.
71 * If the window is not mapped (typically because it's iconified/minimized
72 * or not on the current workspace), then %NULL will be returned.
74 * If memory can't be allocated for the return value, %NULL will be returned
77 * (In short, there are several ways this function can fail, and if it fails
78 * it returns %NULL; so check the return value.)
80 * Return value: (transfer full): A newly-created pixbuf with a reference
81 * count of 1, or %NULL on error
84 gdk_pixbuf_get_from_window (GdkWindow *src,
90 cairo_surface_t *surface;
93 g_return_val_if_fail (GDK_IS_WINDOW (src), NULL);
94 g_return_val_if_fail (gdk_window_is_viewable (src), NULL);
96 surface = _gdk_window_ref_cairo_surface (src);
97 dest = gdk_pixbuf_get_from_surface (surface,
100 cairo_surface_destroy (surface);
105 static cairo_format_t
106 gdk_cairo_format_for_content (cairo_content_t content)
110 case CAIRO_CONTENT_COLOR:
111 return CAIRO_FORMAT_RGB24;
112 case CAIRO_CONTENT_ALPHA:
113 return CAIRO_FORMAT_A8;
114 case CAIRO_CONTENT_COLOR_ALPHA:
116 return CAIRO_FORMAT_ARGB32;
120 static cairo_surface_t *
121 gdk_cairo_surface_coerce_to_image (cairo_surface_t *surface,
122 cairo_content_t content,
128 cairo_surface_t *copy;
131 copy = cairo_image_surface_create (gdk_cairo_format_for_content (content),
135 cr = cairo_create (copy);
136 cairo_set_operator (cr, CAIRO_OPERATOR_SOURCE);
137 cairo_set_source_surface (cr, surface, -src_x, -src_y);
145 convert_alpha (guchar *dest_data,
156 src_data += src_stride * src_y + src_x * 4;
158 for (y = 0; y < height; y++) {
159 guint32 *src = (guint32 *) src_data;
161 for (x = 0; x < width; x++) {
162 guint alpha = src[x] >> 24;
166 dest_data[x * 4 + 0] = 0;
167 dest_data[x * 4 + 1] = 0;
168 dest_data[x * 4 + 2] = 0;
172 dest_data[x * 4 + 0] = (((src[x] & 0xff0000) >> 16) * 255 + alpha / 2) / alpha;
173 dest_data[x * 4 + 1] = (((src[x] & 0x00ff00) >> 8) * 255 + alpha / 2) / alpha;
174 dest_data[x * 4 + 2] = (((src[x] & 0x0000ff) >> 0) * 255 + alpha / 2) / alpha;
176 dest_data[x * 4 + 3] = alpha;
179 src_data += src_stride;
180 dest_data += dest_stride;
185 convert_no_alpha (guchar *dest_data,
196 src_data += src_stride * src_y + src_x * 4;
198 for (y = 0; y < height; y++) {
199 guint32 *src = (guint32 *) src_data;
201 for (x = 0; x < width; x++) {
202 dest_data[x * 3 + 0] = src[x] >> 16;
203 dest_data[x * 3 + 1] = src[x] >> 8;
204 dest_data[x * 3 + 2] = src[x];
207 src_data += src_stride;
208 dest_data += dest_stride;
213 * gdk_pixbuf_get_from_surface:
214 * @surface: surface to copy from
215 * @src_x: Source X coordinate within @surface
216 * @src_y: Source Y coordinate within @surface
217 * @width: Width in pixels of region to get
218 * @height: Height in pixels of region to get
220 * Transfers image data from a #cairo_surface_t and converts it to an RGB(A)
221 * representation inside a #GdkPixbuf. This allows you to efficiently read
222 * individual pixels from cairo surfaces. For #GdkWindows, use
223 * gdk_pixbuf_get_from_window() instead.
225 * This function will create an RGB pixbuf with 8 bits per channel.
226 * The pixbuf will contain an alpha channel if the @surface contains one.
228 * Return value: (transfer full): A newly-created pixbuf with a reference
229 * count of 1, or %NULL on error
232 gdk_pixbuf_get_from_surface (cairo_surface_t *surface,
238 cairo_content_t content;
241 /* General sanity checks */
242 g_return_val_if_fail (surface != NULL, NULL);
243 g_return_val_if_fail (width > 0 && height > 0, NULL);
245 content = cairo_surface_get_content (surface) | CAIRO_CONTENT_COLOR;
246 dest = gdk_pixbuf_new (GDK_COLORSPACE_RGB,
247 !!(content & CAIRO_CONTENT_ALPHA),
251 surface = gdk_cairo_surface_coerce_to_image (surface, content,
254 cairo_surface_flush (surface);
255 if (cairo_surface_status (surface) || dest == NULL)
257 cairo_surface_destroy (surface);
261 if (gdk_pixbuf_get_has_alpha (dest))
262 convert_alpha (gdk_pixbuf_get_pixels (dest),
263 gdk_pixbuf_get_rowstride (dest),
264 cairo_image_surface_get_data (surface),
265 cairo_image_surface_get_stride (surface),
269 convert_no_alpha (gdk_pixbuf_get_pixels (dest),
270 gdk_pixbuf_get_rowstride (dest),
271 cairo_image_surface_get_data (surface),
272 cairo_image_surface_get_stride (surface),
276 cairo_surface_destroy (surface);