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gtk/gdk/gdkpixbuf-drawable.c
Benjamin Otte a1a1b135ac API: remove gdk_pixbuf_get_from_image()
2010-08-10 21:02:26 +02:00

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/* GdkPixbuf library - convert X drawable information to RGB
*
* Copyright (C) 1999 Michael Zucchi
*
* Authors: Michael Zucchi <zucchi@zedzone.mmc.com.au>
* Cody Russell <bratsche@dfw.net>
* Federico Mena-Quintero <federico@gimp.org>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
#include "config.h"
#include <gdk-pixbuf/gdk-pixbuf.h>
#include "gdkcolor.h"
#include "gdkwindow.h"
#include "gdkpixbuf.h"
#include "gdkpixmap.h"
#include "gdkinternals.h"
/* Exported functions */
/**
* gdk_pixbuf_get_from_drawable:
* @dest: (allow-none): Destination pixbuf, or %NULL if a new pixbuf should be created.
* @src: Source drawable.
* @cmap: A colormap if @src doesn't have one set.
* @src_x: Source X coordinate within drawable.
* @src_y: Source Y coordinate within drawable.
* @dest_x: Destination X coordinate in pixbuf, or 0 if @dest is NULL.
* @dest_y: Destination Y coordinate in pixbuf, or 0 if @dest is NULL.
* @width: Width in pixels of region to get.
* @height: Height in pixels of region to get.
*
* Transfers image data from a #GdkDrawable and converts it to an RGB(A)
* representation inside a #GdkPixbuf. In other words, copies
* image data from a server-side drawable to a client-side RGB(A) buffer.
* This allows you to efficiently read individual pixels on the client side.
*
* If the drawable @src has no colormap (gdk_drawable_get_colormap()
* returns %NULL), then a suitable colormap must be specified.
* Typically a #GdkWindow or a pixmap created by passing a #GdkWindow
* to gdk_pixmap_new() will already have a colormap associated with
* it. If the drawable has a colormap, the @cmap argument will be
* ignored. If the drawable is a bitmap (1 bit per pixel pixmap),
* then a colormap is not required; pixels with a value of 1 are
* assumed to be white, and pixels with a value of 0 are assumed to be
* black. For taking screenshots, gdk_colormap_get_system() returns
* the correct colormap to use.
*
* If the specified destination pixbuf @dest is %NULL, then this
* function will create an RGB pixbuf with 8 bits per channel and no
* alpha, with the same size specified by the @width and @height
* arguments. In this case, the @dest_x and @dest_y arguments must be
* specified as 0. If the specified destination pixbuf is not %NULL
* and it contains alpha information, then the filled pixels will be
* set to full opacity (alpha = 255).
*
* If the specified drawable is a pixmap, then the requested source
* rectangle must be completely contained within the pixmap, otherwise
* the function will return %NULL. For pixmaps only (not for windows)
* passing -1 for width or height is allowed to mean the full width
* or height of the pixmap.
*
* If the specified drawable is a window, and the window is off the
* screen, then there is no image data in the obscured/offscreen
* regions to be placed in the pixbuf. The contents of portions of the
* pixbuf corresponding to the offscreen region are undefined.
*
* If the window you're obtaining data from is partially obscured by
* other windows, then the contents of the pixbuf areas corresponding
* to the obscured regions are undefined.
*
* If the target drawable is not mapped (typically because it's
* iconified/minimized or not on the current workspace), then %NULL
* will be returned.
*
* If memory can't be allocated for the return value, %NULL will be returned
* instead.
*
* (In short, there are several ways this function can fail, and if it fails
* it returns %NULL; so check the return value.)
*
* Return value: The same pixbuf as @dest if it was non-%NULL, or a newly-created
* pixbuf with a reference count of 1 if no destination pixbuf was specified, or %NULL on error
**/
GdkPixbuf *
gdk_pixbuf_get_from_drawable (GdkPixbuf *dest,
GdkDrawable *src,
GdkColormap *cmap,
int src_x, int src_y,
int dest_x, int dest_y,
int width, int height)
{
int src_width, src_height;
cairo_surface_t *surface;
int depth;
/* General sanity checks */
g_return_val_if_fail (src != NULL, NULL);
if (GDK_IS_WINDOW (src))
/* FIXME: this is not perfect, since is_viewable() only tests
* recursively up the Gdk parent window tree, but stops at
* foreign windows or Gdk toplevels. I.e. if a window manager
* unmapped one of its own windows, this won't work.
*/
g_return_val_if_fail (gdk_window_is_viewable (src), NULL);
if (!dest)
g_return_val_if_fail (dest_x == 0 && dest_y == 0, NULL);
else
{
g_return_val_if_fail (gdk_pixbuf_get_colorspace (dest) == GDK_COLORSPACE_RGB, NULL);
g_return_val_if_fail (gdk_pixbuf_get_n_channels (dest) == 3 ||
gdk_pixbuf_get_n_channels (dest) == 4, NULL);
g_return_val_if_fail (gdk_pixbuf_get_bits_per_sample (dest) == 8, NULL);
}
if (cmap == NULL)
cmap = gdk_drawable_get_colormap (src);
depth = gdk_drawable_get_depth (src);
if (depth != 1 && cmap == NULL)
{
g_warning ("%s: Source drawable has no colormap; either pass "
"in a colormap, or set the colormap on the drawable "
"with gdk_drawable_set_colormap()", G_STRLOC);
return NULL;
}
if (cmap != NULL && depth != cmap->visual->depth)
{
g_warning ("%s: Depth of the source drawable is %d where as "
"the visual depth of the colormap passed is %d",
G_STRLOC, depth, cmap->visual->depth);
return NULL;
}
/* Coordinate sanity checks */
if (GDK_IS_PIXMAP (src))
{
gdk_drawable_get_size (src, &src_width, &src_height);
if (width < 0)
width = src_width;
if (height < 0)
height = src_height;
g_return_val_if_fail (src_x >= 0 && src_y >= 0, NULL);
g_return_val_if_fail (src_x + width <= src_width && src_y + height <= src_height, NULL);
}
surface = _gdk_drawable_ref_cairo_surface (src);
dest = gdk_pixbuf_get_from_surface (dest,
surface,
src_x, src_y,
dest_x, dest_y,
width, height);
cairo_surface_destroy (surface);
return dest;
}
static cairo_format_t
gdk_cairo_format_for_content (cairo_content_t content)
{
switch (content)
{
case CAIRO_CONTENT_COLOR:
return CAIRO_FORMAT_RGB24;
case CAIRO_CONTENT_ALPHA:
return CAIRO_FORMAT_A8;
case CAIRO_CONTENT_COLOR_ALPHA:
default:
return CAIRO_FORMAT_ARGB32;
}
}
static cairo_surface_t *
gdk_cairo_surface_coerce_to_image (cairo_surface_t *surface,
cairo_content_t content,
int width,
int height)
{
cairo_surface_t *copy;
cairo_t *cr;
if (cairo_surface_get_type (surface) == CAIRO_SURFACE_TYPE_IMAGE &&
cairo_surface_get_content (surface) == content &&
cairo_image_surface_get_width (surface) >= width &&
cairo_image_surface_get_height (surface) >= height)
return cairo_surface_reference (surface);
copy = cairo_image_surface_create (gdk_cairo_format_for_content (content),
width,
height);
cr = cairo_create (copy);
cairo_set_operator (cr, CAIRO_OPERATOR_SOURCE);
cairo_set_source_surface (cr, surface, 0, 0);
cairo_paint (cr);
cairo_destroy (cr);
return copy;
}
static void
convert_alpha (guchar *dest_data,
int dest_stride,
guchar *src_data,
int src_stride,
int src_x,
int src_y,
int dest_x,
int dest_y,
int width,
int height)
{
int x, y;
dest_data += dest_stride * dest_y + dest_x * 4;
src_data += src_stride * src_y + src_x * 4;
for (y = 0; y < height; y++) {
guint32 *src = (guint32 *) src_data;
for (x = 0; x < width; x++) {
guint alpha = src[x] >> 24;
if (alpha == 0)
{
dest_data[x * 4 + 0] = 0;
dest_data[x * 4 + 1] = 0;
dest_data[x * 4 + 2] = 0;
}
else
{
dest_data[x * 4 + 0] = (((src[x] & 0xff0000) >> 16) * 255 + alpha / 2) / alpha;
dest_data[x * 4 + 1] = (((src[x] & 0x00ff00) >> 8) * 255 + alpha / 2) / alpha;
dest_data[x * 4 + 2] = (((src[x] & 0x0000ff) >> 0) * 255 + alpha / 2) / alpha;
}
dest_data[x * 4 + 3] = alpha;
}
src_data += src_stride;
dest_data += dest_stride;
}
}
static void
convert_no_alpha (guchar *dest_data,
int dest_stride,
guchar *src_data,
int src_stride,
int src_x,
int src_y,
int dest_x,
int dest_y,
int width,
int height)
{
int x, y;
dest_data += dest_stride * dest_y + dest_x * 3;
src_data += src_stride * src_y + src_x * 4;
for (y = 0; y < height; y++) {
guint32 *src = (guint32 *) src_data;
for (x = 0; x < width; x++) {
dest_data[x * 3 + 0] = src[x] >> 16;
dest_data[x * 3 + 1] = src[x] >> 8;
dest_data[x * 3 + 2] = src[x];
}
src_data += src_stride;
dest_data += dest_stride;
}
}
/**
* gdk_pixbuf_get_from_surface:
* @dest: (allow-none): Destination pixbuf, or %NULL if a new pixbuf should be created.
* @surface: surface to copy from
* @src_x: Source X coordinate within drawable.
* @src_y: Source Y coordinate within drawable.
* @dest_x: Destination X coordinate in pixbuf, or 0 if @dest is NULL.
* @dest_y: Destination Y coordinate in pixbuf, or 0 if @dest is NULL.
* @width: Width in pixels of region to get.
* @height: Height in pixels of region to get.
*
* Transfers image data from a #cairo_surface_t and converts it to an RGB(A)
* representation inside a #GdkPixbuf. This allows you to efficiently read individual
* pixels from Cairo surfaces. For #GdkWindows, use gdk_pixbuf_get_from_drawable()
* instead.
*
* If the specified destination pixbuf @dest is %NULL, then this
* function will create an RGB pixbuf with 8 bits per channel. The pixbuf will
* contain an alpha channel if the @surface contains one. In this case, the @dest_x
* and @dest_y arguments must be specified as 0.
*
* If the specified drawable is a window, and the window is off the
* screen, then there is no image data in the obscured/offscreen
* regions to be placed in the pixbuf. The contents of portions of the
* pixbuf corresponding to the offscreen region are undefined.
*
* If the window you're obtaining data from is partially obscured by
* other windows, then the contents of the pixbuf areas corresponding
* to the obscured regions are undefined.
*
* If memory can't be allocated for the return value, %NULL will be returned
* instead.
*
* (In short, there are several ways this function can fail, and if it fails
* it returns %NULL; so check the return value.)
*
* Return value: The same pixbuf as @dest if it was non-%NULL, or a newly-created
* pixbuf with a reference count of 1 if no destination pixbuf was specified, or %NULL on error
**/
GdkPixbuf *
gdk_pixbuf_get_from_surface (GdkPixbuf *dest,
cairo_surface_t *surface,
int src_x,
int src_y,
int dest_x,
int dest_y,
int width,
int height)
{
cairo_content_t content;
/* General sanity checks */
g_return_val_if_fail (surface != NULL, NULL);
g_return_val_if_fail (src_x >= 0 && src_y >= 0, NULL);
g_return_val_if_fail (width > 0 && height > 0, NULL);
if (!dest)
{
g_return_val_if_fail (dest_x == 0 && dest_y == 0, NULL);
content = cairo_surface_get_content (surface) | CAIRO_CONTENT_COLOR;
dest = gdk_pixbuf_new (GDK_COLORSPACE_RGB,
!!(content & CAIRO_CONTENT_ALPHA),
8,
width, height);
}
else
{
g_return_val_if_fail (gdk_pixbuf_get_colorspace (dest) == GDK_COLORSPACE_RGB, NULL);
g_return_val_if_fail (gdk_pixbuf_get_n_channels (dest) == 3 ||
gdk_pixbuf_get_n_channels (dest) == 4, NULL);
g_return_val_if_fail (gdk_pixbuf_get_bits_per_sample (dest) == 8, NULL);
g_return_val_if_fail (dest_x >= 0 && dest_y >= 0, NULL);
g_return_val_if_fail (dest_x + width <= gdk_pixbuf_get_width (dest), NULL);
g_return_val_if_fail (dest_y + height <= gdk_pixbuf_get_height (dest), NULL);
content = gdk_pixbuf_get_has_alpha (dest) ? CAIRO_CONTENT_COLOR_ALPHA : CAIRO_CONTENT_COLOR;
}
surface = gdk_cairo_surface_coerce_to_image (surface, content, src_x + width, src_y + height);
cairo_surface_flush (surface);
if (cairo_surface_status (surface) || dest == NULL)
{
cairo_surface_destroy (surface);
return NULL;
}
if (gdk_pixbuf_get_has_alpha (dest))
convert_alpha (gdk_pixbuf_get_pixels (dest),
gdk_pixbuf_get_rowstride (dest),
cairo_image_surface_get_data (surface),
cairo_image_surface_get_stride (surface),
src_x, src_y,
dest_x, dest_y,
width, height);
else
convert_no_alpha (gdk_pixbuf_get_pixels (dest),
gdk_pixbuf_get_rowstride (dest),
cairo_image_surface_get_data (surface),
cairo_image_surface_get_stride (surface),
src_x, src_y,
dest_x, dest_y,
width, height);
cairo_surface_destroy (surface);
return dest;
}
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