/* 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, see <http://www.gnu.org/licenses/>.
*/
#include "config.h"
#include "gdkpixbuf.h"
#include "gdkwindow.h"
#include "gdkinternals.h"
#include <gdk-pixbuf/gdk-pixbuf.h>
/**
* SECTION:pixbufs
* @Short_description: Functions for obtaining pixbufs
* @Title: Pixbufs
*
* Pixbufs are client-side images. For details on how to create
* and manipulate pixbufs, see the #GdkPixbuf API documentation.
*
* The functions described here allow to obtain pixbufs from
* #GdkWindows and cairo surfaces.
*/
/**
* gdk_pixbuf_get_from_window:
* @window: Source window
* @src_x: Source X coordinate within @window
* @src_y: Source Y coordinate within @window
* @width: Width in pixels of region to get
* @height: Height in pixels of region to get
*
* Transfers image data from a #GdkWindow 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.
*
* This function will create an RGB pixbuf with 8 bits per channel with
* the size specified by the @width and @height arguments scaled by the
* scale factor of @window. The pixbuf will contain an alpha channel if
* the @window contains one.
*
* If 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 window 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.)
*
* Returns: (nullable) (transfer full): A newly-created pixbuf with a
* reference count of 1, or %NULL on error
*/
GdkPixbuf *
gdk_pixbuf_get_from_window (GdkWindow *src,
gint src_x,
gint src_y,
gint width,
gint height)
{
cairo_surface_t *surface;
cairo_surface_t *copy;
cairo_t *cr;
GdkPixbuf *dest;
int scale;
g_return_val_if_fail (GDK_IS_WINDOW (src), NULL);
g_return_val_if_fail (gdk_window_is_viewable (src), NULL);
surface = _gdk_window_ref_cairo_surface (src);
scale = gdk_window_get_scale_factor (src);
/* We do not know what happened to this surface outside of GDK.
* Especially for foreign windows, they will have been modified
* by external applications.
* So be on the safe side and:
*/
cairo_surface_mark_dirty (surface);
if (cairo_surface_get_content (surface) & CAIRO_CONTENT_ALPHA)
copy = cairo_image_surface_create (CAIRO_FORMAT_ARGB32, width * scale, height * scale);
else
copy = cairo_image_surface_create (CAIRO_FORMAT_RGB24, width * scale, height * scale);
cairo_surface_set_device_scale (copy, scale, scale);
cr = cairo_create (copy);
cairo_set_operator (cr, CAIRO_OPERATOR_SOURCE);
cairo_set_source_surface (cr, surface, -src_x, -src_y);
cairo_paint (cr);
cairo_destroy (cr);
dest = gdk_pixbuf_get_from_surface (copy, 0, 0, width * scale, height * scale);
cairo_surface_destroy (copy);
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 src_x,
int src_y,
int width,
int height)
{
cairo_surface_t *copy;
cairo_t *cr;
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, -src_x, -src_y);
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 width,
int height)
{
int x, y;
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 width,
int height)
{
int x, y;
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:
* @surface: surface to copy from
* @src_x: Source X coordinate within @surface
* @src_y: Source Y coordinate within @surface
* @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_window() instead.
*
* This function will create an RGB pixbuf with 8 bits per channel.
* The pixbuf will contain an alpha channel if the @surface contains one.
*
* Returns: (nullable) (transfer full): A newly-created pixbuf with a
* reference count of 1, or %NULL on error
*/
GdkPixbuf *
gdk_pixbuf_get_from_surface (cairo_surface_t *surface,
gint src_x,
gint src_y,
gint width,
gint height)
{
cairo_content_t content;
GdkPixbuf *dest;
/* General sanity checks */
g_return_val_if_fail (surface != NULL, NULL);
g_return_val_if_fail (width > 0 && height > 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);
if (cairo_surface_get_type (surface) == CAIRO_SURFACE_TYPE_IMAGE &&
cairo_image_surface_get_format (surface) == gdk_cairo_format_for_content (content))
surface = cairo_surface_reference (surface);
else
{
surface = gdk_cairo_surface_coerce_to_image (surface, content,
src_x, src_y,
width, height);
src_x = 0;
src_y = 0;
}
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,
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,
width, height);
cairo_surface_destroy (surface);
return dest;
}