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eel-gdk-pixbuf-extensions.c
1474 lines (1258 loc) · 44.6 KB
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eel-gdk-pixbuf-extensions.c
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/* -*- Mode: C; indent-tabs-mode: t; c-basic-offset: 8; tab-width: 8 -*- */
/* eel-gdk-pixbuf-extensions.c: Routines to augment what's in gdk-pixbuf.
Copyright (C) 2000 Eazel, Inc.
The Mate Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
The Mate 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the Mate Library; see the file COPYING.LIB. If not,
write to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
Boston, MA 02110-1301, USA.
Authors: Darin Adler <darin@eazel.com>
Ramiro Estrugo <ramiro@eazel.com>
*/
#include <config.h>
#include "eel-gdk-pixbuf-extensions.h"
#include "eel-debug.h"
#include "eel-gdk-extensions.h"
#include "eel-glib-extensions.h"
#include "eel-graphic-effects.h"
#include "eel-lib-self-check-functions.h"
#include "eel-string.h"
#include <gdk-pixbuf/gdk-pixbuf.h>
#include <gdk/gdkprivate.h>
#include <gdk/gdkx.h>
#include <gio/gio.h>
#include <math.h>
#include <stdlib.h>
#include <stdio.h>
#define LOAD_BUFFER_SIZE 65536
const EelIRect eel_gdk_pixbuf_whole_pixbuf = { G_MININT, G_MININT, G_MAXINT, G_MAXINT };
struct EelPixbufLoadHandle
{
GCancellable *cancellable;
GInputStream *stream;
EelPixbufLoadCallback callback;
gpointer callback_data;
GdkPixbufLoader *loader;
char buffer[LOAD_BUFFER_SIZE];
};
GdkPixbuf *
eel_gdk_pixbuf_load (const char *uri)
{
GdkPixbuf *pixbuf;
GFile *file;
GFileInputStream *stream;
g_return_val_if_fail (uri != NULL, NULL);
file = g_file_new_for_uri (uri);
stream = g_file_read (file, NULL, NULL);
g_object_unref (file);
if (stream == NULL)
{
return NULL;
}
pixbuf = eel_gdk_pixbuf_load_from_stream (G_INPUT_STREAM (stream));
g_object_unref (stream);
return pixbuf;
}
GdkPixbuf *
eel_gdk_pixbuf_load_from_stream (GInputStream *stream)
{
return eel_gdk_pixbuf_load_from_stream_at_size (stream, -1);
}
static void
pixbuf_loader_size_prepared (GdkPixbufLoader *loader,
int width,
int height,
gpointer desired_size_ptr)
{
int size, desired_size;
float scale;
size = MAX (width, height);
desired_size = GPOINTER_TO_INT (desired_size_ptr);
if (size != desired_size)
{
scale = (float) desired_size / size;
gdk_pixbuf_loader_set_size (loader,
floor (scale * width + 0.5),
floor (scale * height + 0.5));
}
}
GdkPixbuf *
eel_gdk_pixbuf_load_from_stream_at_size (GInputStream *stream,
int size)
{
char buffer[LOAD_BUFFER_SIZE];
gssize bytes_read;
GdkPixbufLoader *loader;
GdkPixbuf *pixbuf;
gboolean got_eos;
g_return_val_if_fail (stream != NULL, NULL);
got_eos = FALSE;
loader = gdk_pixbuf_loader_new ();
if (size > 0)
{
g_signal_connect (loader, "size-prepared",
G_CALLBACK (pixbuf_loader_size_prepared),
GINT_TO_POINTER (size));
}
while (1)
{
bytes_read = g_input_stream_read (stream, buffer, sizeof (buffer),
NULL, NULL);
if (bytes_read < 0)
{
break;
}
if (bytes_read == 0)
{
got_eos = TRUE;
break;
}
if (!gdk_pixbuf_loader_write (loader,
buffer,
bytes_read,
NULL))
{
break;
}
}
g_input_stream_close (stream, NULL, NULL);
gdk_pixbuf_loader_close (loader, NULL);
pixbuf = NULL;
if (got_eos)
{
pixbuf = gdk_pixbuf_loader_get_pixbuf (loader);
if (pixbuf != NULL)
{
g_object_ref (pixbuf);
}
}
g_object_unref (loader);
return pixbuf;
}
static void
free_pixbuf_load_handle (EelPixbufLoadHandle *handle)
{
g_object_unref (handle->cancellable);
if (handle->loader != NULL)
{
g_object_unref (handle->loader);
}
if (handle->stream)
{
g_input_stream_close_async (handle->stream, 0, NULL, NULL, NULL);
g_object_unref (handle->stream);
}
g_free (handle);
}
static void
load_done (EelPixbufLoadHandle *handle, GError *error, gboolean get_pixbuf)
{
GdkPixbuf *pixbuf;
if (handle->loader != NULL)
{
gdk_pixbuf_loader_close (handle->loader, NULL);
}
pixbuf = get_pixbuf ? gdk_pixbuf_loader_get_pixbuf (handle->loader) : NULL;
handle->callback (error, pixbuf, handle->callback_data);
free_pixbuf_load_handle (handle);
}
static void
file_read_callback (GObject *source_object,
GAsyncResult *res,
gpointer user_data)
{
EelPixbufLoadHandle *handle;
gssize bytes_read;
GError *error;
handle = user_data;
if (g_cancellable_is_cancelled (handle->cancellable))
{
free_pixbuf_load_handle (handle);
return;
}
error = NULL;
bytes_read = g_input_stream_read_finish (G_INPUT_STREAM (source_object),
res, &error);
if (bytes_read > 0)
{
if (!gdk_pixbuf_loader_write (handle->loader,
handle->buffer,
bytes_read,
&error))
{
bytes_read = -1;
}
else
{
g_input_stream_read_async (handle->stream,
handle->buffer,
sizeof (handle->buffer),
0,
handle->cancellable,
file_read_callback, handle);
return;
}
}
load_done (handle, error, bytes_read == 0);
if (error != NULL)
{
g_error_free (error);
}
}
static void
file_opened_callback (GObject *source_object,
GAsyncResult *res,
gpointer user_data)
{
EelPixbufLoadHandle *handle;
GFileInputStream *stream;
GError *error;
handle = user_data;
if (g_cancellable_is_cancelled (handle->cancellable))
{
free_pixbuf_load_handle (handle);
return;
}
error = NULL;
stream = g_file_read_finish (G_FILE (source_object), res, &error);
if (stream == NULL)
{
load_done (handle, error, FALSE);
g_error_free (error);
return;
}
handle->stream = G_INPUT_STREAM (stream);
handle->loader = gdk_pixbuf_loader_new ();
g_input_stream_read_async (handle->stream,
handle->buffer,
sizeof (handle->buffer),
0,
handle->cancellable,
file_read_callback, handle);
}
EelPixbufLoadHandle *
eel_gdk_pixbuf_load_async (const char *uri,
int priority,
EelPixbufLoadCallback callback,
gpointer callback_data)
{
EelPixbufLoadHandle *handle;
GFile *file;
handle = g_new0 (EelPixbufLoadHandle, 1);
handle->cancellable = g_cancellable_new ();
handle->callback = callback;
handle->callback_data = callback_data;
file = g_file_new_for_uri (uri);
g_file_read_async (file, priority, handle->cancellable,
file_opened_callback, handle);
return handle;
}
void
eel_cancel_gdk_pixbuf_load (EelPixbufLoadHandle *handle)
{
if (handle == NULL)
{
return;
}
g_cancellable_cancel (handle->cancellable);
}
/* return the average value of each component */
guint32
eel_gdk_pixbuf_average_value (GdkPixbuf *pixbuf)
{
guint64 a_total, r_total, g_total, b_total;
guint row, column;
int row_stride;
const guchar *pixels, *p;
int r, g, b, a;
guint64 dividend;
guint width, height;
width = gdk_pixbuf_get_width (pixbuf);
height = gdk_pixbuf_get_height (pixbuf);
row_stride = gdk_pixbuf_get_rowstride (pixbuf);
pixels = gdk_pixbuf_get_pixels (pixbuf);
/* iterate through the pixbuf, counting up each component */
a_total = 0;
r_total = 0;
g_total = 0;
b_total = 0;
if (gdk_pixbuf_get_has_alpha (pixbuf))
{
for (row = 0; row < height; row++)
{
p = pixels + (row * row_stride);
for (column = 0; column < width; column++)
{
r = *p++;
g = *p++;
b = *p++;
a = *p++;
a_total += a;
r_total += r * a;
g_total += g * a;
b_total += b * a;
}
}
dividend = height * width * 0xFF;
a_total *= 0xFF;
}
else
{
for (row = 0; row < height; row++)
{
p = pixels + (row * row_stride);
for (column = 0; column < width; column++)
{
r = *p++;
g = *p++;
b = *p++;
r_total += r;
g_total += g;
b_total += b;
}
}
dividend = height * width;
a_total = dividend * 0xFF;
}
return ((a_total + dividend / 2) / dividend) << 24
| ((r_total + dividend / 2) / dividend) << 16
| ((g_total + dividend / 2) / dividend) << 8
| ((b_total + dividend / 2) / dividend);
}
double
eel_gdk_scale_to_fit_factor (int width, int height,
int max_width, int max_height,
int *scaled_width, int *scaled_height)
{
double scale_factor;
scale_factor = MIN (max_width / (double) width, max_height / (double) height);
*scaled_width = floor (width * scale_factor + .5);
*scaled_height = floor (height * scale_factor + .5);
return scale_factor;
}
/* Returns a scaled copy of pixbuf, preserving aspect ratio. The copy will
* be scaled as large as possible without exceeding the specified width and height.
*/
GdkPixbuf *
eel_gdk_pixbuf_scale_to_fit (GdkPixbuf *pixbuf, int max_width, int max_height)
{
int scaled_width;
int scaled_height;
eel_gdk_scale_to_fit_factor (gdk_pixbuf_get_width(pixbuf), gdk_pixbuf_get_height(pixbuf),
max_width, max_height,
&scaled_width, &scaled_height);
return gdk_pixbuf_scale_simple (pixbuf, scaled_width, scaled_height, GDK_INTERP_BILINEAR);
}
/* Returns a copy of pixbuf scaled down, preserving aspect ratio, to fit
* within the specified width and height. If it already fits, a copy of
* the original, without scaling, is returned.
*/
GdkPixbuf *
eel_gdk_pixbuf_scale_down_to_fit (GdkPixbuf *pixbuf, int max_width, int max_height)
{
int scaled_width;
int scaled_height;
double scale_factor;
scale_factor = eel_gdk_scale_to_fit_factor (gdk_pixbuf_get_width(pixbuf), gdk_pixbuf_get_height(pixbuf),
max_width, max_height,
&scaled_width, &scaled_height);
if (scale_factor >= 1.0)
{
return gdk_pixbuf_copy (pixbuf);
}
else
{
return eel_gdk_pixbuf_scale_down (pixbuf, scaled_width, scaled_height);
}
}
double
eel_gdk_scale_to_min_factor (int width, int height,
int min_width, int min_height,
int *scaled_width, int *scaled_height)
{
double scale_factor;
scale_factor = MAX (min_width / (double) width, min_height / (double) height);
*scaled_width = floor (width * scale_factor + .5);
*scaled_height = floor (height * scale_factor + .5);
return scale_factor;
}
/* Returns a scaled copy of pixbuf, preserving aspect ratio. The copy will
* be scaled as small as possible without going under the specified width and height.
*/
GdkPixbuf *
eel_gdk_pixbuf_scale_to_min (GdkPixbuf *pixbuf, int min_width, int min_height)
{
int scaled_width;
int scaled_height;
eel_gdk_scale_to_min_factor (gdk_pixbuf_get_width(pixbuf), gdk_pixbuf_get_height(pixbuf),
min_width, min_height,
&scaled_width, &scaled_height);
return gdk_pixbuf_scale_simple (pixbuf, scaled_width, scaled_height, GDK_INTERP_BILINEAR);
}
/**
* eel_gdk_pixbuf_is_valid:
* @pixbuf: A GdkPixbuf
*
* Return value: A boolean indicating whether the given pixbuf is valid.
*
* A pixbuf is valid if:
*
* 1. It is non NULL
* 2. It is has non NULL pixel data.
* 3. It has width and height greater than 0.
*/
gboolean
eel_gdk_pixbuf_is_valid (const GdkPixbuf *pixbuf)
{
return ((pixbuf != NULL)
&& (gdk_pixbuf_get_pixels (pixbuf) != NULL)
&& (gdk_pixbuf_get_width (pixbuf) > 0)
&& (gdk_pixbuf_get_height (pixbuf) > 0));
}
/**
* eel_gdk_pixbuf_get_dimensions:
* @pixbuf: A GdkPixbuf
*
* Return value: The dimensions of the pixbuf as a EelDimensions.
*
* This function is useful in code that uses libart rect
* intersection routines.
*/
EelDimensions
eel_gdk_pixbuf_get_dimensions (const GdkPixbuf *pixbuf)
{
EelDimensions dimensions;
g_return_val_if_fail (eel_gdk_pixbuf_is_valid (pixbuf), eel_dimensions_empty);
dimensions.width = gdk_pixbuf_get_width (pixbuf);
dimensions.height = gdk_pixbuf_get_height (pixbuf);
return dimensions;
}
/**
* eel_gdk_pixbuf_fill_rectangle_with_color:
* @pixbuf: Target pixbuf to fill into.
* @area: Rectangle to fill.
* @color: The color to use.
*
* Fill the rectangle with the the given color.
*/
void
eel_gdk_pixbuf_fill_rectangle_with_color (GdkPixbuf *pixbuf,
EelIRect area,
guint32 color)
{
EelIRect target;
guchar red;
guchar green;
guchar blue;
guchar alpha;
guchar *pixels;
gboolean has_alpha;
guint pixel_offset;
guint rowstride;
guchar *row_offset;
int x;
int y;
g_return_if_fail (eel_gdk_pixbuf_is_valid (pixbuf));
target = eel_gdk_pixbuf_intersect (pixbuf, 0, 0, area);
if (eel_irect_is_empty (&target))
{
return;
}
pixels = gdk_pixbuf_get_pixels (pixbuf);
rowstride = gdk_pixbuf_get_rowstride (pixbuf);
has_alpha = gdk_pixbuf_get_has_alpha (pixbuf);
pixel_offset = has_alpha ? 4 : 3;
red = EEL_RGBA_COLOR_GET_R (color);
green = EEL_RGBA_COLOR_GET_G (color);
blue = EEL_RGBA_COLOR_GET_B (color);
alpha = EEL_RGBA_COLOR_GET_A (color);
row_offset = pixels + target.y0 * rowstride;
for (y = target.y0; y < target.y1; y++)
{
guchar *offset = row_offset + (target.x0 * pixel_offset);
for (x = target.x0; x < target.x1; x++)
{
*(offset++) = red;
*(offset++) = green;
*(offset++) = blue;
if (has_alpha)
{
*(offset++) = alpha;
}
}
row_offset += rowstride;
}
}
gboolean
eel_gdk_pixbuf_save_to_file (const GdkPixbuf *pixbuf,
const char *file_name)
{
return gdk_pixbuf_save ((GdkPixbuf *) pixbuf,
file_name, "png", NULL, NULL);
}
void
eel_gdk_pixbuf_ref_if_not_null (GdkPixbuf *pixbuf_or_null)
{
if (pixbuf_or_null != NULL)
{
g_object_ref (pixbuf_or_null);
}
}
void
eel_gdk_pixbuf_unref_if_not_null (GdkPixbuf *pixbuf_or_null)
{
if (pixbuf_or_null != NULL)
{
g_object_unref (pixbuf_or_null);
}
}
void
eel_gdk_pixbuf_draw_to_drawable (const GdkPixbuf *pixbuf,
GdkDrawable *drawable,
int source_x,
int source_y,
EelIRect destination_area)
{
EelDimensions dimensions;
EelIRect target;
EelIRect source;
int target_width;
int target_height;
int source_width;
int source_height;
cairo_t *cr;
g_return_if_fail (eel_gdk_pixbuf_is_valid (pixbuf));
g_return_if_fail (drawable != NULL);
g_return_if_fail (!eel_irect_is_empty (&destination_area));
dimensions = eel_gdk_pixbuf_get_dimensions (pixbuf);
g_return_if_fail (source_x >= 0);
g_return_if_fail (source_y >= 0);
g_return_if_fail (source_x < dimensions.width);
g_return_if_fail (source_y < dimensions.height);
/* Clip the destination area to the pixbuf dimensions; bail if no work */
target = eel_gdk_pixbuf_intersect (pixbuf,
destination_area.x0,
destination_area.y0,
destination_area);
if (eel_irect_is_empty (&target))
{
return;
}
/* Assign the source area */
source = eel_irect_assign (source_x,
source_y,
dimensions.width - source_x,
dimensions.height - source_y);
/* Adjust the target width if the source area is smaller than the
* source pixbuf dimensions */
target_width = target.x1 - target.x0;
target_height = target.y1 - target.y0;
source_width = source.x1 - source.x0;
source_height = source.y1 - source.y0;
target.x1 = target.x0 + MIN (target_width, source_width);
target.y1 = target.y0 + MIN (target_height, source_height);
cr = gdk_cairo_create (drawable);
gdk_cairo_set_source_pixbuf (cr, (GdkPixbuf *) pixbuf,
source.x0 - target.x0, source.y0 - target.y0);
cairo_rectangle (cr, target.x0, target.y0,
target.x1 - target.x0,
target.y1 - target.y0);
cairo_fill (cr);
cairo_destroy (cr);
}
/**
* eel_gdk_pixbuf_draw_to_pixbuf:
* @pixbuf: The source pixbuf to draw.
* @destination_pixbuf: The destination pixbuf.
* @source_x: The source pixbuf x coordiate to composite from.
* @source_y: The source pixbuf y coordiate to composite from.
* @destination_area: The destination area within the destination pixbuf.
* This area will be clipped if invalid in any way.
*
* Copy one pixbuf onto another another.. This function has some advantages
* over plain gdk_pixbuf_copy_area():
*
* Composition paramters (source coordinate, destination area) are
* given in a way that is consistent with the rest of the extensions
* in this file. That is, it matches the declaration of
* eel_gdk_pixbuf_draw_to_pixbuf_alpha() and
* eel_gdk_pixbuf_draw_to_drawable() very closely.
*
* All values are clipped to make sure they are valid.
*
*/
void
eel_gdk_pixbuf_draw_to_pixbuf (const GdkPixbuf *pixbuf,
GdkPixbuf *destination_pixbuf,
int source_x,
int source_y,
EelIRect destination_area)
{
EelDimensions dimensions;
EelIRect target;
EelIRect source;
int target_width;
int target_height;
int source_width;
int source_height;
g_return_if_fail (eel_gdk_pixbuf_is_valid (pixbuf));
g_return_if_fail (eel_gdk_pixbuf_is_valid (destination_pixbuf));
g_return_if_fail (!eel_irect_is_empty (&destination_area));
dimensions = eel_gdk_pixbuf_get_dimensions (pixbuf);
g_return_if_fail (source_x >= 0);
g_return_if_fail (source_y >= 0);
g_return_if_fail (source_x < dimensions.width);
g_return_if_fail (source_y < dimensions.height);
/* Clip the destination area to the pixbuf dimensions; bail if no work */
target = eel_gdk_pixbuf_intersect (destination_pixbuf, 0, 0, destination_area);
if (eel_irect_is_empty (&target))
{
return;
}
/* Assign the source area */
source = eel_irect_assign (source_x,
source_y,
dimensions.width - source_x,
dimensions.height - source_y);
/* Adjust the target width if the source area is smaller than the
* source pixbuf dimensions */
target_width = target.x1 - target.x0;
target_height = target.y1 - target.y0;
source_width = source.x1 - source.x0;
source_height = source.y1 - source.y0;
target.x1 = target.x0 + MIN (target_width, source_width);
target.y1 = target.y0 + MIN (target_height, source_height);
gdk_pixbuf_copy_area (pixbuf,
source.x0,
source.y0,
target.x1 - target.x0,
target.y1 - target.y0,
destination_pixbuf,
target.x0,
target.y0);
}
/**
* eel_gdk_pixbuf_draw_to_pixbuf_alpha:
* @pixbuf: The source pixbuf to draw.
* @destination_pixbuf: The destination pixbuf.
* @source_x: The source pixbuf x coordiate to composite from.
* @source_y: The source pixbuf y coordiate to composite from.
* @destination_area: The destination area within the destination pixbuf.
* This area will be clipped if invalid in any way.
* @opacity: The opacity of the drawn tiles where 0 <= opacity <= 255.
* @interpolation_mode: The interpolation mode. See <gdk-pixbuf.h>
*
* Composite one pixbuf over another. This function has some advantages
* over plain gdk_pixbuf_composite():
*
* Composition paramters (source coordinate, destination area) are
* given in a way that is consistent with the rest of the extensions
* in this file. That is, it matches the declaration of
* eel_gdk_pixbuf_draw_to_pixbuf() and
* eel_gdk_pixbuf_draw_to_drawable() very closely.
*
* All values are clipped to make sure they are valid.
*
* Workaround a limitation in gdk_pixbuf_composite() that does not allow
* the source (x,y) to be greater than (0,0)
*
*/
void
eel_gdk_pixbuf_draw_to_pixbuf_alpha (const GdkPixbuf *pixbuf,
GdkPixbuf *destination_pixbuf,
int source_x,
int source_y,
EelIRect destination_area,
int opacity,
GdkInterpType interpolation_mode)
{
EelDimensions dimensions;
EelIRect target;
EelIRect source;
int target_width;
int target_height;
int source_width;
int source_height;
g_return_if_fail (eel_gdk_pixbuf_is_valid (pixbuf));
g_return_if_fail (eel_gdk_pixbuf_is_valid (destination_pixbuf));
g_return_if_fail (!eel_irect_is_empty (&destination_area));
g_return_if_fail (opacity >= EEL_OPACITY_FULLY_TRANSPARENT);
g_return_if_fail (opacity <= EEL_OPACITY_FULLY_OPAQUE);
g_return_if_fail (interpolation_mode >= GDK_INTERP_NEAREST);
g_return_if_fail (interpolation_mode <= GDK_INTERP_HYPER);
dimensions = eel_gdk_pixbuf_get_dimensions (pixbuf);
g_return_if_fail (source_x >= 0);
g_return_if_fail (source_y >= 0);
g_return_if_fail (source_x < dimensions.width);
g_return_if_fail (source_y < dimensions.height);
/* Clip the destination area to the pixbuf dimensions; bail if no work */
target = eel_gdk_pixbuf_intersect (destination_pixbuf, 0, 0, destination_area);
if (eel_irect_is_empty (&target))
{
return;
}
/* Assign the source area */
source = eel_irect_assign (source_x,
source_y,
dimensions.width - source_x,
dimensions.height - source_y);
/* Adjust the target width if the source area is smaller than the
* source pixbuf dimensions */
target_width = target.x1 - target.x0;
target_height = target.y1 - target.y0;
source_width = source.x1 - source.x0;
source_height = source.y1 - source.y0;
target.x1 = target.x0 + MIN (target_width, source_width);
target.y1 = target.y0 + MIN (target_height, source_height);
/* If the source point is not (0,0), then we need to create a sub pixbuf
* with only the source area. This is needed to work around a limitation
* in gdk_pixbuf_composite() that requires the source area to be (0,0). */
if (source.x0 != 0 || source.y0 != 0)
{
EelIRect area;
int width;
int height;
width = dimensions.width - source.x0;
height = dimensions.height - source.y0;
area.x0 = source.x0;
area.y0 = source.y0;
area.x1 = area.x0 + width;
area.y1 = area.y0 + height;
pixbuf = eel_gdk_pixbuf_new_from_pixbuf_sub_area ((GdkPixbuf *) pixbuf, area);
}
else
{
g_object_ref (G_OBJECT (pixbuf));
}
gdk_pixbuf_composite (pixbuf,
destination_pixbuf,
target.x0,
target.y0,
target.x1 - target.x0,
target.y1 - target.y0,
target.x0,
target.y0,
1.0,
1.0,
interpolation_mode,
opacity);
g_object_unref (G_OBJECT (pixbuf));
}
static void
pixbuf_destroy_callback (guchar *pixels,
gpointer callback_data)
{
g_assert (pixels != NULL);
g_assert (callback_data != NULL);
g_object_unref (callback_data);
}
/**
* eel_gdk_pixbuf_new_from_pixbuf_sub_area:
* @pixbuf: The source pixbuf.
* @area: The area within the source pixbuf to use for the sub pixbuf.
* This area needs to be contained within the bounds of the
* source pixbuf, otherwise it will be clipped to that.
*
* Return value: A newly allocated pixbuf that shares the pixel data
* of the source pixbuf in order to represent a sub area.
*
* Create a pixbuf from a sub area of another pixbuf. The resulting pixbuf
* will share the pixel data of the source pixbuf. Memory bookeeping is
* all taken care for the caller. All you need to do is g_object_unref()
* the resulting pixbuf to properly free resources.
*/
GdkPixbuf *
eel_gdk_pixbuf_new_from_pixbuf_sub_area (GdkPixbuf *pixbuf,
EelIRect area)
{
GdkPixbuf *sub_pixbuf;
EelIRect target;
guchar *pixels;
g_return_val_if_fail (eel_gdk_pixbuf_is_valid (pixbuf), NULL);
g_return_val_if_fail (!eel_irect_is_empty (&area), NULL);
/* Clip the pixbuf by the given area; bail if no work */
target = eel_gdk_pixbuf_intersect (pixbuf, 0, 0, area);
if (eel_irect_is_empty (&target))
{
return NULL;
}
/* Since we are going to be sharing the given pixbuf's data, we need
* to ref it. It will be unreffed in the destroy function above */
g_object_ref (pixbuf);
/* Compute the offset into the pixel data */
pixels =
gdk_pixbuf_get_pixels (pixbuf)
+ (target.y0 * gdk_pixbuf_get_rowstride (pixbuf))
+ (target.x0 * (gdk_pixbuf_get_has_alpha (pixbuf) ? 4 : 3));
/* Make a pixbuf pretending its real estate is the sub area */
sub_pixbuf = gdk_pixbuf_new_from_data (pixels,
GDK_COLORSPACE_RGB,
gdk_pixbuf_get_has_alpha (pixbuf),
8,
eel_irect_get_width (target),
eel_irect_get_height (target),
gdk_pixbuf_get_rowstride (pixbuf),
pixbuf_destroy_callback,
pixbuf);
return sub_pixbuf;
}
/**
* eel_gdk_pixbuf_new_from_existing_buffer:
* @buffer: The existing buffer.
* @buffer_rowstride: The existing buffer's rowstride.
* @buffer_has_alpha: A boolean value indicating whether the buffer has alpha.
* @area: The area within the existing buffer to use for the pixbuf.
* This area needs to be contained within the bounds of the
* buffer, otherwise memory will be trashed.
*
* Return value: A newly allocated pixbuf that uses the existing buffer
* for its pixel data.
*
* Create a pixbuf from an existing buffer.
*
* The resulting pixbuf is only valid for as long as &buffer is valid. It is
* up to the caller to make sure they both exist in the same scope.
* Also, it is up to the caller to make sure that the given area is fully
* contained in the buffer, otherwise memory trashing will happen.
*/
GdkPixbuf *
eel_gdk_pixbuf_new_from_existing_buffer (guchar *buffer,
int buffer_rowstride,
gboolean buffer_has_alpha,
EelIRect area)
{
GdkPixbuf *pixbuf;
guchar *pixels;
g_return_val_if_fail (buffer != NULL, NULL);
g_return_val_if_fail (buffer_rowstride > 0, NULL);
g_return_val_if_fail (!eel_irect_is_empty (&area), NULL);
/* Compute the offset into the buffer */
pixels =
buffer
+ (area.y0 * buffer_rowstride)
+ (area.x0 * (buffer_has_alpha ? 4 : 3));
pixbuf = gdk_pixbuf_new_from_data (pixels,
GDK_COLORSPACE_RGB,
buffer_has_alpha,
8,
eel_irect_get_width (area),
eel_irect_get_height (area),
buffer_rowstride,
NULL,
NULL);