gtk/gdk-pixbuf/gdk-pixbuf.c
1999-11-04 21:52:08 +00:00

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/* GdkPixbuf library - Basic memory management
*
* Copyright (C) 1999 The Free Software Foundation
*
* Authors: Mark Crichton <crichton@gimp.org>
* Miguel de Icaza <miguel@gnu.org>
* 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 Library 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
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library 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 <math.h>
#include <libart_lgpl/art_misc.h>
#include <libart_lgpl/art_affine.h>
#include <libart_lgpl/art_pixbuf.h>
#include <libart_lgpl/art_rgb_pixbuf_affine.h>
#include <libart_lgpl/art_alphagamma.h>
#include "gdk-pixbuf.h"
/* Reference counting */
/**
* gdk_pixbuf_ref:
* @pixbuf: A pixbuf.
*
* Adds a reference to a pixbuf. It must be released afterwards using
* gdk_pixbuf_unref().
**/
void
gdk_pixbuf_ref (GdkPixbuf *pixbuf)
{
g_return_if_fail (pixbuf != NULL);
g_return_if_fail (pixbuf->ref_count > 0);
pixbuf->ref_count++;
}
/**
* gdk_pixbuf_unref:
* @pixbuf: A pixbuf.
*
* Removes a reference from a pixbuf. It will be destroyed when the reference
* count drops to zero.
**/
void
gdk_pixbuf_unref (GdkPixbuf *pixbuf)
{
g_return_if_fail (pixbuf != NULL);
g_return_if_fail (pixbuf->ref_count > 0);
pixbuf->ref_count--;
if (pixbuf->ref_count == 0) {
art_pixbuf_free (pixbuf->art_pixbuf);
pixbuf->art_pixbuf = NULL;
g_free (pixbuf);
}
}
/* Wrap a libart pixbuf */
/**
* gdk_pixbuf_new_from_art_pixbuf:
* @art_pixbuf: A libart pixbuf.
*
* Creates a #GdkPixbuf by wrapping a libart pixbuf.
*
* Return value: A newly-created #GdkPixbuf structure with a reference count of
* 1.
**/
GdkPixbuf *
gdk_pixbuf_new_from_art_pixbuf (ArtPixBuf *art_pixbuf)
{
GdkPixbuf *pixbuf;
g_return_val_if_fail (art_pixbuf != NULL, NULL);
pixbuf = g_new (GdkPixbuf, 1);
pixbuf->ref_count = 1;
pixbuf->art_pixbuf = art_pixbuf;
return pixbuf;
}
/* Destroy notification function for gdk_pixbuf_new() */
static void
free_buffer (gpointer user_data, gpointer data)
{
free (data);
}
/* Create an empty pixbuf */
/**
* gdk_pixbuf_new:
* @format: Image format.
* @has_alpha: Whether the image should have transparency information.
* @bits_per_sample: Number of bits per color sample.
* @width: Width of image in pixels.
* @height: Height of image in pixels.
*
* Creates a new #GdkPixbuf structure and allocates a buffer for it. The buffer
* has an optimal rowstride. Note that the buffer is not cleared; you will have
* to fill it completely.
*
* Return value: A newly-created #GdkPixbuf with a reference count of 1, or NULL
* if not enough memory could be allocated for the image buffer.
**/
GdkPixbuf *
gdk_pixbuf_new (ArtPixFormat format, gboolean has_alpha, int bits_per_sample,
int width, int height)
{
guchar *buf;
int channels;
int rowstride;
g_return_val_if_fail (format == ART_PIX_RGB, NULL);
g_return_val_if_fail (bits_per_sample == 8, NULL);
g_return_val_if_fail (width > 0, NULL);
g_return_val_if_fail (height > 0, NULL);
/* Always align rows to 32-bit boundaries */
channels = has_alpha ? 4 : 3;
rowstride = 4 * ((channels * width + 3) / 4);
buf = malloc (height * rowstride);
if (!buf)
return NULL;
return gdk_pixbuf_new_from_data (buf, format, has_alpha, width, height, rowstride,
free_buffer, NULL);
}
/* Convenience functions */
/**
* gdk_pixbuf_get_format:
* @pixbuf: A pixbuf.
*
* Queries the image format (color model) of a pixbuf.
*
* Return value: Image format.
**/
ArtPixFormat
gdk_pixbuf_get_format (GdkPixbuf *pixbuf)
{
/* Unfortunately, there's nothing else to return */
g_return_val_if_fail (pixbuf != NULL, ART_PIX_RGB);
g_assert (pixbuf->art_pixbuf != NULL);
return (pixbuf->art_pixbuf->format);
}
/**
* gdk_pixbuf_get_n_channels:
* @pixbuf: A pixbuf.
*
* Queries the number of channels of a pixbuf.
*
* Return value: Number of channels.
**/
int
gdk_pixbuf_get_n_channels (GdkPixbuf *pixbuf)
{
g_return_val_if_fail (pixbuf != NULL, -1);
g_assert (pixbuf->art_pixbuf != NULL);
return (pixbuf->art_pixbuf->n_channels);
}
/**
* gdk_pixbuf_get_has_alpha:
* @pixbuf: A pixbuf.
*
* Queries whether a pixbuf has an alpha channel (opacity information).
*
* Return value: TRUE if it has an alpha channel, FALSE otherwise.
**/
int
gdk_pixbuf_get_has_alpha (GdkPixbuf *pixbuf)
{
g_return_val_if_fail (pixbuf != NULL, -1);
g_assert (pixbuf->art_pixbuf != NULL);
return (pixbuf->art_pixbuf->has_alpha);
}
/**
* gdk_pixbuf_get_bits_per_sample:
* @pixbuf: A pixbuf.
*
* Queries the number of bits per color sample in a pixbuf.
*
* Return value: Number of bits per color sample.
**/
int
gdk_pixbuf_get_bits_per_sample (GdkPixbuf *pixbuf)
{
g_return_val_if_fail (pixbuf != NULL, -1);
g_assert (pixbuf->art_pixbuf != NULL);
return (pixbuf->art_pixbuf->bits_per_sample);
}
/**
* gdk_pixbuf_get_pixels:
* @pixbuf: A pixbuf.
*
* Queries a pointer to the pixel data of a pixbuf.
*
* Return value: A pointer to the pixbuf's pixel data.
**/
guchar *
gdk_pixbuf_get_pixels (GdkPixbuf *pixbuf)
{
g_return_val_if_fail (pixbuf != NULL, NULL);
g_assert (pixbuf->art_pixbuf != NULL);
return (pixbuf->art_pixbuf->pixels);
}
/**
* gdk_pixbuf_get_width:
* @pixbuf: A pixbuf.
*
* Queries the width of a pixbuf.
*
* Return value: Width in pixels.
**/
int
gdk_pixbuf_get_width (GdkPixbuf *pixbuf)
{
g_return_val_if_fail (pixbuf != NULL, -1);
g_assert (pixbuf->art_pixbuf != NULL);
return (pixbuf->art_pixbuf->width);
}
/**
* gdk_pixbuf_get_height:
* @pixbuf: A pixbuf.
*
* Queries the height of a pixbuf.
*
* Return value: Height in pixels.
**/
int
gdk_pixbuf_get_height (GdkPixbuf *pixbuf)
{
g_return_val_if_fail (pixbuf != NULL, -1);
g_assert (pixbuf->art_pixbuf != NULL);
return (pixbuf->art_pixbuf->height);
}
/**
* gdk_pixbuf_get_rowstride:
* @pixbuf: A pixbuf.
*
* Queries the rowstride of a pixbuf, or the number of bytes between rows.
*
* Return value: Number of bytes between rows.
**/
int
gdk_pixbuf_get_rowstride (GdkPixbuf *pixbuf)
{
g_return_val_if_fail (pixbuf != NULL, -1);
g_assert (pixbuf->art_pixbuf != NULL);
return (pixbuf->art_pixbuf->rowstride);
}