netsurf/image/bitmap.h
John Mark Bell e51ea4e0ee Document the bitmap format properly.
svn path=/trunk/netsurf/; revision=10623
2010-07-09 21:11:06 +00:00

91 lines
3.0 KiB
C

/*
* Copyright 2004 James Bursa <bursa@users.sourceforge.net>
*
* This file is part of NetSurf, http://www.netsurf-browser.org/
*
* NetSurf is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 2 of the License.
*
* NetSurf 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/** \file
* Generic bitmap handling (interface).
*
* This interface wraps the native platform-specific image format, so that
* portable image convertors can be written.
*
* Bitmaps are required to be 32bpp with components in the order RR GG BB AA.
*
* For example, an opaque 1x1 pixel image would yield the following bitmap
* data:
*
* Red : 0xff 0x00 0x00 0x00
* Green: 0x00 0xff 0x00 0x00
* Blue : 0x00 0x00 0xff 0x00
*
* Any attempt to read pixels by casting bitmap data to uint32_t or similar
* will need to cater for the order of bytes in a word being different on
* big and little endian systems. To avoid confusion, it is recommended
* that pixel data is loaded as follows:
*
* uint32_t read_pixel(const uint8_t *bmp)
* {
* // red green blue alpha
* return bmp[0] | (bmp[1] << 8) | (bmp[2] << 16) | (bmp[3] << 24);
* }
*
* and *not* as follows:
*
* uint32_t read_pixel(const uint8_t *bmp)
* {
* return *((uint32_t *) bmp);
* }
*/
#ifndef _NETSURF_IMAGE_BITMAP_H_
#define _NETSURF_IMAGE_BITMAP_H_
#include <stdbool.h>
#include <stdlib.h>
#define BITMAP_NEW 0
#define BITMAP_OPAQUE (1 << 0) /** image is opaque */
#define BITMAP_MODIFIED (1 << 1) /** buffer has been modified */
#define BITMAP_PERSISTENT (1 << 2) /** retain between sessions */
#define BITMAP_CLEAR_MEMORY (1 << 3) /** memory should be wiped */
#define BITMAP_SUSPENDED (1 << 4) /** currently suspended */
#define BITMAP_READY (1 << 5) /** fully initialised */
#define BITMAP_SAVE_FULL_ALPHA (1 << 0) /** save with full alpha channel (if not opaque) */
struct content;
/** An opaque image. */
struct bitmap;
void *bitmap_create(int width, int height, unsigned int state);
void bitmap_set_opaque(void *bitmap, bool opaque);
bool bitmap_test_opaque(void *bitmap);
bool bitmap_get_opaque(void *bitmap);
unsigned char *bitmap_get_buffer(void *bitmap);
size_t bitmap_get_rowstride(void *bitmap);
size_t bitmap_get_bpp(void *bitmap);
void bitmap_destroy(void *bitmap);
bool bitmap_save(void *bitmap, const char *path, unsigned flags);
void bitmap_modified(void *bitmap);
void bitmap_set_suspendable(void *bitmap, void *private_word,
void (*invalidate)(void *bitmap, void *private_word));
int bitmap_get_width(void *bitmap);
int bitmap_get_height(void *bitmap);
#endif