mirror of
https://gitee.com/openharmony/third_party_ffmpeg
synced 2024-12-24 04:26:14 +00:00
83 lines
2.3 KiB
C
83 lines
2.3 KiB
C
/*
|
|
* PNG image format
|
|
* Copyright (c) 2003 Fabrice Bellard.
|
|
*
|
|
* This file is part of FFmpeg.
|
|
*
|
|
* FFmpeg 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 2.1 of the License, or (at your option) any later version.
|
|
*
|
|
* FFmpeg 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 FFmpeg; if not, write to the Free Software
|
|
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
|
|
*/
|
|
#include "avcodec.h"
|
|
#include "bytestream.h"
|
|
#include "png.h"
|
|
|
|
const uint8_t ff_pngsig[8] = {137, 80, 78, 71, 13, 10, 26, 10};
|
|
|
|
/* Mask to determine which y pixels are valid in a pass */
|
|
const uint8_t ff_png_pass_ymask[NB_PASSES] = {
|
|
0x80, 0x80, 0x08, 0x88, 0x22, 0xaa, 0x55,
|
|
};
|
|
|
|
/* minimum x value */
|
|
const uint8_t ff_png_pass_xmin[NB_PASSES] = {
|
|
0, 4, 0, 2, 0, 1, 0
|
|
};
|
|
|
|
/* x shift to get row width */
|
|
const uint8_t ff_png_pass_xshift[NB_PASSES] = {
|
|
3, 3, 2, 2, 1, 1, 0
|
|
};
|
|
|
|
/* Mask to determine which pixels are valid in a pass */
|
|
const uint8_t ff_png_pass_mask[NB_PASSES] = {
|
|
0x80, 0x08, 0x88, 0x22, 0xaa, 0x55, 0xff
|
|
};
|
|
|
|
void *ff_png_zalloc(void *opaque, unsigned int items, unsigned int size)
|
|
{
|
|
if(items >= UINT_MAX / size)
|
|
return NULL;
|
|
return av_malloc(items * size);
|
|
}
|
|
|
|
void ff_png_zfree(void *opaque, void *ptr)
|
|
{
|
|
av_free(ptr);
|
|
}
|
|
|
|
int ff_png_get_nb_channels(int color_type)
|
|
{
|
|
int channels;
|
|
channels = 1;
|
|
if ((color_type & (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_PALETTE)) ==
|
|
PNG_COLOR_MASK_COLOR)
|
|
channels = 3;
|
|
if (color_type & PNG_COLOR_MASK_ALPHA)
|
|
channels++;
|
|
return channels;
|
|
}
|
|
|
|
/* compute the row size of an interleaved pass */
|
|
int ff_png_pass_row_size(int pass, int bits_per_pixel, int width)
|
|
{
|
|
int shift, xmin, pass_width;
|
|
|
|
xmin = ff_png_pass_xmin[pass];
|
|
if (width <= xmin)
|
|
return 0;
|
|
shift = ff_png_pass_xshift[pass];
|
|
pass_width = (width - xmin + (1 << shift) - 1) >> shift;
|
|
return (pass_width * bits_per_pixel + 7) >> 3;
|
|
}
|