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/**************************************************************************
*
* Copyright 2011 Jose Fonseca
* Copyright 2008-2010 VMware, Inc.
* All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*
**************************************************************************/
#include <zlib.h>
#include <png.h>
#include <assert.h>
#include <stdint.h>
#include <stdlib.h>
#include <fstream>
#include "image.hpp"
namespace image {
static const int png_compression_level = Z_BEST_SPEED;
bool
Image::writePNG(const char *filename) const {
FILE *fp;
png_structp png_ptr;
png_infop info_ptr;
fp = fopen(filename, "wb");
if (!fp)
goto no_fp;
png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
if (!png_ptr)
goto no_png;
info_ptr = png_create_info_struct(png_ptr);
if (!info_ptr) {
png_destroy_write_struct(&png_ptr, NULL);
goto no_png;
}
if (setjmp(png_jmpbuf(png_ptr))) {
png_destroy_write_struct(&png_ptr, &info_ptr);
goto no_png;
}
png_init_io(png_ptr, fp);
int color_type;
switch (channels) {
case 4:
color_type = PNG_COLOR_TYPE_RGB_ALPHA;
break;
case 3:
color_type = PNG_COLOR_TYPE_RGB;
break;
case 2:
color_type = PNG_COLOR_TYPE_GRAY_ALPHA;
break;
case 1:
color_type = PNG_COLOR_TYPE_GRAY;
break;
default:
assert(0);
return false;
}
png_set_IHDR(png_ptr, info_ptr, width, height, 8, color_type,
PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
png_set_compression_level(png_ptr, png_compression_level);
png_write_info(png_ptr, info_ptr);
if (!flipped) {
for (unsigned y = 0; y < height; ++y) {
png_bytep row = (png_bytep)(pixels + y*width*channels);
png_write_rows(png_ptr, &row, 1);
}
} else {
unsigned y = height;
while (y--) {
png_bytep row = (png_bytep)(pixels + y*width*channels);
png_write_rows(png_ptr, &row, 1);
}
}
png_write_end(png_ptr, info_ptr);
png_destroy_write_struct(&png_ptr, &info_ptr);
fclose(fp);
return true;
no_png:
fclose(fp);
no_fp:
return false;
}
Image *
readPNG(const char *filename)
{
FILE *fp;
png_structp png_ptr;
png_infop info_ptr;
png_infop end_info;
Image *image;
fp = fopen(filename, "rb");
if (!fp)
goto no_fp;
png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
if (!png_ptr)
goto no_png;
info_ptr = png_create_info_struct(png_ptr);
if (!info_ptr) {
png_destroy_read_struct(&png_ptr, NULL, NULL);
goto no_png;
}
end_info = png_create_info_struct(png_ptr);
if (!end_info) {
png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
goto no_png;
}
if (setjmp(png_jmpbuf(png_ptr))) {
png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
goto no_png;
}
png_init_io(png_ptr, fp);
png_read_info(png_ptr, info_ptr);
png_uint_32 width, height;
int bit_depth, color_type, interlace_type, compression_type, filter_method;
png_get_IHDR(png_ptr, info_ptr,
&width, &height,
&bit_depth, &color_type, &interlace_type,
&compression_type, &filter_method);
image = new Image(width, height);
if (!image)
goto no_image;
/* Convert to RGBA8 */
if (color_type == PNG_COLOR_TYPE_PALETTE)
png_set_palette_to_rgb(png_ptr);
if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8)
png_set_expand_gray_1_2_4_to_8(png_ptr);
if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS))
png_set_tRNS_to_alpha(png_ptr);
if (bit_depth == 16)
png_set_strip_16(png_ptr);
for (unsigned y = 0; y < height; ++y) {
png_bytep row = (png_bytep)(image->pixels + y*width*4);
png_read_row(png_ptr, row, NULL);
}
png_read_end(png_ptr, info_ptr);
png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
fclose(fp);
return image;
no_image:
png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
no_png:
fclose(fp);
no_fp:
return NULL;
}
struct png_tmp_buffer
{
char *buffer;
size_t size;
};
static void
pngWriteCallback(png_structp png_ptr, png_bytep data, png_size_t length)
{
struct png_tmp_buffer *buf = (struct png_tmp_buffer*) png_get_io_ptr(png_ptr);
size_t nsize = buf->size + length;
/* allocate or grow buffer */
if (buf->buffer)
buf->buffer = (char*)realloc(buf->buffer, nsize);
else
buf->buffer = (char*)malloc(nsize);
if (!buf->buffer)
png_error(png_ptr, "Buffer allocation error");
memcpy(buf->buffer + buf->size, data, length);
buf->size += length;
}
bool writePixelsToBuffer(unsigned char *pixels,
unsigned width, unsigned height, unsigned numChannels,
bool flipped,
char **buffer,
int *size)
{
struct png_tmp_buffer png_mem;
png_structp png_ptr;
png_infop info_ptr;
int type;
png_mem.buffer = NULL;
png_mem.size = 0;
switch (numChannels) {
case 4:
type = PNG_COLOR_TYPE_RGB_ALPHA;
break;
case 3:
type = PNG_COLOR_TYPE_RGB;
break;
case 2:
type = PNG_COLOR_TYPE_GRAY_ALPHA;
break;
case 1:
type = PNG_COLOR_TYPE_GRAY;
break;
default:
goto no_png;
}
png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
if (!png_ptr)
goto no_png;
info_ptr = png_create_info_struct(png_ptr);
if (!info_ptr) {
png_destroy_write_struct(&png_ptr, NULL);
goto no_png;
}
if (setjmp(png_jmpbuf(png_ptr))) {
png_destroy_write_struct(&png_ptr, &info_ptr);
goto no_png;
}
png_set_write_fn(png_ptr, &png_mem, pngWriteCallback, NULL);
png_set_IHDR(png_ptr, info_ptr, width, height, 8,
type, PNG_INTERLACE_NONE,
PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
png_set_compression_level(png_ptr, png_compression_level);
png_write_info(png_ptr, info_ptr);
if (!flipped) {
for (unsigned y = 0; y < height; ++y) {
png_bytep row = (png_bytep)(pixels + y*width*numChannels);
png_write_rows(png_ptr, &row, 1);
}
} else {
unsigned y = height;
while (y--) {
png_bytep row = (png_bytep)(pixels + y*width*numChannels);
png_write_rows(png_ptr, &row, 1);
}
}
png_write_end(png_ptr, info_ptr);
png_destroy_write_struct(&png_ptr, &info_ptr);
*buffer = png_mem.buffer;
*size = png_mem.size;
return true;
no_png:
*buffer = NULL;
*size = 0;
if (png_mem.buffer)
free(png_mem.buffer);
return false;
}
} /* namespace image */
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