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// Copyright (c) 2015 YamaArashi
#include <stdio.h>
#include <setjmp.h>
#include <png.h>
#include "global.h"
#include "convert_png.h"
#include "gfx.h"
void ReadPng(char *path, struct Image *image)
{
FILE *fp = fopen(path, "rb");
if (fp == NULL)
FATAL_ERROR("Failed to open \"%s\" for reading.\n", path);
unsigned char sig[8];
if (fread(sig, 8, 1, fp) != 1)
FATAL_ERROR("Failed to read PNG signature from \"%s\".\n", path);
if (png_sig_cmp(sig, 0, 8))
FATAL_ERROR("\"%s\" does not have a valid PNG signature.\n", path);
png_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
if (!png_ptr)
FATAL_ERROR("Failed to create PNG read struct.\n");
png_infop info_ptr = png_create_info_struct(png_ptr);
if (!info_ptr)
FATAL_ERROR("Failed to create PNG info struct.\n");
if (setjmp(png_jmpbuf(png_ptr)))
FATAL_ERROR("Failed to init I/O for reading \"%s\".\n", path);
png_init_io(png_ptr, fp);
png_set_sig_bytes(png_ptr, 8);
png_read_info(png_ptr, info_ptr);
int bit_depth = png_get_bit_depth(png_ptr, info_ptr);
if (bit_depth != image->bitDepth)
FATAL_ERROR("\"%s\" has a bit depth of %d, but the expected bit depth is %d.\n", path, bit_depth, image->bitDepth);
int color_type = png_get_color_type(png_ptr, info_ptr);
if (color_type != PNG_COLOR_TYPE_GRAY && color_type != PNG_COLOR_TYPE_PALETTE)
FATAL_ERROR("\"%s\" has an unsupported color type.\n", path);
// Check if the image has a palette so that we can tell if the colors need to be inverted later.
// Don't read the palette because it's not needed for now.
image->hasPalette = (color_type == PNG_COLOR_TYPE_PALETTE);
image->width = png_get_image_width(png_ptr, info_ptr);
image->height = png_get_image_height(png_ptr, info_ptr);
int rowbytes = png_get_rowbytes(png_ptr, info_ptr);
image->pixels = malloc(image->height * rowbytes);
if (image->pixels == NULL)
FATAL_ERROR("Failed to allocate pixel buffer.\n");
png_bytepp row_pointers = malloc(image->height * sizeof(png_bytep));
if (row_pointers == NULL)
FATAL_ERROR("Failed to allocate row pointers.\n");
for (int i = 0; i < image->height; i++)
row_pointers[i] = (png_bytep)(image->pixels + (i * rowbytes));
if (setjmp(png_jmpbuf(png_ptr)))
FATAL_ERROR("Error reading from \"%s\".\n", path);
png_read_image(png_ptr, row_pointers);
png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
free(row_pointers);
fclose(fp);
}
void SetPngPalette(png_structp png_ptr, png_infop info_ptr, struct Palette *palette)
{
png_colorp colors = malloc(palette->numColors * sizeof(png_color));
if (colors == NULL)
FATAL_ERROR("Failed to allocate PNG palette.\n");
for (int i = 0; i < palette->numColors; i++) {
colors[i].red = palette->colors[i].red;
colors[i].green = palette->colors[i].green;
colors[i].blue = palette->colors[i].blue;
}
png_set_PLTE(png_ptr, info_ptr, colors, palette->numColors);
free(colors);
}
void WritePng(char *path, struct Image *image)
{
FILE *fp = fopen(path, "wb");
if (fp == NULL)
FATAL_ERROR("Failed to open \"%s\" for writing.\n", path);
png_structp png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
if (!png_ptr)
FATAL_ERROR("Failed to create PNG write struct.\n");
png_infop info_ptr = png_create_info_struct(png_ptr);
if (!info_ptr)
FATAL_ERROR("Failed to create PNG info struct.\n");
if (setjmp(png_jmpbuf(png_ptr)))
FATAL_ERROR("Failed to init I/O for writing \"%s\".\n", path);
png_init_io(png_ptr, fp);
if (setjmp(png_jmpbuf(png_ptr)))
FATAL_ERROR("Error writing header for \"%s\".\n", path);
int color_type = image->hasPalette ? PNG_COLOR_TYPE_PALETTE : PNG_COLOR_TYPE_GRAY;
png_set_IHDR(png_ptr, info_ptr, image->width, image->height,
image->bitDepth, color_type, PNG_INTERLACE_NONE,
PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
if (image->hasPalette) {
SetPngPalette(png_ptr, info_ptr, &image->palette);
if (image->hasTransparency) {
png_byte trans = 0;
png_set_tRNS(png_ptr, info_ptr, &trans, 1, 0);
}
}
png_write_info(png_ptr, info_ptr);
png_bytepp row_pointers = malloc(image->height * sizeof(png_bytep));
if (row_pointers == NULL)
FATAL_ERROR("Failed to allocate row pointers.\n");
int rowbytes = png_get_rowbytes(png_ptr, info_ptr);
for (int i = 0; i < image->height; i++)
row_pointers[i] = (png_bytep)(image->pixels + (i * rowbytes));
if (setjmp(png_jmpbuf(png_ptr)))
FATAL_ERROR("Error writing \"%s\".\n", path);
png_write_image(png_ptr, row_pointers);
if (setjmp(png_jmpbuf(png_ptr)))
FATAL_ERROR("Error ending write of \"%s\".\n", path);
png_write_end(png_ptr, NULL);
fclose(fp);
png_destroy_write_struct(&png_ptr, &info_ptr);
free(row_pointers);
}
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