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/*************************************************************************
* Copyright (C) 2008 Tavian Barnes <tavianator@gmail.com> *
* *
* This file is part of The Dimension Library. *
* *
* The Dimension Library 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 3 of the *
* License, or (at your option) any later version. *
* *
* The Dimension 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 *
* Lesser General Public License for more details. *
* *
* You should have received a copy of the GNU Lesser General Public *
* License along with this program. If not, see *
* <http://www.gnu.org/licenses/>. *
*************************************************************************/
#include "dimension.h"
#include <pthread.h>
#include <png.h>
#include <setjmp.h>
#include <arpa/inet.h>
#include <stdlib.h>
typedef struct {
dmnsn_progress *progress;
const dmnsn_canvas *canvas;
FILE *file;
} dmnsn_png_write_payload;
typedef struct {
dmnsn_progress *progress;
dmnsn_canvas **canvas;
FILE *file;
} dmnsn_png_read_payload;
static void *dmnsn_png_write_canvas_thread(void *ptr);
static int dmnsn_png_write_canvas_impl(const dmnsn_canvas *canvas, FILE *file);
static void *dmnsn_png_read_canvas_thread(void *ptr);
static dmnsn_canvas *dmnsn_png_read_canvas_impl(FILE *file);
/* Write a canvas to a png file, using libpng. Return 0 on success, nonzero on
failure. */
int
dmnsn_png_write_canvas(const dmnsn_canvas *canvas, FILE *file)
{
dmnsn_progress *progress = dmnsn_png_write_canvas_async(canvas, file);
return dmnsn_finish_progress(progress);
}
/* Write a canvas to a png file in the background */
dmnsn_progress *
dmnsn_png_write_canvas_async(const dmnsn_canvas *canvas, FILE *file)
{
dmnsn_progress *progress = dmnsn_new_progress();
dmnsn_png_write_payload *payload;
if (progress) {
payload = malloc(sizeof(dmnsn_png_write_payload));
if (!payload) {
dmnsn_delete_progress(progress);
return NULL;
}
payload->progress = progress;
payload->canvas = canvas;
payload->file = file;
if (pthread_create(&progress->thread, NULL, &dmnsn_png_write_canvas_thread,
payload)
!= 0) {
dmnsn_error(DMNSN_SEVERITY_MEDIUM,
"Creating png writing worker thread failed.");
}
}
return progress;
}
/* Read a canvas from the PNG file `file'. Return NULL on error. */
dmnsn_canvas *
dmnsn_png_read_canvas(FILE *file)
{
dmnsn_canvas *canvas;
dmnsn_progress *progress = dmnsn_png_read_canvas_async(&canvas, file);
dmnsn_finish_progress(progress);
return canvas;
}
/* Read a canvas from a png file in the background */
dmnsn_progress *
dmnsn_png_read_canvas_async(dmnsn_canvas **canvas, FILE *file)
{
dmnsn_progress *progress = dmnsn_new_progress();
dmnsn_png_read_payload *payload;
if (progress) {
payload = malloc(sizeof(dmnsn_png_write_payload));
if (!payload) {
dmnsn_delete_progress(progress);
return NULL;
}
payload->progress = progress;
payload->canvas = canvas;
payload->file = file;
if (pthread_create(&progress->thread, NULL, &dmnsn_png_read_canvas_thread,
payload)
!= 0) {
dmnsn_error(DMNSN_SEVERITY_MEDIUM,
"Creating png writing worker thread failed.");
}
}
return progress;
}
static void *
dmnsn_png_write_canvas_thread(void *ptr)
{
dmnsn_png_write_payload *payload = ptr;
int *retval = malloc(sizeof(int));
if (retval) {
*retval = dmnsn_png_write_canvas_impl(payload->canvas, payload->file);
}
return retval;
}
static int
dmnsn_png_write_canvas_impl(const dmnsn_canvas *canvas, FILE *file)
{
png_structp png_ptr;
png_infop info_ptr;
png_uint_32 width, height;
unsigned int x, y;
uint16_t *row = NULL;
dmnsn_color color;
dmnsn_sRGB sRGB;
if (!file) return 1; /* file was NULL */
width = canvas->x;
height = canvas->y;
png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
if (!png_ptr) return 1; /* Couldn't create libpng write struct */
info_ptr = png_create_info_struct(png_ptr);
if (!info_ptr) {
/* Couldn't create libpng info struct */
png_destroy_write_struct(&png_ptr, NULL);
return 1;
}
/* libpng will longjmp here if it encounters an error from here on */
if (setjmp(png_jmpbuf(png_ptr))) {
/* libpng error */
if (row) free(row);
png_destroy_write_struct(&png_ptr, &info_ptr);
return 1;
}
/* Associate file with the libpng write struct */
png_init_io(png_ptr, file);
/* Set header correctly for 16-bit sRGB image */
png_set_IHDR(png_ptr, info_ptr, width, height, 16,
PNG_COLOR_TYPE_RGB_ALPHA, PNG_INTERLACE_NONE,
PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
png_set_sRGB_gAMA_and_cHRM(png_ptr, info_ptr, PNG_sRGB_INTENT_ABSOLUTE);
/* We think of transparency in the opposite way that PNG does */
png_set_invert_alpha(png_ptr);
/* Write the info struct */
png_write_info(png_ptr, info_ptr);
if (htonl(1) != 1) {
/* We are little-endian; swap the byte order of the pixels */
png_set_swap(png_ptr);
}
/* Allocate the temporary row of RGBA values */
row = malloc(4*sizeof(uint16_t)*width);
if (!row) {
png_destroy_write_struct(&png_ptr, &info_ptr);
return 1;
}
/* Write the pixels */
for (y = 0; y < height; ++y) {
for (x = 0; x < width; ++x) {
/* Invert the rows. PNG coordinates are fourth quadrant. */
color = dmnsn_get_pixel(canvas, x, height - y - 1);
sRGB = dmnsn_sRGB_from_color(color);
/* Saturate R, G, and B to [0, UINT16_MAX] */
if (sRGB.R <= 0.0) {
row[4*x] = 0;
} else if (sRGB.R >= 1.0) {
row[4*x] = UINT16_MAX;
} else {
row[4*x] = sRGB.R*UINT16_MAX;
}
if (sRGB.G <= 0.0) {
row[4*x + 1] = 0;
} else if (sRGB.G >= 1.0) {
row[4*x + 1] = UINT16_MAX;
} else {
row[4*x + 1] = sRGB.G*UINT16_MAX;
}
if (sRGB.B <= 0.0) {
row[4*x + 2] = 0;
} else if (sRGB.B >= 1.0) {
row[4*x + 2] = UINT16_MAX;
} else {
row[4*x + 2] = sRGB.B*UINT16_MAX;
}
/* color.filter + color.trans is in [0.0, 1.0] by definition */
row[4*x + 3] = (color.filter + color.trans)*UINT16_MAX;
}
/* Write the row */
png_write_row(png_ptr, (png_bytep)row);
}
/* Finish the PNG file */
png_write_end(png_ptr, info_ptr);
free(row);
png_destroy_write_struct(&png_ptr, &info_ptr);
return 0;
}
static void *
dmnsn_png_read_canvas_thread(void *ptr)
{
dmnsn_png_read_payload *payload = ptr;
int *retval = malloc(sizeof(int));
if (retval) {
*payload->canvas = dmnsn_png_read_canvas_impl(payload->file);
*retval = payload->canvas ? 1 : 0;
}
return retval;
}
static dmnsn_canvas *
dmnsn_png_read_canvas_impl(FILE *file)
{
dmnsn_canvas *canvas;
png_byte header[8] = { 0, 0, 0, 0, 0, 0, 0, 0 };
png_structp png_ptr;
png_infop info_ptr;
png_uint_32 width, height, rowbytes;
int bit_depth, color_type, interlace_type, compression_type, filter_method;
png_bytep image = NULL;
png_bytep *row_pointers = NULL;
unsigned int x, y;
dmnsn_color color;
dmnsn_sRGB sRGB;
png_bytep png_pixel;
if (!file) return NULL; /* file was NULL */
fread(header, 1, 8, file);
if (png_sig_cmp(header, 0, 8)) return NULL; /* file is not a PNG file */
/* Create the libpng read struct */
png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
if (!png_ptr) return NULL;
/* Create the libpng info struct */
info_ptr = png_create_info_struct(png_ptr);
if (!info_ptr) {
png_destroy_read_struct(&png_ptr, NULL, NULL);
return NULL;
}
/* libpng will longjmp here if it encounters an error from here on */
if (setjmp(png_jmpbuf(png_ptr))) {
/* libpng error */
if (row_pointers) free(row_pointers);
if (image) free(image);
png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
return NULL;
}
/* Associate the read struct with the file, and tell it we've already checked
8 bytes of signature */
png_init_io(png_ptr, file);
png_set_sig_bytes(png_ptr, 8);
/* Read the PNG header into info struct */
png_read_info(png_ptr, info_ptr);
/* Get useful information from the info struct */
png_get_IHDR(png_ptr, info_ptr, &width, &height, &bit_depth, &color_type,
&interlace_type, &compression_type, &filter_method);
/*
* - Convert paletted images to RGB.
* - Convert a tRNS chunk to an alpha channel
* - Convert grayscale to RGB
* - Invert the alpha channel
*/
if (color_type == PNG_COLOR_TYPE_PALETTE) {
png_set_palette_to_rgb(png_ptr);
}
if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)) {
png_set_tRNS_to_alpha(png_ptr);
}
if (color_type == PNG_COLOR_TYPE_GRAY
|| color_type == PNG_COLOR_TYPE_GRAY_ALPHA) {
png_set_gray_to_rgb(png_ptr);
}
png_set_invert_alpha(png_ptr);
/* Update the info struct */
png_read_update_info(png_ptr, info_ptr);
/* Get bytes/image row */
rowbytes = png_get_rowbytes(png_ptr, info_ptr);
/* Allocate the temporary image buffer */
image = malloc(rowbytes*height);
if (!image) {
png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
return NULL;
}
/* Allocate and set an array of pointers to rows in image */
row_pointers = malloc(sizeof(png_bytep)*height);
if (!row_pointers) {
free(image);
png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
return NULL;
}
for (y = 0; y < height; ++y) {
row_pointers[y] = image + y*rowbytes;
}
/* Read the image to image all at once. At the expense of greater memory use,
this handles interlacing for us. */
png_read_image(png_ptr, row_pointers);
/* Allocate the canvas */
canvas = dmnsn_new_canvas(width, height);
if (!canvas) {
free(row_pointers);
free(image);
png_read_end(png_ptr, NULL);
png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
return NULL;
}
/* Now we convert the image to our canvas format. This depends on the image
bit depth (which has been scaled up to at least 8 or 16), and the presence
of an alpha channel. For performance reasons, the tests are outside the
loops, although that doesn't really matter for a decent compiler. */
if (bit_depth == 16) {
if (color_type & PNG_COLOR_MASK_ALPHA) {
for (x = 0; x < width; ++x) {
for (y = 0; y < height; ++y) {
png_pixel = image + 8*(y*width + x);
sRGB.R = ((double)((png_pixel[0] << UINT16_C(8)) + png_pixel[1]))
/UINT16_MAX;
sRGB.G = ((double)((png_pixel[2] << UINT16_C(8)) + png_pixel[3]))
/UINT16_MAX;
sRGB.B = ((double)((png_pixel[4] << UINT16_C(8)) + png_pixel[5]))
/UINT16_MAX;
color = dmnsn_color_from_sRGB(sRGB);
color.trans = ((double)((png_pixel[6] << UINT16_C(8))
+ png_pixel[7]))/UINT16_MAX;
dmnsn_set_pixel(canvas, x, height - y - 1, color);
}
}
} else {
for (x = 0; x < width; ++x) {
for (y = 0; y < height; ++y) {
png_pixel = image + 6*(y*width + x);
sRGB.R = ((double)((png_pixel[0] << UINT16_C(8)) + png_pixel[1]))
/UINT16_MAX;
sRGB.G = ((double)((png_pixel[2] << UINT16_C(8)) + png_pixel[3]))
/UINT16_MAX;
sRGB.B = ((double)((png_pixel[4] << UINT16_C(8)) + png_pixel[5]))
/UINT16_MAX;
color = dmnsn_color_from_sRGB(sRGB);
dmnsn_set_pixel(canvas, x, height - y - 1, color);
}
}
}
} else {
/* Bit depth is 8 */
if (color_type & PNG_COLOR_MASK_ALPHA) {
for (x = 0; x < width; ++x) {
for (y = 0; y < height; ++y) {
png_pixel = image + 4*(y*width + x);
sRGB.R = ((double)png_pixel[0])/UINT8_MAX;
sRGB.G = ((double)png_pixel[1])/UINT8_MAX;
sRGB.B = ((double)png_pixel[2])/UINT8_MAX;
color = dmnsn_color_from_sRGB(sRGB);
color.trans = ((double)png_pixel[3])/UINT8_MAX;
dmnsn_set_pixel(canvas, x, height - y - 1, color);
}
}
} else {
for (x = 0; x < width; ++x) {
for (y = 0; y < height; ++y) {
png_pixel = image + 3*(y*width + x);
sRGB.R = ((double)png_pixel[0])/UINT8_MAX;
sRGB.G = ((double)png_pixel[1])/UINT8_MAX;
sRGB.B = ((double)png_pixel[2])/UINT8_MAX;
color = dmnsn_color_from_sRGB(sRGB);
dmnsn_set_pixel(canvas, x, height - y - 1, color);
}
}
}
}
free(row_pointers);
free(image);
png_read_end(png_ptr, NULL);
png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
return canvas;
}
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