nuclear@2: /*
nuclear@2: libimago - a multi-format image file input/output library.
nuclear@2: Copyright (C) 2010 John Tsiombikas <nuclear@member.fsf.org>
nuclear@2: 
nuclear@2: This program is free software: you can redistribute it and/or modify
nuclear@2: it under the terms of the GNU Lesser General Public License as published
nuclear@2: by the Free Software Foundation, either version 3 of the License, or
nuclear@2: (at your option) any later version.
nuclear@2: 
nuclear@2: This program is distributed in the hope that it will be useful,
nuclear@2: but WITHOUT ANY WARRANTY; without even the implied warranty of
nuclear@2: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
nuclear@2: GNU Lesser General Public License for more details.
nuclear@2: 
nuclear@2: You should have received a copy of the GNU Lesser General Public License
nuclear@2: along with this program.  If not, see <http://www.gnu.org/licenses/>.
nuclear@2: */
nuclear@2: 
nuclear@2: /* -- PNG module -- */
nuclear@2: 
nuclear@2: #include <stdlib.h>
nuclear@2: #include <png.h>
nuclear@2: #include "imago2.h"
nuclear@2: #include "ftype_module.h"
nuclear@2: 
nuclear@2: static int check_file(struct img_io *io);
nuclear@2: static int read_file(struct img_pixmap *img, struct img_io *io);
nuclear@2: static int write_file(struct img_pixmap *img, struct img_io *io);
nuclear@2: 
nuclear@2: static void read_func(png_struct *png, unsigned char *data, size_t len);
nuclear@2: static void write_func(png_struct *png, unsigned char *data, size_t len);
nuclear@2: static void flush_func(png_struct *png);
nuclear@2: 
nuclear@2: static int png_type_to_fmt(int color_type, int channel_bits);
nuclear@2: static int fmt_to_png_type(enum img_fmt fmt);
nuclear@2: 
nuclear@2: 
nuclear@2: int img_register_png(void)
nuclear@2: {
nuclear@2: 	static struct ftype_module mod = {".png", check_file, read_file, write_file};
nuclear@2: 	return img_register_module(&mod);
nuclear@2: }
nuclear@2: 
nuclear@2: static int check_file(struct img_io *io)
nuclear@2: {
nuclear@2: 	unsigned char sig[8];
nuclear@2: 	int res;
nuclear@2: 	long pos = io->seek(0, SEEK_CUR, io->uptr);
nuclear@2: 
nuclear@2: 	if(io->read(sig, 8, io->uptr) < 8) {
nuclear@2: 		io->seek(pos, SEEK_SET, io->uptr);
nuclear@2: 		return -1;
nuclear@2: 	}
nuclear@2: 
nuclear@2: 	res = png_sig_cmp(sig, 0, 8) == 0 ? 0 : -1;
nuclear@2: 	io->seek(pos, SEEK_SET, io->uptr);
nuclear@2: 	return res;
nuclear@2: }
nuclear@2: 
nuclear@2: static int read_file(struct img_pixmap *img, struct img_io *io)
nuclear@2: {
nuclear@2: 	png_struct *png;
nuclear@2: 	png_info *info;
nuclear@2: 	unsigned char **lineptr, *dest;
nuclear@2: 	int i, channel_bits, color_type, ilace_type, compression, filtering, fmt;
nuclear@2: 	unsigned long xsz, ysz;
nuclear@2: 
nuclear@2: 	if(!(png = png_create_read_struct(PNG_LIBPNG_VER_STRING, 0, 0, 0))) {
nuclear@2: 		return -1;
nuclear@2: 	}
nuclear@2: 
nuclear@2: 	if(!(info = png_create_info_struct(png))) {
nuclear@2: 		png_destroy_read_struct(&png, 0, 0);
nuclear@2: 		return -1;
nuclear@2: 	}
nuclear@2: 
nuclear@2: 	if(setjmp(png_jmpbuf(png))) {
nuclear@2: 		png_destroy_read_struct(&png, &info, 0);
nuclear@2: 		return -1;
nuclear@2: 	}
nuclear@2: 
nuclear@2: 	png_set_read_fn(png, io, read_func);
nuclear@2: 	png_set_sig_bytes(png, 0);
nuclear@2: 	png_read_png(png, info, 0, 0);
nuclear@2: 
nuclear@2: 	png_get_IHDR(png, info, &xsz, &ysz, &channel_bits, &color_type, &ilace_type,
nuclear@2: 			&compression, &filtering);
nuclear@2: 	if((fmt = png_type_to_fmt(color_type, channel_bits)) == -1) {
nuclear@2: 		png_destroy_read_struct(&png, &info, 0);
nuclear@2: 		return -1;
nuclear@2: 	}
nuclear@2: 
nuclear@2: 	if(img_set_pixels(img, xsz, ysz, fmt, 0) == -1) {
nuclear@2: 		png_destroy_read_struct(&png, &info, 0);
nuclear@2: 		return -1;
nuclear@2: 	}
nuclear@2: 
nuclear@2: 	lineptr = (unsigned char**)png_get_rows(png, info);
nuclear@2: 
nuclear@2: 	dest = img->pixels;
nuclear@2: 	for(i=0; i<ysz; i++) {
nuclear@2: 		memcpy(dest, lineptr[i], xsz * img->pixelsz);
nuclear@2: 		dest += xsz * img->pixelsz;
nuclear@2: 	}
nuclear@2: 	png_destroy_read_struct(&png, &info, 0);
nuclear@2: 	return 0;
nuclear@2: }
nuclear@2: 
nuclear@2: 
nuclear@2: static int write_file(struct img_pixmap *img, struct img_io *io)
nuclear@2: {
nuclear@2: 	png_struct *png;
nuclear@2: 	png_info *info;
nuclear@2: 	png_text txt;
nuclear@2: 	struct img_pixmap tmpimg;
nuclear@2: 	unsigned char **rows;
nuclear@2: 	unsigned char *pixptr;
nuclear@2: 	int i, coltype;
nuclear@2: 
nuclear@2: 	img_init(&tmpimg);
nuclear@2: 
nuclear@2: 	if(!(png = png_create_write_struct(PNG_LIBPNG_VER_STRING, 0, 0, 0))) {
nuclear@2: 		return -1;
nuclear@2: 	}
nuclear@2: 	if(!(info = png_create_info_struct(png))) {
nuclear@2: 		png_destroy_write_struct(&png, 0);
nuclear@2: 		return -1;
nuclear@2: 	}
nuclear@2: 
nuclear@2: 	/* if the input image is floating-point, we need to convert it to integer */
nuclear@2: 	if(img_is_float(img)) {
nuclear@2: 		if(img_copy(&tmpimg, img) == -1) {
nuclear@2: 			return -1;
nuclear@2: 		}
nuclear@2: 		if(img_to_integer(&tmpimg) == -1) {
nuclear@2: 			img_destroy(&tmpimg);
nuclear@2: 			return -1;
nuclear@2: 		}
nuclear@2: 		img = &tmpimg;
nuclear@2: 	}
nuclear@2: 
nuclear@2: 	txt.compression = PNG_TEXT_COMPRESSION_NONE;
nuclear@2: 	txt.key = "Software";
nuclear@2: 	txt.text = "libimago2";
nuclear@2: 	txt.text_length = 0;
nuclear@2: 
nuclear@2: 	if(setjmp(png_jmpbuf(png))) {
nuclear@2: 		png_destroy_write_struct(&png, &info);
nuclear@2: 		img_destroy(&tmpimg);
nuclear@2: 		return -1;
nuclear@2: 	}
nuclear@2: 	png_set_write_fn(png, io, write_func, flush_func);
nuclear@2: 
nuclear@2: 	coltype = fmt_to_png_type(img->fmt);
nuclear@2: 	png_set_IHDR(png, info, img->width, img->height, 8, coltype, PNG_INTERLACE_NONE,
nuclear@2: 			PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
nuclear@2: 	png_set_text(png, info, &txt, 1);
nuclear@2: 
nuclear@2: 	if(!(rows = malloc(img->height * sizeof *rows))) {
nuclear@2: 		png_destroy_write_struct(&png, &info);
nuclear@2: 		img_destroy(&tmpimg);
nuclear@2: 		return -1;
nuclear@2: 	}
nuclear@2: 
nuclear@2: 	pixptr = img->pixels;
nuclear@2: 	for(i=0; i<img->height; i++) {
nuclear@2: 		rows[i] = pixptr;
nuclear@2: 		pixptr += img->width * img->pixelsz;
nuclear@2: 	}
nuclear@2: 	png_set_rows(png, info, rows);
nuclear@2: 
nuclear@2: 	png_write_png(png, info, 0, 0);
nuclear@2: 	png_write_end(png, info);
nuclear@2: 	png_destroy_write_struct(&png, &info);
nuclear@2: 
nuclear@2: 	free(rows);
nuclear@2: 
nuclear@2: 	img_destroy(&tmpimg);
nuclear@2: 	return 0;
nuclear@2: }
nuclear@2: 
nuclear@2: static void read_func(png_struct *png, unsigned char *data, size_t len)
nuclear@2: {
nuclear@2: 	struct img_io *io = (struct img_io*)png_get_io_ptr(png);
nuclear@2: 
nuclear@2: 	if(io->read(data, len, io->uptr) == -1) {
nuclear@2: 		longjmp(png_jmpbuf(png), 1);
nuclear@2: 	}
nuclear@2: }
nuclear@2: 
nuclear@2: static void write_func(png_struct *png, unsigned char *data, size_t len)
nuclear@2: {
nuclear@2: 	struct img_io *io = (struct img_io*)png_get_io_ptr(png);
nuclear@2: 
nuclear@2: 	if(io->write(data, len, io->uptr) == -1) {
nuclear@2: 		longjmp(png_jmpbuf(png), 1);
nuclear@2: 	}
nuclear@2: }
nuclear@2: 
nuclear@2: static void flush_func(png_struct *png)
nuclear@2: {
nuclear@2: 	/* XXX does it matter that we can't flush? */
nuclear@2: }
nuclear@2: 
nuclear@2: static int png_type_to_fmt(int color_type, int channel_bits)
nuclear@2: {
nuclear@2: 	/* we don't support non-8bit-per-channel images yet */
nuclear@2: 	if(channel_bits > 8) {
nuclear@2: 		return -1;
nuclear@2: 	}
nuclear@2: 
nuclear@2: 	switch(color_type) {
nuclear@2: 	case PNG_COLOR_TYPE_RGB:
nuclear@2: 		return IMG_FMT_RGB24;
nuclear@2: 
nuclear@2: 	case PNG_COLOR_TYPE_RGB_ALPHA:
nuclear@2: 		return IMG_FMT_RGBA32;
nuclear@2: 
nuclear@2: 	case PNG_COLOR_TYPE_GRAY:
nuclear@2: 		return IMG_FMT_GREY8;
nuclear@2: 
nuclear@2: 	default:
nuclear@2: 		break;
nuclear@2: 	}
nuclear@2: 	return -1;
nuclear@2: }
nuclear@2: 
nuclear@2: static int fmt_to_png_type(enum img_fmt fmt)
nuclear@2: {
nuclear@2: 	switch(fmt) {
nuclear@2: 	case IMG_FMT_GREY8:
nuclear@2: 		return PNG_COLOR_TYPE_GRAY;
nuclear@2: 
nuclear@2: 	case IMG_FMT_RGB24:
nuclear@2: 		return PNG_COLOR_TYPE_RGB;
nuclear@2: 
nuclear@2: 	case IMG_FMT_RGBA32:
nuclear@2: 		return PNG_COLOR_TYPE_RGBA;
nuclear@2: 
nuclear@2: 	default:
nuclear@2: 		break;
nuclear@2: 	}
nuclear@2: 	return -1;
nuclear@2: }