nuclear@14: /*
nuclear@14: libimago - a multi-format image file input/output library.
nuclear@14: Copyright (C) 2010 John Tsiombikas <nuclear@member.fsf.org>
nuclear@14: 
nuclear@14: This program is free software: you can redistribute it and/or modify
nuclear@14: it under the terms of the GNU Lesser General Public License as published
nuclear@14: by the Free Software Foundation, either version 3 of the License, or
nuclear@14: (at your option) any later version.
nuclear@14: 
nuclear@14: This program is distributed in the hope that it will be useful,
nuclear@14: but WITHOUT ANY WARRANTY; without even the implied warranty of
nuclear@14: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
nuclear@14: GNU Lesser General Public License for more details.
nuclear@14: 
nuclear@14: You should have received a copy of the GNU Lesser General Public License
nuclear@14: along with this program.  If not, see <http://www.gnu.org/licenses/>.
nuclear@14: */
nuclear@14: 
nuclear@14: /* -- PNG module -- */
nuclear@14: 
nuclear@14: #include <stdlib.h>
nuclear@14: #include <png.h>
nuclear@14: #include "imago2.h"
nuclear@14: #include "ftype_module.h"
nuclear@14: 
nuclear@14: static int check_file(struct img_io *io);
nuclear@14: static int read_file(struct img_pixmap *img, struct img_io *io);
nuclear@14: static int write_file(struct img_pixmap *img, struct img_io *io);
nuclear@14: 
nuclear@14: static void read_func(png_struct *png, unsigned char *data, size_t len);
nuclear@14: static void write_func(png_struct *png, unsigned char *data, size_t len);
nuclear@14: static void flush_func(png_struct *png);
nuclear@14: 
nuclear@14: static int png_type_to_fmt(int color_type, int channel_bits);
nuclear@14: static int fmt_to_png_type(enum img_fmt fmt);
nuclear@14: 
nuclear@14: 
nuclear@14: int img_register_png(void)
nuclear@14: {
nuclear@14: 	static struct ftype_module mod = {".png", check_file, read_file, write_file};
nuclear@14: 	return img_register_module(&mod);
nuclear@14: }
nuclear@14: 
nuclear@14: static int check_file(struct img_io *io)
nuclear@14: {
nuclear@14: 	unsigned char sig[8];
nuclear@14: 	int res;
nuclear@14: 	long pos = io->seek(0, SEEK_CUR, io->uptr);
nuclear@14: 
nuclear@14: 	if(io->read(sig, 8, io->uptr) < 8) {
nuclear@14: 		io->seek(pos, SEEK_SET, io->uptr);
nuclear@14: 		return -1;
nuclear@14: 	}
nuclear@14: 
nuclear@14: 	res = png_sig_cmp(sig, 0, 8) == 0 ? 0 : -1;
nuclear@14: 	io->seek(pos, SEEK_SET, io->uptr);
nuclear@14: 	return res;
nuclear@14: }
nuclear@14: 
nuclear@14: static int read_file(struct img_pixmap *img, struct img_io *io)
nuclear@14: {
nuclear@14: 	png_struct *png;
nuclear@14: 	png_info *info;
nuclear@14: 	int channel_bits, color_type, ilace_type, compression, filtering, fmt;
nuclear@14: 	png_uint_32 xsz, ysz;
nuclear@14: 
nuclear@14: 	if(!(png = png_create_read_struct(PNG_LIBPNG_VER_STRING, 0, 0, 0))) {
nuclear@14: 		return -1;
nuclear@14: 	}
nuclear@14: 
nuclear@14: 	if(!(info = png_create_info_struct(png))) {
nuclear@14: 		png_destroy_read_struct(&png, 0, 0);
nuclear@14: 		return -1;
nuclear@14: 	}
nuclear@14: 
nuclear@14: 	if(setjmp(png_jmpbuf(png))) {
nuclear@14: 		png_destroy_read_struct(&png, &info, 0);
nuclear@14: 		return -1;
nuclear@14: 	}
nuclear@14: 
nuclear@14: 	png_set_read_fn(png, io, read_func);
nuclear@14: 	png_set_sig_bytes(png, 0);
nuclear@14: 	png_read_png(png, info, 0, 0);
nuclear@14: 
nuclear@14: 	png_get_IHDR(png, info, &xsz, &ysz, &channel_bits, &color_type, &ilace_type,
nuclear@14: 			&compression, &filtering);
nuclear@14: 	if((fmt = png_type_to_fmt(color_type, channel_bits)) == -1) {
nuclear@14: 		png_destroy_read_struct(&png, &info, 0);
nuclear@14: 		return -1;
nuclear@14: 	}
nuclear@14: 
nuclear@14: 	if(img_set_pixels(img, xsz, ysz, fmt, 0) == -1) {
nuclear@14: 		png_destroy_read_struct(&png, &info, 0);
nuclear@14: 		return -1;
nuclear@14: 	}
nuclear@14: 
nuclear@14: 
nuclear@14: 	if(channel_bits == 8) {
nuclear@14: 		unsigned int i;
nuclear@14: 		unsigned char **lineptr = (unsigned char**)png_get_rows(png, info);
nuclear@14: 		unsigned char *dest = img->pixels;
nuclear@14: 
nuclear@14: 		for(i=0; i<ysz; i++) {
nuclear@14: 			memcpy(dest, lineptr[i], xsz * img->pixelsz);
nuclear@14: 			dest += xsz * img->pixelsz;
nuclear@14: 		}
nuclear@14: 	} else {
nuclear@14: 		unsigned int i, j, num_elem;
nuclear@14: 		unsigned char **lineptr = (unsigned char**)png_get_rows(png, info);
nuclear@14: 		float *dest = img->pixels;
nuclear@14: 
nuclear@14: 		num_elem = img->pixelsz / sizeof(float);
nuclear@14: 		for(i=0; i<ysz; i++) {
nuclear@14: 			for(j=0; j<xsz * num_elem; j++) {
nuclear@14: 				unsigned short val = (lineptr[i][j * 2] << 8) | lineptr[i][j * 2 + 1];
nuclear@14: 				*dest++ = (float)val / 65535.0;
nuclear@14: 			}
nuclear@14: 		}
nuclear@14: 	}
nuclear@14: 
nuclear@14: 
nuclear@14: 	png_destroy_read_struct(&png, &info, 0);
nuclear@14: 	return 0;
nuclear@14: }
nuclear@14: 
nuclear@14: 
nuclear@14: static int write_file(struct img_pixmap *img, struct img_io *io)
nuclear@14: {
nuclear@14: 	png_struct *png;
nuclear@14: 	png_info *info;
nuclear@14: 	png_text txt;
nuclear@14: 	struct img_pixmap tmpimg;
nuclear@14: 	unsigned char **rows;
nuclear@14: 	unsigned char *pixptr;
nuclear@14: 	int i, coltype;
nuclear@14: 
nuclear@14: 	img_init(&tmpimg);
nuclear@14: 
nuclear@14: 	if(!(png = png_create_write_struct(PNG_LIBPNG_VER_STRING, 0, 0, 0))) {
nuclear@14: 		return -1;
nuclear@14: 	}
nuclear@14: 	if(!(info = png_create_info_struct(png))) {
nuclear@14: 		png_destroy_write_struct(&png, 0);
nuclear@14: 		return -1;
nuclear@14: 	}
nuclear@14: 
nuclear@14: 	/* if the input image is floating-point, we need to convert it to integer */
nuclear@14: 	if(img_is_float(img)) {
nuclear@14: 		if(img_copy(&tmpimg, img) == -1) {
nuclear@14: 			return -1;
nuclear@14: 		}
nuclear@14: 		if(img_to_integer(&tmpimg) == -1) {
nuclear@14: 			img_destroy(&tmpimg);
nuclear@14: 			return -1;
nuclear@14: 		}
nuclear@14: 		img = &tmpimg;
nuclear@14: 	}
nuclear@14: 
nuclear@14: 	txt.compression = PNG_TEXT_COMPRESSION_NONE;
nuclear@14: 	txt.key = "Software";
nuclear@14: 	txt.text = "libimago2";
nuclear@14: 	txt.text_length = 0;
nuclear@14: 
nuclear@14: 	if(setjmp(png_jmpbuf(png))) {
nuclear@14: 		png_destroy_write_struct(&png, &info);
nuclear@14: 		img_destroy(&tmpimg);
nuclear@14: 		return -1;
nuclear@14: 	}
nuclear@14: 	png_set_write_fn(png, io, write_func, flush_func);
nuclear@14: 
nuclear@14: 	coltype = fmt_to_png_type(img->fmt);
nuclear@14: 	png_set_IHDR(png, info, img->width, img->height, 8, coltype, PNG_INTERLACE_NONE,
nuclear@14: 			PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
nuclear@14: 	png_set_text(png, info, &txt, 1);
nuclear@14: 
nuclear@14: 	if(!(rows = malloc(img->height * sizeof *rows))) {
nuclear@14: 		png_destroy_write_struct(&png, &info);
nuclear@14: 		img_destroy(&tmpimg);
nuclear@14: 		return -1;
nuclear@14: 	}
nuclear@14: 
nuclear@14: 	pixptr = img->pixels;
nuclear@14: 	for(i=0; i<img->height; i++) {
nuclear@14: 		rows[i] = pixptr;
nuclear@14: 		pixptr += img->width * img->pixelsz;
nuclear@14: 	}
nuclear@14: 	png_set_rows(png, info, rows);
nuclear@14: 
nuclear@14: 	png_write_png(png, info, 0, 0);
nuclear@14: 	png_write_end(png, info);
nuclear@14: 	png_destroy_write_struct(&png, &info);
nuclear@14: 
nuclear@14: 	free(rows);
nuclear@14: 
nuclear@14: 	img_destroy(&tmpimg);
nuclear@14: 	return 0;
nuclear@14: }
nuclear@14: 
nuclear@14: static void read_func(png_struct *png, unsigned char *data, size_t len)
nuclear@14: {
nuclear@14: 	struct img_io *io = (struct img_io*)png_get_io_ptr(png);
nuclear@14: 
nuclear@14: 	if(io->read(data, len, io->uptr) == -1) {
nuclear@14: 		longjmp(png_jmpbuf(png), 1);
nuclear@14: 	}
nuclear@14: }
nuclear@14: 
nuclear@14: static void write_func(png_struct *png, unsigned char *data, size_t len)
nuclear@14: {
nuclear@14: 	struct img_io *io = (struct img_io*)png_get_io_ptr(png);
nuclear@14: 
nuclear@14: 	if(io->write(data, len, io->uptr) == -1) {
nuclear@14: 		longjmp(png_jmpbuf(png), 1);
nuclear@14: 	}
nuclear@14: }
nuclear@14: 
nuclear@14: static void flush_func(png_struct *png)
nuclear@14: {
nuclear@14: 	/* XXX does it matter that we can't flush? */
nuclear@14: }
nuclear@14: 
nuclear@14: static int png_type_to_fmt(int color_type, int channel_bits)
nuclear@14: {
nuclear@14: 	/* only 8 and 16 bits per channel ar supported at the moment */
nuclear@14: 	if(channel_bits != 8 && channel_bits != 16) {
nuclear@14: 		return -1;
nuclear@14: 	}
nuclear@14: 
nuclear@14: 	switch(color_type) {
nuclear@14: 	case PNG_COLOR_TYPE_RGB:
nuclear@14: 		return channel_bits == 16 ? IMG_FMT_RGBF : IMG_FMT_RGB24;
nuclear@14: 
nuclear@14: 	case PNG_COLOR_TYPE_RGB_ALPHA:
nuclear@14: 		return channel_bits == 16 ? IMG_FMT_RGBAF : IMG_FMT_RGBA32;
nuclear@14: 
nuclear@14: 	case PNG_COLOR_TYPE_GRAY:
nuclear@14: 		return channel_bits == 16 ? IMG_FMT_GREYF : IMG_FMT_GREY8;
nuclear@14: 
nuclear@14: 	default:
nuclear@14: 		break;
nuclear@14: 	}
nuclear@14: 	return -1;
nuclear@14: }
nuclear@14: 
nuclear@14: static int fmt_to_png_type(enum img_fmt fmt)
nuclear@14: {
nuclear@14: 	switch(fmt) {
nuclear@14: 	case IMG_FMT_GREY8:
nuclear@14: 		return PNG_COLOR_TYPE_GRAY;
nuclear@14: 
nuclear@14: 	case IMG_FMT_RGB24:
nuclear@14: 		return PNG_COLOR_TYPE_RGB;
nuclear@14: 
nuclear@14: 	case IMG_FMT_RGBA32:
nuclear@14: 		return PNG_COLOR_TYPE_RGBA;
nuclear@14: 
nuclear@14: 	default:
nuclear@14: 		break;
nuclear@14: 	}
nuclear@14: 	return -1;
nuclear@14: }