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/*
* io-png.c: GdkPixBuf I/O for PNG files.
* Copyright (C) 1999 Mark Crichton
* Author: Mark Crichton <crichton@gimp.org>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This 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
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Cambridge, MA 02139, USA.
*
*/
#include <config.h>
#include <stdio.h>
#include <glib.h>
#include "gdk-pixbuf.h"
#include "gdk-pixbuf-io.h"
#include <png.h>
/* Shared library entry point */
GdkPixBuf *image_load(FILE * f)
{
png_structp png_ptr;
png_infop info_ptr, end_info;
gint i, depth, ctype, inttype, passes, bpp; /* bpp = BYTES/pixel */
png_uint_32 w, h, x, y;
png_bytepp rows;
art_u8 *pixels, *temp, *rowdata;
GdkPixBuf *pixbuf;
g_return_val_if_fail(f != NULL, NULL);
png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL,
NULL);
info_ptr = png_create_info_struct(png_ptr);
if (!info_ptr) {
png_destroy_read_struct(&png_ptr, NULL, NULL);
return NULL;
}
end_info = png_create_info_struct(png_ptr);
if (!end_info) {
png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
return NULL;
}
if (setjmp(png_ptr->jmpbuf)) {
png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
return NULL;
}
png_init_io(png_ptr, f);
png_read_info(png_ptr, info_ptr);
png_get_IHDR(png_ptr, info_ptr, &w, &h, &depth, &ctype, &inttype,
NULL, NULL);
/* Ok, we want to work with 24 bit images.
* However, PNG can vary depth per channel.
* So, we use the png_set_expand function to expand
* everything into a format libart expects.
* We also use png_set_strip_16 to reduce down to 8 bit/chan.
*/
if (ctype == PNG_COLOR_TYPE_PALETTE && depth <= 8)
png_set_expand(png_ptr);
if (ctype == PNG_COLOR_TYPE_GRAY && depth < 8)
png_set_expand(png_ptr);
if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS))
png_set_expand(png_ptr);
if (depth == 16)
png_set_strip_16(png_ptr);
/* We also have png "packing" bits into bytes if < 8 */
if (depth < 8)
png_set_packing(png_ptr);
/* Lastly, if the PNG is greyscale, convert to RGB */
if (ctype == PNG_COLOR_TYPE_GRAY || ctype == PNG_COLOR_TYPE_GRAY_ALPHA)
png_set_gray_to_rgb(png_ptr);
/* ...and if we're interlaced... */
passes = png_set_interlace_handling(png_ptr);
/* Update our info structs */
png_read_update_info(png_ptr, info_ptr);
/* Allocate some memory and set up row array */
/* This "inhales vigirously"... */
if (ctype & PNG_COLOR_MASK_ALPHA)
bpp = 4;
else
bpp = 3;
pixels = art_alloc(w * h * bpp);
rows = g_malloc(h * sizeof(png_bytep));
if ((!pixels) || (!rows)) {
png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
return NULL;
}
/* Icky code, but it has to be done... */
for (i = 0; i < h; i++) {
if ((rows[i] = g_malloc(w * sizeof(art_u8) * bpp)) == NULL) {
int n;
for (n = 0; n < i; n++)
g_free(rows[i]);
g_free(rows);
art_free(pixels);
png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
return NULL;
}
}
/* And we FINALLY get here... */
png_read_image(png_ptr, rows);
png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
/* Now stuff the bytes into pixels & free rows[y] */
temp = pixels;
for (y = 0; y < h; y++) {
(png_bytep) rowdata = rows[y];
for (x = 0; x < w; x++) {
temp[0] = rowdata[(x * bpp)];
temp[1] = rowdata[(x * bpp) + 1];
temp[2] = rowdata[(x * bpp) + 2];
if (bpp == 4)
temp[3] = rowdata[(x * bpp) + 3];
temp += bpp;
}
g_free(rows[y]);
}
g_free(rows);
/* Return the GdkPixBuf */
pixbuf = g_new(GdkPixBuf, 1);
if (ctype & PNG_COLOR_MASK_ALPHA)
pixbuf->art_pixbuf = art_pixbuf_new_rgba(pixels, w, h, (w * 4));
else
pixbuf->art_pixbuf = art_pixbuf_new_rgb(pixels, w, h, (w * 3));
/* Ok, I'm anal...shoot me */
if (!(pixbuf->art_pixbuf)) {
art_free(pixels);
g_free(pixbuf);
return NULL;
}
pixbuf->ref_count = 0;
pixbuf->unref_func = NULL;
return pixbuf;
}
int image_save(GdkPixBuf *pixbuf, FILE *file)
{
png_structp png_ptr;
png_infop info_ptr;
art_u8 *data;
gint y, h, w;
png_bytep row_ptr;
png_color_8 sig_bit;
gint type;
g_return_val_if_fail(f != NULL, NULL);
g_return_val_if_fail(pixbuf != NULL, NULL);
h = pixbuf->art_pixbuf->height;
w = pixbuf->art_pixbuf->width;
png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING,
NULL, NULL, NULL);
if (png_ptr == NULL) {
fclose(file);
return NULL;
}
info_ptr = png_create_info_struct(png_ptr);
if (info_ptr == NULL) {
fclose(file);
png_destroy_write_struct(&png_ptr, (png_infopp) NULL);
return NULL;
}
if (setjmp(png_ptr->jmpbuf)) {
fclose(file);
png_destroy_write_struct(&png_ptr, (png_infopp) NULL);
return NULL;
}
png_init_io(png_ptr, file);
if (pixbuf->art_pixbuf->has_alpha) {
sig_bit.alpha = 8;
type = PNG_COLOR_TYPE_RGB_ALPHA;
} else {
sig_bit.alpha = 0;
type = PNG_COLOR_TYPE_RGB;
}
sig_bit.red = sig_bit.green = sig_bit.blue = 8;
png_set_IHDR(png_ptr, info_ptr, w, h, 8, type, PNG_INTERLACE_NONE,
PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
png_set_sBIT(png_ptr, info_ptr, &sig_bit);
png_write_info(png_ptr, info_ptr);
png_set_shift(png_ptr, &sig_bit);
png_set_packing(png_ptr);
data = pixbuf->art_pixbuf->pixels;
for (y = 0; y < h; y++) {
if (pixbuf->art_pixbuf->has_alpha)
row_ptr[y] = data + (w * y * 4);
else
row_ptr[y] = data + (w * y * 3);
}
png_write_image(png_ptr, row_ptr);
png_write_end(png_ptr, info_ptr);
png_destroy_write_struct(&png_ptr, (png_infopp) NULL);
return TRUE;
}
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