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[wmaker-crm.git] / wrlib / png.c
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1 /* png.c - load PNG image from file
2 *
3 * Raster graphics library
4 *
5 * Copyright (c) 1997 Alfredo K. Kojima
7 * This library is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Library General Public
9 * License as published by the Free Software Foundation; either
10 * version 2 of the License, or (at your option) any later version.
12 * This library is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Library General Public License for more details.
17 * You should have received a copy of the GNU Library General Public
18 * License along with this library; if not, write to the Free
19 * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
22 #include <config.h>
24 /* AIX requires this to be the first thing in the file. */
25 #ifdef __GNUC__
26 # define alloca __builtin_alloca
27 #else
28 # if HAVE_ALLOCA_H
29 # include <alloca.h>
30 # else
31 # ifdef _AIX
32 # pragma alloca
33 # else
34 # ifndef alloca /* predefined by HP cc +Olibcalls */
35 char *alloca ();
36 # endif
37 # endif
38 # endif
39 #endif
42 #ifdef USE_PNG
44 #include <stdlib.h>
45 #include <stdio.h>
46 #include <string.h>
48 #include <png.h>
50 #include "wraster.h"
53 RImage*
54 RLoadPNG(RContext *context, char *file, int index)
56 char *tmp;
57 RImage *image=NULL;
58 FILE *f;
59 png_structp png;
60 png_infop pinfo, einfo;
61 png_color_16p bkcolor;
62 int alpha;
63 int x, y, i;
64 double gamma, sgamma;
65 png_uint_32 width, height;
66 int depth, junk, color_type;
67 png_bytep *png_rows;
68 unsigned char *ptr;
70 f = fopen(file, "r");
71 if (!f) {
72 RErrorCode = RERR_OPEN;
73 return NULL;
75 png = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL,
76 (png_error_ptr)NULL, (png_error_ptr)NULL);
77 if (!png) {
78 RErrorCode = RERR_NOMEMORY;
79 fclose(f);
80 return NULL;
83 pinfo = png_create_info_struct(png);
84 if (!pinfo) {
85 RErrorCode = RERR_NOMEMORY;
86 fclose(f);
87 png_destroy_read_struct(&png, NULL, NULL);
88 return NULL;
91 einfo = png_create_info_struct(png);
92 if (!einfo) {
93 RErrorCode = RERR_NOMEMORY;
94 fclose(f);
95 png_destroy_read_struct(&png, &pinfo, NULL);
96 return NULL;
99 RErrorCode = RERR_INTERNAL;
100 if (setjmp(png->jmpbuf)) {
101 fclose(f);
102 png_destroy_read_struct(&png, &pinfo, &einfo);
103 if (image)
104 RDestroyImage(image);
105 return NULL;
108 png_init_io(png, f);
110 png_read_info(png, pinfo);
112 png_get_IHDR(png, pinfo, &width, &height, &depth, &color_type,
113 &junk, &junk, &junk);
116 /* check for an alpha channel */
117 if (png_get_valid(png, pinfo, PNG_INFO_tRNS))
118 alpha = True;
119 else
120 alpha = (color_type & PNG_COLOR_MASK_ALPHA);
122 /* allocate RImage */
123 image = RCreateImage(width, height, alpha);
124 if (!image) {
125 fclose(f);
126 png_destroy_read_struct(&png, &pinfo, &einfo);
127 return NULL;
130 /* normalize to 8bpp with alpha channel */
131 if (color_type == PNG_COLOR_TYPE_PALETTE && depth <= 8)
132 png_set_expand(png);
134 if (color_type == PNG_COLOR_TYPE_GRAY && depth <= 8)
135 png_set_expand(png);
137 if (png_get_valid(png, pinfo, PNG_INFO_tRNS))
138 png_set_expand(png);
140 if (depth == 16)
141 png_set_strip_16(png);
143 if (color_type == PNG_COLOR_TYPE_GRAY ||
144 color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
145 png_set_gray_to_rgb(png);
147 /* set gamma correction */
148 if ((context->attribs->flags & RC_GammaCorrection)
149 && context->depth != 8) {
150 sgamma = (context->attribs->rgamma + context->attribs->ggamma +
151 context->attribs->bgamma) / 3;
152 } else if ((tmp = getenv("DISPLAY_GAMMA")) != NULL) {
153 sgamma = atof(tmp);
154 if (sgamma==0)
155 sgamma = 1;
156 } else {
157 /* blah */
158 sgamma = 2.2;
161 if (png_get_gAMA(png, pinfo, &gamma))
162 png_set_gamma(png, sgamma, gamma);
163 else
164 png_set_gamma(png, sgamma, 0.45);
166 /* do the transforms */
167 png_read_update_info(png, pinfo);
169 /* set background color */
170 if (png_get_bKGD(png, pinfo, &bkcolor)) {
171 image->background.red = bkcolor->red >> 8;
172 image->background.green = bkcolor->green >> 8;
173 image->background.blue = bkcolor->blue >> 8;
176 png_rows = alloca(sizeof(char*)*height);
177 if (!png_rows) {
178 RErrorCode = RERR_NOMEMORY;
179 fclose(f);
180 RDestroyImage(image);
181 png_destroy_read_struct(&png, &pinfo, &einfo);
182 #ifdef C_ALLOCA
183 alloca(0);
184 #endif
185 return NULL;
187 for (y=0; y<height; y++) {
188 png_rows[y] = alloca(png_get_rowbytes(png, pinfo));
189 if (!png_rows[y]) {
190 RErrorCode = RERR_NOMEMORY;
191 fclose(f);
192 RDestroyImage(image);
193 png_destroy_read_struct(&png, &pinfo, &einfo);
194 #ifdef C_ALLOCA
195 alloca(0);
196 #endif
197 return NULL;
200 /* read data */
201 png_read_image(png, png_rows);
203 png_read_end(png, einfo);
205 png_destroy_read_struct(&png, &pinfo, &einfo);
207 fclose(f);
209 ptr = image->data;
211 /* convert to RImage */
212 if (alpha) {
213 for (y=0; y<height; y++) {
214 for (x=0, i=width*4; x<i; x++, ptr++) {
215 *ptr = *(png_rows[y]+x);
218 } else {
219 for (y=0; y<height; y++) {
220 for (x=0, i=width*3; x<i; x++, ptr++) {
221 *ptr = *(png_rows[y]+x);
225 #ifdef C_ALLOCA
226 alloca(0);
227 #endif
228 return image;
231 #endif /* USE_PNG */