1 /* png.c - load PNG image from file
3 * Raster graphics library
5 * Copyright (c) 1997-2003 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.
24 /* AIX requires this to be the first thing in the file. */
26 # define alloca __builtin_alloca
34 # ifndef alloca /* predefined by HP cc +Olibcalls */
51 RImage
*RLoadPNG(RContext
* context
, char *file
, int index
)
57 png_infop pinfo
, einfo
;
58 png_color_16p bkcolor
;
62 png_uint_32 width
, height
;
63 int depth
, junk
, color_type
;
67 f
= fopen(file
, "rb");
69 RErrorCode
= RERR_OPEN
;
72 png
= png_create_read_struct(PNG_LIBPNG_VER_STRING
, NULL
, (png_error_ptr
) NULL
, (png_error_ptr
) NULL
);
74 RErrorCode
= RERR_NOMEMORY
;
79 pinfo
= png_create_info_struct(png
);
81 RErrorCode
= RERR_NOMEMORY
;
83 png_destroy_read_struct(&png
, NULL
, NULL
);
87 einfo
= png_create_info_struct(png
);
89 RErrorCode
= RERR_NOMEMORY
;
91 png_destroy_read_struct(&png
, &pinfo
, NULL
);
95 RErrorCode
= RERR_INTERNAL
;
96 if (setjmp(png
->jmpbuf
)) {
98 png_destroy_read_struct(&png
, &pinfo
, &einfo
);
100 RReleaseImage(image
);
106 png_read_info(png
, pinfo
);
108 png_get_IHDR(png
, pinfo
, &width
, &height
, &depth
, &color_type
, &junk
, &junk
, &junk
);
111 if (width
< 1 || height
< 1) {
113 png_destroy_read_struct(&png
, &pinfo
, &einfo
);
114 RErrorCode
= RERR_BADIMAGEFILE
;
118 /* check for an alpha channel */
119 if (png_get_valid(png
, pinfo
, PNG_INFO_tRNS
))
122 alpha
= (color_type
& PNG_COLOR_MASK_ALPHA
);
124 /* allocate RImage */
125 image
= RCreateImage(width
, height
, alpha
);
128 png_destroy_read_struct(&png
, &pinfo
, &einfo
);
132 /* normalize to 8bpp with alpha channel */
133 if (color_type
== PNG_COLOR_TYPE_PALETTE
&& depth
<= 8)
136 if (color_type
== PNG_COLOR_TYPE_GRAY
&& depth
<= 8)
139 if (png_get_valid(png
, pinfo
, PNG_INFO_tRNS
))
143 png_set_strip_16(png
);
145 if (color_type
== PNG_COLOR_TYPE_GRAY
|| color_type
== PNG_COLOR_TYPE_GRAY_ALPHA
)
146 png_set_gray_to_rgb(png
);
148 /* set gamma correction */
149 if ((context
->attribs
->flags
& RC_GammaCorrection
)
150 && context
->depth
!= 8) {
151 sgamma
= (context
->attribs
->rgamma
+ context
->attribs
->ggamma
+ context
->attribs
->bgamma
) / 3;
152 } else if ((tmp
= getenv("DISPLAY_GAMMA")) != NULL
) {
161 if (png_get_gAMA(png
, pinfo
, &gamma
))
162 png_set_gamma(png
, sgamma
, gamma
);
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
);
178 RErrorCode
= RERR_NOMEMORY
;
180 RReleaseImage(image
);
181 png_destroy_read_struct(&png
, &pinfo
, &einfo
);
187 for (y
= 0; y
< height
; y
++) {
188 png_rows
[y
] = alloca(png_get_rowbytes(png
, pinfo
));
190 RErrorCode
= RERR_NOMEMORY
;
192 RReleaseImage(image
);
193 png_destroy_read_struct(&png
, &pinfo
, &einfo
);
201 png_read_image(png
, png_rows
);
203 png_read_end(png
, einfo
);
205 png_destroy_read_struct(&png
, &pinfo
, &einfo
);
211 /* convert to RImage */
213 for (y
= 0; y
< height
; y
++) {
214 for (x
= 0, i
= width
* 4; x
< i
; x
++, ptr
++) {
215 *ptr
= *(png_rows
[y
] + x
);
219 for (y
= 0; y
< height
; y
++) {
220 for (x
= 0, i
= width
* 3; x
< i
; x
++, ptr
++) {
221 *ptr
= *(png_rows
[y
] + x
);