Visualization Library 2.0.0-b5

A lightweight C++ OpenGL middleware for 2D/3D graphics

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readppm.c
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1 /*---------------------------------------------------------------------------
2 
3  rpng - simple PNG display program readppm.c
4 
5  ---------------------------------------------------------------------------
6 
7  This is a special-purpose replacement for readpng.c that allows binary
8  PPM files to be used in place of PNG images.
9 
10  ---------------------------------------------------------------------------
11 
12  Copyright (c) 1998-2007 Greg Roelofs. All rights reserved.
13 
14  This software is provided "as is," without warranty of any kind,
15  express or implied. In no event shall the author or contributors
16  be held liable for any damages arising in any way from the use of
17  this software.
18 
19  The contents of this file are DUAL-LICENSED. You may modify and/or
20  redistribute this software according to the terms of one of the
21  following two licenses (at your option):
22 
23 
24  LICENSE 1 ("BSD-like with advertising clause"):
25 
26  Permission is granted to anyone to use this software for any purpose,
27  including commercial applications, and to alter it and redistribute
28  it freely, subject to the following restrictions:
29 
30  1. Redistributions of source code must retain the above copyright
31  notice, disclaimer, and this list of conditions.
32  2. Redistributions in binary form must reproduce the above copyright
33  notice, disclaimer, and this list of conditions in the documenta-
34  tion and/or other materials provided with the distribution.
35  3. All advertising materials mentioning features or use of this
36  software must display the following acknowledgment:
37 
38  This product includes software developed by Greg Roelofs
39  and contributors for the book, "PNG: The Definitive Guide,"
40  published by O'Reilly and Associates.
41 
42 
43  LICENSE 2 (GNU GPL v2 or later):
44 
45  This program is free software; you can redistribute it and/or modify
46  it under the terms of the GNU General Public License as published by
47  the Free Software Foundation; either version 2 of the License, or
48  (at your option) any later version.
49 
50  This program is distributed in the hope that it will be useful,
51  but WITHOUT ANY WARRANTY; without even the implied warranty of
52  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
53  GNU General Public License for more details.
54 
55  You should have received a copy of the GNU General Public License
56  along with this program; if not, write to the Free Software Foundation,
57  Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
58 
59  ---------------------------------------------------------------------------*/
60 
61 #include <stdio.h>
62 #include <stdlib.h>
63 
64 #include "readpng.h" /* typedefs, common macros, public prototypes */
65 
66 
71 
72 
74 {
75  fprintf(stderr, " Compiled without libpng, zlib or PBMPLUS/NetPBM.\n");
76 }
77 
78 
79 /* return value = 0 for success, 1 for bad sig, 2 for bad IHDR, 4 for no mem */
80 
81 int readpng_init(FILE *infile, ulg *pWidth, ulg *pHeight)
82 {
83  static uch ppmline[256];
84  int maxval;
85 
86 
88 
89  fgets(ppmline, 256, infile);
90  if (ppmline[0] != 'P' || ppmline[1] != '6') {
91  fprintf(stderr, "ERROR: not a PPM file\n");
92  return 1;
93  }
94  /* possible color types: P5 = grayscale (0), P6 = RGB (2), P8 = RGBA (6) */
95  if (ppmline[1] == '6') {
96  color_type = 2;
97  channels = 3;
98  } else if (ppmline[1] == '8') {
99  color_type = 6;
100  channels = 4;
101  } else /* if (ppmline[1] == '5') */ {
102  color_type = 0;
103  channels = 1;
104  }
105 
106  do {
107  fgets(ppmline, 256, infile);
108  } while (ppmline[0] == '#');
109  sscanf(ppmline, "%lu %lu", &width, &height);
110 
111  do {
112  fgets(ppmline, 256, infile);
113  } while (ppmline[0] == '#');
114  sscanf(ppmline, "%d", &maxval);
115  if (maxval != 255) {
116  fprintf(stderr, "ERROR: maxval = %d\n", maxval);
117  return 2;
118  }
119  bit_depth = 8;
120 
121  *pWidth = width;
122  *pHeight = height;
123 
124  return 0;
125 }
126 
127 
128 
129 
130 /* returns 0 if succeeds, 1 if fails due to no bKGD chunk, 2 if libpng error;
131  * scales values to 8-bit if necessary */
132 
134 {
135  return 1;
136 }
137 
138 
139 
140 
141 /* display_exponent == LUT_exponent * CRT_exponent */
142 
143 uch *readpng_get_image(double display_exponent, int *pChannels, ulg *pRowbytes)
144 {
145  ulg rowbytes;
146 
147 
148  /* expand palette images to RGB, low-bit-depth grayscale images to 8 bits,
149  * transparency chunks to full alpha channel; strip 16-bit-per-sample
150  * images to 8 bits per sample; and convert grayscale to RGB[A] */
151 
152  /* GRR WARNING: grayscale needs to be expanded and channels reset! */
153 
154  *pRowbytes = rowbytes = channels*width;
155  *pChannels = channels;
156 
157  if ((image_data = (uch *)malloc(rowbytes*height)) == NULL) {
158  return NULL;
159  }
160 
161  Trace((stderr, "readpng_get_image: rowbytes = %ld, height = %ld\n", rowbytes, height));
162 
163 
164  /* now we can go ahead and just read the whole image */
165 
166  fread(image_data, 1L, rowbytes*height, saved_infile);
167 
168 
169  return image_data;
170 }
171 
172 
173 void readpng_cleanup(int free_image_data)
174 {
175  if (free_image_data && image_data) {
176  free(image_data);
177  image_data = NULL;
178  }
179 }
void readpng_cleanup(int free_image_data)
Definition: readppm.c:173
GLint GLint GLsizei GLsizei height
#define NULL
Definition: ftobjs.h:61
char * malloc()
GLint GLint GLsizei width
FILE * saved_infile
Definition: readppm.c:70
GLfloat green
unsigned long ulg
Definition: zutil.h:38
int color_type
Definition: readppm.c:68
ulg height
Definition: readppm.c:67
int channels
Definition: readppm.c:68
uch * image_data
Definition: readppm.c:69
GLfloat GLfloat blue
int bit_depth
Definition: readppm.c:68
ulg width
Definition: readppm.c:67
int free()
uch * readpng_get_image(double display_exponent, int *pChannels, ulg *pRowbytes)
Definition: readppm.c:143
#define Trace(x)
Definition: zutil.h:197
FILE * infile
Definition: cdjpeg.h:141
void readpng_version_info()
Definition: readppm.c:73
int readpng_init(FILE *infile, ulg *pWidth, ulg *pHeight)
Definition: readppm.c:81
int double red
Definition: png.h:1498
int readpng_get_bgcolor(uch *red, uch *green, uch *blue)
Definition: readppm.c:133
unsigned char uch
Definition: zutil.h:34