1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
|
/*
* $Id: readpng.cxx,v 4.4 2008/01/22 13:54:22 hut66au Exp $
*
* Imview, the portable image analysis application
* http://imview.sourceforge.net
* ----------------------------------------------------------
*
* Imview is an attempt to provide an image display application
* suitable for professional image analysis. It was started in
* 1997 and is mostly the result of the efforts of Hugues Talbot,
* Image Analysis Project, CSIRO Mathematical and Information
* Sciences, with help from others (see the CREDITS files for
* more information)
*
* Imview is Copyrighted (C) 1997-2007 by Hugues Talbot and was
* supported in parts by the Australian Commonwealth Science and
* Industry Research Organisation. Please see the COPYRIGHT file
* for full details. Imview also includes the contributions of
* many others. Please see the CREDITS file for full details.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
* */
/*------------------------------------------------------------------------
*
* Read PNG natively.
* A very important codec.
*
* This code shamelessly taken from FLTK.
*
* Hugues Talbot 9 Jun 2007
*
*
*-----------------------------------------------------------------------*/
#include "imnmspc.hxx" // name space definition if needed
#include <stdio.h>
#include <stdlib.h>
//#include <setjmp.h>
#include "imview.hxx"
#if defined(HAVE_PNG) && defined(HAVE_LIBZ)
# include <zlib.h>
# include <png.h>
#endif // HAVE_LIBPNG && HAVE_LIBZ
#include "imageIO.hxx"
extern imageIO *IOBlackBox;
int pngnbcomp(const char *ident)
{
return 1; // we need to use MNG if we want movies
}
// read a PNG image, the index is always ignored.
// Limitations :
// - we do not read 16-bit images correctly (they get cast to 8-bit)
// - we do not yield separate buffers per components.
//
int readPNGImage(const char *pngfilename, int index) // I - File to read
{
int retval = 0;
#if defined(HAVE_PNG) && defined(HAVE_LIBZ)
int i; // Looping var
FILE *fp; // File pointer
int channels; // Number of color channels
png_structp pp; // PNG read pointer
png_infop info; // PNG info pointers
png_bytep *rows; // PNG row pointers
int w, h, d;
uchar *array;
// Open the PNG file...
if ((fp = fopen(pngfilename, "rb")) == NULL) {
errprintf("readPNGimage : cannot open file %s\n", pngfilename);
return 102;
}
// Setup the PNG data structures...
pp = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
info = png_create_info_struct(pp);
if (setjmp(png_jmpbuf(pp)))
{
errprintf("PNG file \"%s\" contains errors!\n", pngfilename);
return 103;
}
// Initialize the PNG read "engine"...
png_init_io(pp, fp);
// Get the image dimensions and convert to grayscale or RGB...
png_read_info(pp, info);
png_uint_32 width;
png_uint_32 height;
int bit_depth;
int color_type;
int interlace_type;
int compression_type;
int filter_method;
png_get_IHDR(pp, info, &width, &height,
&bit_depth, &color_type, &interlace_type,
&compression_type, &filter_method);
if (color_type == PNG_COLOR_TYPE_PALETTE)
png_set_expand(pp);
if (color_type & PNG_COLOR_MASK_COLOR)
channels = 3;
else
channels = 1;
int num_trans;
png_get_tRNS(pp, info, NULL, &num_trans, NULL);
if ((color_type & PNG_COLOR_MASK_ALPHA) || num_trans)
channels ++;
w = (int)(width);
h = (int)(height);
d = channels;
if (bit_depth < 8)
{
png_set_packing(pp);
png_set_expand(pp);
}
// we ought to read the 16-bit data correctly, since we can !
else if (bit_depth == 16)
png_set_strip_16(pp);
# if defined(HAVE_PNG_GET_VALID) && defined(HAVE_PNG_SET_TRNS_TO_ALPHA)
// Handle transparency...
if (png_get_valid(pp, info, PNG_INFO_tRNS))
png_set_tRNS_to_alpha(pp);
# endif // HAVE_PNG_GET_VALID && HAVE_PNG_SET_TRNS_TO_ALPHA
array = new uchar[w * h * d];
// Allocate pointers...
rows = new png_bytep[h];
for (i = 0; i < h; i ++)
rows[i] = (png_bytep)(array + i * w * d);
// Read the image, handling interlacing as needed...
for (i = png_set_interlace_handling(pp); i > 0; i --)
png_read_rows(pp, rows, NULL, h);
#ifdef WIN32
// Some Windows graphics drivers don't honor transparency when RGB == white
if (channels == 4) {
// Convert RGB to 0 when alpha == 0...
uchar *ptr = (uchar *)array;
for (i = w * h; i > 0; i --, ptr += 4)
if (!ptr[3]) ptr[0] = ptr[1] = ptr[2] = 0;
}
#endif // WIN32
// Free memory and return...
delete[] rows;
png_read_end(pp, info);
png_destroy_read_struct(&pp, &info, NULL);
// this will require no translation
IOBlackBox->setImData(array);
IOBlackBox->setCurrImgWidth(w);
IOBlackBox->setCurrImgHeight(h);
IOBlackBox->setCurrImgThickness(1);
IOBlackBox->setXOffset(0);
IOBlackBox->setYOffset(0);
IOBlackBox->setZOffset(0);
IOBlackBox->setCurrImgNbComps(1); // only a single image in a PNG file
IOBlackBox->setCurrImgNbSamples(d);
IOBlackBox->setCurrImgSpp(d); // needed here because no currBuffp
IOBlackBox->setCurrPixType(IM_UINT1);
IOBlackBox->setCurrImgType((d == 1) ? IM_SINGLE : ((d == 3) ? IM_RGB : IM_SPECTRUM));
IOBlackBox->setImgDesc("PNG");
fclose(fp);
#else
errprintf("This version of imview cannot read PNG files\n");
retval = 101; // not supported
#endif // HAVE_PNG && HAVE_LIBZ
return retval;
}
|
