1 /**************************************************************************
3 * Copyright 2011 Jose Fonseca
4 * Copyright 2008-2010 VMware, Inc.
7 * Permission is hereby granted, free of charge, to any person obtaining a copy
8 * of this software and associated documentation files (the "Software"), to deal
9 * in the Software without restriction, including without limitation the rights
10 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
11 * copies of the Software, and to permit persons to whom the Software is
12 * furnished to do so, subject to the following conditions:
14 * The above copyright notice and this permission notice shall be included in
15 * all copies or substantial portions of the Software.
17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
18 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
19 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
20 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
21 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
22 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
25 **************************************************************************/
39 * http://en.wikipedia.org/wiki/Netpbm_format
40 * http://netpbm.sourceforge.net/doc/ppm.html
43 Image::writePNM(std::ostream &os, const char *comment) const {
44 assert(channels == 1 || channels >= 3);
46 os << (channels == 1 ? "P5" : "P6") << "\n";
48 os << "#" << comment << "\n";
50 os << width << " " << height << "\n";
53 const unsigned char *row;
55 if (channels == 1 || channels == 3) {
56 for (row = start(); row != end(); row += stride()) {
57 os.write((const char *)row, width*channels);
60 unsigned char *tmp = new unsigned char[width*3];
62 for (row = start(); row != end(); row += stride()) {
63 const uint32_t *src = (const uint32_t *)row;
64 uint32_t *dst = (uint32_t *)tmp;
66 for (x = 0; x + 4 <= width; x += 4) {
68 * It's much faster to access dwords than bytes.
70 * FIXME: Big-endian version.
73 uint32_t rgba0 = *src++ & 0xffffff;
74 uint32_t rgba1 = *src++ & 0xffffff;
75 uint32_t rgba2 = *src++ & 0xffffff;
76 uint32_t rgba3 = *src++ & 0xffffff;
79 uint32_t rgb1 = (rgba1 >> 8)
81 uint32_t rgb2 = (rgba2 >> 16)
87 for (; x < width; ++x) {
88 tmp[x*3 + 0] = row[x*4 + 0];
89 tmp[x*3 + 1] = row[x*4 + 1];
90 tmp[x*3 + 2] = row[x*4 + 2];
92 os.write((const char *)tmp, width*3);
94 } else if (channels == 2) {
95 for (row = start(); row != end(); row += stride()) {
96 const unsigned char *src = row;
97 unsigned char *dst = tmp;
98 for (unsigned x = 0; x < width; ++x) {
103 os.write((const char *)tmp, width*3);
113 readPNMHeader(const char *buffer, size_t bufferSize, unsigned *channels, unsigned *width, unsigned *height)
119 const char *currentBuffer = buffer;
120 const char *nextBuffer;
122 // parse number of channels
123 int scannedChannels = sscanf(currentBuffer, "P%d\n", channels);
124 if (scannedChannels != 1) { // validate scanning of channels
125 // invalid channel line
128 // convert channel token to number of channels
129 *channels = (*channels == 5) ? 1 : 3;
131 // advance past channel line
132 nextBuffer = (const char *) memchr((const void *) currentBuffer, '\n', bufferSize) + 1;
133 bufferSize -= nextBuffer - currentBuffer;
134 currentBuffer = nextBuffer;
136 // skip over optional comment
137 if (*currentBuffer == '#') {
138 // advance past comment line
139 nextBuffer = (const char *) memchr((const void *) currentBuffer, '\n', bufferSize) + 1;
140 bufferSize -= nextBuffer - currentBuffer;
141 currentBuffer = nextBuffer;
144 // parse dimensions of image
145 int scannedDimensions = sscanf(currentBuffer, "%d %d\n", width, height);
146 if (scannedDimensions != 2) { // validate scanning of dimensions
147 // invalid dimension line
151 // advance past dimension line
152 nextBuffer = (const char *) memchr((const void *) currentBuffer, '\n', bufferSize) + 1;
153 bufferSize -= nextBuffer - currentBuffer;
154 currentBuffer = nextBuffer;
156 // skip over "255\n" at end of header
157 nextBuffer = (const char *) memchr((const void *) currentBuffer, '\n', bufferSize) + 1;
159 // return start of image data
163 } /* namespace image */