1 /*
2 * Copyright (c) 2006-2009, Google Inc. All rights reserved.
3 * Copyright (c) 2009 Torch Mobile, Inc. All rights reserved.
4 * Copyright (C) Research In Motion Limited 2009-2010. All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions are
8 * met:
9 *
10 * * Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * * Redistributions in binary form must reproduce the above
13 * copyright notice, this list of conditions and the following disclaimer
14 * in the documentation and/or other materials provided with the
15 * distribution.
16 * * Neither the name of Google Inc. nor the names of its
17 * contributors may be used to endorse or promote products derived from
18 * this software without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
21 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
23 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
24 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
25 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
26 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
27 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
28 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
29 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
30 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31 */
32
33 #include "config.h"
34 #include "PNGImageEncoder.h"
35
36 #include "IntSize.h"
37 #include "png.h"
38 #include <wtf/Vector.h>
39
40 namespace WebCore {
41
42 // Encoder --------------------------------------------------------------------
43 //
44 // This section of the code is based on nsPNGEncoder.cpp in Mozilla
45 // (Copyright 2005 Google Inc.)
46
47 // Passed around as the io_ptr in the png structs so our callbacks know where
48 // to write data.
49 struct PNGEncoderState {
PNGEncoderStateWebCore::PNGEncoderState50 PNGEncoderState(Vector<char>* o) : m_dump(o) {}
51 Vector<char>* m_dump;
52 };
53
54 // Called by libpng to flush its internal buffer to ours.
encoderWriteCallback(png_structp png,png_bytep data,png_size_t size)55 void encoderWriteCallback(png_structp png, png_bytep data, png_size_t size)
56 {
57 PNGEncoderState* state = static_cast<PNGEncoderState*>(png_get_io_ptr(png));
58 ASSERT(state->m_dump);
59
60 size_t oldSize = state->m_dump->size();
61 state->m_dump->resize(oldSize + size);
62 char* destination = state->m_dump->data() + oldSize;
63 memcpy(destination, data, size);
64 }
65
66 // Automatically destroys the given write structs on destruction to make
67 // cleanup and error handling code cleaner.
68 class PNGWriteStructDestroyer {
69 public:
PNGWriteStructDestroyer(png_struct ** ps,png_info ** pi)70 PNGWriteStructDestroyer(png_struct** ps, png_info** pi)
71 : m_pngStruct(ps)
72 , m_pngInfo(pi)
73 {
74 }
75
~PNGWriteStructDestroyer()76 ~PNGWriteStructDestroyer()
77 {
78 png_destroy_write_struct(m_pngStruct, m_pngInfo);
79 }
80
81 private:
82 png_struct** m_pngStruct;
83 png_info** m_pngInfo;
84 };
85
compressRGBABigEndianToPNG(unsigned char * rgbaBigEndianData,const IntSize & size,Vector<char> & pngData)86 bool compressRGBABigEndianToPNG(unsigned char* rgbaBigEndianData, const IntSize& size, Vector<char>& pngData)
87 {
88 png_struct* pngPtr = png_create_write_struct(PNG_LIBPNG_VER_STRING, png_voidp_NULL, png_error_ptr_NULL, png_error_ptr_NULL);
89 if (!pngPtr)
90 return false;
91
92 png_info* infoPtr = png_create_info_struct(pngPtr);
93 if (!infoPtr) {
94 png_destroy_write_struct(&pngPtr, 0);
95 return false;
96 }
97 PNGWriteStructDestroyer destroyer(&pngPtr, &infoPtr);
98
99 // The destroyer will ensure that the structures are cleaned up in this
100 // case, even though we may get here as a jump from random parts of the
101 // PNG library called below.
102 if (setjmp(png_jmpbuf(pngPtr)))
103 return false;
104
105 // Set our callback for libpng to give us the data.
106 PNGEncoderState state(&pngData);
107 png_set_write_fn(pngPtr, &state, encoderWriteCallback, 0);
108
109 int pngOutputColorType = PNG_COLOR_TYPE_RGB_ALPHA;
110
111 png_set_IHDR(pngPtr, infoPtr, size.width(), size.height(), 8, pngOutputColorType,
112 PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_DEFAULT,
113 PNG_FILTER_TYPE_DEFAULT);
114 png_write_info(pngPtr, infoPtr);
115
116 unsigned bytesPerRow = size.width() * 4;
117 for (unsigned y = 0; y < size.height(); ++y) {
118 png_write_row(pngPtr, rgbaBigEndianData);
119 rgbaBigEndianData += bytesPerRow;
120 }
121
122 png_write_end(pngPtr, infoPtr);
123 return true;
124 }
125
126 } // namespace WebCore
127