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
|
/*
* Copyright (c) 2010, Google Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following disclaimer
* in the documentation and/or other materials provided with the
* distribution.
* * Neither the name of Google Inc. nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "config.h"
#include "JPEGImageEncoder.h"
#include "IntSize.h"
#include "SkBitmap.h"
#include "SkColorPriv.h"
#include "SkUnPreMultiply.h"
extern "C" {
#include <stdio.h> // jpeglib.h needs stdio.h FILE
#include "jpeglib.h"
#include <setjmp.h>
}
namespace WebCore {
struct JPEGOutputBuffer : public jpeg_destination_mgr {
Vector<unsigned char>* output;
Vector<unsigned char> buffer;
};
static void prepareOutput(j_compress_ptr cinfo)
{
JPEGOutputBuffer* out = static_cast<JPEGOutputBuffer*>(cinfo->dest);
const size_t internalBufferSize = 8192;
out->buffer.resize(internalBufferSize);
out->next_output_byte = out->buffer.data();
out->free_in_buffer = out->buffer.size();
}
static boolean writeOutput(j_compress_ptr cinfo)
{
JPEGOutputBuffer* out = static_cast<JPEGOutputBuffer*>(cinfo->dest);
out->output->append(out->buffer.data(), out->buffer.size());
out->next_output_byte = out->buffer.data();
out->free_in_buffer = out->buffer.size();
return TRUE;
}
static void finishOutput(j_compress_ptr cinfo)
{
JPEGOutputBuffer* out = static_cast<JPEGOutputBuffer*>(cinfo->dest);
const size_t size = out->buffer.size() - out->free_in_buffer;
out->output->append(out->buffer.data(), size);
}
static void handleError(j_common_ptr common)
{
jmp_buf* jumpBufferPtr = static_cast<jmp_buf*>(common->client_data);
longjmp(*jumpBufferPtr, -1);
}
// FIXME: is alpha unpremultiplication correct, or should the alpha channel
// be ignored? See bug http://webkit.org/b/40147.
void preMultipliedBGRAtoRGB(const SkPMColor* input, unsigned int pixels, unsigned char* output)
{
static const SkUnPreMultiply::Scale* scale = SkUnPreMultiply::GetScaleTable();
for (; pixels-- > 0; ++input) {
const unsigned alpha = SkGetPackedA32(*input);
if ((alpha != 0) && (alpha != 255)) {
*output++ = SkUnPreMultiply::ApplyScale(scale[alpha], SkGetPackedR32(*input));
*output++ = SkUnPreMultiply::ApplyScale(scale[alpha], SkGetPackedG32(*input));
*output++ = SkUnPreMultiply::ApplyScale(scale[alpha], SkGetPackedB32(*input));
} else {
*output++ = SkGetPackedR32(*input);
*output++ = SkGetPackedG32(*input);
*output++ = SkGetPackedB32(*input);
}
}
}
bool JPEGImageEncoder::encode(const SkBitmap& bitmap, int quality, Vector<unsigned char>* output)
{
if (bitmap.config() != SkBitmap::kARGB_8888_Config)
return false; // Only support ARGB 32 bpp skia bitmaps.
SkAutoLockPixels bitmapLock(bitmap);
IntSize imageSize(bitmap.width(), bitmap.height());
imageSize.clampNegativeToZero();
JPEGOutputBuffer destination;
destination.output = output;
Vector<JSAMPLE> row;
jpeg_compress_struct cinfo;
jpeg_error_mgr error;
cinfo.err = jpeg_std_error(&error);
error.error_exit = handleError;
jmp_buf jumpBuffer;
cinfo.client_data = &jumpBuffer;
if (setjmp(jumpBuffer)) {
jpeg_destroy_compress(&cinfo);
return false;
}
jpeg_create_compress(&cinfo);
cinfo.dest = &destination;
cinfo.dest->init_destination = prepareOutput;
cinfo.dest->empty_output_buffer = writeOutput;
cinfo.dest->term_destination = finishOutput;
cinfo.image_height = imageSize.height();
cinfo.image_width = imageSize.width();
cinfo.in_color_space = JCS_RGB;
cinfo.input_components = 3;
jpeg_set_defaults(&cinfo);
jpeg_set_quality(&cinfo, quality, TRUE);
jpeg_start_compress(&cinfo, TRUE);
const SkPMColor* pixels = static_cast<SkPMColor*>(bitmap.getPixels());
row.resize(cinfo.image_width * cinfo.input_components);
while (cinfo.next_scanline < cinfo.image_height) {
preMultipliedBGRAtoRGB(pixels, cinfo.image_width, row.data());
jpeg_write_scanlines(&cinfo, row.dataSlot(), 1);
pixels += cinfo.image_width;
}
jpeg_finish_compress(&cinfo);
jpeg_destroy_compress(&cinfo);
return true;
}
} // namespace WebCore
|
