aboutsummaryrefslogtreecommitdiffhomepage
path: root/src/images/SkWEBPImageEncoder.cpp
blob: aad06ac1d3b2726144435fe1658fd4edf0fa5b54 (plain)
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
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
/*
 * Copyright 2010, The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "SkImageEncoderPriv.h"

#ifdef SK_HAS_WEBP_LIBRARY

#include "SkBitmap.h"
#include "SkColorPriv.h"
#include "SkStream.h"
#include "SkTemplates.h"
#include "SkUnPreMultiply.h"
#include "SkUtils.h"

// A WebP decoder only, on top of (subset of) libwebp
// For more information on WebP image format, and libwebp library, see:
//   http://code.google.com/speed/webp/
//   http://www.webmproject.org/code/#libwebp_webp_image_decoder_library
//   http://review.webmproject.org/gitweb?p=libwebp.git

#include <stdio.h>
extern "C" {
// If moving libwebp out of skia source tree, path for webp headers must be
// updated accordingly. Here, we enforce using local copy in webp sub-directory.
#include "webp/encode.h"
}

typedef void (*ScanlineImporter)(const uint8_t* in, uint8_t* out, int width,
                                 const SkPMColor* SK_RESTRICT ctable);

static void ARGB_8888_To_RGB(const uint8_t* in, uint8_t* rgb, int width,
                             const SkPMColor*) {
  const uint32_t* SK_RESTRICT src = (const uint32_t*)in;
  for (int i = 0; i < width; ++i) {
      const uint32_t c = *src++;
      rgb[0] = SkGetPackedR32(c);
      rgb[1] = SkGetPackedG32(c);
      rgb[2] = SkGetPackedB32(c);
      rgb += 3;
  }
}

static void ARGB_8888_To_RGBA(const uint8_t* in, uint8_t* rgb, int width,
                              const SkPMColor*) {
  const uint32_t* SK_RESTRICT src = (const uint32_t*)in;
  const SkUnPreMultiply::Scale* SK_RESTRICT table =
      SkUnPreMultiply::GetScaleTable();
  for (int i = 0; i < width; ++i) {
      const uint32_t c = *src++;
      uint8_t a = SkGetPackedA32(c);
      uint8_t r = SkGetPackedR32(c);
      uint8_t g = SkGetPackedG32(c);
      uint8_t b = SkGetPackedB32(c);
      if (0 != a && 255 != a) {
        SkUnPreMultiply::Scale scale = table[a];
        r = SkUnPreMultiply::ApplyScale(scale, r);
        g = SkUnPreMultiply::ApplyScale(scale, g);
        b = SkUnPreMultiply::ApplyScale(scale, b);
      }
      rgb[0] = r;
      rgb[1] = g;
      rgb[2] = b;
      rgb[3] = a;
      rgb += 4;
  }
}

static void RGB_565_To_RGB(const uint8_t* in, uint8_t* rgb, int width,
                           const SkPMColor*) {
  const uint16_t* SK_RESTRICT src = (const uint16_t*)in;
  for (int i = 0; i < width; ++i) {
      const uint16_t c = *src++;
      rgb[0] = SkPacked16ToR32(c);
      rgb[1] = SkPacked16ToG32(c);
      rgb[2] = SkPacked16ToB32(c);
      rgb += 3;
  }
}

static void ARGB_4444_To_RGB(const uint8_t* in, uint8_t* rgb, int width,
                             const SkPMColor*) {
  const SkPMColor16* SK_RESTRICT src = (const SkPMColor16*)in;
  for (int i = 0; i < width; ++i) {
      const SkPMColor16 c = *src++;
      rgb[0] = SkPacked4444ToR32(c);
      rgb[1] = SkPacked4444ToG32(c);
      rgb[2] = SkPacked4444ToB32(c);
      rgb += 3;
  }
}

static void ARGB_4444_To_RGBA(const uint8_t* in, uint8_t* rgb, int width,
                              const SkPMColor*) {
  const SkPMColor16* SK_RESTRICT src = (const SkPMColor16*)in;
  const SkUnPreMultiply::Scale* SK_RESTRICT table =
      SkUnPreMultiply::GetScaleTable();
  for (int i = 0; i < width; ++i) {
      const SkPMColor16 c = *src++;
      uint8_t a = SkPacked4444ToA32(c);
      uint8_t r = SkPacked4444ToR32(c);
      uint8_t g = SkPacked4444ToG32(c);
      uint8_t b = SkPacked4444ToB32(c);
      if (0 != a && 255 != a) {
        SkUnPreMultiply::Scale scale = table[a];
        r = SkUnPreMultiply::ApplyScale(scale, r);
        g = SkUnPreMultiply::ApplyScale(scale, g);
        b = SkUnPreMultiply::ApplyScale(scale, b);
      }
      rgb[0] = r;
      rgb[1] = g;
      rgb[2] = b;
      rgb[3] = a;
      rgb += 4;
  }
}

static void Index8_To_RGB(const uint8_t* in, uint8_t* rgb, int width,
                          const SkPMColor* SK_RESTRICT ctable) {
  const uint8_t* SK_RESTRICT src = (const uint8_t*)in;
  for (int i = 0; i < width; ++i) {
      const uint32_t c = ctable[*src++];
      rgb[0] = SkGetPackedR32(c);
      rgb[1] = SkGetPackedG32(c);
      rgb[2] = SkGetPackedB32(c);
      rgb += 3;
  }
}

static ScanlineImporter ChooseImporter(SkColorType ct, bool  hasAlpha, int*  bpp) {
    switch (ct) {
        case kN32_SkColorType:
            if (hasAlpha) {
                *bpp = 4;
                return ARGB_8888_To_RGBA;
            } else {
                *bpp = 3;
                return ARGB_8888_To_RGB;
            }
        case kARGB_4444_SkColorType:
            if (hasAlpha) {
                *bpp = 4;
                return ARGB_4444_To_RGBA;
            } else {
                *bpp = 3;
                return ARGB_4444_To_RGB;
            }
        case kRGB_565_SkColorType:
            *bpp = 3;
            return RGB_565_To_RGB;
        case kIndex_8_SkColorType:
            *bpp = 3;
            return Index8_To_RGB;
        default:
            return nullptr;
    }
}

static int stream_writer(const uint8_t* data, size_t data_size,
                         const WebPPicture* const picture) {
  SkWStream* const stream = (SkWStream*)picture->custom_ptr;
  return stream->write(data, data_size) ? 1 : 0;
}

bool SkEncodeImageAsWEBP(SkWStream* stream, const SkPixmap& pixmap, int quality) {
    const bool hasAlpha = !pixmap.isOpaque();
    int bpp = -1;
    const ScanlineImporter scanline_import = ChooseImporter(pixmap.colorType(), hasAlpha, &bpp);
    if (nullptr == scanline_import) {
        return false;
    }
    if (-1 == bpp) {
        return false;
    }

    if (nullptr == pixmap.addr()) {
        return false;
    }

    WebPConfig webp_config;
    if (!WebPConfigPreset(&webp_config, WEBP_PRESET_DEFAULT, (float) quality)) {
        return false;
    }

    WebPPicture pic;
    WebPPictureInit(&pic);
    pic.width = pixmap.width();
    pic.height = pixmap.height();
    pic.writer = stream_writer;
    pic.custom_ptr = (void*)stream;

    const SkPMColor* colors = pixmap.ctable() ? pixmap.ctable()->readColors() : nullptr;
    const uint8_t* src = (uint8_t*)pixmap.addr();
    const int rgbStride = pic.width * bpp;
    const size_t rowBytes = pixmap.rowBytes();

    // Import (for each scanline) the bit-map image (in appropriate color-space)
    // to RGB color space.
    std::unique_ptr<uint8_t[]> rgb(new uint8_t[rgbStride * pic.height]);
    for (int y = 0; y < pic.height; ++y) {
        scanline_import(src + y * rowBytes, &rgb[y * rgbStride], pic.width, colors);
    }

    bool ok;
    if (bpp == 3) {
        ok = SkToBool(WebPPictureImportRGB(&pic, &rgb[0], rgbStride));
    } else {
        ok = SkToBool(WebPPictureImportRGBA(&pic, &rgb[0], rgbStride));
    }

    ok = ok && WebPEncode(&webp_config, &pic);
    WebPPictureFree(&pic);

    return ok;
}
#endif