1 /*
2  * Copyright 2015 Google Inc.
3  *
4  * Use of this source code is governed by a BSD-style license that can be
5  * found in the LICENSE file.
6  */
7 
8 #include "SkBmpCodec.h"
9 #include "SkImageInfo.h"
10 #include "SkMaskSwizzler.h"
11 #include "SkTypes.h"
12 
13 /*
14  * This class implements the decoding for bmp images using bit masks
15  */
16 class SkBmpMaskCodec : public SkBmpCodec {
17 public:
18 
19     /*
20      * Creates an instance of the decoder
21      *
22      * Called only by SkBmpCodec::NewFromStream
23      * There should be no other callers despite this being public
24      *
25      * @param srcInfo contains the source width and height
26      * @param stream the stream of encoded image data
27      * @param bitsPerPixel the number of bits used to store each pixel
28      * @param masks color masks for certain bmp formats
29      * @param rowOrder indicates whether rows are ordered top-down or bottom-up
30      */
31     SkBmpMaskCodec(const SkImageInfo& srcInfo, SkStream* stream,
32             uint16_t bitsPerPixel, SkMasks* masks,
33             SkCodec::SkScanlineOrder rowOrder);
34 
35 protected:
36 
37     Result onGetPixels(const SkImageInfo& dstInfo, void* dst,
38                        size_t dstRowBytes, const Options&, SkPMColor*,
39                        int*, int*) override;
40 
41     SkCodec::Result prepareToDecode(const SkImageInfo& dstInfo,
42             const SkCodec::Options& options, SkPMColor inputColorPtr[],
43             int* inputColorCount) override;
44 
45 private:
46 
getSampler(bool createIfNecessary)47     SkSampler* getSampler(bool createIfNecessary) override {
48         SkASSERT(fMaskSwizzler);
49         return fMaskSwizzler;
50     }
51 
52     int decodeRows(const SkImageInfo& dstInfo, void* dst, size_t dstRowBytes,
53             const Options& opts) override;
54 
55     SkAutoTDelete<SkMasks>              fMasks;        // owned
56     SkAutoTDelete<SkMaskSwizzler>       fMaskSwizzler;
57     SkAutoTDeleteArray<uint8_t>         fSrcBuffer;
58 
59     typedef SkBmpCodec INHERITED;
60 };
61