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1 | |
2 /* | |
3 * Copyright 2011 Google Inc. | |
4 * | |
5 * Use of this source code is governed by a BSD-style license that can be | |
6 * found in the LICENSE file. | |
7 */ | |
8 #ifndef SkScaledBitmapSampler_DEFINED | |
9 #define SkScaledBitmapSampler_DEFINED | |
10 | |
11 #include "SkTypes.h" | |
12 #include "SkColor.h" | |
13 #include "SkImageDecoder.h" | |
14 | |
15 class SkBitmap; | |
16 | |
17 class SkScaledBitmapSampler { | |
18 public: | |
19 SkScaledBitmapSampler(int origWidth, int origHeight, int cellSize); | |
20 | |
21 int scaledWidth() const { return fScaledWidth; } | |
22 int scaledHeight() const { return fScaledHeight; } | |
23 | |
24 int srcY0() const { return fY0; } | |
25 int srcDX() const { return fDX; } | |
26 int srcDY() const { return fDY; } | |
27 | |
28 enum SrcConfig { | |
29 kGray, // 1 byte per pixel | |
30 kIndex, // 1 byte per pixel | |
31 kRGB, // 3 bytes per pixel | |
32 kRGBX, // 4 byes per pixel (ignore 4th) | |
33 kRGBA, // 4 bytes per pixel | |
34 kRGB_565 // 2 bytes per pixel | |
35 }; | |
36 | |
37 struct Options { | |
38 bool fDither; | |
39 bool fPremultiplyAlpha; | |
40 bool fSkipZeros; | |
41 explicit Options(const SkImageDecoder &dec) | |
42 : fDither(dec.getDitherImage()) | |
43 , fPremultiplyAlpha(!dec.getRequireUnpremultipliedColors()) | |
44 , fSkipZeros(dec.getSkipWritingZeroes()) | |
45 { } | |
46 }; | |
47 | |
48 // Given a dst bitmap (with pixels already allocated) and a src-config, | |
49 // prepares iterator to process the src colors and write them into dst. | |
50 // Returns false if the request cannot be fulfulled. | |
51 bool begin(SkBitmap* dst, SrcConfig sc, const SkImageDecoder& decoder, | |
52 const SkPMColor* = nullptr); | |
53 bool begin(SkBitmap* dst, SrcConfig sc, const Options& opts, | |
54 const SkPMColor* = nullptr); | |
55 // call with row of src pixels, for y = 0...scaledHeight-1. | |
56 // returns true if the row had non-opaque alpha in it | |
57 bool next(const uint8_t* SK_RESTRICT src); | |
58 | |
59 // Like next(), but specifies the y value of the source row, so the | |
60 // rows can come in any order. If the row is not part of the output | |
61 // sample, it will be skipped. Only sampleInterlaced OR next should | |
62 // be called for one SkScaledBitmapSampler. | |
63 bool sampleInterlaced(const uint8_t* SK_RESTRICT src, int srcY); | |
64 | |
65 typedef bool (*RowProc)(void* SK_RESTRICT dstRow, | |
66 const uint8_t* SK_RESTRICT src, | |
67 int width, int deltaSrc, int y, | |
68 const SkPMColor[]); | |
69 | |
70 private: | |
71 int fScaledWidth; | |
72 int fScaledHeight; | |
73 | |
74 int fX0; // first X coord to sample | |
75 int fY0; // first Y coord (scanline) to sample | |
76 int fDX; // step between X samples | |
77 int fDY; // step between Y samples | |
78 | |
79 #ifdef SK_DEBUG | |
80 // Keep track of whether the caller is using next or sampleInterlaced. | |
81 // Only one can be used per sampler. | |
82 enum SampleMode { | |
83 kUninitialized_SampleMode, | |
84 kConsecutive_SampleMode, | |
85 kInterlaced_SampleMode, | |
86 }; | |
87 | |
88 SampleMode fSampleMode; | |
89 #endif | |
90 | |
91 // setup state | |
92 char* fDstRow; // points into bitmap's pixels | |
93 size_t fDstRowBytes; | |
94 int fCurrY; // used for dithering | |
95 int fSrcPixelSize; // 1, 3, 4 | |
96 RowProc fRowProc; | |
97 | |
98 // optional reference to the src colors if the src is a palette model | |
99 const SkPMColor* fCTable; | |
100 | |
101 #ifdef SK_DEBUG | |
102 // Helper class allowing a test to have access to fRowProc. | |
103 friend class RowProcTester; | |
104 #endif | |
105 }; | |
106 | |
107 #endif | |
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