/src/skia/src/codec/SkSampler.h
Line | Count | Source |
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 | | #ifndef SkSampler_DEFINED |
8 | | #define SkSampler_DEFINED |
9 | | |
10 | | #include "include/codec/SkCodec.h" |
11 | | #include "include/core/SkTypes.h" |
12 | | #include "include/private/base/SkNoncopyable.h" |
13 | | #include "src/codec/SkCodecPriv.h" |
14 | | |
15 | | #include <cstddef> |
16 | | |
17 | | struct SkImageInfo; |
18 | | |
19 | | class SkSampler : public SkNoncopyable { |
20 | | public: |
21 | | /** |
22 | | * Update the sampler to sample every sampleX'th pixel. Returns the |
23 | | * width after sampling. |
24 | | */ |
25 | 4.30k | int setSampleX(int sampleX) { |
26 | 4.30k | return this->onSetSampleX(sampleX); |
27 | 4.30k | } |
28 | | |
29 | | /** |
30 | | * Update the sampler to sample every sampleY'th row. |
31 | | */ |
32 | 401 | void setSampleY(int sampleY) { |
33 | 401 | fSampleY = sampleY; |
34 | 401 | } |
35 | | |
36 | | /** |
37 | | * Retrieve the value set for sampleY. |
38 | | */ |
39 | 3.74k | int sampleY() const { |
40 | 3.74k | return fSampleY; |
41 | 3.74k | } |
42 | | |
43 | | /** |
44 | | * Based on fSampleY, return whether this row belongs in the output. |
45 | | * |
46 | | * @param row Row of the image, starting with the first row in the subset. |
47 | | */ |
48 | 30.4k | bool rowNeeded(int row) const { |
49 | 30.4k | return (row - get_start_coord(fSampleY)) % fSampleY == 0; |
50 | 30.4k | } |
51 | | |
52 | | /** |
53 | | * Fill the remainder of the destination with 0. |
54 | | * |
55 | | * 0 has a different meaning depending on the SkColorType. For color types |
56 | | * with transparency, this means transparent. For k565 and kGray, 0 is |
57 | | * black. |
58 | | * |
59 | | * @param info |
60 | | * Contains the color type of the rows to fill. |
61 | | * Contains the pixel width of the destination rows to fill |
62 | | * Contains the number of rows that we need to fill. |
63 | | * |
64 | | * @param dst |
65 | | * The destination row to fill. |
66 | | * |
67 | | * @param rowBytes |
68 | | * Stride in bytes of the destination. |
69 | | * |
70 | | * @param zeroInit |
71 | | * Indicates whether memory is already zero initialized. |
72 | | */ |
73 | | static void Fill(const SkImageInfo& info, void* dst, size_t rowBytes, |
74 | | SkCodec::ZeroInitialized zeroInit); |
75 | | |
76 | | virtual int fillWidth() const = 0; |
77 | | |
78 | | SkSampler() |
79 | | : fSampleY(1) |
80 | 24.9k | {} |
81 | | |
82 | 24.9k | virtual ~SkSampler() {} |
83 | | private: |
84 | | int fSampleY; |
85 | | |
86 | | virtual int onSetSampleX(int) = 0; |
87 | | }; |
88 | | |
89 | | #endif // SkSampler_DEFINED |