| 1 | /* |
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| 2 | * Copyright 2021 Google Inc. |
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| 3 | * |
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| 4 | * Use of this source code is governed by a BSD-style license that can be |
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| 5 | * found in the LICENSE file. |
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| 6 | */ |
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| 7 | #ifndef SkTextCoordShader_DEFINED |
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| 8 | #define SkTextCoordShader_DEFINED |
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| 9 | |
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| 10 | #include "include/core/SkScalar.h" |
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| 11 | #include "include/private/base/SkAssert.h" |
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| 12 | #include "src/shaders/SkShaderBase.h" |
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| 13 | |
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| 14 | class SkMatrix; |
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| 15 | struct SkStageRec; |
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| 16 | |
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| 17 | // SkTransformShader applies a matrix transform to the shader coordinates, like a local matrix |
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| 18 | // shader. The difference with a typical local matrix shader is that this shader's matrix is |
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| 19 | // not combined with the inverse CTM or other local matrices in order to facilitate modifying the |
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| 20 | // matrix between uses of the SkVM or SkRasterPipeline. This supports drawVertices and drawAtlas, in |
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| 21 | // which the mapping from each triangle (when explicit texture coords are used) or atlas quad to |
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| 22 | // shader space is different. |
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| 23 | class SkTransformShader : public SkShaderBase { |
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| 24 | public: |
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| 25 | explicit SkTransformShader(const SkShaderBase& shader, bool allowPerspective); |
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| 26 | |
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| 27 | // Adds a pipestage to multiply the incoming coords in 'r' and 'g' by the matrix. The child |
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| 28 | // shader is called with no pending local matrix and the total transform as unknowable. |
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| 29 | bool appendStages(const SkStageRec& rec, const SkShaders::MatrixRec&) const override; |
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| 30 | |
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| 31 | // Change the matrix used by the generated SkRasterPipeline. |
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| 32 | bool update(const SkMatrix& matrix); |
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| 33 | |
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| 34 | ShaderType type() const override { return ShaderType::kTransform; } |
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| 35 | |
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| 36 | // These are never serialized/deserialized |
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| 37 | Factory getFactory() const override { |
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| 38 | SkDEBUGFAIL("SkTransformShader shouldn't be serialized." ); |
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| 39 | return {}; |
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| 40 | } |
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| 41 | const char* getTypeName() const override { |
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| 42 | SkDEBUGFAIL("SkTransformShader shouldn't be serialized." ); |
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| 43 | return nullptr; |
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| 44 | } |
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| 45 | |
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| 46 | bool isOpaque() const override { return fShader.isOpaque(); } |
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| 47 | |
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| 48 | private: |
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| 49 | const SkShaderBase& fShader; |
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| 50 | SkScalar fMatrixStorage[9]; // actual memory used by generated RP or VM |
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| 51 | bool fAllowPerspective; |
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| 52 | }; |
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| 53 | #endif //SkTextCoordShader_DEFINED |
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| 54 | |
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