1 files changed, 252 insertions, 0 deletions
diff --git a/gfx/skia/skia/src/shaders/SkShaderBase.h b/gfx/skia/skia/src/shaders/SkShaderBase.h
new file mode 100644
index 0000000000..e071e22db9
--- /dev/null
+++ b/gfx/skia/skia/src/shaders/SkShaderBase.h
@@ -0,0 +1,252 @@
+/*
+ * Copyright 2017 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkShaderBase_DEFINED
+#define SkShaderBase_DEFINED
+
+#include "include/core/SkFilterQuality.h"
+#include "include/core/SkMatrix.h"
+#include "include/core/SkShader.h"
+#include "include/private/SkNoncopyable.h"
+#include "src/core/SkEffectPriv.h"
+#include "src/core/SkMask.h"
+#include "src/core/SkTLazy.h"
+
+#if SK_SUPPORT_GPU
+#include "src/gpu/GrFPArgs.h"
+#endif
+
+class GrContext;
+class GrFragmentProcessor;
+class SkArenaAlloc;
+class SkColorSpace;
+class SkImage;
+struct SkImageInfo;
+class SkPaint;
+class SkRasterPipeline;
+
+/**
+ *  Shaders can optionally return a subclass of this when appending their stages.
+ *  Doing so tells the caller that the stages can be reused with different CTMs (but nothing
+ *  else can change), by calling the updater's udpate() method before each use.
+ *
+ *  This can be a perf-win bulk draws like drawAtlas and drawVertices, where most of the setup
+ *  (i.e. uniforms) are constant, and only something small is changing (i.e. matrices). This
+ *  reuse skips the cost of computing the stages (and/or avoids having to allocate a separate
+ *  shader for each small draw.
+ */
+class SkStageUpdater {
+public:
+    virtual ~SkStageUpdater() {}
+
+    virtual bool update(const SkMatrix& ctm, const SkMatrix* localM) = 0;
+};
+
+class SkShaderBase : public SkShader {
+public:
+    ~SkShaderBase() override;
+
+    /**
+     *  Returns true if the shader is guaranteed to produce only a single color.
+     *  Subclasses can override this to allow loop-hoisting optimization.
+     */
+    virtual bool isConstant() const { return false; }
+
+    const SkMatrix& getLocalMatrix() const { return fLocalMatrix; }
+
+    enum Flags {
+        //!< set if all of the colors will be opaque
+        kOpaqueAlpha_Flag = 1 << 0,
+
+        /** set if the spans only vary in X (const in Y).
+            e.g. an Nx1 bitmap that is being tiled in Y, or a linear-gradient
+            that varies from left-to-right. This flag specifies this for
+            shadeSpan().
+         */
+        kConstInY32_Flag = 1 << 1,
+
+        /** hint for the blitter that 4f is the preferred shading mode.
+         */
+        kPrefers4f_Flag  = 1 << 2,
+    };
+
+    /**
+     *  ContextRec acts as a parameter bundle for creating Contexts.
+     */
+    struct ContextRec {
+        ContextRec(const SkPaint& paint, const SkMatrix& matrix, const SkMatrix* localM,
+                   SkColorType dstColorType, SkColorSpace* dstColorSpace)
+            : fPaint(&paint)
+            , fMatrix(&matrix)
+            , fLocalMatrix(localM)
+            , fDstColorType(dstColorType)
+            , fDstColorSpace(dstColorSpace) {}
+
+        const SkPaint*  fPaint;            // the current paint associated with the draw
+        const SkMatrix* fMatrix;           // the current matrix in the canvas
+        const SkMatrix* fLocalMatrix;      // optional local matrix
+        SkColorType     fDstColorType;     // the color type of the dest surface
+        SkColorSpace*   fDstColorSpace;    // the color space of the dest surface (if any)
+
+        bool isLegacyCompatible(SkColorSpace* shadersColorSpace) const;
+    };
+
+    class Context : public ::SkNoncopyable {
+    public:
+        Context(const SkShaderBase& shader, const ContextRec&);
+
+        virtual ~Context();
+
+        /**
+         *  Called sometimes before drawing with this shader. Return the type of
+         *  alpha your shader will return. The default implementation returns 0.
+         *  Your subclass should override if it can (even sometimes) report a
+         *  non-zero value, since that will enable various blitters to perform
+         *  faster.
+         */
+        virtual uint32_t getFlags() const { return 0; }
+
+        /**
+         *  Called for each span of the object being drawn. Your subclass should
+         *  set the appropriate colors (with premultiplied alpha) that correspond
+         *  to the specified device coordinates.
+         */
+        virtual void shadeSpan(int x, int y, SkPMColor[], int count) = 0;
+
+    protected:
+        // Reference to shader, so we don't have to dupe information.
+        const SkShaderBase& fShader;
+
+        uint8_t         getPaintAlpha() const { return fPaintAlpha; }
+        const SkMatrix& getTotalInverse() const { return fTotalInverse; }
+        const SkMatrix& getCTM() const { return fCTM; }
+
+    private:
+        SkMatrix    fCTM;
+        SkMatrix    fTotalInverse;
+        uint8_t     fPaintAlpha;
+
+        typedef SkNoncopyable INHERITED;
+    };
+
+    /**
+     * Make a context using the memory provided by the arena.
+     *
+     * @return pointer to context or nullptr if can't be created
+     */
+    Context* makeContext(const ContextRec&, SkArenaAlloc*) const;
+
+#if SK_SUPPORT_GPU
+    /**
+     *  Returns a GrFragmentProcessor that implements the shader for the GPU backend. NULL is
+     *  returned if there is no GPU implementation.
+     *
+     *  The GPU device does not call SkShader::createContext(), instead we pass the view matrix,
+     *  local matrix, and filter quality directly.
+     *
+     *  The GrContext may be used by the to create textures that are required by the returned
+     *  processor.
+     *
+     *  The returned GrFragmentProcessor should expect an unpremultiplied input color and
+     *  produce a premultiplied output.
+     */
+    virtual std::unique_ptr<GrFragmentProcessor> asFragmentProcessor(const GrFPArgs&) const;
+#endif
+
+    /**
+     *  If the shader can represent its "average" luminance in a single color, return true and
+     *  if color is not NULL, return that color. If it cannot, return false and ignore the color
+     *  parameter.
+     *
+     *  Note: if this returns true, the returned color will always be opaque, as only the RGB
+     *  components are used to compute luminance.
+     */
+    bool asLuminanceColor(SkColor*) const;
+
+    // If this returns false, then we draw nothing (do not fall back to shader context)
+    bool appendStages(const SkStageRec&) const;
+
+    bool SK_WARN_UNUSED_RESULT computeTotalInverse(const SkMatrix& ctm,
+                                                   const SkMatrix* outerLocalMatrix,
+                                                   SkMatrix* totalInverse) const;
+
+    // Returns the total local matrix for this shader:
+    //
+    //   M = postLocalMatrix x shaderLocalMatrix x preLocalMatrix
+    //
+    SkTCopyOnFirstWrite<SkMatrix> totalLocalMatrix(const SkMatrix* preLocalMatrix,
+                                                   const SkMatrix* postLocalMatrix = nullptr) const;
+
+    virtual SkImage* onIsAImage(SkMatrix*, SkTileMode[2]) const {
+        return nullptr;
+    }
+    virtual SkPicture* isAPicture(SkMatrix*, SkTileMode[2], SkRect* tile) const { return nullptr; }
+
+    static Type GetFlattenableType() { return kSkShaderBase_Type; }
+    Type getFlattenableType() const override { return GetFlattenableType(); }
+
+    static sk_sp<SkShaderBase> Deserialize(const void* data, size_t size,
+                                             const SkDeserialProcs* procs = nullptr) {
+        return sk_sp<SkShaderBase>(static_cast<SkShaderBase*>(
+                SkFlattenable::Deserialize(GetFlattenableType(), data, size, procs).release()));
+    }
+    static void RegisterFlattenables();
+
+    /** DEPRECATED. skbug.com/8941
+     *  If this shader can be represented by another shader + a localMatrix, return that shader and
+     *  the localMatrix. If not, return nullptr and ignore the localMatrix parameter.
+     */
+    virtual sk_sp<SkShader> makeAsALocalMatrixShader(SkMatrix* localMatrix) const;
+
+    SkStageUpdater* appendUpdatableStages(const SkStageRec& rec) const {
+        return this->onAppendUpdatableStages(rec);
+    }
+
+protected:
+    SkShaderBase(const SkMatrix* localMatrix = nullptr);
+
+    void flatten(SkWriteBuffer&) const override;
+
+#ifdef SK_ENABLE_LEGACY_SHADERCONTEXT
+    /**
+     * Specialize creating a SkShader context using the supplied allocator.
+     * @return pointer to context owned by the arena allocator.
+     */
+    virtual Context* onMakeContext(const ContextRec&, SkArenaAlloc*) const {
+        return nullptr;
+    }
+#endif
+
+    virtual bool onAsLuminanceColor(SkColor*) const {
+        return false;
+    }
+
+    // Default impl creates shadercontext and calls that (not very efficient)
+    virtual bool onAppendStages(const SkStageRec&) const;
+
+    virtual SkStageUpdater* onAppendUpdatableStages(const SkStageRec&) const { return nullptr; }
+
+private:
+    // This is essentially const, but not officially so it can be modified in constructors.
+    SkMatrix fLocalMatrix;
+
+    typedef SkShader INHERITED;
+};
+
+inline SkShaderBase* as_SB(SkShader* shader) {
+    return static_cast<SkShaderBase*>(shader);
+}
+
+inline const SkShaderBase* as_SB(const SkShader* shader) {
+    return static_cast<const SkShaderBase*>(shader);
+}
+
+inline const SkShaderBase* as_SB(const sk_sp<SkShader>& shader) {
+    return static_cast<SkShaderBase*>(shader.get());
+}
+
+#endif // SkShaderBase_DEFINED