#include "SkPaint.h"
class SkPath;
+class SkPicture;
class GrContext;
class GrEffectRef;
public:
SK_DECLARE_INST_COUNT(SkShader)
- SkShader();
+ SkShader(const SkMatrix* localMatrix = NULL);
virtual ~SkShader();
/**
- * Returns true if the local matrix is not an identity matrix.
+ * Returns true if the local matrix is not an identity matrix.
*/
bool hasLocalMatrix() const { return !fLocalMatrix.isIdentity(); }
*/
kIntrinsicly16_Flag = 0x04,
- /** set (after setContext) if the spans only vary in X (const in Y).
+ /** 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().
};
/**
- * 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() { return 0; }
-
- /**
* Returns true if the shader is guaranteed to produce only opaque
* colors, subject to the SkPaint using the shader to apply an opaque
* alpha value. Subclasses should override this to allow some
- * optimizations. isOpaque() can be called at any time, unlike getFlags,
- * which only works properly when the context is set.
+ * optimizations.
*/
virtual bool isOpaque() const { return false; }
/**
- * Return the alpha associated with the data returned by shadeSpan16(). If
- * kHasSpan16_Flag is not set, this value is meaningless.
+ * ContextRec acts as a parameter bundle for creating Contexts.
*/
- virtual uint8_t getSpan16Alpha() const { return fPaintAlpha; }
+ struct ContextRec {
+ ContextRec() : fDevice(NULL), fPaint(NULL), fMatrix(NULL), fLocalMatrix(NULL) {}
+ ContextRec(const SkBitmap& device, const SkPaint& paint, const SkMatrix& matrix)
+ : fDevice(&device)
+ , fPaint(&paint)
+ , fMatrix(&matrix)
+ , fLocalMatrix(NULL) {}
+
+ const SkBitmap* fDevice; // the bitmap we are drawing into
+ 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
+ };
- /**
- * Called once before drawing, with the current paint and device matrix.
- * Return true if your shader supports these parameters, or false if not.
- * If false is returned, nothing will be drawn. If true is returned, then
- * a balancing call to endContext() will be made before the next call to
- * setContext.
- *
- * Subclasses should be sure to call their INHERITED::setContext() if they
- * override this method.
- */
- virtual bool setContext(const SkBitmap& device, const SkPaint& paint,
- const SkMatrix& matrix);
+ class Context : public ::SkNoncopyable {
+ public:
+ Context(const SkShader& shader, const ContextRec&);
- /**
- * Assuming setContext returned true, endContext() will be called when
- * the draw using the shader has completed. It is an error for setContext
- * to be called twice w/o an intervening call to endContext().
- *
- * Subclasses should be sure to call their INHERITED::endContext() if they
- * override this method.
- */
- virtual void endContext();
+ virtual ~Context();
- SkDEBUGCODE(bool setContextHasBeenCalled() const { return SkToBool(fInSetContext); })
+ /**
+ * 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;
+ /**
+ * Return the alpha associated with the data returned by shadeSpan16(). If
+ * kHasSpan16_Flag is not set, this value is meaningless.
+ */
+ virtual uint8_t getSpan16Alpha() const { return fPaintAlpha; }
+
+ /**
+ * 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;
- typedef void (*ShadeProc)(void* ctx, int x, int y, SkPMColor[], int count);
- virtual ShadeProc asAShadeProc(void** ctx);
+ typedef void (*ShadeProc)(void* ctx, int x, int y, SkPMColor[], int count);
+ virtual ShadeProc asAShadeProc(void** ctx);
- /**
- * Called only for 16bit devices when getFlags() returns
- * kOpaqueAlphaFlag | kHasSpan16_Flag
- */
- virtual void shadeSpan16(int x, int y, uint16_t[], int count);
+ /**
+ * Called only for 16bit devices when getFlags() returns
+ * kOpaqueAlphaFlag | kHasSpan16_Flag
+ */
+ virtual void shadeSpan16(int x, int y, uint16_t[], int count);
+
+ /**
+ * Similar to shadeSpan, but only returns the alpha-channel for a span.
+ * The default implementation calls shadeSpan() and then extracts the alpha
+ * values from the returned colors.
+ */
+ virtual void shadeSpanAlpha(int x, int y, uint8_t alpha[], int count);
+
+ /**
+ * Helper function that returns true if this shader's shadeSpan16() method
+ * can be called.
+ */
+ bool canCallShadeSpan16() {
+ return SkShader::CanCallShadeSpan16(this->getFlags());
+ }
+
+ protected:
+ // Reference to shader, so we don't have to dupe information.
+ const SkShader& fShader;
+
+ enum MatrixClass {
+ kLinear_MatrixClass, // no perspective
+ kFixedStepInX_MatrixClass, // fast perspective, need to call fixedStepInX() each
+ // scanline
+ kPerspective_MatrixClass // slow perspective, need to mappoints each pixel
+ };
+ static MatrixClass ComputeMatrixClass(const SkMatrix&);
+
+ uint8_t getPaintAlpha() const { return fPaintAlpha; }
+ const SkMatrix& getTotalInverse() const { return fTotalInverse; }
+ MatrixClass getInverseClass() const { return (MatrixClass)fTotalInverseClass; }
+ const SkMatrix& getCTM() const { return fCTM; }
+ private:
+ SkMatrix fCTM;
+ SkMatrix fTotalInverse;
+ uint8_t fPaintAlpha;
+ uint8_t fTotalInverseClass;
+
+ typedef SkNoncopyable INHERITED;
+ };
/**
- * Similar to shadeSpan, but only returns the alpha-channel for a span.
- * The default implementation calls shadeSpan() and then extracts the alpha
- * values from the returned colors.
+ * Create the actual object that does the shading.
+ * Size of storage must be >= contextSize.
*/
- virtual void shadeSpanAlpha(int x, int y, uint8_t alpha[], int count);
+ Context* createContext(const ContextRec&, void* storage) const;
/**
- * Helper function that returns true if this shader's shadeSpan16() method
- * can be called.
+ * Return the size of a Context returned by createContext.
+ *
+ * Override this if your subclass overrides createContext, to return the correct size of
+ * your subclass' context.
*/
- bool canCallShadeSpan16() {
- return SkShader::CanCallShadeSpan16(this->getFlags());
- }
+ virtual size_t contextSize() const;
/**
* Helper to check the flags to know if it is legal to call shadeSpan16()
* The incoming color to the effect has r=g=b=a all extracted from the SkPaint's alpha.
* The output color should be the computed SkShader premul color modulated by the incoming
* color. The GrContext may be used by the effect to create textures. The GPU device does not
- * call setContext. Instead we pass the SkPaint here in case the shader needs paint info.
+ * call createContext. Instead we pass the SkPaint here in case the shader needs paint info.
*/
virtual GrEffectRef* asNewEffect(GrContext* context, const SkPaint& paint) const;
//////////////////////////////////////////////////////////////////////////
// Factory methods for stock shaders
+ /**
+ * Call this to create a new "empty" shader, that will not draw anything.
+ */
+ static SkShader* CreateEmptyShader();
+
/** Call this to create a new shader that will draw with the specified bitmap.
*
* If the bitmap cannot be used (e.g. has no pixels, or its dimensions
* exceed implementation limits (currently at 64K - 1)) then SkEmptyShader
* may be returned.
*
+ * If the src is kA8_Config then that mask will be colorized using the color on
+ * the paint.
+ *
* @param src The bitmap to use inside the shader
* @param tmx The tiling mode to use when sampling the bitmap in the x-direction.
* @param tmy The tiling mode to use when sampling the bitmap in the y-direction.
* @return Returns a new shader object. Note: this function never returns null.
*/
static SkShader* CreateBitmapShader(const SkBitmap& src,
- TileMode tmx, TileMode tmy);
+ TileMode tmx, TileMode tmy,
+ const SkMatrix* localMatrix = NULL);
- SkDEVCODE(virtual void toString(SkString* str) const;)
+ /** Call this to create a new shader that will draw with the specified picture.
+ *
+ * @param src The picture to use inside the shader (if not NULL, its ref count
+ * is incremented). The SkPicture must not be changed after
+ * successfully creating a picture shader.
+ * FIXME: src cannot be const due to SkCanvas::drawPicture
+ * @param tmx The tiling mode to use when sampling the bitmap in the x-direction.
+ * @param tmy The tiling mode to use when sampling the bitmap in the y-direction.
+ * @return Returns a new shader object. Note: this function never returns null.
+ */
+ static SkShader* CreatePictureShader(SkPicture* src, TileMode tmx, TileMode tmy,
+ const SkMatrix* localMatrix = NULL);
+ SK_TO_STRING_VIRT()
SK_DEFINE_FLATTENABLE_TYPE(SkShader)
protected:
- enum MatrixClass {
- kLinear_MatrixClass, // no perspective
- kFixedStepInX_MatrixClass, // fast perspective, need to call fixedStepInX() each scanline
- kPerspective_MatrixClass // slow perspective, need to mappoints each pixel
- };
- static MatrixClass ComputeMatrixClass(const SkMatrix&);
+ SkShader(SkReadBuffer& );
+ virtual void flatten(SkWriteBuffer&) const SK_OVERRIDE;
- // These can be called by your subclass after setContext() has been called
- uint8_t getPaintAlpha() const { return fPaintAlpha; }
- SkBitmap::Config getDeviceConfig() const { return (SkBitmap::Config)fDeviceConfig; }
- const SkMatrix& getTotalInverse() const { return fTotalInverse; }
- MatrixClass getInverseClass() const { return (MatrixClass)fTotalInverseClass; }
+ bool computeTotalInverse(const ContextRec&, SkMatrix* totalInverse) const;
+
+ /**
+ * Your subclass must also override contextSize() if it overrides onCreateContext().
+ * Base class impl returns NULL.
+ */
+ virtual Context* onCreateContext(const ContextRec&, void* storage) const;
- SkShader(SkFlattenableReadBuffer& );
- virtual void flatten(SkFlattenableWriteBuffer&) const SK_OVERRIDE;
private:
- SkMatrix fLocalMatrix;
- SkMatrix fTotalInverse;
- uint8_t fPaintAlpha;
- uint8_t fDeviceConfig;
- uint8_t fTotalInverseClass;
- SkDEBUGCODE(SkBool8 fInSetContext;)
+ SkMatrix fLocalMatrix;
- static SkShader* CreateBitmapShader(const SkBitmap& src,
- TileMode, TileMode,
- void* storage, size_t storageSize);
- friend class SkAutoBitmapShaderInstall;
typedef SkFlattenable INHERITED;
};
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