Erode and dilate image filter effects, CPU and GPU implementations.

Review URL:  http://codereview.appspot.com/5656067/



git-svn-id: http://skia.googlecode.com/svn/trunk@3310 2bbb7eff-a529-9590-31e7-b0007b416f81

4 files changed, 146 insertions, 43 deletions

diff --git a/include/core/SkImageFilter.h b/include/core/SkImageFilter.h
index 22b9569156..7d7c1404f1 100644
--- a/include/core/SkImageFilter.h
+++ b/include/core/SkImageFilter.h
@@ -80,6 +80,22 @@ public:
      */
     virtual bool asABlur(SkSize* sigma) const;
 
+    /**
+     *  Experimental.
+     *
+     *  If the filter can be expressed as an erode, return true and
+     *  set the radius in X and Y.
+     */
+    virtual bool asAnErode(SkISize* radius) const;
+
+    /**
+     *  Experimental.
+     *
+     *  If the filter can be expressed as a dilation, return true and
+     *  set the radius in X and Y.
+     */
+    virtual bool asADilate(SkISize* radius) const;
+
 protected:
     SkImageFilter() {}
     explicit SkImageFilter(SkFlattenableReadBuffer& rb) : INHERITED(rb) {}
diff --git a/include/effects/SkMorphologyImageFilter.h b/include/effects/SkMorphologyImageFilter.h
new file mode 100644
index 0000000000..2297938cef
--- /dev/null
+++ b/include/effects/SkMorphologyImageFilter.h
@@ -0,0 +1,65 @@
+/*
+ * Copyright 2012 The Android Open Source Project
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+
+#ifndef SkMorphologyImageFilter_DEFINED
+#define SkMorphologyImageFilter_DEFINED
+
+#include "SkImageFilter.h"
+
+class SK_API SkMorphologyImageFilter : public SkImageFilter {
+public:
+    explicit SkMorphologyImageFilter(SkFlattenableReadBuffer& buffer);
+    SkMorphologyImageFilter(int radiusX, int radiusY);
+
+protected:
+    virtual void flatten(SkFlattenableWriteBuffer& buffer) SK_OVERRIDE;
+    SkISize    radius() const { return fRadius; }
+
+private:
+    SkISize    fRadius;
+    typedef SkImageFilter INHERITED;
+};
+
+class SK_API SkDilateImageFilter : public SkMorphologyImageFilter {
+public:
+    SkDilateImageFilter(int radiusX, int radiusY) : INHERITED(radiusX, radiusY) {}
+    explicit SkDilateImageFilter(SkFlattenableReadBuffer& buffer) : INHERITED(buffer) {}
+
+    virtual bool asADilate(SkISize* radius) const SK_OVERRIDE;
+    virtual bool onFilterImage(Proxy*, const SkBitmap& src, const SkMatrix&,
+                               SkBitmap* result, SkIPoint* offset) SK_OVERRIDE;
+    static SkFlattenable* CreateProc(SkFlattenableReadBuffer& buffer) {
+        return SkNEW_ARGS(SkDilateImageFilter, (buffer));
+    }
+    virtual Factory getFactory() SK_OVERRIDE { return CreateProc; }
+    SK_DECLARE_FLATTENABLE_REGISTRAR()
+
+    typedef SkMorphologyImageFilter INHERITED;
+};
+
+class SK_API SkErodeImageFilter : public SkMorphologyImageFilter {
+public:
+    SkErodeImageFilter(int radiusX, int radiusY) : INHERITED(radiusX, radiusY) {}
+    explicit SkErodeImageFilter(SkFlattenableReadBuffer& buffer) : INHERITED(buffer) {}
+
+    virtual bool asAnErode(SkISize* radius) const SK_OVERRIDE;
+    virtual bool onFilterImage(Proxy*, const SkBitmap& src, const SkMatrix&,
+                               SkBitmap* result, SkIPoint* offset) SK_OVERRIDE;
+
+    static SkFlattenable* CreateProc(SkFlattenableReadBuffer& buffer) {
+        return SkNEW_ARGS(SkErodeImageFilter, (buffer));
+    }
+    virtual Factory getFactory() SK_OVERRIDE { return CreateProc; }
+    SK_DECLARE_FLATTENABLE_REGISTRAR()
+
+private:
+    typedef SkMorphologyImageFilter INHERITED;
+};
+
+#endif
+
diff --git a/include/gpu/GrContext.h b/include/gpu/GrContext.h
index b939c9e37a..ffb5065925 100644
--- a/include/gpu/GrContext.h
+++ b/include/gpu/GrContext.h
@@ -577,30 +577,33 @@ public:
     void resolveRenderTarget(GrRenderTarget* target);
 
     /**
-     * Applies a 1D convolution kernel in the X direction to a rectangle of
+     * Applies a 1D convolution kernel in the given direction to a rectangle of
      * pixels from a given texture.
      * @param texture         the texture to read from
      * @param rect            the destination rectangle
      * @param kernel          the convolution kernel (kernelWidth elements)
      * @param kernelWidth     the width of the convolution kernel
+     * @param direction       the direction in which to apply the kernel
      */
-    void convolveInX(GrTexture* texture,
-                     const SkRect& rect,
-                     const float* kernel,
-                     int kernelWidth);
+    void convolve(GrTexture* texture,
+                  const SkRect& rect,
+                  const float* kernel,
+                  int kernelWidth,
+                  GrSamplerState::FilterDirection direction);
     /**
-     * Applies a 1D convolution kernel in the Y direction to a rectangle of
+     * Applies a 1D morphology in the given direction to a rectangle of
      * pixels from a given texture.
-     * direction.
      * @param texture         the texture to read from
      * @param rect            the destination rectangle
-     * @param kernel          the convolution kernel (kernelWidth elements)
-     * @param kernelWidth     the width of the convolution kernel
-     */
-    void convolveInY(GrTexture* texture,
-                     const SkRect& rect,
-                     const float* kernel,
-                     int kernelWidth);
+     * @param radius          the radius of the morphological operator
+     * @param filter          the filter kernel (must be kDilate or kErode)
+     * @param direction       the direction in which to apply the morphology
+     */
+    void applyMorphology(GrTexture* texture,
+                         const SkRect& rect,
+                         int radius,
+                         GrSamplerState::Filter filter,
+                         GrSamplerState::FilterDirection direction);
     ///////////////////////////////////////////////////////////////////////////
     // Helpers
 
@@ -699,12 +702,6 @@ private:
                                     GrPathFill fill,
                                     bool antiAlias);
 
-    void convolve(GrTexture* texture,
-                  const SkRect& rect,
-                  float imageIncrement[2],
-                  const float* kernel,
-                  int kernelWidth);
-
     /**
      * Flags to the internal read/write pixels funcs
      */
diff --git a/include/gpu/GrSamplerState.h b/include/gpu/GrSamplerState.h
index 81dfdb3969..50a6cc9ec7 100644
--- a/include/gpu/GrSamplerState.h
+++ b/include/gpu/GrSamplerState.h
@@ -39,6 +39,14 @@ public:
          * Apply a separable convolution kernel.
          */
         kConvolution_Filter,
+        /**
+         * Apply a dilate filter (max over a 1D radius).
+         */
+        kDilate_Filter,
+        /**
+         * Apply an erode filter (min over a 1D radius).
+         */
+        kErode_Filter,
 
         kDefault_Filter = kNearest_Filter
     };
@@ -87,6 +95,17 @@ public:
     };
 
     /**
+     * For the filters which perform more than one texture sample (convolution,
+     * erode, dilate), this determines the direction in which the texture
+     * coordinates will be incremented.
+     */
+    enum FilterDirection {
+        kX_FilterDirection,
+        kY_FilterDirection,
+
+        kDefault_FilterDirection = kX_FilterDirection,
+    };
+    /**
      * Default sampler state is set to clamp, use normal sampling mode, be
      * unfiltered, and use identity matrix.
      */
@@ -99,6 +118,7 @@ public:
 
     WrapMode getWrapX() const { return fWrapX; }
     WrapMode getWrapY() const { return fWrapY; }
+    FilterDirection getFilterDirection() const { return fFilterDirection; }
     SampleMode getSampleMode() const { return fSampleMode; }
     const GrMatrix& getMatrix() const { return fMatrix; }
     const GrRect& getTextureDomain() const { return fTextureDomain; }
@@ -106,7 +126,6 @@ public:
     Filter getFilter() const { return fFilter; }
     int getKernelWidth() const { return fKernelWidth; }
     const float* getKernel() const { return fKernel; }
-    const float* getImageIncrement() const { return fImageIncrement; }
     bool swapsRAndB() const { return fSwapRAndB; }
 
     bool isGradient() const {
@@ -118,6 +137,7 @@ public:
     void setWrapX(WrapMode mode) { fWrapX = mode; }
     void setWrapY(WrapMode mode) { fWrapY = mode; }
     void setSampleMode(SampleMode mode) { fSampleMode = mode; }
+    void setFilterDirection(FilterDirection mode) { fFilterDirection = mode; }
     
     /**
      * Access the sampler's matrix. See SampleMode for explanation of
@@ -158,24 +178,29 @@ public:
 
     void reset(WrapMode wrapXAndY,
                Filter filter,
+               FilterDirection direction,
                const GrMatrix& matrix) {
         fWrapX = wrapXAndY;
         fWrapY = wrapXAndY;
         fSampleMode = kDefault_SampleMode;
         fFilter = filter;
+        fFilterDirection = direction;
         fMatrix = matrix;
         fTextureDomain.setEmpty();
         fSwapRAndB = false;
     }
+    void reset(WrapMode wrapXAndY, Filter filter, const GrMatrix& matrix) {
+        this->reset(wrapXAndY, filter, kDefault_FilterDirection, matrix);
+    }
     void reset(WrapMode wrapXAndY,
                Filter filter) {
-        this->reset(wrapXAndY, filter, GrMatrix::I());
+        this->reset(wrapXAndY, filter, kDefault_FilterDirection, GrMatrix::I());
     }
     void reset(const GrMatrix& matrix) {
-        this->reset(kDefault_WrapMode, kDefault_Filter, matrix);
+        this->reset(kDefault_WrapMode, kDefault_Filter, kDefault_FilterDirection, matrix);
     }
     void reset() {
-        this->reset(kDefault_WrapMode, kDefault_Filter, GrMatrix::I());
+        this->reset(kDefault_WrapMode, kDefault_Filter, kDefault_FilterDirection, GrMatrix::I());
     }
 
     GrScalar getRadial2CenterX1() const { return fRadial2CenterX1; }
@@ -198,37 +223,37 @@ public:
         fRadial2PosRoot = posRoot;
     }
 
-    void setConvolutionParams(int kernelWidth, const float* kernel, float imageIncrement[2]) {
+    void setConvolutionParams(int kernelWidth, const float* kernel) {
         GrAssert(kernelWidth >= 0 && kernelWidth <= MAX_KERNEL_WIDTH);
         fKernelWidth = kernelWidth;
         if (NULL != kernel) {
             memcpy(fKernel, kernel, kernelWidth * sizeof(float));
         }
-        if (NULL != imageIncrement) {
-            memcpy(fImageIncrement, imageIncrement, sizeof(fImageIncrement));
-        } else {
-            memset(fImageIncrement, 0, sizeof(fImageIncrement));
-        }
+    }
+
+    void setMorphologyRadius(int radius) {
+        GrAssert(radius >= 0 && radius <= MAX_KERNEL_WIDTH);
+        fKernelWidth = radius;
     }
 
 private:
-    WrapMode    fWrapX : 8;
-    WrapMode    fWrapY : 8;
-    SampleMode  fSampleMode : 8;
-    Filter      fFilter : 8;
-    GrMatrix    fMatrix;
-    bool        fSwapRAndB;
-    GrRect      fTextureDomain;
+    WrapMode            fWrapX : 8;
+    WrapMode            fWrapY : 8;
+    FilterDirection     fFilterDirection : 8;
+    SampleMode          fSampleMode : 8;
+    Filter              fFilter : 8;
+    GrMatrix            fMatrix;
+    bool                fSwapRAndB;
+    GrRect              fTextureDomain;
 
     // these are undefined unless fSampleMode == kRadial2_SampleMode
-    GrScalar    fRadial2CenterX1;
-    GrScalar    fRadial2Radius0;
-    SkBool8     fRadial2PosRoot;
+    GrScalar            fRadial2CenterX1;
+    GrScalar            fRadial2Radius0;
+    SkBool8             fRadial2PosRoot;
 
     // These are undefined unless fFilter == kConvolution_Filter
-    uint8_t     fKernelWidth;
-    float       fImageIncrement[2];
-    float       fKernel[MAX_KERNEL_WIDTH];
+    uint8_t             fKernelWidth;
+    float               fKernel[MAX_KERNEL_WIDTH];
 };
 
 #endif