SkPatch abstraction

include/core/SkPatch.h

+/*
+ * Copyright 2014 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkPatch_DEFINED
+#define SkPatch_DEFINED
+
+#include "SkColor.h"
+#include "SkPreConfig.h"
+#include "SkPoint.h"
+
+/**
+ * Class that represents a coons patch.
+ */
+class SK_API SkPatch {
+
+public:
+    /**
+     * Structure that holds the vertex data related to the tessellation of a SkPatch. It is passed 
+     * as a parameter to the function getVertexData.

[bsalomon, 2014/07/25 14:16:37]

"The generated arrays can be used with SkCanvas::drawVertices to render the
patch"? Or is the idea that there will be a future SkCanvas::drawPatch() (and
maybe drawPatchMesh())? If so then maybe drawVertices isn't worth mentioning.

[dandov, 2014/07/25 15:07:09]

The idea is to add a SkCanvas::drawPatch. 

+     */
+    struct PatchData {
+        int fVertexCount, fIndexCount;
+        SkPoint* fPoints;
+        SkPoint* fTexCoords;
+        uint32_t* fColors;
+        uint16_t* fIndices;
+        
+        PatchData()
+        : fVertexCount(0)
+        , fIndexCount(0)
+        , fPoints(NULL)
+        , fTexCoords(NULL)
+        , fColors(NULL)
+        , fIndices(NULL) { }
+        
+        ~PatchData() {
+            SkDELETE_ARRAY(fPoints);
+            SkDELETE_ARRAY(fTexCoords);
+            SkDELETE_ARRAY(fColors);
+            SkDELETE_ARRAY(fIndices);
+        }
+    };
+    
+    enum SkCubicCtrlPts {

[egdaniel, 2014/07/25 14:49:27]

Remove the Sk since we are already inside of SkPatch

[dandov, 2014/07/25 15:07:09]

Done.

+        kTopP0_CubicCtrlPts=0,

[egdaniel, 2014/07/25 14:49:26]

Nit space around =

[dandov, 2014/07/25 15:07:09]

Done.

+        kTopP1_CubicCtrlPts=1,
+        kTopP2_CubicCtrlPts=2,
+        kTopP3_CubicCtrlPts=3,
+        
+        kRightP0_CubicCtrlPts=3,
+        kRightP1_CubicCtrlPts=4,
+        kRightP2_CubicCtrlPts=5,
+        kRightP3_CubicCtrlPts=6,
+        
+        kBottomP0_CubicCtrlPts=9,
+        kBottomP1_CubicCtrlPts=8,
+        kBottomP2_CubicCtrlPts=7,
+        kBottomP3_CubicCtrlPts=6,
+        
+        kLeftP0_CubicCtrlPts=0,
+        kLeftP1_CubicCtrlPts=11,
+        kLeftP2_CubicCtrlPts=10,
+        kLeftP3_CubicCtrlPts=9,
+    };
+    
+    /**
+     * Points are in the following order:
+     *              (top curve)
+     *                0 1 2 3
+     * (left curve)  11     4   (right curve)
+     *               10     5
+     *                9 8 7 6
+     *              (bottom curve)
+     * Used pointer to an array to guarantee that this method receives an array of 4 SkColors
+     */
+    SkPatch(SkPoint points[12], SkColor colors[4]);
+
+    bool getVertexData(SkPatch::PatchData* data, int divisions);

[bsalomon, 2014/07/25 14:16:37]

Comment about what divisions means?

[dandov, 2014/07/25 15:07:09]

Done.

+
+    void getTopPoints(SkPoint points[4]) {
+        points[0] = fCtrlPoints[kTopP0_CubicCtrlPts];
+        points[1] = fCtrlPoints[kTopP1_CubicCtrlPts];
+        points[2] = fCtrlPoints[kTopP2_CubicCtrlPts];
+        points[3] = fCtrlPoints[kTopP3_CubicCtrlPts];
+    }
+    
+    const void getBottomPoints(SkPoint points[4]) {
+        points[0] = fCtrlPoints[kBottomP0_CubicCtrlPts];
+        points[1] = fCtrlPoints[kBottomP1_CubicCtrlPts];
+        points[2] = fCtrlPoints[kBottomP2_CubicCtrlPts];
+        points[3] = fCtrlPoints[kBottomP3_CubicCtrlPts];
+    }
+
+    const void getLeftPoints(SkPoint points[4]) {
+        points[0] = fCtrlPoints[kLeftP0_CubicCtrlPts];
+        points[1] = fCtrlPoints[kLeftP1_CubicCtrlPts];
+        points[2] = fCtrlPoints[kLeftP2_CubicCtrlPts];
+        points[3] = fCtrlPoints[kLeftP3_CubicCtrlPts];
+    }
+
+    const void getRightPoints(SkPoint points[4]) {
+        points[0] = fCtrlPoints[kRightP0_CubicCtrlPts];
+        points[1] = fCtrlPoints[kRightP1_CubicCtrlPts];
+        points[2] = fCtrlPoints[kRightP2_CubicCtrlPts];
+        points[3] = fCtrlPoints[kRightP3_CubicCtrlPts];
+    }
+    
+private:
+    SkPoint fCtrlPoints[12];
+    SkPMColor fCornerColors[4];
+};
+
+#endif