SkPatchGrid interface (after SkPatch/SkPicture rebase).

gm/patchgrid.cpp

Index: gm/patchgrid.cpp
diff --git a/gm/patchgrid.cpp b/gm/patchgrid.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..79baf9425388f230a6b7b674e5bbd205f7347d65
--- /dev/null
+++ b/gm/patchgrid.cpp
@@ -0,0 +1,165 @@
+
+/*
+ * Copyright 2014 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "gm.h"
+#include "SkPatchGrid.h"
+
+static void draw_control_points(SkCanvas* canvas, const SkPoint cubics[12]) {
+    //draw control points
+    SkPaint paint;
+    SkPoint bottom[4];
+    SkPatchUtils::getBottomCubic(cubics, bottom);
+    SkPoint top[4];
+    SkPatchUtils::getTopCubic(cubics, top);
+    SkPoint left[4];
+    SkPatchUtils::getLeftCubic(cubics, left);
+    SkPoint right[4];
+    SkPatchUtils::getRightCubic(cubics, right);
+
+    paint.setColor(SK_ColorBLACK);
+    paint.setStrokeWidth(0.5);
+    SkPoint corners[4] = { bottom[0], bottom[3], top[0], top[3] };
+    canvas->drawPoints(SkCanvas::kLines_PointMode, 4, bottom, paint);
+    canvas->drawPoints(SkCanvas::kLines_PointMode, 2, bottom+1, paint);
+    canvas->drawPoints(SkCanvas::kLines_PointMode, 4, top, paint);
+    canvas->drawPoints(SkCanvas::kLines_PointMode, 4, left, paint);
+    canvas->drawPoints(SkCanvas::kLines_PointMode, 4, right, paint);
+
+    canvas->drawPoints(SkCanvas::kLines_PointMode, 2, top+1, paint);
+    canvas->drawPoints(SkCanvas::kLines_PointMode, 2, left+1, paint);
+    canvas->drawPoints(SkCanvas::kLines_PointMode, 2, right+1, paint);
+
+    paint.setStrokeWidth(2);
+
+    paint.setColor(SK_ColorRED);
+    canvas->drawPoints(SkCanvas::kPoints_PointMode, 4, corners, paint);
+
+    paint.setColor(SK_ColorBLUE);
+    canvas->drawPoints(SkCanvas::kPoints_PointMode, 2, bottom+1, paint);
+
+    paint.setColor(SK_ColorCYAN);
+    canvas->drawPoints(SkCanvas::kPoints_PointMode, 2, top+1, paint);
+
+    paint.setColor(SK_ColorYELLOW);
+    canvas->drawPoints(SkCanvas::kPoints_PointMode, 2, left+1, paint);
+
+    paint.setColor(SK_ColorGREEN);
+    canvas->drawPoints(SkCanvas::kPoints_PointMode, 2, right+1, paint);
+}
+
+namespace skiagm {
+/**
+ * This GM draws a grid of patches, it only uses colors so it could be considered a mesh gradient.
+ */
+class SkPatchGridGM : public GM {
+    
+public:
+    SkPatchGridGM() {
+        this->setBGColor(0xFFFFFFFF);
+    }
+
+protected:
+    virtual SkString onShortName() SK_OVERRIDE {
+        return SkString("patch_grid");
+    }
+
+    virtual SkISize onISize() SK_OVERRIDE {
+        return SkISize::Make(800, 800);
+    }
+
+    virtual uint32_t onGetFlags() const SK_OVERRIDE {
+        return kSkipTiled_Flag;
+    }
+
+    virtual void onDraw(SkCanvas* canvas) SK_OVERRIDE {
+
+        SkPaint paint;
+        
+        SkPoint vertices[4][5] = {
+            {{50,50}, {150,50}, {250,50},{350,50},{450,50}},
+            {{50,150}, {120,120}, {250,150},{350,150},{450,150}},
+            {{50,250}, {150,250}, {250,250},{350,250},{450,250}},
+            {{100,300}, {150,350}, {250,350},{350,350},{450,350}}
+        };
+        
+        SkColor cornerColors[4][5] = {
+            {SK_ColorBLUE, SK_ColorRED, SK_ColorBLUE, SK_ColorRED, SK_ColorBLUE},
+            {SK_ColorRED, SK_ColorBLUE, SK_ColorRED, SK_ColorBLUE, SK_ColorRED},
+            {SK_ColorBLUE, SK_ColorRED, SK_ColorBLUE, SK_ColorRED, SK_ColorBLUE},
+            {SK_ColorRED, SK_ColorBLUE, SK_ColorRED, SK_ColorBLUE, SK_ColorRED},
+        };
+        
+        SkPoint hrzCtrl[4][8] = {
+            {{75,30},{125,45},{175,70},{225,20},{275,50},{325,50},{375,5},{425,90}},
+            {{75,150},{125,150},{175,150},{225,150},{275,150},{325,150},{375,150},{425,150}},
+            {{75,250},{125,250},{175,250},{225,250},{275,200},{325,150},{375,250},{425,250}},
+            {{75,350},{125,350},{175,350},{225,350},{275,350},{325,350},{375,350},{425,350}}
+        };
+        
+        SkPoint vrtCtrl[6][5] = {
+            {{50,75},{150,75},{250,75},{350,75},{450,75}},
+            {{50,125},{150,125},{250,125},{350,125},{450,125}},
+            {{50,175},{150,175},{220,225},{350,175},{470,225}},
+            {{50,225},{150,225},{220,175},{350,225},{470,155}},
+            {{50,275},{150,275},{250,275},{350,275},{400,305}},
+            {{50,325},{150,325},{250,325},{350,325},{450,325}}
+        };
+        
+        static const int kRows = 3;
+        static const int kCols = 4;
+        
+        canvas->scale(3, 3);
+        SkPatchGrid grid(kRows, kCols, SkPatchGrid::kColors_VertexType, NULL);
+        for (int i = 0; i < kRows; i++) {
+            for (int j = 0; j < kCols; j++) {
+                SkPoint points[12];
+                
+                //set corners
+                points[SkPatchUtils::kTopP0_CubicCtrlPts] = vertices[i][j];
+                points[SkPatchUtils::kTopP3_CubicCtrlPts] = vertices[i][j + 1];
+                points[SkPatchUtils::kBottomP0_CubicCtrlPts] = vertices[i + 1][j];
+                points[SkPatchUtils::kBottomP3_CubicCtrlPts] = vertices[i + 1][j + 1];
+                
+                points[SkPatchUtils::kTopP1_CubicCtrlPts] = hrzCtrl[i][j * 2];
+                points[SkPatchUtils::kTopP2_CubicCtrlPts] = hrzCtrl[i][j * 2 + 1];
+                points[SkPatchUtils::kBottomP1_CubicCtrlPts] = hrzCtrl[i + 1][j * 2];
+                points[SkPatchUtils::kBottomP2_CubicCtrlPts] = hrzCtrl[i + 1][j * 2 + 1];
+                
+                points[SkPatchUtils::kLeftP1_CubicCtrlPts] = vrtCtrl[i * 2][j];
+                points[SkPatchUtils::kLeftP2_CubicCtrlPts] = vrtCtrl[i * 2 + 1][j];
+                points[SkPatchUtils::kRightP1_CubicCtrlPts] = vrtCtrl[i * 2][j + 1];
+                points[SkPatchUtils::kRightP2_CubicCtrlPts] = vrtCtrl[i * 2 + 1][j + 1];
+                
+                SkColor colors[4];
+                colors[0] = cornerColors[i][j];
+                colors[1] = cornerColors[i][j + 1];
+                colors[3] = cornerColors[i + 1][j];
+                colors[2] = cornerColors[i + 1][j + 1];
+                
+                grid.setPatch(j, i, points, colors, NULL);
+            }
+        }
+        
+        grid.draw(canvas, paint);
+        SkISize dims = grid.getDimensions();
+        for (int y = 0; y < dims.height(); y++) {
+            for (int x = 0; x < dims.width(); x++) {
+                SkPoint cubics[12];
+                grid.getPatch(x, y, cubics, NULL, NULL);
+                draw_control_points(canvas, cubics);
+            }
+        }
+    }
+
+private:
+    typedef GM INHERITED;
+};
+
+DEF_GM(return SkNEW(SkPatchGridGM); )
+
+}