Add GM to track thin rectangle rendering

gm/thinrects.cpp

+/*
+ * Copyright 2013 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"
+
+namespace skiagm {
+
+// Draw various width thin rects at 1/8 horizontal pixel increments
+class ThinRectsGM : public GM {
+public:
+    ThinRectsGM() {
+        this->setBGColor(0xFF000000);
+    }
+
+protected:
+    virtual SkString onShortName() SK_OVERRIDE {
+        return SkString("thinrects");
+    }
+
+    virtual SkISize onISize() SK_OVERRIDE {
+        return make_isize(240, 320);
+    }
+
+    virtual void onDraw(SkCanvas* canvas) SK_OVERRIDE {
+
+        SkPaint white;
+        white.setColor(SK_ColorWHITE);
+        white.setAntiAlias(true);
+
+        SkPaint green;
+        green.setColor(SK_ColorGREEN);
+        green.setAntiAlias(true);
+
+        for (int i = 0; i < 8; ++i) {
+            canvas->save();
+                canvas->translate(i*0.125f, i*40.0f);
+                DrawVertRects(canvas, white);
+
+                canvas->translate(40.0f, 0.0f);
+                DrawVertRects(canvas, green);
+            canvas->restore();
+
+            canvas->save();
+                canvas->translate(80.0f, i*40.0f + i*0.125f);
+                DrawHorizRects(canvas, white);
+
+                canvas->translate(40.0f, 0.0f);
+                DrawHorizRects(canvas, green);
+            canvas->restore();
+
+            canvas->save();
+                canvas->translate(160.0f + i*0.125f, 
+                                  i*40.0f + i*0.125f);
+                DrawSquares(canvas, white);
+
+                canvas->translate(40.0f, 0.0f);
+                DrawSquares(canvas, green);
+            canvas->restore();
+        }
+    }
+
+private:
+    static void DrawVertRects(SkCanvas* canvas, const SkPaint& p) {
+        static const SkRect vertRects[] = {
+            { 1,  1,    5.0f, 21 }, // 4 pix wide
+            { 8,  1,   10.0f, 21 }, // 2 pix wide
+            { 13, 1,   14.0f, 21 }, // 1 pix wide
+            { 17, 1,   17.5f, 21 }, // 1/2 pix wide
+            { 21, 1,  21.25f, 21 }, // 1/4 pix wide
+            { 25, 1, 25.125f, 21 }, // 1/8 pix wide
+            { 29, 1,   29.0f, 21 }  // 0 pix wide
+        };
+
+        for (int j = 0; j < SK_ARRAY_COUNT(vertRects); ++j) {
+            canvas->drawRect(vertRects[j], p);
+        }
+    }
+
+    static void DrawHorizRects(SkCanvas* canvas, const SkPaint& p) {
+        static const SkRect horizRects[] = {
+            { 1, 1,  21,    5.0f }, // 4 pix high
+            { 1, 8,  21,   10.0f }, // 2 pix high
+            { 1, 13, 21,   14.0f }, // 1 pix high
+            { 1, 17, 21,   17.5f }, // 1/2 pix high
+            { 1, 21, 21,  21.25f }, // 1/4 pix high
+            { 1, 25, 21, 25.125f }, // 1/8 pix high
+            { 1, 29, 21,   29.0f }  // 0 pix high
+        };
+
+        for (int j = 0; j < SK_ARRAY_COUNT(horizRects); ++j) {
+            canvas->drawRect(horizRects[j], p);
+        }
+    }
+
+    static void DrawSquares(SkCanvas* canvas, const SkPaint& p) {
+        static const SkRect squares[] = {
+            { 1,  1,     5.0f,    5.0f }, // 4 pix
+            { 8,  8,    10.0f,   10.0f }, // 2 pix
+            { 13, 13,   14.0f,   14.0f }, // 1 pix
+            { 17, 17,   17.5f,   17.5f }, // 1/2 pix
+            { 21, 21,  21.25f,  21.25f }, // 1/4 pix
+            { 25, 25, 25.125f, 25.125f }, // 1/8 pix
+            { 29, 29,   29.0f,   29.0f }  // 0 pix
+        };
+
+        for (int j = 0; j < SK_ARRAY_COUNT(squares); ++j) {
+            canvas->drawRect(squares[j], p);
+        }
+    }
+
+    typedef GM INHERITED;
+};
+
+//////////////////////////////////////////////////////////////////////////////
+
+static GM* MyFactory(void*) { return new ThinRectsGM; }
+static GMRegistry reg(MyFactory);
+
+}