Add GM with convex polygon clips

gm/convexpolyclip.cpp

Index: gm/convexpolyclip.cpp
diff --git a/gm/convexpolyclip.cpp b/gm/convexpolyclip.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..db357bbfd7e6ab607a692af05c9f76fd12bad547
--- /dev/null
+++ b/gm/convexpolyclip.cpp
@@ -0,0 +1,194 @@
+
+/*
+ * 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 "SkBitmap.h"
+#include "SkGradientShader.h"
+#include "SkTLList.h"
+
+static SkBitmap make_bmp(int w, int h) {
+    SkBitmap bmp;
+    bmp.allocN32Pixels(w, h, true);
+
+    SkCanvas canvas(bmp);
+    SkScalar wScalar = SkIntToScalar(w);
+    SkScalar hScalar = SkIntToScalar(h);
+
+    SkPoint     pt = { wScalar / 2, hScalar / 2 };
+
+    SkScalar    radius = 3 * SkMaxScalar(wScalar, hScalar);
+
+    SkColor     colors[] = { SK_ColorDKGRAY, 0xFF222255,
+                             0xFF331133, 0xFF884422,
+                             0xFF000022, SK_ColorWHITE,
+                             0xFFAABBCC};
+
+    SkScalar    pos[] = {0,
+                         SK_Scalar1 / 6,
+                         2 * SK_Scalar1 / 6,
+                         3 * SK_Scalar1 / 6,
+                         4 * SK_Scalar1 / 6,
+                         5 * SK_Scalar1 / 6,
+                         SK_Scalar1};
+
+    SkPaint paint;
+    paint.setShader(SkGradientShader::CreateRadial(
+                    pt, radius,
+                    colors, pos,
+                    SK_ARRAY_COUNT(colors),
+                    SkShader::kRepeat_TileMode))->unref();
+    SkRect rect = SkRect::MakeWH(wScalar, hScalar);
+    SkMatrix mat = SkMatrix::I();
+    for (int i = 0; i < 4; ++i) {
+        paint.getShader()->setLocalMatrix(mat);
+        canvas.drawRect(rect, paint);
+        rect.inset(wScalar / 8, hScalar / 8);
+        mat.preTranslate(6 * wScalar, 6 * hScalar);
+        mat.postScale(SK_Scalar1 / 3, SK_Scalar1 / 3);
+    }
+
+    paint.setAntiAlias(true);
+    paint.setTextSize(wScalar / 2.2f);
+    paint.setShader(0);
+    paint.setColor(SK_ColorLTGRAY);
+    static const char kTxt[] = "Skia";
+    SkPoint texPos = { wScalar / 17, hScalar / 2 + paint.getTextSize() / 2.5f };
+    canvas.drawText(kTxt, SK_ARRAY_COUNT(kTxt)-1, texPos.fX, texPos.fY, paint);
+    paint.setColor(SK_ColorBLACK);
+    paint.setStyle(SkPaint::kStroke_Style);
+    paint.setStrokeWidth(SK_Scalar1);
+    canvas.drawText(kTxt, SK_ARRAY_COUNT(kTxt)-1, texPos.fX, texPos.fY, paint);
+    return bmp;
+}
+
+namespace skiagm {
+/**
+ * This GM tests convex polygon clips.
+ */
+class ConvexPolyClip : public GM {
+public:
+    ConvexPolyClip() {
+        this->setBGColor(0xFFFFFFFF);
+    }
+
+protected:
+    virtual SkString onShortName() SK_OVERRIDE {
+        return SkString("convex_poly_clip");
+    }
+
+    virtual SkISize onISize() SK_OVERRIDE {
+        return make_isize(435, 440);
+    }
+
+    virtual void onOnceBeforeDraw() SK_OVERRIDE {
+        SkPath tri;
+        tri.moveTo(5.f, 5.f);
+        tri.lineTo(100.f, 20.f);
+        tri.lineTo(15.f, 100.f);
+
+        fPaths.addToTail(tri);
+
+        SkPath hexagon;
+        static const SkScalar kRadius = 45.f;
+        const SkPoint center = { kRadius, kRadius };
+        for (int i = 0; i < 6; ++i) {
+            SkScalar angle = 2 * SK_ScalarPI * i / 6;
+            SkPoint point;
+            point.fY = SkScalarSinCos(angle, &point.fX);
+            point.scale(kRadius);
+            point = center + point;
+            if (0 == i) {
+                hexagon.moveTo(point);
+            } else {
+                hexagon.lineTo(point);
+            }
+        }
+        fPaths.addToTail(hexagon);
+
+        SkMatrix scaleM;
+        scaleM.setScale(1.1f, 0.4f, kRadius, kRadius);
+        hexagon.transform(scaleM);
+        fPaths.addToTail(hexagon);
+
+        SkPath rotRect;
+        SkRect rect = SkRect::MakeLTRB(10.f, 12.f, 80.f, 86.f);
+        rotRect.addRect(rect);
+        SkMatrix rotM;
+        rotM.setRotate(23.f, rect.centerX(), rect.centerY());
+        rotRect.transform(rotM);
+        fPaths.addToTail(rotRect);
+
+        fBmp = make_bmp(100, 100);
+    }
+
+    virtual void onDraw(SkCanvas* canvas) SK_OVERRIDE {
+        const SkPath* path;
+        SkScalar y = 0;
+        static const SkScalar kMargin = 10.f;
+
+        SkPaint bgPaint;
+        bgPaint.setAlpha(0x15);
+        SkISize size = canvas->getDeviceSize();
+        SkRect dstRect = SkRect::MakeWH(SkIntToScalar(size.fWidth),
+                                        SkIntToScalar(size.fHeight));
+        canvas->drawBitmapRectToRect(fBmp, NULL, dstRect, &bgPaint);
+
+        for (SkTLList<SkPath>::Iter iter(fPaths, SkTLList<SkPath>::Iter::kHead_IterStart);
+             NULL != (path = iter.get());
+             iter.next()) {
+            SkScalar x = 0;
+            for (int aa = 0; aa < 2; ++aa) {
+                canvas->save();
+                canvas->translate(x, y);
+                canvas->clipPath(*path, SkRegion::kIntersect_Op, SkToBool(aa));
+                canvas->drawBitmap(fBmp, 0, 0);
+                canvas->restore();
+                x += fBmp.width() + kMargin;
+            }
+            for (int aa = 0; aa < 2; ++aa) {
+                static const char kTxt[] = "Clip Me!";
+                SkPaint txtPaint;
+                txtPaint.setTextSize(23.f);
+                txtPaint.setAntiAlias(true);
+                txtPaint.setColor(SK_ColorDKGRAY);
+
+                SkPaint clipOutlinePaint;
+                clipOutlinePaint.setAntiAlias(true);
+                clipOutlinePaint.setColor(0x50505050);
+                clipOutlinePaint.setStyle(SkPaint::kStroke_Style);
+                clipOutlinePaint.setStrokeWidth(0);
+
+                canvas->save();
+                canvas->translate(x, y);
+                SkPath closedClipPath = *path;
+                closedClipPath.close();
+                canvas->drawPath(closedClipPath, clipOutlinePaint);
+                canvas->clipPath(*path, SkRegion::kIntersect_Op, SkToBool(aa));
+                canvas->scale(1.f, 1.8f);
+                canvas->drawText(kTxt, SK_ARRAY_COUNT(kTxt)-1,
+                                 0, 1.5f * txtPaint.getTextSize(),
+                                 txtPaint);
+                canvas->restore();
+                x += fBmp.width() + kMargin;
+            }
+
+            y += fBmp.height() + kMargin;
+        }
+    }
+
+private:
+    SkTLList<SkPath> fPaths;
+    SkBitmap         fBmp;
+
+    typedef GM INHERITED;
+};
+
+DEF_GM( return SkNEW(ConvexPolyClip); )
+
+}