thick stroke Beziers

gm/beziers.cpp

+/*
+ * 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 "SkRandom.h"
+
+#define W   400
+#define H   400
+#define N   10
+
+static const SkScalar SW = SkIntToScalar(W);
+static const SkScalar SH = SkIntToScalar(H);
+
+static void rnd_quad(SkPath* p, SkPaint* paint, SkLCGRandom& rand) {
+    p->moveTo(rand.nextRangeScalar(0,  W), rand.nextRangeScalar(0,  H));
+    for (int x = 0; x < 2; ++x) {
+        p->quadTo(rand.nextRangeScalar(W / 4,  W), rand.nextRangeScalar(0,  H),
+                rand.nextRangeScalar(0,  W), rand.nextRangeScalar(H / 4,  H));
+    }
+    paint->setColor(rand.nextU());
+    SkScalar width = rand.nextRangeScalar(1, 5);
+    width *= width;
+    paint->setStrokeWidth(width);
+    paint->setAlpha(0xFF);
+}
+
+static void rnd_cubic(SkPath* p, SkPaint* paint, SkLCGRandom& rand) {
+    p->moveTo(rand.nextRangeScalar(0,  W), rand.nextRangeScalar(0,  H));
+    for (int x = 0; x < 2; ++x) {
+        p->cubicTo(rand.nextRangeScalar(W / 4,  W), rand.nextRangeScalar(0,  H),
+                rand.nextRangeScalar(0,  W), rand.nextRangeScalar(H / 4,  H),
+                rand.nextRangeScalar(W / 4,  W), rand.nextRangeScalar(H / 4,  H));
+    }
+    paint->setColor(rand.nextU());
+    SkScalar width = rand.nextRangeScalar(1, 5);
+    width *= width;
+    paint->setStrokeWidth(width);
+    paint->setAlpha(0xFF);
+}
+
+class BeziersGM : public skiagm::GM {
+public:
+    BeziersGM() {}
+
+protected:
+    virtual uint32_t onGetFlags() const SK_OVERRIDE {
+        return kSkipTiled_Flag;
+    }
+
+    virtual SkString onShortName() {
+        return SkString("beziers");
+    }
+
+    virtual SkISize onISize() {
+        return SkISize::Make(W, H*2);
+    }
+
+    virtual void onDraw(SkCanvas* canvas) {
+        SkPaint paint;
+        paint.setStyle(SkPaint::kStroke_Style);
+        paint.setStrokeWidth(SkIntToScalar(9)/2);
+        paint.setAntiAlias(true);
+
+        SkLCGRandom rand;
+        for (int i = 0; i < N; i++) {
+            SkPath p;
+            rnd_quad(&p, &paint, rand);
+            canvas->drawPath(p, paint);
+        }
+        canvas->translate(0, SH);
+        for (int i = 0; i < N; i++) {
+            SkPath p;
+            rnd_cubic(&p, &paint, rand);
+            canvas->drawPath(p, paint);
+        }
+    }
+
+private:
+    typedef skiagm::GM INHERITED;
+};
+
+static skiagm::GM* F0(void*) { return new BeziersGM; }
+static skiagm::GMRegistry R0(F0);