add sample to exercise hittesting

samplecode/SampleHT.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 "SampleCode.h"
+#include "SkView.h"
+#include "SkCanvas.h"
+#include "SkCanvasDrawable.h"
+#include "SkInterpolator.h"
+#include "SkPictureRecorder.h"
+#include "SkRandom.h"
+
+const SkRect gUnitSquare = { -1, -1, 1, 1 };
+
+static void color_to_floats(SkColor c, SkScalar f[4]) {
+    f[0] = SkIntToScalar(SkColorGetA(c));
+    f[1] = SkIntToScalar(SkColorGetR(c));
+    f[2] = SkIntToScalar(SkColorGetG(c));
+    f[3] = SkIntToScalar(SkColorGetB(c));
+}
+
+static SkColor floats_to_color(const SkScalar f[4]) {
+    return SkColorSetARGB(SkScalarRoundToInt(f[0]),
+                          SkScalarRoundToInt(f[1]),
+                          SkScalarRoundToInt(f[2]),
+                          SkScalarRoundToInt(f[3]));
+}
+
+static bool oval_contains(const SkRect& r, SkScalar x, SkScalar y) {
+    SkMatrix m;
+    m.setRectToRect(r, gUnitSquare, SkMatrix::kFill_ScaleToFit);
+    SkPoint pt;
+    m.mapXY(x, y, &pt);
+    return pt.lengthSqd() <= 1;
+}
+
+static SkColor rand_opaque_color(uint32_t seed) {
+    SkRandom rand(seed);
+    return rand.nextU() | (0xFF << 24);
+}
+
+class HTDrawable : public SkCanvasDrawable {
+    SkRect          fR;
+    SkColor         fColor;
+    SkInterpolator* fInterp;
+
+public:
+    HTDrawable(SkRandom& rand) {
+        fR = SkRect::MakeXYWH(rand.nextRangeF(0, 640), rand.nextRangeF(0, 480),
+                              rand.nextRangeF(20, 200), rand.nextRangeF(20, 200));
+        fColor = rand_opaque_color(rand.nextU());
+        fInterp = NULL;
+    }
+    
+    void spawnAnimation() {
+        SkDELETE(fInterp);
+        fInterp = SkNEW_ARGS(SkInterpolator, (5, 3));
+        SkScalar values[5];
+        color_to_floats(fColor, values); values[4] = 0;
+        fInterp->setKeyFrame(0, SampleCode::GetAnimTime(), values);
+        values[0] = 0; values[4] = 180;
+        fInterp->setKeyFrame(1, SampleCode::GetAnimTime() + 1000, values);
+        color_to_floats(rand_opaque_color(fColor), values); values[4] = 360;
+        fInterp->setKeyFrame(2, SampleCode::GetAnimTime() + 2000, values);
+
+        fInterp->setMirror(true);
+        fInterp->setRepeatCount(3);
+
+        this->notifyDrawingChanged();
+    }
+
+    bool hitTest(SkScalar x, SkScalar y) {
+        return oval_contains(fR, x, y);
+    }
+
+    void onDraw(SkCanvas* canvas) SK_OVERRIDE {
+        SkAutoCanvasRestore acr(canvas, false);
+
+        SkPaint paint;
+        paint.setAntiAlias(true);
+
+        if (fInterp) {
+            SkScalar values[5];
+            SkInterpolator::Result res = fInterp->timeToValues(SampleCode::GetAnimTime(), values);
+            fColor = floats_to_color(values);
+
+            canvas->save();
+            canvas->translate(fR.centerX(), fR.centerY());
+            canvas->rotate(values[4]);
+            canvas->translate(-fR.centerX(), -fR.centerY());
+
+            switch (res) {
+                case SkInterpolator::kFreezeEnd_Result:
+                    SkDELETE(fInterp);
+                    fInterp = NULL;
+                    break;
+                default:
+                    break;
+            }
+        }
+        paint.setColor(fColor);
+        canvas->drawRect(fR, paint);
+    }
+    
+    SkRect onGetBounds() SK_OVERRIDE { return fR; }
+};
+
+class HTView : public SampleView {
+public:
+    enum {
+        N = 50,
+        W = 640,
+        H = 480,
+    };
+    
+    struct Rec {
+        HTDrawable* fDrawable;
+    };
+    Rec fArray[N];
+    SkAutoTUnref<SkCanvasDrawable> fRoot;
+    
+    HTView() {
+        SkRandom rand;
+
+        SkPictureRecorder recorder;
+        SkCanvas* canvas = recorder.beginRecording(SkRect::MakeWH(W, H));
+        for (int i = 0; i < N; ++i) {
+            fArray[i].fDrawable = new HTDrawable(rand);
+            canvas->EXPERIMENTAL_drawDrawable(fArray[i].fDrawable);
+            fArray[i].fDrawable->unref();
+        }
+        fRoot.reset(recorder.EXPERIMENTAL_endRecordingAsDrawable());
+    }
+
+protected:
+    bool onQuery(SkEvent* evt) SK_OVERRIDE {
+        if (SampleCode::TitleQ(*evt)) {
+            SampleCode::TitleR(evt, "HT");
+            return true;
+        }
+        return this->INHERITED::onQuery(evt);
+    }
+
+    void onDrawContent(SkCanvas* canvas) SK_OVERRIDE {
+        canvas->EXPERIMENTAL_drawDrawable(fRoot);
+        this->inval(NULL);
+    }
+
+    SkView::Click* onFindClickHandler(SkScalar x, SkScalar y, unsigned modi) SK_OVERRIDE {
+        // search backwards to find the top-most
+        for (int i = N - 1; i >= 0; --i) {
+            if (fArray[i].fDrawable->hitTest(x, y)) {
+                fArray[i].fDrawable->spawnAnimation();
+                break;
+            }
+        }
+        this->inval(NULL);
+        return NULL;
+    }
+
+private:
+    typedef SampleView INHERITED;
+};
+
+//////////////////////////////////////////////////////////////////////////////
+
+static SkView* MyFactory() { return new HTView; }
+static SkViewRegister reg(MyFactory);