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/*
* 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"
#include "sk_tool_utils.h"
#include "SkAnimTimer.h"
#include "SkCanvas.h"
#include "SkPath.h"
// Reproduces https://code.google.com/p/chromium/issues/detail?id=279014
constexpr int kWidth = 440;
constexpr int kHeight = 440;
constexpr SkScalar kAngle = 0.305f;
constexpr int kMaxNumSteps = 140;
// Renders a string art shape.
// The particular shape rendered can be controlled by adjusting kAngle, from 0 to 1
class StringArtGM : public skiagm::GM {
public:
StringArtGM() : fNumSteps(kMaxNumSteps) {}
protected:
SkString onShortName() override {
return SkString("stringart");
}
SkISize onISize() override {
return SkISize::Make(kWidth, kHeight);
}
void onDraw(SkCanvas* canvas) override {
SkScalar angle = kAngle*SK_ScalarPI + SkScalarHalf(SK_ScalarPI);
SkScalar size = SkIntToScalar(SkMin32(kWidth, kHeight));
SkPoint center = SkPoint::Make(SkScalarHalf(kWidth), SkScalarHalf(kHeight));
SkScalar length = 5;
SkScalar step = angle;
SkPath path;
path.moveTo(center);
for (int i = 0; i < fNumSteps && length < (SkScalarHalf(size) - 10.f); ++i) {
SkPoint rp = SkPoint::Make(length*SkScalarCos(step) + center.fX,
length*SkScalarSin(step) + center.fY);
path.lineTo(rp);
length += angle / SkScalarHalf(SK_ScalarPI);
step += angle;
}
SkPaint paint;
paint.setAntiAlias(true);
paint.setStyle(SkPaint::kStroke_Style);
paint.setColor(sk_tool_utils::color_to_565(0xFF007700));
canvas->drawPath(path, paint);
}
bool onAnimate(const SkAnimTimer& timer) override {
constexpr SkScalar kDesiredDurationSecs = 3.0f;
// Make the animation ping-pong back and forth but start in the fully drawn state
SkScalar fraction = 1.0f - timer.scaled(2.0f/kDesiredDurationSecs, 2.0f);
if (fraction <= 0.0f) {
fraction = -fraction;
}
SkASSERT(fraction >= 0.0f && fraction <= 1.0f);
fNumSteps = (int) (fraction * kMaxNumSteps);
return true;
}
private:
int fNumSteps;
typedef GM INHERITED;
};
DEF_GM( return new StringArtGM; )
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