dbfd7ab108
'static const' means, there must be at most one of these, and initialize it at compile time if possible or runtime if necessary. This leads to unexpected code execution, and TSAN* will complain about races on the guard variables. Generally 'constexpr' or 'const' are better choices. Neither can cause races: they're either intialized at compile time (constexpr) or intialized each time independently (const). This CL prefers constexpr where possible, and uses const where not. It even prefers constexpr over const where they don't make a difference... I want to have lots of examples of constexpr for people to see and mimic. The scoped-to-class static has nothing to do with any of this, and is not changed. * Not yet on the bots, which use an older TSAN. BUG=skia: GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2300623005 Review-Url: https://codereview.chromium.org/2300623005
85 lines
2.3 KiB
C++
85 lines
2.3 KiB
C++
/*
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* Copyright 2013 Google Inc.
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*
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* Use of this source code is governed by a BSD-style license that can be
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* found in the LICENSE file.
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*/
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#include "gm.h"
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#include "SkAnimTimer.h"
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#include "SkCanvas.h"
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#include "SkPath.h"
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// Reproduces https://code.google.com/p/chromium/issues/detail?id=279014
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constexpr int kWidth = 440;
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constexpr int kHeight = 440;
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constexpr SkScalar kAngle = 0.305f;
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constexpr int kMaxNumSteps = 140;
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// Renders a string art shape.
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// The particular shape rendered can be controlled by adjusting kAngle, from 0 to 1
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class StringArtGM : public skiagm::GM {
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public:
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StringArtGM() : fNumSteps(kMaxNumSteps) {}
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protected:
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SkString onShortName() override {
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return SkString("stringart");
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}
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SkISize onISize() override {
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return SkISize::Make(kWidth, kHeight);
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}
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void onDraw(SkCanvas* canvas) override {
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SkScalar angle = kAngle*SK_ScalarPI + SkScalarHalf(SK_ScalarPI);
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SkScalar size = SkIntToScalar(SkMin32(kWidth, kHeight));
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SkPoint center = SkPoint::Make(SkScalarHalf(kWidth), SkScalarHalf(kHeight));
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SkScalar length = 5;
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SkScalar step = angle;
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SkPath path;
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path.moveTo(center);
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for (int i = 0; i < fNumSteps && length < (SkScalarHalf(size) - 10.f); ++i) {
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SkPoint rp = SkPoint::Make(length*SkScalarCos(step) + center.fX,
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length*SkScalarSin(step) + center.fY);
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path.lineTo(rp);
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length += angle / SkScalarHalf(SK_ScalarPI);
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step += angle;
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}
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SkPaint paint;
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paint.setAntiAlias(true);
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paint.setStyle(SkPaint::kStroke_Style);
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paint.setColor(sk_tool_utils::color_to_565(0xFF007700));
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canvas->drawPath(path, paint);
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}
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bool onAnimate(const SkAnimTimer& timer) override {
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constexpr SkScalar kDesiredDurationSecs = 3.0f;
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// Make the animation ping-pong back and forth but start in the fully drawn state
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SkScalar fraction = 1.0f - timer.scaled(2.0f/kDesiredDurationSecs, 2.0f);
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if (fraction <= 0.0f) {
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fraction = -fraction;
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}
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SkASSERT(fraction >= 0.0f && fraction <= 1.0f);
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fNumSteps = (int) (fraction * kMaxNumSteps);
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return true;
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}
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private:
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int fNumSteps;
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typedef GM INHERITED;
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};
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DEF_GM( return new StringArtGM; )
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