skia2/gm/anisotropic.cpp
mtklein dbfd7ab108 Replace a lot of 'static const' with 'constexpr' or 'const'.
'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
2016-09-01 11:24:54 -07:00

114 lines
3.7 KiB
C++

/*
* Copyright 2015 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"
namespace skiagm {
// This GM exercises HighQuality anisotropic filtering.
class AnisotropicGM : public GM {
public:
AnisotropicGM() : fFilterQuality(kHigh_SkFilterQuality) {
this->setBGColor(sk_tool_utils::color_to_565(0xFFCCCCCC));
}
protected:
SkString onShortName() override { return SkString("anisotropic_hq"); }
SkISize onISize() override {
return SkISize::Make(2*kImageSize + 3*kSpacer,
kNumVertImages*kImageSize + (kNumVertImages+1)*kSpacer);
}
// Create an image consisting of lines radiating from its center
void onOnceBeforeDraw() override {
constexpr int kNumLines = 100;
constexpr SkScalar kAngleStep = 360.0f / kNumLines;
constexpr int kInnerOffset = 10;
fBM.allocN32Pixels(kImageSize, kImageSize, true);
SkCanvas canvas(fBM);
canvas.clear(SK_ColorWHITE);
SkPaint p;
p.setAntiAlias(true);
SkScalar angle = 0.0f, sin, cos;
canvas.translate(kImageSize/2.0f, kImageSize/2.0f);
for (int i = 0; i < kNumLines; ++i, angle += kAngleStep) {
sin = SkScalarSinCos(angle, &cos);
canvas.drawLine(cos * kInnerOffset, sin * kInnerOffset,
cos * kImageSize/2, sin * kImageSize/2, p);
}
}
void draw(SkCanvas* canvas, int x, int y, int xSize, int ySize) {
SkRect r = SkRect::MakeXYWH(SkIntToScalar(x), SkIntToScalar(y),
SkIntToScalar(xSize), SkIntToScalar(ySize));
SkPaint p;
p.setFilterQuality(fFilterQuality);
canvas->drawBitmapRect(fBM, r, &p);
}
void onDraw(SkCanvas* canvas) override {
SkScalar gScales[] = { 0.9f, 0.8f, 0.75f, 0.6f, 0.5f, 0.4f, 0.25f, 0.2f, 0.1f };
SkASSERT(kNumVertImages-1 == (int)SK_ARRAY_COUNT(gScales)/2);
// Minimize vertically
for (int i = 0; i < (int)SK_ARRAY_COUNT(gScales); ++i) {
int height = SkScalarFloorToInt(fBM.height() * gScales[i]);
int yOff;
if (i <= (int)SK_ARRAY_COUNT(gScales)/2) {
yOff = kSpacer + i * (fBM.height() + kSpacer);
} else {
// Position the more highly squashed images with their less squashed counterparts
yOff = (SK_ARRAY_COUNT(gScales) - i) * (fBM.height() + kSpacer) - height;
}
this->draw(canvas, kSpacer, yOff, fBM.width(), height);
}
// Minimize horizontally
for (int i = 0; i < (int)SK_ARRAY_COUNT(gScales); ++i) {
int width = SkScalarFloorToInt(fBM.width() * gScales[i]);
int xOff, yOff;
if (i <= (int)SK_ARRAY_COUNT(gScales)/2) {
xOff = fBM.width() + 2*kSpacer;
yOff = kSpacer + i * (fBM.height() + kSpacer);
} else {
// Position the more highly squashed images with their less squashed counterparts
xOff = fBM.width() + 2*kSpacer + fBM.width() - width;
yOff = kSpacer + (SK_ARRAY_COUNT(gScales) - i - 1) * (fBM.height() + kSpacer);
}
this->draw(canvas, xOff, yOff, width, fBM.height());
}
}
private:
static constexpr int kImageSize = 256;
static constexpr int kSpacer = 10;
static constexpr int kNumVertImages = 5;
SkBitmap fBM;
SkFilterQuality fFilterQuality;
typedef GM INHERITED;
};
//////////////////////////////////////////////////////////////////////////////
DEF_GM(return new AnisotropicGM;)
}