skia2/gm/alphagradients.cpp

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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 "SkCanvas.h"
#include "SkGradientShader.h"
class AlphaGradientsGM : public skiagm::GM {
public:
AlphaGradientsGM() {}
protected:
SkString onShortName() override {
return SkString("alphagradients");
}
SkISize onISize() override {
return SkISize::Make(640, 480);
}
static void draw_grad(SkCanvas* canvas, const SkRect& r,
SkColor c0, SkColor c1, bool doPreMul) {
SkColor colors[] = { c0, c1 };
SkPoint pts[] = { { r.fLeft, r.fTop }, { r.fRight, r.fBottom } };
SkPaint paint;
uint32_t flags = doPreMul ? SkGradientShader::kInterpolateColorsInPremul_Flag : 0;
paint.setShader(SkGradientShader::MakeLinear(pts, colors, nullptr, 2,
SkShader::kClamp_TileMode, flags, nullptr));
canvas->drawRect(r, paint);
paint.setShader(nullptr);
paint.setStyle(SkPaint::kStroke_Style);
canvas->drawRect(r, paint);
}
void onDraw(SkCanvas* canvas) override {
constexpr struct {
SkColor fColor0;
SkColor fColor1;
} gRec[] = {
{ 0xFFFFFFFF, 0x00000000 },
{ 0xFFFFFFFF, 0x00FF0000 },
{ 0xFFFFFFFF, 0x00FFFF00 },
{ 0xFFFFFFFF, 0x00FFFFFF },
{ 0xFFFF0000, 0x00000000 },
{ 0xFFFF0000, 0x00FF0000 },
{ 0xFFFF0000, 0x00FFFF00 },
{ 0xFFFF0000, 0x00FFFFFF },
{ 0xFF0000FF, 0x00000000 },
{ 0xFF0000FF, 0x00FF0000 },
{ 0xFF0000FF, 0x00FFFF00 },
{ 0xFF0000FF, 0x00FFFFFF },
};
SkRect r = SkRect::MakeWH(300, 30);
canvas->translate(10, 10);
for (int doPreMul = 0; doPreMul <= 1; ++doPreMul) {
canvas->save();
for (size_t i = 0; i < SK_ARRAY_COUNT(gRec); ++i) {
draw_grad(canvas, r, gRec[i].fColor0, gRec[i].fColor1, SkToBool(doPreMul));
canvas->translate(0, r.height() + 8);
}
canvas->restore();
canvas->translate(r.width() + 10, 0);
}
}
private:
typedef skiagm::GM INHERITED;
};
DEF_GM(return new AlphaGradientsGM;)