skia2/gm/drawatlas.cpp

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/*
* 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"
#include "SkCanvas.h"
#include "SkRSXform.h"
#include "SkSurface.h"
class DrawAtlasGM : public skiagm::GM {
static sk_sp<SkImage> MakeAtlas(SkCanvas* caller, const SkRect& target) {
SkImageInfo info = SkImageInfo::MakeN32Premul(100, 100);
auto surface(caller->makeSurface(info));
if (nullptr == surface) {
surface = SkSurface::MakeRaster(info);
}
SkCanvas* canvas = surface->getCanvas();
// draw red everywhere, but we don't expect to see it in the draw, testing the notion
// that drawAtlas draws a subset-region of the atlas.
canvas->clear(SK_ColorRED);
SkPaint paint;
paint.setXfermodeMode(SkXfermode::kClear_Mode);
SkRect r(target);
r.inset(-1, -1);
// zero out a place (with a 1-pixel border) to land our drawing.
canvas->drawRect(r, paint);
paint.setXfermode(nullptr);
paint.setColor(SK_ColorBLUE);
paint.setAntiAlias(true);
canvas->drawOval(target, paint);
return surface->makeImageSnapshot();
}
sk_sp<SkImage> fAtlas;
public:
DrawAtlasGM() {}
protected:
SkString onShortName() override {
return SkString("draw-atlas");
}
SkISize onISize() override {
return SkISize::Make(640, 480);
}
void onDraw(SkCanvas* canvas) override {
const SkRect target = { 50, 50, 80, 90 };
if (nullptr == fAtlas) {
fAtlas = MakeAtlas(canvas, target);
}
const struct {
SkScalar fScale;
SkScalar fDegrees;
SkScalar fTx;
SkScalar fTy;
void apply(SkRSXform* xform) const {
const SkScalar rad = SkDegreesToRadians(fDegrees);
xform->fSCos = fScale * SkScalarCos(rad);
xform->fSSin = fScale * SkScalarSin(rad);
xform->fTx = fTx;
xform->fTy = fTy;
}
} rec[] = {
{ 1, 0, 10, 10 }, // just translate
{ 2, 0, 110, 10 }, // scale + translate
{ 1, 30, 210, 10 }, // rotate + translate
{ 2, -30, 310, 30 }, // scale + rotate + translate
};
const int N = SK_ARRAY_COUNT(rec);
SkRSXform xform[N];
SkRect tex[N];
SkColor colors[N];
for (int i = 0; i < N; ++i) {
rec[i].apply(&xform[i]);
tex[i] = target;
colors[i] = 0x80FF0000 + (i * 40 * 256);
}
SkPaint paint;
paint.setFilterQuality(kLow_SkFilterQuality);
paint.setAntiAlias(true);
canvas->drawAtlas(fAtlas.get(), xform, tex, N, nullptr, &paint);
canvas->translate(0, 100);
canvas->drawAtlas(fAtlas.get(), xform, tex, colors, N, SkXfermode::kSrcIn_Mode, nullptr, &paint);
}
private:
typedef GM INHERITED;
};
DEF_GM( return new DrawAtlasGM; )