tiledscaledbitmap.cpp

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/*
 * Copyright 2014 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */
 
#include "gm/gm.h"
#include "include/core/SkBitmap.h"
#include "include/core/SkCanvas.h"
#include "include/core/SkColor.h"
#include "include/core/SkMatrix.h"
#include "include/core/SkPaint.h"
#include "include/core/SkShader.h"
#include "include/core/SkSize.h"
#include "include/core/SkString.h"
#include "include/core/SkTileMode.h"
 
 /***
  *
  * This GM reproduces Skia bug 2904, in which a tiled bitmap shader was failing to draw correctly
  * when fractional image scaling was ignored by the high quality bitmap scaler.
  *
  ***/
 
namespace skiagm {
 
class TiledScaledBitmapGM : public GM {
public:
 
    TiledScaledBitmapGM() {
    }
 
protected:
    SkString getName() const override { return SkString("tiledscaledbitmap"); }
 
    SkISize getISize() override { return SkISize::Make(1016, 616); }
 
    static SkBitmap make_bm(int width, int height) {
        SkBitmap bm;
        bm.allocN32Pixels(width, height);
        bm.eraseColor(SK_ColorTRANSPARENT);
        SkCanvas canvas(bm);
        SkPaint paint;
        paint.setAntiAlias(true);
        canvas.drawCircle(width/2.f, height/2.f, width/4.f, paint);
        return bm;
    }
 
    void onOnceBeforeDraw() override {
        fBitmap = make_bm(360, 288);
    }
 
    void onDraw(SkCanvas* canvas) override {
        SkPaint paint;
 
        paint.setAntiAlias(true);
 
        SkMatrix mat;
        mat.setScale(121.f/360.f, 93.f/288.f);
        mat.postTranslate(-72, -72);
 
        paint.setShader(fBitmap.makeShader(SkTileMode::kRepeat, SkTileMode::kRepeat,
                                           SkSamplingOptions(SkCubicResampler::Mitchell()), mat));
        canvas->drawRect({ 8, 8, 1008, 608 }, paint);
    }
 
private:
    SkBitmap fBitmap;
 
    using INHERITED = GM;
};
 
//////////////////////////////////////////////////////////////////////////////
 
DEF_GM(return new TiledScaledBitmapGM;)
}  // namespace skiagm