samplecode/SampleLayers.cpp - skia - Git at Google

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */

 #include "SampleCode.h"
 #include "SkView.h"
 #include "SkCanvas.h"
 #include "SkBlurMaskFilter.h"
 #include "SkCamera.h"
 #include "SkColorFilter.h"
 #include "SkColorPriv.h"
 #include "SkDevice.h"
 #include "SkGradientShader.h"
 #include "SkImage.h"
 #include "SkInterpolator.h"
 #include "SkMaskFilter.h"
 #include "SkPath.h"
 #include "SkRegion.h"
 #include "SkShader.h"
 #include "SkTime.h"
 #include "SkTypeface.h"
 #include "SkUtils.h"
 #include "SkKey.h"
 #include "SkXfermode.h"
 #include "SkDrawFilter.h"

 static void make_paint(SkPaint* paint, const SkMatrix& localMatrix) {
     SkColor colors[] = { 0, SK_ColorWHITE };
     SkPoint pts[] = { { 0, 0 }, { 0, SK_Scalar1*20 } };
     paint->setShader(SkGradientShader::MakeLinear(pts, colors, nullptr, 2,
                                                   SkShader::kClamp_TileMode, 0, &localMatrix));
     paint->setXfermodeMode(SkXfermode::kDstIn_Mode);
 }

 static void dump_layers(const char label[], SkCanvas* canvas) {
     SkDebugf("Dump Layers(%s)\n", label);

     SkCanvas::LayerIter iter(canvas, true);
     int index = 0;
     while (!iter.done()) {
         SkImageInfo info = iter.device()->imageInfo();
         const SkIRect& clip = iter.clip().getBounds();
         SkDebugf("Layer[%d] bitmap [%d %d] X=%d Y=%d clip=[%d %d %d %d] alpha=%d\n", index++,
                  info.width(), info.height(), iter.x(), iter.y(),
                  clip.fLeft, clip.fTop, clip.fRight, clip.fBottom,
                  iter.paint().getAlpha());
         iter.next();
     }
 }

 // test drawing with strips of fading gradient above and below
 static void test_fade(SkCanvas* canvas) {
     SkAutoCanvasRestore ar(canvas, true);

     SkRect r;

     SkPaint p;
     p.setAlpha(0x88);

     SkAutoCanvasRestore ar2(canvas, false);

     // create the layers

     r.set(0, 0, SkIntToScalar(100), SkIntToScalar(100));
     canvas->clipRect(r);

     r.fBottom = SkIntToScalar(20);
     canvas->saveLayer(&r, nullptr);

     r.fTop = SkIntToScalar(80);
     r.fBottom = SkIntToScalar(100);
     canvas->saveLayer(&r, nullptr);

     // now draw the "content"

     if (true) {
         r.set(0, 0, SkIntToScalar(100), SkIntToScalar(100));

         canvas->saveLayerAlpha(&r, 0x80);

         SkPaint p;
         p.setColor(SK_ColorRED);
         p.setAntiAlias(true);
         canvas->drawOval(r, p);

         dump_layers("inside layer alpha", canvas);

         canvas->restore();
     } else {
         r.set(0, 0, SkIntToScalar(100), SkIntToScalar(100));

         SkPaint p;
         p.setColor(SK_ColorRED);
         p.setAntiAlias(true);
         canvas->drawOval(r, p);
     }

 //    return;

     dump_layers("outside layer alpha", canvas);

     // now apply an effect
     SkMatrix m;
     m.setScale(SK_Scalar1, -SK_Scalar1);
     m.postTranslate(0, SkIntToScalar(100));

     SkPaint paint;
     make_paint(&paint, m);
     r.set(0, 0, SkIntToScalar(100), SkIntToScalar(20));
 //    SkDebugf("--------- draw top grad\n");
     canvas->drawRect(r, paint);

     r.fTop = SkIntToScalar(80);
     r.fBottom = SkIntToScalar(100);
 //    SkDebugf("--------- draw bot grad\n");
     canvas->drawRect(r, paint);
 }

 class RedFilter : public SkDrawFilter {
 public:
     bool filter(SkPaint* p, SkDrawFilter::Type) override {
         fColor = p->getColor();
         if (fColor == SK_ColorRED) {
             p->setColor(SK_ColorGREEN);
         }
         return true;
     }

 private:
     SkColor fColor;
 };

 class LayersView : public SkView {
 public:
     LayersView() {}

 protected:
     // overrides from SkEventSink
     bool onQuery(SkEvent* evt) override {
         if (SampleCode::TitleQ(*evt)) {
             SampleCode::TitleR(evt, "Layers");
             return true;
         }
         return this->INHERITED::onQuery(evt);
     }

     void drawBG(SkCanvas* canvas) {
         canvas->drawColor(SK_ColorGRAY);
     }

     void onDraw(SkCanvas* canvas) override {
         this->drawBG(canvas);

         if (true) {
             SkRect r;
             r.set(SkIntToScalar(0), SkIntToScalar(0),
                   SkIntToScalar(220), SkIntToScalar(120));
             SkPaint p;
             canvas->saveLayer(&r, &p);
             canvas->drawColor(0xFFFF0000);
             p.setAlpha(0);  // or 0
             p.setXfermodeMode(SkXfermode::kSrc_Mode);
             canvas->drawOval(r, p);
             canvas->restore();
             return;
         }

         if (false) {
             SkRect r;
             r.set(SkIntToScalar(0), SkIntToScalar(0),
                   SkIntToScalar(220), SkIntToScalar(120));
             SkPaint p;
             p.setAlpha(0x88);
             p.setAntiAlias(true);

             if (true) {
                 canvas->saveLayer(&r, &p);
                 p.setColor(0xFFFF0000);
                 canvas->drawOval(r, p);
                 canvas->restore();
             }

             p.setColor(0xFF0000FF);
             r.offset(SkIntToScalar(20), SkIntToScalar(50));
             canvas->drawOval(r, p);
         }

         if (false) {
             SkPaint p;
             p.setAlpha(0x88);
             p.setAntiAlias(true);

             canvas->translate(SkIntToScalar(300), 0);

             SkRect r;
             r.set(SkIntToScalar(0), SkIntToScalar(0),
                   SkIntToScalar(220), SkIntToScalar(60));

             canvas->saveLayer(&r, &p);

             r.set(SkIntToScalar(0), SkIntToScalar(0),
                   SkIntToScalar(220), SkIntToScalar(120));
             p.setColor(SK_ColorBLUE);
             canvas->drawOval(r, p);
             canvas->restore();
             return;
         }

         test_fade(canvas);
     }

     SkView::Click* onFindClickHandler(SkScalar x, SkScalar y, unsigned modi) override {
         this->inval(nullptr);

         return this->INHERITED::onFindClickHandler(x, y, modi);
     }

     bool onClick(Click* click) override {
         return this->INHERITED::onClick(click);
     }

     virtual bool handleKey(SkKey) {
         this->inval(nullptr);
         return true;
     }

 private:
     typedef SkView INHERITED;
 };
 DEF_SAMPLE( return new LayersView; )

 //////////////////////////////////////////////////////////////////////////////

 #include "SkBlurImageFilter.h"
 #include "SkMatrixConvolutionImageFilter.h"
 #include "SkMorphologyImageFilter.h"

 #include "Resources.h"
 #include "SkAnimTimer.h"

 class BackdropView : public SampleView {
     SkPoint fCenter;
     SkScalar fAngle;
     sk_sp<SkImage> fImage;
     sk_sp<SkImageFilter> fFilter;
 public:
     BackdropView() {
         fCenter.set(200, 150);
         fAngle = 0;
         fImage = GetResourceAsImage("mandrill_512.png");
         fFilter = SkDilateImageFilter::Make(8, 8, nullptr);
     }

 protected:
     // overrides from SkEventSink
     bool onQuery(SkEvent* evt) override {
         if (SampleCode::TitleQ(*evt)) {
             SampleCode::TitleR(evt, "Backdrop");
             return true;
         }
         return this->INHERITED::onQuery(evt);
     }

     void onDrawContent(SkCanvas* canvas) override {
         canvas->drawImage(fImage.get(), 0, 0, nullptr);

         const SkScalar w = 250;
         const SkScalar h = 150;
         SkPath path;
         path.addOval(SkRect::MakeXYWH(-w/2, -h/2, w, h));
         SkMatrix m;
         m.setRotate(fAngle);
         m.postTranslate(fCenter.x(), fCenter.y());
         path.transform(m);

         canvas->clipPath(path, SkRegion::kIntersect_Op, true);
         const SkRect bounds = path.getBounds();

         SkPaint paint;
         paint.setAlpha(0xCC);
         canvas->saveLayer({ &bounds, &paint, fFilter.get(), 0 });

         canvas->restore();
     }

     bool onAnimate(const SkAnimTimer& timer) override {
         fAngle = SkDoubleToScalar(fmod(timer.secs() * 360 / 5, 360));
         return true;
     }

     SkView::Click* onFindClickHandler(SkScalar x, SkScalar y, unsigned modi) override {
         this->inval(nullptr);
         return new Click(this);
     }

     bool onClick(Click* click) override {
         this->inval(nullptr);
         fCenter = click->fCurr;
         return this->INHERITED::onClick(click);
     }

 private:
     typedef SampleView INHERITED;
 };
 DEF_SAMPLE( return new BackdropView; )
	/*
	* Copyright 2011 Google Inc.
	*
	* Use of this source code is governed by a BSD-style license that can be
	* found in the LICENSE file.
	*/

	#include "SampleCode.h"
	#include "SkView.h"
	#include "SkCanvas.h"
	#include "SkBlurMaskFilter.h"
	#include "SkCamera.h"
	#include "SkColorFilter.h"
	#include "SkColorPriv.h"
	#include "SkDevice.h"
	#include "SkGradientShader.h"
	#include "SkImage.h"
	#include "SkInterpolator.h"
	#include "SkMaskFilter.h"
	#include "SkPath.h"
	#include "SkRegion.h"
	#include "SkShader.h"
	#include "SkTime.h"
	#include "SkTypeface.h"
	#include "SkUtils.h"
	#include "SkKey.h"
	#include "SkXfermode.h"
	#include "SkDrawFilter.h"

	static void make_paint(SkPaint* paint, const SkMatrix& localMatrix) {
	SkColor colors[] = { 0, SK_ColorWHITE };
	SkPoint pts[] = { { 0, 0 }, { 0, SK_Scalar1*20 } };
	paint->setShader(SkGradientShader::MakeLinear(pts, colors, nullptr, 2,
	SkShader::kClamp_TileMode, 0, &localMatrix));
	paint->setXfermodeMode(SkXfermode::kDstIn_Mode);
	}

	static void dump_layers(const char label[], SkCanvas* canvas) {
	SkDebugf("Dump Layers(%s)\n", label);

	SkCanvas::LayerIter iter(canvas, true);
	int index = 0;
	while (!iter.done()) {
	SkImageInfo info = iter.device()->imageInfo();
	const SkIRect& clip = iter.clip().getBounds();
	SkDebugf("Layer[%d] bitmap [%d %d] X=%d Y=%d clip=[%d %d %d %d] alpha=%d\n", index++,
	info.width(), info.height(), iter.x(), iter.y(),
	clip.fLeft, clip.fTop, clip.fRight, clip.fBottom,
	iter.paint().getAlpha());
	iter.next();
	}
	}

	// test drawing with strips of fading gradient above and below
	static void test_fade(SkCanvas* canvas) {
	SkAutoCanvasRestore ar(canvas, true);

	SkRect r;

	SkPaint p;
	p.setAlpha(0x88);

	SkAutoCanvasRestore ar2(canvas, false);

	// create the layers

	r.set(0, 0, SkIntToScalar(100), SkIntToScalar(100));
	canvas->clipRect(r);

	r.fBottom = SkIntToScalar(20);
	canvas->saveLayer(&r, nullptr);

	r.fTop = SkIntToScalar(80);
	r.fBottom = SkIntToScalar(100);
	canvas->saveLayer(&r, nullptr);

	// now draw the "content"

	if (true) {
	r.set(0, 0, SkIntToScalar(100), SkIntToScalar(100));

	canvas->saveLayerAlpha(&r, 0x80);

	SkPaint p;
	p.setColor(SK_ColorRED);
	p.setAntiAlias(true);
	canvas->drawOval(r, p);

	dump_layers("inside layer alpha", canvas);

	canvas->restore();
	} else {
	r.set(0, 0, SkIntToScalar(100), SkIntToScalar(100));

	SkPaint p;
	p.setColor(SK_ColorRED);
	p.setAntiAlias(true);
	canvas->drawOval(r, p);
	}

	// return;

	dump_layers("outside layer alpha", canvas);

	// now apply an effect
	SkMatrix m;
	m.setScale(SK_Scalar1, -SK_Scalar1);
	m.postTranslate(0, SkIntToScalar(100));

	SkPaint paint;
	make_paint(&paint, m);
	r.set(0, 0, SkIntToScalar(100), SkIntToScalar(20));
	// SkDebugf("--------- draw top grad\n");
	canvas->drawRect(r, paint);

	r.fTop = SkIntToScalar(80);
	r.fBottom = SkIntToScalar(100);
	// SkDebugf("--------- draw bot grad\n");
	canvas->drawRect(r, paint);
	}

	class RedFilter : public SkDrawFilter {
	public:
	bool filter(SkPaint* p, SkDrawFilter::Type) override {
	fColor = p->getColor();
	if (fColor == SK_ColorRED) {
	p->setColor(SK_ColorGREEN);
	}
	return true;
	}

	private:
	SkColor fColor;
	};

	class LayersView : public SkView {
	public:
	LayersView() {}

	protected:
	// overrides from SkEventSink
	bool onQuery(SkEvent* evt) override {
	if (SampleCode::TitleQ(*evt)) {
	SampleCode::TitleR(evt, "Layers");
	return true;
	}
	return this->INHERITED::onQuery(evt);
	}

	void drawBG(SkCanvas* canvas) {
	canvas->drawColor(SK_ColorGRAY);
	}

	void onDraw(SkCanvas* canvas) override {
	this->drawBG(canvas);

	if (true) {
	SkRect r;
	r.set(SkIntToScalar(0), SkIntToScalar(0),
	SkIntToScalar(220), SkIntToScalar(120));
	SkPaint p;
	canvas->saveLayer(&r, &p);
	canvas->drawColor(0xFFFF0000);
	p.setAlpha(0); // or 0
	p.setXfermodeMode(SkXfermode::kSrc_Mode);
	canvas->drawOval(r, p);
	canvas->restore();
	return;
	}

	if (false) {
	SkRect r;
	r.set(SkIntToScalar(0), SkIntToScalar(0),
	SkIntToScalar(220), SkIntToScalar(120));
	SkPaint p;
	p.setAlpha(0x88);
	p.setAntiAlias(true);

	if (true) {
	canvas->saveLayer(&r, &p);
	p.setColor(0xFFFF0000);
	canvas->drawOval(r, p);
	canvas->restore();
	}

	p.setColor(0xFF0000FF);
	r.offset(SkIntToScalar(20), SkIntToScalar(50));
	canvas->drawOval(r, p);
	}

	if (false) {
	SkPaint p;
	p.setAlpha(0x88);
	p.setAntiAlias(true);

	canvas->translate(SkIntToScalar(300), 0);

	SkRect r;
	r.set(SkIntToScalar(0), SkIntToScalar(0),
	SkIntToScalar(220), SkIntToScalar(60));

	canvas->saveLayer(&r, &p);

	r.set(SkIntToScalar(0), SkIntToScalar(0),
	SkIntToScalar(220), SkIntToScalar(120));
	p.setColor(SK_ColorBLUE);
	canvas->drawOval(r, p);
	canvas->restore();
	return;
	}

	test_fade(canvas);
	}

	SkView::Click* onFindClickHandler(SkScalar x, SkScalar y, unsigned modi) override {
	this->inval(nullptr);

	return this->INHERITED::onFindClickHandler(x, y, modi);
	}

	bool onClick(Click* click) override {
	return this->INHERITED::onClick(click);
	}

	virtual bool handleKey(SkKey) {
	this->inval(nullptr);
	return true;
	}

	private:
	typedef SkView INHERITED;
	};
	DEF_SAMPLE( return new LayersView; )

	//////////////////////////////////////////////////////////////////////////////

	#include "SkBlurImageFilter.h"
	#include "SkMatrixConvolutionImageFilter.h"
	#include "SkMorphologyImageFilter.h"

	#include "Resources.h"
	#include "SkAnimTimer.h"

	class BackdropView : public SampleView {
	SkPoint fCenter;
	SkScalar fAngle;
	sk_sp<SkImage> fImage;
	sk_sp<SkImageFilter> fFilter;
	public:
	BackdropView() {
	fCenter.set(200, 150);
	fAngle = 0;
	fImage = GetResourceAsImage("mandrill_512.png");
	fFilter = SkDilateImageFilter::Make(8, 8, nullptr);
	}

	protected:
	// overrides from SkEventSink
	bool onQuery(SkEvent* evt) override {
	if (SampleCode::TitleQ(*evt)) {
	SampleCode::TitleR(evt, "Backdrop");
	return true;
	}
	return this->INHERITED::onQuery(evt);
	}

	void onDrawContent(SkCanvas* canvas) override {
	canvas->drawImage(fImage.get(), 0, 0, nullptr);

	const SkScalar w = 250;
	const SkScalar h = 150;
	SkPath path;
	path.addOval(SkRect::MakeXYWH(-w/2, -h/2, w, h));
	SkMatrix m;
	m.setRotate(fAngle);
	m.postTranslate(fCenter.x(), fCenter.y());
	path.transform(m);

	canvas->clipPath(path, SkRegion::kIntersect_Op, true);
	const SkRect bounds = path.getBounds();

	SkPaint paint;
	paint.setAlpha(0xCC);
	canvas->saveLayer({ &bounds, &paint, fFilter.get(), 0 });

	canvas->restore();
	}

	bool onAnimate(const SkAnimTimer& timer) override {
	fAngle = SkDoubleToScalar(fmod(timer.secs() * 360 / 5, 360));
	return true;
	}

	SkView::Click* onFindClickHandler(SkScalar x, SkScalar y, unsigned modi) override {
	this->inval(nullptr);
	return new Click(this);
	}

	bool onClick(Click* click) override {
	this->inval(nullptr);
	fCenter = click->fCurr;
	return this->INHERITED::onClick(click);
	}

	private:
	typedef SampleView INHERITED;
	};
	DEF_SAMPLE( return new BackdropView; )