gm/image.cpp - platform/external/skqp - Gitiles

 /*
  * 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 "gm.h"
 #include "SkData.h"
 #include "SkCanvas.h"
 #include "SkRandom.h"
 #include "SkStream.h"
 #include "SkSurface.h"

 #if SK_SUPPORT_GPU
 #include "GrContext.h"
 #endif

 static void drawJpeg(SkCanvas* canvas, const SkISize& size) {
     // TODO: Make this draw a file that is checked in, so it can
     // be exercised on machines other than mike's. Will require a
     // rebaseline.
     SkAutoDataUnref data(SkData::NewFromFileName("/Users/mike/Downloads/skia.google.jpeg"));
     if (nullptr == data.get()) {
         return;
     }
     SkImage* image = SkImage::NewFromEncoded(data);
     if (image) {
         SkAutoCanvasRestore acr(canvas, true);
         canvas->scale(size.width() * 1.0f / image->width(),
                       size.height() * 1.0f / image->height());
         canvas->drawImage(image, 0, 0, nullptr);
         image->unref();
     }
 }

 static void drawContents(SkSurface* surface, SkColor fillC) {
     SkSize size = SkSize::Make(SkIntToScalar(surface->width()),
                                SkIntToScalar(surface->height()));
     SkCanvas* canvas = surface->getCanvas();

     SkScalar stroke = size.fWidth / 10;
     SkScalar radius = (size.fWidth - stroke) / 2;

     SkPaint paint;

     paint.setAntiAlias(true);
     paint.setColor(fillC);
     canvas->drawCircle(size.fWidth/2, size.fHeight/2, radius, paint);

     paint.setStyle(SkPaint::kStroke_Style);
     paint.setStrokeWidth(stroke);
     paint.setColor(SK_ColorBLACK);
     canvas->drawCircle(size.fWidth/2, size.fHeight/2, radius, paint);
 }

 static void test_surface(SkCanvas* canvas, SkSurface* surf, bool usePaint) {
     drawContents(surf, SK_ColorRED);
     SkImage* imgR = surf->newImageSnapshot();

     if (true) {
         SkImage* imgR2 = surf->newImageSnapshot();
         SkASSERT(imgR == imgR2);
         imgR2->unref();
     }

     drawContents(surf, SK_ColorGREEN);
     SkImage* imgG = surf->newImageSnapshot();

     // since we've drawn after we snapped imgR, imgG will be a different obj
     SkASSERT(imgR != imgG);

     drawContents(surf, SK_ColorBLUE);

     SkPaint paint;
 //    paint.setFilterBitmap(true);
 //    paint.setAlpha(0x80);

     canvas->drawImage(imgR, 0, 0, usePaint ? &paint : nullptr);
     canvas->drawImage(imgG, 0, 80, usePaint ? &paint : nullptr);
     surf->draw(canvas, 0, 160, usePaint ? &paint : nullptr);

     SkRect src1, src2, src3;
     src1.iset(0, 0, surf->width(), surf->height());
     src2.iset(-surf->width() / 2, -surf->height() / 2,
              surf->width(), surf->height());
     src3.iset(0, 0, surf->width() / 2, surf->height() / 2);

     SkRect dst1, dst2, dst3, dst4;
     dst1.set(0, 240, 65, 305);
     dst2.set(0, 320, 65, 385);
     dst3.set(0, 400, 65, 465);
     dst4.set(0, 480, 65, 545);

     canvas->drawImageRect(imgR, src1, dst1, usePaint ? &paint : nullptr);
     canvas->drawImageRect(imgG, src2, dst2, usePaint ? &paint : nullptr);
     canvas->drawImageRect(imgR, src3, dst3, usePaint ? &paint : nullptr);
     canvas->drawImageRect(imgG, dst4, usePaint ? &paint : nullptr);

     imgG->unref();
     imgR->unref();
 }

 class ImageGM : public skiagm::GM {
     void*   fBuffer;
     size_t  fBufferSize;
     SkSize  fSize;
     enum {
         W = 64,
         H = 64,
         RB = W * 4 + 8,
     };
 public:
     ImageGM() {
         fBufferSize = RB * H;
         fBuffer = sk_malloc_throw(fBufferSize);
         fSize.set(SkIntToScalar(W), SkIntToScalar(H));
     }

     virtual ~ImageGM() {
         sk_free(fBuffer);
     }

 protected:
     SkString onShortName() override {
         return SkString("image-surface");
     }

     SkISize onISize() override {
         return SkISize::Make(960, 1200);
     }

     void onDraw(SkCanvas* canvas) override {
         drawJpeg(canvas, this->getISize());

         canvas->scale(2, 2);

         static const char* kLabel1 = "Original Img";
         static const char* kLabel2 = "Modified Img";
         static const char* kLabel3 = "Cur Surface";
         static const char* kLabel4 = "Full Crop";
         static const char* kLabel5 = "Over-crop";
         static const char* kLabel6 = "Upper-left";
         static const char* kLabel7 = "No Crop";

         static const char* kLabel8 = "Pre-Alloc Img";
         static const char* kLabel9 = "New Alloc Img";
         static const char* kLabel10 = "GPU";

         SkPaint textPaint;
         textPaint.setAntiAlias(true);
         sk_tool_utils::set_portable_typeface(&textPaint);
         textPaint.setTextSize(8);

         canvas->drawText(kLabel1, strlen(kLabel1), 10,  60, textPaint);
         canvas->drawText(kLabel2, strlen(kLabel2), 10, 140, textPaint);
         canvas->drawText(kLabel3, strlen(kLabel3), 10, 220, textPaint);
         canvas->drawText(kLabel4, strlen(kLabel4), 10, 300, textPaint);
         canvas->drawText(kLabel5, strlen(kLabel5), 10, 380, textPaint);
         canvas->drawText(kLabel6, strlen(kLabel6), 10, 460, textPaint);
         canvas->drawText(kLabel7, strlen(kLabel7), 10, 540, textPaint);

         canvas->drawText(kLabel8, strlen(kLabel8),  80, 10, textPaint);
         canvas->drawText(kLabel9, strlen(kLabel9), 160, 10, textPaint);
         canvas->drawText(kLabel10, strlen(kLabel10), 265, 10, textPaint);

         canvas->translate(80, 20);

         // since we draw into this directly, we need to start fresh
         sk_bzero(fBuffer, fBufferSize);

         SkImageInfo info = SkImageInfo::MakeN32Premul(W, H);
         SkAutoTUnref<SkSurface> surf0(SkSurface::NewRasterDirect(info, fBuffer, RB));
         SkAutoTUnref<SkSurface> surf1(SkSurface::NewRaster(info));
         SkAutoTUnref<SkSurface> surf2;  // gpu

 #if SK_SUPPORT_GPU
         surf2.reset(SkSurface::NewRenderTarget(canvas->getGrContext(),
                                                SkSurface::kNo_Budgeted, info));
 #endif

         test_surface(canvas, surf0, true);
         canvas->translate(80, 0);
         test_surface(canvas, surf1, true);
         if (surf2) {
             canvas->translate(80, 0);
             test_surface(canvas, surf2, true);
         }
     }

 private:
     typedef skiagm::GM INHERITED;
 };
 DEF_GM( return new ImageGM; )

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

 #include "SkPictureRecorder.h"

 static void draw_pixmap(SkCanvas* canvas, const SkPixmap& pmap) {
     SkBitmap bitmap;
     bitmap.installPixels(pmap);
     canvas->drawBitmap(bitmap, 0, 0, nullptr);
 }

 static void show_scaled_pixels(SkCanvas* canvas, SkImage* image) {
     SkAutoCanvasRestore acr(canvas, true);

     canvas->drawImage(image, 0, 0, nullptr);
     canvas->translate(110, 10);

     const SkImageInfo info = SkImageInfo::MakeN32Premul(40, 40);
     SkAutoPixmapStorage storage;
     storage.alloc(info);

     const SkImage::CachingHint chints[] = {
         SkImage::kAllow_CachingHint, SkImage::kDisallow_CachingHint,
     };
     const SkFilterQuality qualities[] = {
         kNone_SkFilterQuality, kLow_SkFilterQuality, kMedium_SkFilterQuality, kHigh_SkFilterQuality,
     };

     for (auto ch : chints) {
         canvas->save();
         for (auto q : qualities) {
             if (image->scalePixels(storage, q, ch)) {
                 draw_pixmap(canvas, storage);
             }
             canvas->translate(70, 0);
         }
         canvas->restore();
         canvas->translate(0, 45);
     }
 }

 static void draw_contents(SkCanvas* canvas) {
     SkPaint paint;
     paint.setStyle(SkPaint::kStroke_Style);
     paint.setStrokeWidth(20);
     canvas->drawCircle(50, 50, 35, paint);
 }

 static SkImage* make_raster(const SkImageInfo& info, GrContext*, void (*draw)(SkCanvas*)) {
     SkAutoTUnref<SkSurface> surface(SkSurface::NewRaster(info));
     draw(surface->getCanvas());
     return surface->newImageSnapshot();
 }

 static SkImage* make_picture(const SkImageInfo& info, GrContext*, void (*draw)(SkCanvas*)) {
     SkPictureRecorder recorder;
     draw(recorder.beginRecording(SkRect::MakeIWH(info.width(), info.height())));
     SkAutoTUnref<SkPicture> pict(recorder.endRecording());
     return SkImage::NewFromPicture(pict, info.dimensions(), nullptr, nullptr);
 }

 static SkImage* make_codec(const SkImageInfo& info, GrContext*, void (*draw)(SkCanvas*)) {
     SkAutoTUnref<SkImage> image(make_raster(info, nullptr, draw));
     SkAutoTUnref<SkData> data(image->encode());
     return SkImage::NewFromEncoded(data);
 }

 static SkImage* make_gpu(const SkImageInfo& info, GrContext* ctx, void (*draw)(SkCanvas*)) {
     if (!ctx) { return nullptr; }
     SkAutoTUnref<SkSurface> surface(SkSurface::NewRenderTarget(ctx, SkSurface::kNo_Budgeted, info));
     draw(surface->getCanvas());
     return surface->newImageSnapshot();
 }

 typedef SkImage* (*ImageMakerProc)(const SkImageInfo&, GrContext*, void (*)(SkCanvas*));

 class ScalePixelsGM : public skiagm::GM {
 public:
     ScalePixelsGM() {}

 protected:
     SkString onShortName() override {
         return SkString("scale-pixels");
     }

     SkISize onISize() override {
         return SkISize::Make(960, 1200);
     }

     void onDraw(SkCanvas* canvas) override {
         const SkImageInfo info = SkImageInfo::MakeN32Premul(100, 100);

         const ImageMakerProc procs[] = {
             make_codec, make_raster, make_picture, make_codec, make_gpu,
         };
         for (auto& proc : procs) {
             SkAutoTUnref<SkImage> image(proc(info, canvas->getGrContext(), draw_contents));
             if (image) {
                 show_scaled_pixels(canvas, image);
             }
             canvas->translate(0, 120);
         }
     }

 private:
     typedef skiagm::GM INHERITED;
 };
 DEF_GM( return new ScalePixelsGM; )

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

 #include "SkImageGenerator.h"

 static SkImageInfo make_info(SkImage* img) {
     return SkImageInfo::MakeN32(img->width(), img->height(),
                                 img->isOpaque() ? kOpaque_SkAlphaType : kPremul_SkAlphaType);
 }

 // Its simple, but I wonder if we should expose this formally?
 //
 class ImageGeneratorFromImage : public SkImageGenerator {
 public:
     ImageGeneratorFromImage(SkImage* img) : INHERITED(make_info(img)), fImg(SkRef(img)) {}

 protected:
     bool onGetPixels(const SkImageInfo& info, void* pixels, size_t rowBytes, SkPMColor ctable[],
                      int* ctableCount) override {
         return fImg->readPixels(info, pixels, rowBytes, 0, 0);
     }

 private:
     SkAutoTUnref<SkImage> fImg;

     typedef SkImageGenerator INHERITED;
 };

 static void draw_opaque_contents(SkCanvas* canvas) {
     canvas->drawColor(0xFFFF8844);

     SkPaint paint;
     paint.setStyle(SkPaint::kStroke_Style);
     paint.setStrokeWidth(20);
     canvas->drawCircle(50, 50, 35, paint);
 }

 static SkImageGenerator* gen_raster(const SkImageInfo& info) {
     SkAutoTUnref<SkSurface> surface(SkSurface::NewRaster(info));
     draw_opaque_contents(surface->getCanvas());
     SkAutoTUnref<SkImage> img(surface->newImageSnapshot());
     return new ImageGeneratorFromImage(img);
 }

 static SkImageGenerator* gen_picture(const SkImageInfo& info) {
     SkPictureRecorder recorder;
     draw_opaque_contents(recorder.beginRecording(SkRect::MakeIWH(info.width(), info.height())));
     SkAutoTUnref<SkPicture> pict(recorder.endRecording());
     return SkImageGenerator::NewFromPicture(info.dimensions(), pict, nullptr, nullptr);
 }

 static SkImageGenerator* gen_png(const SkImageInfo& info) {
     SkAutoTUnref<SkImage> image(make_raster(info, nullptr, draw_opaque_contents));
     SkAutoTUnref<SkData> data(image->encode(SkImageEncoder::kPNG_Type, 100));
     return SkImageGenerator::NewFromEncoded(data);
 }

 static SkImageGenerator* gen_jpg(const SkImageInfo& info) {
     SkAutoTUnref<SkImage> image(make_raster(info, nullptr, draw_opaque_contents));
     SkAutoTUnref<SkData> data(image->encode(SkImageEncoder::kJPEG_Type, 100));
     return SkImageGenerator::NewFromEncoded(data);
 }

 typedef SkImageGenerator* (*GeneratorMakerProc)(const SkImageInfo&);

 static void show_scaled_generator(SkCanvas* canvas, SkImageGenerator* gen) {
     const SkImageInfo genInfo = gen->getInfo();

     SkAutoCanvasRestore acr(canvas, true);

     SkBitmap bm;
     bm.allocPixels(genInfo);
     if (gen->getPixels(bm.info(), bm.getPixels(), bm.rowBytes())) {
         canvas->drawBitmap(bm, 0, 0, nullptr);
     }
     canvas->translate(110, 0);

     const float scales[] = { 0.75f, 0.5f, 0.25f };
     for (auto scale : scales) {
         SkImageGenerator::SupportedSizes sizes;
         if (gen->computeScaledDimensions(scale, &sizes)) {
             const SkImageInfo info = SkImageInfo::MakeN32Premul(sizes.fSizes[0].width(),
                                                                 sizes.fSizes[0].height());
             bm.allocPixels(info);
             SkPixmap pmap;
             bm.peekPixels(&pmap);
             if (gen->generateScaledPixels(pmap)) {
                 canvas->drawBitmap(bm, 0, SkIntToScalar(genInfo.height() - info.height())/2);
             }
         }
         canvas->translate(100, 0);
     }
 }

 class ScaleGeneratorGM : public skiagm::GM {
 public:
     ScaleGeneratorGM() {}

 protected:
     SkString onShortName() override {
         return SkString("scale-generator");
     }

     SkISize onISize() override {
         return SkISize::Make(500, 500);
     }

     void onDraw(SkCanvas* canvas) override {
         canvas->translate(10, 10);

         // explicitly make it opaque, so we can test JPEG (which is only ever opaque)
         const SkImageInfo info = SkImageInfo::MakeN32(100, 100, kOpaque_SkAlphaType);

         const GeneratorMakerProc procs[] = {
             gen_raster, gen_picture, gen_png, gen_jpg,
         };
         for (auto& proc : procs) {
             SkAutoTDelete<SkImageGenerator> gen(proc(info));
             if (gen) {
                 show_scaled_generator(canvas, gen);
             }
             canvas->translate(0, 120);
         }
     }

 private:
     typedef skiagm::GM INHERITED;
 };
 DEF_GM( return new ScaleGeneratorGM; )
	/*
	* 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 "gm.h"
	#include "SkData.h"
	#include "SkCanvas.h"
	#include "SkRandom.h"
	#include "SkStream.h"
	#include "SkSurface.h"

	#if SK_SUPPORT_GPU
	#include "GrContext.h"
	#endif

	static void drawJpeg(SkCanvas* canvas, const SkISize& size) {
	// TODO: Make this draw a file that is checked in, so it can
	// be exercised on machines other than mike's. Will require a
	// rebaseline.
	SkAutoDataUnref data(SkData::NewFromFileName("/Users/mike/Downloads/skia.google.jpeg"));
	if (nullptr == data.get()) {
	return;
	}
	SkImage* image = SkImage::NewFromEncoded(data);
	if (image) {
	SkAutoCanvasRestore acr(canvas, true);
	canvas->scale(size.width() * 1.0f / image->width(),
	size.height() * 1.0f / image->height());
	canvas->drawImage(image, 0, 0, nullptr);
	image->unref();
	}
	}

	static void drawContents(SkSurface* surface, SkColor fillC) {
	SkSize size = SkSize::Make(SkIntToScalar(surface->width()),
	SkIntToScalar(surface->height()));
	SkCanvas* canvas = surface->getCanvas();

	SkScalar stroke = size.fWidth / 10;
	SkScalar radius = (size.fWidth - stroke) / 2;

	SkPaint paint;

	paint.setAntiAlias(true);
	paint.setColor(fillC);
	canvas->drawCircle(size.fWidth/2, size.fHeight/2, radius, paint);

	paint.setStyle(SkPaint::kStroke_Style);
	paint.setStrokeWidth(stroke);
	paint.setColor(SK_ColorBLACK);
	canvas->drawCircle(size.fWidth/2, size.fHeight/2, radius, paint);
	}

	static void test_surface(SkCanvas* canvas, SkSurface* surf, bool usePaint) {
	drawContents(surf, SK_ColorRED);
	SkImage* imgR = surf->newImageSnapshot();

	if (true) {
	SkImage* imgR2 = surf->newImageSnapshot();
	SkASSERT(imgR == imgR2);
	imgR2->unref();
	}

	drawContents(surf, SK_ColorGREEN);
	SkImage* imgG = surf->newImageSnapshot();

	// since we've drawn after we snapped imgR, imgG will be a different obj
	SkASSERT(imgR != imgG);

	drawContents(surf, SK_ColorBLUE);

	SkPaint paint;
	// paint.setFilterBitmap(true);
	// paint.setAlpha(0x80);

	canvas->drawImage(imgR, 0, 0, usePaint ? &paint : nullptr);
	canvas->drawImage(imgG, 0, 80, usePaint ? &paint : nullptr);
	surf->draw(canvas, 0, 160, usePaint ? &paint : nullptr);

	SkRect src1, src2, src3;
	src1.iset(0, 0, surf->width(), surf->height());
	src2.iset(-surf->width() / 2, -surf->height() / 2,
	surf->width(), surf->height());
	src3.iset(0, 0, surf->width() / 2, surf->height() / 2);

	SkRect dst1, dst2, dst3, dst4;
	dst1.set(0, 240, 65, 305);
	dst2.set(0, 320, 65, 385);
	dst3.set(0, 400, 65, 465);
	dst4.set(0, 480, 65, 545);

	canvas->drawImageRect(imgR, src1, dst1, usePaint ? &paint : nullptr);
	canvas->drawImageRect(imgG, src2, dst2, usePaint ? &paint : nullptr);
	canvas->drawImageRect(imgR, src3, dst3, usePaint ? &paint : nullptr);
	canvas->drawImageRect(imgG, dst4, usePaint ? &paint : nullptr);

	imgG->unref();
	imgR->unref();
	}

	class ImageGM : public skiagm::GM {
	void* fBuffer;
	size_t fBufferSize;
	SkSize fSize;
	enum {
	W = 64,
	H = 64,
	RB = W * 4 + 8,
	};
	public:
	ImageGM() {
	fBufferSize = RB * H;
	fBuffer = sk_malloc_throw(fBufferSize);
	fSize.set(SkIntToScalar(W), SkIntToScalar(H));
	}

	virtual ~ImageGM() {
	sk_free(fBuffer);
	}

	protected:
	SkString onShortName() override {
	return SkString("image-surface");
	}

	SkISize onISize() override {
	return SkISize::Make(960, 1200);
	}

	void onDraw(SkCanvas* canvas) override {
	drawJpeg(canvas, this->getISize());

	canvas->scale(2, 2);

	static const char* kLabel1 = "Original Img";
	static const char* kLabel2 = "Modified Img";
	static const char* kLabel3 = "Cur Surface";
	static const char* kLabel4 = "Full Crop";
	static const char* kLabel5 = "Over-crop";
	static const char* kLabel6 = "Upper-left";
	static const char* kLabel7 = "No Crop";

	static const char* kLabel8 = "Pre-Alloc Img";
	static const char* kLabel9 = "New Alloc Img";
	static const char* kLabel10 = "GPU";

	SkPaint textPaint;
	textPaint.setAntiAlias(true);
	sk_tool_utils::set_portable_typeface(&textPaint);
	textPaint.setTextSize(8);

	canvas->drawText(kLabel1, strlen(kLabel1), 10, 60, textPaint);
	canvas->drawText(kLabel2, strlen(kLabel2), 10, 140, textPaint);
	canvas->drawText(kLabel3, strlen(kLabel3), 10, 220, textPaint);
	canvas->drawText(kLabel4, strlen(kLabel4), 10, 300, textPaint);
	canvas->drawText(kLabel5, strlen(kLabel5), 10, 380, textPaint);
	canvas->drawText(kLabel6, strlen(kLabel6), 10, 460, textPaint);
	canvas->drawText(kLabel7, strlen(kLabel7), 10, 540, textPaint);

	canvas->drawText(kLabel8, strlen(kLabel8), 80, 10, textPaint);
	canvas->drawText(kLabel9, strlen(kLabel9), 160, 10, textPaint);
	canvas->drawText(kLabel10, strlen(kLabel10), 265, 10, textPaint);

	canvas->translate(80, 20);

	// since we draw into this directly, we need to start fresh
	sk_bzero(fBuffer, fBufferSize);

	SkImageInfo info = SkImageInfo::MakeN32Premul(W, H);
	SkAutoTUnref<SkSurface> surf0(SkSurface::NewRasterDirect(info, fBuffer, RB));
	SkAutoTUnref<SkSurface> surf1(SkSurface::NewRaster(info));
	SkAutoTUnref<SkSurface> surf2; // gpu

	#if SK_SUPPORT_GPU
	surf2.reset(SkSurface::NewRenderTarget(canvas->getGrContext(),
	SkSurface::kNo_Budgeted, info));
	#endif

	test_surface(canvas, surf0, true);
	canvas->translate(80, 0);
	test_surface(canvas, surf1, true);
	if (surf2) {
	canvas->translate(80, 0);
	test_surface(canvas, surf2, true);
	}
	}

	private:
	typedef skiagm::GM INHERITED;
	};
	DEF_GM( return new ImageGM; )

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

	#include "SkPictureRecorder.h"

	static void draw_pixmap(SkCanvas* canvas, const SkPixmap& pmap) {
	SkBitmap bitmap;
	bitmap.installPixels(pmap);
	canvas->drawBitmap(bitmap, 0, 0, nullptr);
	}

	static void show_scaled_pixels(SkCanvas* canvas, SkImage* image) {
	SkAutoCanvasRestore acr(canvas, true);

	canvas->drawImage(image, 0, 0, nullptr);
	canvas->translate(110, 10);

	const SkImageInfo info = SkImageInfo::MakeN32Premul(40, 40);
	SkAutoPixmapStorage storage;
	storage.alloc(info);

	const SkImage::CachingHint chints[] = {
	SkImage::kAllow_CachingHint, SkImage::kDisallow_CachingHint,
	};
	const SkFilterQuality qualities[] = {
	kNone_SkFilterQuality, kLow_SkFilterQuality, kMedium_SkFilterQuality, kHigh_SkFilterQuality,
	};

	for (auto ch : chints) {
	canvas->save();
	for (auto q : qualities) {
	if (image->scalePixels(storage, q, ch)) {
	draw_pixmap(canvas, storage);
	}
	canvas->translate(70, 0);
	}
	canvas->restore();
	canvas->translate(0, 45);
	}
	}

	static void draw_contents(SkCanvas* canvas) {
	SkPaint paint;
	paint.setStyle(SkPaint::kStroke_Style);
	paint.setStrokeWidth(20);
	canvas->drawCircle(50, 50, 35, paint);
	}

	static SkImage* make_raster(const SkImageInfo& info, GrContext, void (draw)(SkCanvas*)) {
	SkAutoTUnref<SkSurface> surface(SkSurface::NewRaster(info));
	draw(surface->getCanvas());
	return surface->newImageSnapshot();
	}

	static SkImage* make_picture(const SkImageInfo& info, GrContext, void (draw)(SkCanvas*)) {
	SkPictureRecorder recorder;
	draw(recorder.beginRecording(SkRect::MakeIWH(info.width(), info.height())));
	SkAutoTUnref<SkPicture> pict(recorder.endRecording());
	return SkImage::NewFromPicture(pict, info.dimensions(), nullptr, nullptr);
	}

	static SkImage* make_codec(const SkImageInfo& info, GrContext, void (draw)(SkCanvas*)) {
	SkAutoTUnref<SkImage> image(make_raster(info, nullptr, draw));
	SkAutoTUnref<SkData> data(image->encode());
	return SkImage::NewFromEncoded(data);
	}

	static SkImage* make_gpu(const SkImageInfo& info, GrContext* ctx, void (draw)(SkCanvas)) {
	if (!ctx) { return nullptr; }
	SkAutoTUnref<SkSurface> surface(SkSurface::NewRenderTarget(ctx, SkSurface::kNo_Budgeted, info));
	draw(surface->getCanvas());
	return surface->newImageSnapshot();
	}

	typedef SkImage* (ImageMakerProc)(const SkImageInfo&, GrContext, void ()(SkCanvas));

	class ScalePixelsGM : public skiagm::GM {
	public:
	ScalePixelsGM() {}

	protected:
	SkString onShortName() override {
	return SkString("scale-pixels");
	}

	SkISize onISize() override {
	return SkISize::Make(960, 1200);
	}

	void onDraw(SkCanvas* canvas) override {
	const SkImageInfo info = SkImageInfo::MakeN32Premul(100, 100);

	const ImageMakerProc procs[] = {
	make_codec, make_raster, make_picture, make_codec, make_gpu,
	};
	for (auto& proc : procs) {
	SkAutoTUnref<SkImage> image(proc(info, canvas->getGrContext(), draw_contents));
	if (image) {
	show_scaled_pixels(canvas, image);
	}
	canvas->translate(0, 120);
	}
	}

	private:
	typedef skiagm::GM INHERITED;
	};
	DEF_GM( return new ScalePixelsGM; )

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

	#include "SkImageGenerator.h"

	static SkImageInfo make_info(SkImage* img) {
	return SkImageInfo::MakeN32(img->width(), img->height(),
	img->isOpaque() ? kOpaque_SkAlphaType : kPremul_SkAlphaType);
	}

	// Its simple, but I wonder if we should expose this formally?
	//
	class ImageGeneratorFromImage : public SkImageGenerator {
	public:
	ImageGeneratorFromImage(SkImage* img) : INHERITED(make_info(img)), fImg(SkRef(img)) {}

	protected:
	bool onGetPixels(const SkImageInfo& info, void* pixels, size_t rowBytes, SkPMColor ctable[],
	int* ctableCount) override {
	return fImg->readPixels(info, pixels, rowBytes, 0, 0);
	}

	private:
	SkAutoTUnref<SkImage> fImg;

	typedef SkImageGenerator INHERITED;
	};

	static void draw_opaque_contents(SkCanvas* canvas) {
	canvas->drawColor(0xFFFF8844);

	SkPaint paint;
	paint.setStyle(SkPaint::kStroke_Style);
	paint.setStrokeWidth(20);
	canvas->drawCircle(50, 50, 35, paint);
	}

	static SkImageGenerator* gen_raster(const SkImageInfo& info) {
	SkAutoTUnref<SkSurface> surface(SkSurface::NewRaster(info));
	draw_opaque_contents(surface->getCanvas());
	SkAutoTUnref<SkImage> img(surface->newImageSnapshot());
	return new ImageGeneratorFromImage(img);
	}

	static SkImageGenerator* gen_picture(const SkImageInfo& info) {
	SkPictureRecorder recorder;
	draw_opaque_contents(recorder.beginRecording(SkRect::MakeIWH(info.width(), info.height())));
	SkAutoTUnref<SkPicture> pict(recorder.endRecording());
	return SkImageGenerator::NewFromPicture(info.dimensions(), pict, nullptr, nullptr);
	}

	static SkImageGenerator* gen_png(const SkImageInfo& info) {
	SkAutoTUnref<SkImage> image(make_raster(info, nullptr, draw_opaque_contents));
	SkAutoTUnref<SkData> data(image->encode(SkImageEncoder::kPNG_Type, 100));
	return SkImageGenerator::NewFromEncoded(data);
	}

	static SkImageGenerator* gen_jpg(const SkImageInfo& info) {
	SkAutoTUnref<SkImage> image(make_raster(info, nullptr, draw_opaque_contents));
	SkAutoTUnref<SkData> data(image->encode(SkImageEncoder::kJPEG_Type, 100));
	return SkImageGenerator::NewFromEncoded(data);
	}

	typedef SkImageGenerator* (*GeneratorMakerProc)(const SkImageInfo&);

	static void show_scaled_generator(SkCanvas* canvas, SkImageGenerator* gen) {
	const SkImageInfo genInfo = gen->getInfo();

	SkAutoCanvasRestore acr(canvas, true);

	SkBitmap bm;
	bm.allocPixels(genInfo);
	if (gen->getPixels(bm.info(), bm.getPixels(), bm.rowBytes())) {
	canvas->drawBitmap(bm, 0, 0, nullptr);
	}
	canvas->translate(110, 0);

	const float scales[] = { 0.75f, 0.5f, 0.25f };
	for (auto scale : scales) {
	SkImageGenerator::SupportedSizes sizes;
	if (gen->computeScaledDimensions(scale, &sizes)) {
	const SkImageInfo info = SkImageInfo::MakeN32Premul(sizes.fSizes[0].width(),
	sizes.fSizes[0].height());
	bm.allocPixels(info);
	SkPixmap pmap;
	bm.peekPixels(&pmap);
	if (gen->generateScaledPixels(pmap)) {
	canvas->drawBitmap(bm, 0, SkIntToScalar(genInfo.height() - info.height())/2);
	}
	}
	canvas->translate(100, 0);
	}
	}

	class ScaleGeneratorGM : public skiagm::GM {
	public:
	ScaleGeneratorGM() {}

	protected:
	SkString onShortName() override {
	return SkString("scale-generator");
	}

	SkISize onISize() override {
	return SkISize::Make(500, 500);
	}

	void onDraw(SkCanvas* canvas) override {
	canvas->translate(10, 10);

	// explicitly make it opaque, so we can test JPEG (which is only ever opaque)
	const SkImageInfo info = SkImageInfo::MakeN32(100, 100, kOpaque_SkAlphaType);

	const GeneratorMakerProc procs[] = {
	gen_raster, gen_picture, gen_png, gen_jpg,
	};
	for (auto& proc : procs) {
	SkAutoTDelete<SkImageGenerator> gen(proc(info));
	if (gen) {
	show_scaled_generator(canvas, gen);
	}
	canvas->translate(0, 120);
	}
	}

	private:
	typedef skiagm::GM INHERITED;
	};
	DEF_GM( return new ScaleGeneratorGM; )