gm/bitmapshader.cpp

/*
 * 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 "SkBitmap.h"
#include "SkPaint.h"
#include "SkShader.h"

namespace skiagm {

static void draw_bm(SkBitmap* bm) {
	SkPaint bluePaint;
	bluePaint.setColor(SK_ColorBLUE);

	bm->setConfig(SkBitmap::kARGB_8888_Config, 20, 20);
	bm->allocPixels();
	bm->eraseColor(SK_ColorRED);

	SkCanvas canvas(*bm);
	canvas.drawCircle(10, 10, 5, bluePaint);
}

static void draw_mask(SkBitmap* bm) {
	SkPaint circlePaint;
	circlePaint.setColor(SK_ColorBLACK);

	bm->setConfig(SkBitmap::kA8_Config, 20, 20);
	bm->allocPixels();
	bm->eraseColor(SK_ColorTRANSPARENT);

	SkCanvas canvas(*bm);
	canvas.drawCircle(10, 10, 10, circlePaint);
}

class BitmapShaderGM : public GM {
public:

    BitmapShaderGM() {
        this->setBGColor(SK_ColorGRAY);
        draw_bm(&fBitmap);
        draw_mask(&fMask);
    }

protected:
    virtual SkString onShortName() {
        return SkString("bitmapshaders");
    }

    virtual SkISize onISize() {
        return make_isize(75, 100);
    }

    virtual void onDraw(SkCanvas* canvas) {
    	SkShader* shader = SkShader::CreateBitmapShader(fBitmap,
    			                                        SkShader::kClamp_TileMode,
    			                                        SkShader::kClamp_TileMode);
    	SkPaint paint;
    	paint.setShader(shader);
    	// release the shader ref as the paint now holds a reference
    	shader->unref();

    	// draw the shader with a bitmap mask
    	canvas->drawBitmap(fMask, 0, 0, &paint);
    	canvas->drawBitmap(fMask, 30, 0, &paint);

       	canvas->translate(0, 25);

    	// draw the shader with standard geometry
       	canvas->drawCircle(10, 10, 10, paint);
       	canvas->drawCircle(40, 10, 10, paint); // no blue circle expected

       	canvas->translate(0, 25);

    	shader = SkShader::CreateBitmapShader(fMask,
    	                                      SkShader::kRepeat_TileMode,
    	                                      SkShader::kRepeat_TileMode);
    	paint.setShader(shader);
    	paint.setColor(SK_ColorRED);
    	shader->unref();

       	// draw the mask using the shader and a color
       	canvas->drawRect(SkRect::MakeXYWH(0, 0, 20, 20), paint);
       	canvas->drawRect(SkRect::MakeXYWH(30, 0, 20, 20), paint);
    }

private:
    SkBitmap fBitmap;
    SkBitmap fMask;

    typedef GM INHERITED;
};

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

static GM* MyFactory(void*) { return new BitmapShaderGM; }
static GMRegistry reg(MyFactory);

}