Android Api Demos登顶之路（九十四）Graphics-->Xfermodes

/*
 * 这个demon演示了图像的整合模式
 */
public class MainActivity extends Activity {

    private Bitmap makeDest(int w, int h) {
        Bitmap bm = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888);
        Canvas c = new Canvas(bm);
        Paint p = new Paint(Paint.ANTI_ALIAS_FLAG);
        p.setColor();
        c.drawOval(new RectF(, , w *  / , h *  / ), p);
        return bm;
    }

    private Bitmap makeSrc(int w, int h) {
        Bitmap bm = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888);
        Canvas c = new Canvas(bm);
        Paint p = new Paint(Paint.ANTI_ALIAS_FLAG);
        p.setColor();
        c.drawRect(w / , h / , w *  / , h *  / , p);
        return bm;
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(new SampleView(this));
    }

    private class SampleView extends View {
        private static final int W = ;
        private static final int H = ;
        private static final int ROW_MAX = ;

        private Bitmap mSrcB;
        private Bitmap mDstB;
        private Shader mBG;

        private Xfermode[] sModes = {
                new PorterDuffXfermode(PorterDuff.Mode.CLEAR),
                new PorterDuffXfermode(PorterDuff.Mode.SRC),
                new PorterDuffXfermode(PorterDuff.Mode.DST),
                new PorterDuffXfermode(PorterDuff.Mode.SRC_OVER),
                new PorterDuffXfermode(PorterDuff.Mode.DST_OVER),
                new PorterDuffXfermode(PorterDuff.Mode.SRC_IN),
                new PorterDuffXfermode(PorterDuff.Mode.DST_IN),
                new PorterDuffXfermode(PorterDuff.Mode.SRC_OUT),
                new PorterDuffXfermode(PorterDuff.Mode.DST_OUT),
                new PorterDuffXfermode(PorterDuff.Mode.SRC_ATOP),
                new PorterDuffXfermode(PorterDuff.Mode.DST_ATOP),
                new PorterDuffXfermode(PorterDuff.Mode.XOR),
                new PorterDuffXfermode(PorterDuff.Mode.DARKEN),
                new PorterDuffXfermode(PorterDuff.Mode.LIGHTEN),
                new PorterDuffXfermode(PorterDuff.Mode.MULTIPLY),
                new PorterDuffXfermode(PorterDuff.Mode.SCREEN) };

        private String[] sLabels = { "Clear", "Src", "Dst", "SrcOver",
                "DstOver", "SrcIn", "DstIn", "SrcOut", "DstOut", "SrcATop",
                "DstATop", "Xor", "Darken", "Lighten", "Multiply", "Screen" };

        public SampleView(Context context) {
            super(context);

            mSrcB = makeSrc(W, H);
            mDstB = makeDest(W, H);
            // 创建一个位图图案，用于作为背景，宽和高为2个像素第1个颜色值表示第一行第一个像素点，第二个颜色值表示第一行第二个像素点
            // 第三个颜色值表示第二行第一个像素点，第四个颜色值表示第二行第二个像素点
            Bitmap bm = Bitmap.createBitmap(new int[] { , ,
                    ,  }, , , Bitmap.Config.RGB_565);

            mBG = new BitmapShader(bm, Shader.TileMode.REPEAT,
                    Shader.TileMode.REPEAT);
            Matrix m = new Matrix();
            // 将图案放大6倍
            m.setScale(, );
            mBG.setLocalMatrix(m);
        }

        @Override
        protected void onDraw(Canvas canvas) {
            canvas.drawColor(Color.WHITE);
            Paint paint = new Paint();
            // 关闭图像过滤，如果打开会使背景变得模糊，因为我们需要得到清晰、边缘分明的背景，所以不需要滤波
            paint.setFilterBitmap(false);
            // paint.setAntiAlias(true);
            canvas.translate(, );

            Paint labelP=new Paint(Paint.ANTI_ALIAS_FLAG);
            labelP.setTextAlign(Paint.Align.CENTER);

            int x = ;
            int y = ;
            //canvas.drawBitmap(mSrcB, 0, 0, paint);
            for (int i = ; i < sModes.length; i++) {
                //画边框
                paint.setStyle(Paint.Style.STROKE);
                paint.setShader(null);
                canvas.drawRect(x - f, y - f, x + W + f, y + H + f,
                        paint);
                //画背景
                paint.setStyle(Paint.Style.FILL);
                paint.setShader(mBG);
                canvas.drawRect(x, y, x + W, y + H, paint);

                int sc = canvas.saveLayer(x, y, x + W, y + H, null,
                        Canvas.MATRIX_SAVE_FLAG |
                        Canvas.CLIP_SAVE_FLAG |
                        Canvas.HAS_ALPHA_LAYER_SAVE_FLAG |
                        Canvas.FULL_COLOR_LAYER_SAVE_FLAG |
                        Canvas.CLIP_TO_LAYER_SAVE_FLAG);
                canvas.translate(x, y);
                //绘制目标图形
                canvas.drawBitmap(mDstB, , , paint);
                //设置整合模式
                paint.setXfermode(sModes[i]);
                //绘制源图形
                canvas.drawBitmap(mSrcB, , , paint);
                paint.setXfermode(null);
                canvas.restoreToCount(sc);

                //绘制说明文字
                canvas.drawText(sLabels[i], x+W/, y-labelP.getTextSize()/, labelP);

                x+=W+;
                if((i%ROW_MAX)==ROW_MAX-){
                    x=;
                    y+=H+;
                }
            }
        }

    }

}