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(0xffffcc44);
c.drawOval(new RectF(0, 0, w * 3 / 4, h * 3 / 4), 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(0xff66aaff);
c.drawRect(w / 3, h / 3, w * 19 / 20, h * 19 / 20, 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 = 64;
private static final int H = 64;
private static final int ROW_MAX = 4;

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[] { 0xffffffff, 0xffcccccc,
0xffcccccc, 0xffffffff }, 2, 2, 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(6, 6);
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(15, 35);

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

int x = 0;
int y = 0;
//canvas.drawBitmap(mSrcB, 0, 0, paint);
for (int i = 0; i < sModes.length; i++) {
//画边框
paint.setStyle(Paint.Style.STROKE);
paint.setShader(null);
canvas.drawRect(x - 0.5f, y - 0.5f, x + W + 0.5f, y + H + 0.5f,
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, 0, 0, paint);
//设置整合模式
paint.setXfermode(sModes[i]);
//绘制源图形
canvas.drawBitmap(mSrcB, 0, 0, paint);
paint.setXfermode(null);
canvas.restoreToCount(sc);

//绘制说明文字
canvas.drawText(sLabels[i], x+W/2, y-labelP.getTextSize()/2, labelP);

x+=W+10;
if((i%ROW_MAX)==ROW_MAX-1){
x=0;
y+=H+30;
}
}
}

}

}