Android心电图效果

使用的是Xfermode的SRC_IN，核心代码

    @Override
    protected void onDraw(Canvas canvas) {
        //使用SRC_IN
        canvas.drawRect(bitmapSrc.getWidth() - dx, 0, bitmapSrc.getWidth(), bitmapSrc.getHeight(), mPaint);

        mPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));
        canvas.drawBitmap(bitmapSrc, 0, 0, mPaint);
        mPaint.setXfermode(null);

        dx += 20;
        if (dx > bitmapSrc.getWidth()) dx = 0;
        postInvalidateDelayed(20);
    }

项目地址：https://gitee.com/aruba/Xfermode.git