Android：自定义ImageView展示大图中的指定区域并切圆角（雪碧图）

@Overrideprotected void onDraw(Canvas canvas){    Drawable drawable = getDrawable();    if (drawable instanceof BitmapDrawable)    {        Bitmap bitmap = ((BitmapDrawable) drawable).getBitmap();        Paint paint = new Paint();        ...//根据需要计算展示区域在大图中的位置        // 绘制大图的某个区域，左上右下        Rect src = new Rect(left, top, right, bottom);        // 绘制区域，填满控件        Rect des = new Rect(0, 0, getWidth(), getHeight());        // 圆角        Path clipPath = new Path();        clipPath.addRoundRect(new RectF(des), radius, radius, Path.Direction.CW);        canvas.clipPath(clipPath);        canvas.drawBitmap(bitmap, src, des, paint);    }    else    {        super.onDraw(canvas);    }}