iOS 绘图方式重绘图片3种模式

-(void)drawRect:(CGRect)rect {
    UIImage *image =[UIImage imageNamed:@"1"];

    //裁剪(超过裁剪区域以外的内容,都会被自动裁剪掉)
    //设置裁剪区域一定要在绘制之前进行设置
    //UIRectClip(CGRectMake(0,0,50,50));
    //UIRectFill(CGRectMake(50,50,50,50));

    //1.drawAtPoint绘制的是原始图片的大小
    [image drawAtPoint:CGPointZero];
    //2.把要绘制的图片给填充到给定的区域当中.
    //[image drawInRect:rect];
    //3.平铺
    //[image drawAsPatternInRect:self.bounds];
}