iOS 图片平铺 drawAsPatternInRect

    UIImage *imgQuestionBgBottom = [UIImage imageNamed:@"profile_arrow.png"];

    UIImage *imgQuestionBgMiddle = [UIImage imageNamed:@"profile_arrow1.png"];    

    float tileHeight = 8;

    float tileWidth = 9;

    float imageHeight = tileHeight*5;

    UIGraphicsBeginImageContext(CGSizeMake(tileWidth, imageHeight+imgQuestionBgBottom.size.height));

    [imgQuestionBgMiddle drawAsPatternInRect:CGRectMake(0, 0, tileWidth, imageHeight)];

    [imgQuestionBgBottom drawInRect:CGRectMake(0, imageHeight, imgQuestionBgBottom.size.width, imgQuestionBgBottom.size.height)];

    UIImage* imgBg = UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

    

    self.leftTopImageView.image = imgBg;

    self.leftTopImageView.frame = CGRectMake(0, 0, imgBg.size.width, imgBg.size.height);

实例：

下面分别是imgQuestionBgMiddle，imgQuestionBgBottom组成imgBg。