iOS图片重复填充
有两种方式：
方式一：colorWithPatternImage用背景颜色设置图片
UIImageView * imageView = [[UIImageView alloc]initWithFrame:CGRectMake(20, 100, 400, 18)];
[self.view addSubview:imageView];
imageView.backgroundColor = [UIColor colorWithPatternImage:[UIImage imageNamed:@"ico_pk_bar_blue.png"]];
【iOS图片重复填充】方式二：
UIImageResizingModeTileresize图片UIImageView * imageView = [[UIImageView alloc]initWithFrame:CGRectMake(20, 100, 400, 18)];
[self.view addSubview:imageView];
UIImage *image = [UIImage imageNamed:@"ico_pk_bar_blue.png"];
UIImage * newImage = [image resizableImageWithCapInsets:UIEdgeInsetsZero resizingMode:UIImageResizingModeTile];
imageView.image = newImage;
