QQ聊天文字背影图片拉伸方法

//将图片用瓦片拉伸的方式进行拉伸
- (UIImage *)changeImgWith:(NSString *)imgName
{
    UIImage *img = [UIImage imageNamed:imgName];
    CGFloat W = img.size.width*0.5;
    CGFloat H = img.size.height*0.5;
    return  [img resizableImageWithCapInsets:UIEdgeInsetsMake(W,H,W,H) resizingMode:UIImageResizingModeTile];
    
}

//设置btn的内边距
 Btn.contentEdgeInsets = UIEdgeInsetsMake(30, 30, 30, 30);

//因为内边距增加了所以size也要增加
_BtnF = CGRectMake(textX, textY, textSize.width+60,textSize.height+60);