UI拉伸图片和获取字符串的的size

／／获取字符串size  font：字体    maxsize（最大宽度和最大高度）

－(CGSize)sizeWithFont:(UIFont *)font maxSize:(CGSize)maxSize{

    NSDictionary *attrs = @{NSFontAttributeName : font};

    return [self boundingRectWithSize:maxSize options:NSStringDrawingUsesLineFragmentOrigin attributes:attrs context:nil].size;

}

+(UIImage *)resizeImage:(NSString *)name{

    UIImage *normal = [UIImage imageNamed:name];

    CGFloat w = normal.size.width*0.5;

    CGFloat h = normal.size.height*0.5;

    

    return [normal resizableImageWithCapInsets:UIEdgeInsetsMake(h, w, h, w)];

}