根据指定颜色生成图片

+ (UIImage *)imageFromColor:(UIColor *)color size:(CGSize)size{

    CGRect rect = CGRectMake(0, 0, size.width, size.height);

    UIGraphicsBeginImageContext(rect.size);

    CGContextRef context = UIGraphicsGetCurrentContext(); //// memory leak

    CGContextSetFillColorWithColor(context, [color CGColor]);

    CGContextFillRect(context, rect);

    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

    // CFRelease(context);

    return image;

}