이미지 리사이징(이율 유지)

//이미지 비율을 유지하면서 최대 가로 or 높이보다 작은 이미지 사이즈 생성

+ (UIImage *)getScaledImage:(UIImage *)image scaledToMaxWidth:(CGFloat)width maxHeight:(CGFloat)height {

    CGFloat oldWidth = image.size.width;

    CGFloat oldHeight = image.size.height;

    

    if (oldWidth < width && oldHeight < height)

        return image;

    

    CGFloat scaleFactorW =1;

    CGFloat scaleFactorH =1;

    

    if (oldWidth > width)

        scaleFactorW = width / oldWidth;

    if(oldHeight > height)

        scaleFactorH = height / oldHeight;

    

    CGFloat scaleFactor = (scaleFactorW<scaleFactorH)?scaleFactorW:scaleFactorH;

    

    

    CGFloat newHeight = oldHeight * scaleFactor;

    //CGFloat newWidth = oldWidth * scaleFactor;

    CGSize newSize = CGSizeMake(width, newHeight);

    

    UIGraphicsBeginImageContext(newSize);

    [image drawInRect:CGRectMake(0, 0, newSize.width, newSize.height)];

    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

    

    return newImage;

}

//이미지 비율을 유지하면서 최대 가로 보다 작은 이미지 사이즈 생성

+ (UIImage *)getScaledImage:(UIImage *)image scaledToMaxWidth:(CGFloat)width {

    CGFloat oldWidth = image.size.width;

    CGFloat oldHeight = image.size.height;

    

    CGFloat scaleFactor=1;

    

    if (oldWidth > width) {

        scaleFactor = width / oldWidth;

    } else  //oldWidth<width and height==0이면, scale하지 않음.

        return image;

    

    CGFloat newHeight = oldHeight * scaleFactor;

    CGFloat newWidth = oldWidth * scaleFactor;

    CGSize newSize = CGSizeMake(newWidth, newHeight);

    

    UIGraphicsBeginImageContext(newSize);

    [image drawInRect:CGRectMake(0, 0, newSize.width, newSize.height)];

    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

    

    return newImage;

}