CFLib.org – Common Function Library Project

Description:
This function will give you the properly resized dimensions of an image. In other words, you give it the original dimensions, the new maximum size, and the UDF returns the new size numbers while maintaining the aspect ratio. This could be very handy to use with the ImageSize UDF already published on CFLib.org which returns an image's width and height.

Return Values:
Returns a structure.

Example:

<CFSet Image = imageResizeAspectRatio(400,300,300)>
<CFOutput>
    #Image.width#<br>
    #Image.height#<br>
</CFOutput>

or... using the ImageSize UDF...

<CFSet OriginalSize = imageSize("c:\inetpub\wwwroot\sample.jpg")>
<CFSet NewImageSize = imageResizeAspectRatio(OriginalSize.width,OriginalSize.height,150)>
<CFOutput>
    #NewImageSize.width#<br>
    #NewImageSize.height#<br>
</CFOutput>

Parameters:

Full UDF Source:

/**
 * Returns the proper dimensions of an image resized to a certain maximum size.
 * 
 * @param originalWidth      Width of image. (Required)
 * @param originalHeight      Height of image. (Required)
 * @param target      New target size. (Required)
 * @return Returns a structure. 
 * @author Christopher Jordan (cjordan@placs.net) 
 * @version 1, February 22, 2006 
 */
function imageResizeAspectRatio(originalWidth,originalHeight,target){
    var width        = 0;
    var height        = 0;
    var percentage    = 0;
    var imageProperties    = structnew();

    percentage = (target / originalHeight);
    if (originalWidth gt originalHeight) { 
        percentage = (target / originalWidth);
    }
    
    newWidth                = round(originalWidth * percentage);
    newHeight                = round(originalHeight * percentage);
    imageProperties.width    = newWidth;
    imageProperties.height    = newHeight;
    
    return imageProperties;        
}