My Favorite Commands: Image manipulation

Way back in the dark ages when Webcrossing was "just" a message board, its developers came up with the radical idea of allowing users to upload little pictures to go with their user accounts. Wacky, right?

As an outgrowth of that, Webcrossing has a small but powerful set of image manipulation commands, so that users need not be limited to uploading files of only certain sizes or dimensions. Using these commands you can post-process any JPEG or GIF uploads to fit whatever requirements you choose to establish. The commands are:

image.imageCropToJpeg(top, left, width, height, quality)

top and left define the upper left corner of the portion of the image to crop, based on 0,0 as the upper left corner of the image. width and height are in pixels and define the size of the portion to crop, and quality is a percentage defining the compression and hence quality of the JPEG the command returns.

image.imageResizeToJpeg(percent, quality)

This command proportionally resizes your image proportionally. percent is the percent to scale (which can be larger than 100).

image.imageResizeWHJpeg(width, height, quality)

This command allows you to resize to a specific width and height (in pixels), and can be non-proportional.

image.imageRotateToJpeg(degreesCounterclockwise, quality)

This command rotates the image counterclockwise. To rotate clockwise, use 360-[clockwise rotation].

All of these commands return the altered image as a stream of binary data which you can save directly to file. The parameter image is the binary data of the original file, and getting that may not always be completely obvious. Here's a little helper function that will extract the binary data from an attachment. This function can also be used to get the data of a file attached to an incoming email message.

%% function getImageData(enclosureLoc) {
        var image = Stored.lookup(enclosureLoc);
        if (image.storedIsDocument && image.documentIsImage) {
                return Mime.getBody(image.documentData);
        } else {
                return "";
        }
} %%