Using the command line to process images might sound senseless but the tools offered by ImageMagick certainly prove that it has its place. I have always been wary of using bulk processing for my digital photo files (some digitised from film prints with a scanner) but I do agree that some of it is needed to free up some time for other more necessary things. With this in mind, it is encouraging to see the results from ImageMagick and I can see it making a major difference to how I maintain my online photo gallery.

For instance, making thumbnail images for the gallery certainly seems to be one of those operations where command line bulk processing comes into its own and ImageMagick’s own convert command is heaven sent for this one. For resizing images, all that’s needed is the following:

convert -resize 40% input.jpg output.jpg

Add a spot of further shell scripting and even a dash of Perl and the possibilities for this sort of thing become clearer and this is but the pinnacle of the proverbial iceberg. The -rotate switch will do what the name suggests and there are a whole plethora of other options on tap. So long as you have Ghostscript on your system, conversion of graphics to Postscript (and Encapsulated Postscript too) and PDF files is possible with the -page option controlling the margin around the image itself in the resulting outputs. Unfortunately, portrait is the sole orientation on offer but a bit of judicious post processing will turn things around. Here’s a command that’ll do the trick:

convert -page 792×612+72+72 input.png ps2:output.ps

For retrieving image metadata like its resolution and size, the identify command comes into play. The -verbose option invokes the output of all manner of image metadata so using grep or egrep is perhaps advisable, especially for bulking processing with the likes of Perl. Having the ability to stream image metadata makes loading databases like MySQL less of a chore than the manual data entry that has been my way of doing things until now.

The fancy artwork that comes with Ubuntu Studio does look appealing so I got lured into converting my vanilla Ubuntu 7.10 into something a bit more avant garde. The theme’s all very dark (you can have a peek here; file size is 1.1 MB) but it looks very smart, even if the merging of application title bar and top desktop panel due to their having the same colour and texture is a little disconcerting. My momentary lapse of discipline also got me adding a whole array of audio, graphics and movie applications that I may never use; it’s good to have them if I ever fancy a fiddle but removal is not off the agenda either. The other thing that came with the package was an alternate kernel that looks as if it might be of the real time variety, at least if the "rt" in its package name is to be believed. The main reason for mentioning that is that VMware has ceased working so I need to snag the correct kernel source code to get things going again. Let’s hope that it’s a successful venture…

Update: After a spot of poking, Synaptic offered up the required kernel header files and VMware was reinstated with only a modicum of effort. All’s well that ends well.

What I never realised was that PHP could do image generation and it’s an intriguing possibility that I may yet use myself. This useful ability comes courtesy of GD and this is included in some PHP distributions.