GNU/Linux Desktop Survival Guide
by Graham Williams
ImageMagick Tricks, by Sohail Salehi, 230 pages published by PACKT Publishing, 2006, ISBN 1904811868. Available from http://www.packtpub.com/imagemagick/book. This is an interesting and very useful guide to getting so much more out of Imagemagick than one might expect from reading just the simple documentation otherwise provided. It provides an invaluable resource to programmatically construct and modify graphics, with a tutorial like presentation for illustrating many trick and tips in using ImageMagick.
Without a doubt, one of the most useful command line driven graphical processing tools is ImageMagick. As an open source and freely available application for popular operating systems including GNU/Linux and MS/Windows, ImageMagick has become a stapple of effective, repeatable image processing. Unlike graphical interfaces which can sometimes become a burden, often requiring fiddly and manual interactions, the precision and scriptability offered by ImageMagick makes it a powerful tool for the production line digital image editor.
As an occasional image editor, as many of us are in this day and age of digital photography and accessible graphical arts software, I have regularly returned to ImageMagick to perform numerous image conversion and manipulation tasks. Being able to capture the digital image processing task as a series of commands provides the ability to fine tune the process, and to then repeat it automatically, as necessary.
However, as with many such command line driven tools, there is a learning curve to get on top of. One must learn the tricks and traps of the language before one becomes proficient. And often, this means reading through manuals of varying quality and completeness.
There has for a long time been the need for a collection of "this is how you do this" examples using the ImageMagick suite of tools -- the need for a programming-by-example cookbook for ImageMagick.
This book, "ImageMagick Tricks" begins to fill this gap. Salehi uses a chatty narrative style to walk us through many of the common tasks on which ImageMagick might be deployed.
A recent task brought home again the powerful simplicity of using ImagemMagick, guided by the tips and tricks presented in the book. I had to annotate a map of the main Island of Indonesia, Java, with numerous towns, and then to identify particular linkages between those towns.
I was faced with two options (at least). Gimp, the Gnome Image Processor, is a very sophisticated graphical tool, well suited to digital photo manipulation. It can be used to add elements to an image, including text, dots, and lines. But this task required revisiting some of the points, changing their characteristics, changing names to old spelling, and so one. Using an interactive, graphical tool, was not the right way to do this.
Instead, using the various examples presented in ImageMagick Tricks lead to a command line process that transformed the original image into precisely what was required. The first attempt was not perfect by any means, but a few adjustments to the numbers and commands, and eventually I could very repeatably build the image I wanted.
ImageMagick has an impressive variety of optoins, and of course any book can only cover a subset of the full functionality. And this is perhaps where Salehi has had to draw the line and the line may not always correspond with the tasks you want to perform. Including many more recipes in the book to illustrate the various options would have added considerably to the usefulness of the book overall. Nonetheless, Salehi has done a good job in bringing the power of ImageMagick easily to others.
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