Scripted drawing with ImageMagick Silhouette

ImageMagick can do more than just edit existing images. The free software can even be scripted to create simple drawings.

- RALF KIRSCHNER

Although you would normally use a bona fide graphics program for drawing and painting, there are definitely situations in which you need to draw regular shapes in an image repeatedly at fixed intervals – as shown here, for example, when creating the silhouette of an imaginary city (Figure 1). This does not require an expensive graphics program with a sophisticated macro language. Using the free and open source ImageMagick software package at the command line is more than up to this task.

To compose more extensive images, you will need the support of a scripting language such as Bash, which uses loops and other control structures to repeatedly insert image content into the graphic. ImageMagick can be found in the package sources of most Linux distributions, but it can also be downloaded for installation from the download section of the project page [1].

magick logo: logo.gif

Painting by Commands

After completing the install, type at the command line. ImageMagick will create the logo.gif file in the current directory. It shows the magician seen in the upper right corner of Figure 1. You can easily check this by opening the file in a suitable image viewer. Image names ending with a colon are internal test images in ImageMagick. You can create more test images with the rose: and wizard: [2] options.

To demonstrate that you can actually draw at the command line with ImageMagick, see the command in Listing 1.

Listing 1: Rectangle