Perl Graphics Programming

Sample Image::Magick Applications

ImageMagick can do almost anything to an image or group of images. Some common applications are:

• Creating animated GIFs

• Creating composite images from a sequence

• Easily reducing or thumbnailing images

• Setting transparent colors

• Reducing and correcting colors

• Converting between 60+ formats (e.g., Photo CD to JPEG, PDF to GIF, BMP to PNG)

• Creating special effects and adding text to images

Examples of two of these applications are described in the following sections.

Thumbnails with Image::Magick

Suppose you have a bunch of image files (or PostScript or PDF files) for which you want to create smaller thumbnail images. The ImageMagick package provides several ways to do this. One high-level approach is ImageMagick’s Visual Image Directory virtual file format. You can convert a number of image files into a Visual Image Directory with the convert utility:

convert 'vid:*.gif' png:imageindex.png

This command converts every GIF file in the current directory into a single image that contains thumbnails of all the images, and saves it as a PNG file called imageindex.png. The resulting image looks like Figure 3-2.

Figure 3-2. ImageMagick’s Visual Image Directory allows you to create thumbnails

The Visual Image Directory is essentially a high-level function that uses some of the lower-level ImageMagick routines to read in a bunch of images, scale them into thumbnails, provide ...