Automated GIMP Processing of Web Site Images

Take advantage of The GIMP to perform mundane but needed image processing for Web sites.

To generate the properly aliased button, run the command shown in Listing 4. The result will look like Figure 5. Notice that the shadow is now a soft graduation to the green background.

Figure 5. The green background now plays a role in the partially transparent pixels.

The final output GIF image is created with the command shown in Listing 5.

For more-specific image settings for GIF files for use on the Internet using gimp-monkeyiq-webgif, see Listing 6. Here, the depth of the GIF is set to less than 256 colors, and the image is dithered to try to compensate for the lower number of available colors.

Some Simple Scripts

As imageOutput() exports all the visible layers of an image by default, a few other scripts allow you to slice up the layers in an xcf file to make only the desired layers visible and thus exported to the final image. Ignoring the boilerplate registration code for each script, hiding all layers can be done with the script shown in Listing 7. Then, a regular expression can be used to show desired layers (Listing 8).

The Layers_hideAll() and Layers_showByRE() functions are in the shared MonkeyIQGIMP module, so that all scripts easily can toggle layer visibility too.