User Guide

GNU Image Manipulation Program
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11.2.6 Image-Dependent Scripts
These are scripts that perform operations on an existing image. In many ways they are like the plug-ins in the Filters menu. The
following script groups are installed by default:
• Alchemy
• Alpha to logo
• Animators
• Decor
• Render
• Selection
• Shadow
• Stencil Ops
• Utils
Stencil Ops Here, you’ll find two scripts: Carve-It and Chrome-It, which can render some truly nice artistic effects on grayscale
images.
Drop Shadow Drop Shadow will cast a shadow behind your selected object. It has three important parameters. X and Y offset
determine where the shadow will be placed in relation to the selected object. Offset is measured in pixels. High values
make the shadow look like it’s far away, and low values will make it look closer to the object. The blur value is also
important, because a shadow that is cast far from the object has a higher blur level.
Perspective Shadow Perspective Shadow has a very important parameter: the perspective angle. If this angle is set to 0 or 180,
there will be no shadow, because the script assumes that the object has no thickness. This also means that this script looks
fine in certain angles, but unnatural in others. The other parameters are quite self-explanatory. You’ll get more blur if the
horizon is far away, and the shadow length is the length in relation to the selected object.
11.3 A Script-Fu Tutorial
In this training course, we’ll introduce you to the fundamentals of Scheme necessary to use Script-Fu, and then build a handy
script that you can add to your toolbox of scripts. The script prompts the user for some text, then creates a new image sized
perfectly to the text. We will then enhance the script to allow for a buffer of space around the text. We will conclude with a few
suggestions for ways to ramp up your knowledge of Script-Fu.
Note
This section as adapted from a tutorial written for the GIMP 1 User Manual by Mike Terry.
11.3.1 Getting Acquainted With Scheme
11.3.1.1 Let’s Start Scheme’ing
The first thing to learn is that:
Every statement in Scheme is surrounded by parentheses ().