Chapter 4

Images as Values

4.1  Creating Images through Code

DrScheme supports the use of images as ordinary Scheme values. The following program demonstrates the construction of a face through a sequence of operations.

The Stepper (which we discuss later) supports images as values, so a programmer can see the above program in action.

4.2  Including Image Files in Source

Program source files can also contains images. DrScheme saves such files in a custom, cross-platform portable format. Images are first-class values, which means programmers can pass them to and return them from functions, store them in data structures, and so on. Use Special | Insert Image ... to insert an image into the file being edited in the Definitions window.

4.3  Editing Image Files

Naturally, programs can include external image files and edit them using code.