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17 Graphics

MIT/GNU Scheme has a simple two-dimensional line-graphics interface that is suitable for many graphics applications. In particular it is often used for plotting data points from experiments. The interface is generic in that it can support different types of graphics devices in a uniform manner. At the present time only one type of graphics device is implemented on each operating system.

Procedures are available for drawing points, lines, and text; defining the coordinate system; clipping graphics output; controlling some of the drawing characteristics; and controlling the output buffer (for devices that perform buffering). Additionally, devices may support custom operations, such as control of colors.

There are some constraints on the arguments to the procedures described in this chapter. Any argument named graphics-device must be a graphics device object that was returned from a call to make-graphics-device. Any argument that is a coordinate must be either an exact integer or an inexact real.