Custom Graphics Operations - MIT/GNU Scheme 9.1
Description: MIT/GNU Scheme 9.1

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### 17.7 Custom Graphics Operations

In addition to the standard operations, a graphics device may support custom operations. For example, most devices have custom operations to control color. `graphics-operation` is used to invoke custom operations.

— procedure: graphics-operation graphics-device name object ...

> Invokes the graphics operation on graphics-device whose name is the symbol name, passing it the remaining arguments. This procedure can be used to invoke the standard operations, as well as custom operations that are specific to a particular graphics device type. The names of the standard graphics operations are formed by removing the `graphics-` prefix from the corresponding procedure. For example, the following are equivalent:

>               (graphics-draw-point device x y)
>               (graphics-operation device 'draw-point x y)

> For information on the custom operations for a particular device, see the documentation for its type.