1.1 Basic elements and data structures

1.1.10 Positions and regions

The Window Tool Kit has two basic data structures: positions and regions. The unit of measurement for these structures is a bit.

Positions usually refer to a point relative to the root viewport or to the viewport upon which a particular operation is to be performed. Some window constructs allow keyword options for specifying positions relative to other objects, such as bitmaps.

The width, height, x, and y locations of viewports and windows can be described or specified as a region. Bitmaps do not have a location on the screen by themselves; thus, they cannot be described as a region.

The Window Tool Kit includes functions for accessing the dimensions of a region, for testing containment and equality of regions, for testing whether a position is inside a region, and for making active regions.

The Window Tool Kit - 9 SEP 1996

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