6.2 Properties of Sheets

Sheets have the following properties: [annotate]

A coordinate system
Provides the ability to refer to locations in a sheet's abstract plane. [annotate]
Note: Surely.... that is defined by this sheet's transformation, so this is redundant? [edit]-- Matt 2020-02-12 16:46Z
 
A region
Defines an area within a sheet's coordinate system that indicates the area of interest within the plane, that is, a clipping region for output and input. This typically corresponds to the visible region of the sheet on the display. [annotate]
A parent
A sheet that is the parent in a windowing relationship in which this sheet is a child. [annotate]
Children
An ordered set of sheets that are each a child in a windowing relationship in which this sheet is a parent. The ordering of the set corresponds to the stacking order of the sheets. Not all sheets have children. [annotate]
A transformation
Determines how points in this sheet's coordinate system are mapped into points in its parents. [annotate]
Note: It's really not clear which coordinate system this mapping is defined [edit]-- Matt 2020-02-12 16:50Z
 
An enabled flag
Indicates whether the sheet is currently actively participating in the windowing relationship with its parent and siblings. [annotate]
An event handler
A procedure invoked when the display server wishes to inform CLIM of external events. [annotate]
Output state
A set of values used when CLIM causes graphical or textual output to appear on the display. This state is often represented by a medium. [annotate]