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]
- 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]
- 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]