Element: graphic_window.redraw { }

Type

callback

Description

One of the command procedures to be executed when graphic_window is repainted due to a recalculation of its contents.

When window redraw procedures are defined and invoked, the following steps are executed:

1. The window pre_redraw procedure (if defined) is called.

2. The window background (color and/or image and/or cloth) is painted.

3. The window redraw procedure (if defined) is called.

4. If the window has a populate procedure defined, it is called for every group viewable in the window. If the window does not have a populate procedure defined, the window foreground (entity graphics) is painted.

5. The window foreground (entity graphics) is painted.

6. The window post_redraw procedure (if defined) is called.

7. The window auto-grid and/or auto-vane are painted.

When linked to an external process this permits such a process to repaint the window’s background image. The external process can paint over the background image by means of the window element graphic_window.raster_id.

When a redraw procedure is executed, the window identifier is passed to the procedure as a parameter.

The redraw procedure is not invoked on repaints due to simple window exposure, but only on a change of window size and/or a redefinition of its corners.

Within a redraw procedure there should be no commands which change the view of the window. Requests to draw entities or image files (draw/rasdraw commands) result in draws to the background. Commands which add new entities valid for the window are permitted but the entities are not drawn until the foreground is painted. Requests to redraw the window contents will be ignored. This procedure is typically used to add graphics to the background and foreground.

New windows have a redraw procedure of null.

Parameters

window.redraw(<window>)

See Also