| Allegro CL version 8.2 Unrevised from 8.1 to 8.2. 8.1 version |
Arguments: grid-widget row-section column-section drawing-pane section-box
clear-grid-section is called
internally whenever all or part of a grid-section (of a grid-widget
) is
redisplayed. For efficiency, it is called a single time to draw the
empty background of an entire section before draw-cell is called for each of the
individual visible cells of the section. The default method simply
calls erase-contents-box to clear the
section.
An application should not call this function, but may add methods to override the default method if desired. One case where this may be useful is to reduce flashing that may occur for example if clicking and dragging in a cell produces an animation effect by repeatedly changing the domain value represented by the cell and invalidating the cell to redraw it at each stage. If the draw-cell methods for all of the cells in the grid-section are written to draw the entire contents of the cells, then clear-grid-section need not do anything and so a method that does nothing could be added to eliminate the flashing caused by the default method clearing the background.
The arguments are:
See also draw-cell, draw-grid-section, draw-grid and grid-widget
.
Copyright (c) 1998-2016, Franz Inc. Oakland, CA., USA. All rights reserved.
This page was not revised from the 8.1 page.
Created 2010.1.21.
| Allegro CL version 8.2 Unrevised from 8.1 to 8.2. 8.1 version |