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Allegro CL version 9.0
Unrevised from 8.2 to 9.0.
8.2 version


Arguments: grid-widget

This method returns the name of the grid-drawing-pane class that a grid-widget should instantiate for the drawing area of the grid. This method may be useful in unusual cases where the widget-windows of a grid-widget need to be subclassed.

Every dialog-item instance that is placed onto a parent window has an associated widget-window or lisp-widget-window instance for the actual window that appears on the screen for the dialog-item. In atypical cases where it is necessary to subclass a widget-window class along with a dialog-item class, a widget-device method is written to tell the dialog-item subclass which widget-window or lisp-widget-window subclass to instantiate automatically.

A grid-widget is a special case in that it has an additional associated widget-window. This window is a child of the main widget-window and contains the entire grid body except for the border at the outside edge of the grid. If this window needs to be subclassed as well, then a grid-drawing-pane-class-for-grid method should be written to tell the grid-widget subclass which grid-drawing-pane subclass to use, just as the widget-device method tells it which grid-top-pane subclass to use. The method should take a grid-widget instance as its only argument and return the name of a subclass of grid-drawing-pane.

There should be no need to subclass a grid-widget's widget-window classes in typical applications that add cell-click, cell-key-down, and draw-cell methods to handle events and drawing on a grid. But if that API is not sufficient and it is necessary to write methods for a grid on lower-level generic functions such as mouse-left-down or virtual-key-down, then the grid-drawing-pane class may be subclassed to provide a class on which to specialize these methods.

The function grid-drawing-pane (called on the main widget-window of a grid-widget) returns the grid-drawing-pane just as the function window (called on a dialog-item) returns the main widget-window.

Here is the default method:

(defmethod grid-drawing-pane-class-for-grid (grid-widget)
  (declare (ignore grid-widget))

Copyright (c) 1998-2012, Franz Inc. Oakland, CA., USA. All rights reserved.
Documentation for Allegro CL version 9.0. This page was not revised from the 8.2 page.
Created 2012.5.30.

Allegro CL version 9.0
Unrevised from 8.2 to 9.0.
8.2 version