grid-drawing-pane-class-for-grid

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))
  'grid-drawing-pane)

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This page was not revised from the 8.1 page.
Created 2010.1.21.