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Allegro CL version 10.1
Unrevised from 10.0 to 10.1.
10.0 version


Arguments: chart-widget

The value of this property can be a function (or the name of a function) that supplies the data values to be displayed in a chart-widget. Otherwise it should be nil (the default), in which case the chart's data must be supplied by calling set-chart-value multiple times. chart-widget must be a chart-widget.

The function will be called automatically every time the chart-widget draws a value. The arguments to the function indicate which chart item and object it is drawing, and which type of value. The function should return a number to display (or an item ID; see below), or else nil if that type of value should not be drawn at all.

Generally when using a chart-value-returner you should also specify the chart-items-max-index property of the chart-widget, and maybe also the chart-items-min-index property, to tell the chart the range of item indices that it should pass to the function. And if the chart contains more than one object, then you should also set up the chart-objects property to tell the chart the range of object indices that it should pass to the function (and typically their object IDs as well).

Note that in the inspector this property is on the Events tab because its value is a function, though it is not actually handling window system events.

See the page for the chart-widget class for an example of a chart-value-returner function, or the chart-widget tutorial (in cg-chart-widget.htm for further examples.

The parameter list of a chart-value-returner function should be this:

Arguments: chart-widget value-type item-index object-index object-id

These arguments are:

See chart-widget and also cg-chart-widget.htm.

Copyright (c) 1998-2022, Franz Inc. Lafayette, CA., USA. All rights reserved.
This page was not revised from the 10.0 page.
Created 2019.8.20.

Allegro CL version 10.1
Unrevised from 10.0 to 10.1.
10.0 version