span-missing-items

Arguments: line-graph-view

Returns the value of the span-missing-items property of a line-graph-view. The value may be set at creation time by passing the span-missing-items initarg, or any time later by calling (setf span-missing-items).

A boolean value indicating whether line segments will be drawn across chart items that have no values in a line-graph-view of a chart-widget. The default value is nil.

The chart-widget allows any combination of a chart item and chart object to either have a value or not. When there is no value, nothing is drawn on the chart for that chart item and object.

A special case is that a chart object may have no value for a sequence of one or more chart items, but have values for items on both sides of that sequence of items. This raises the question as to whether a line should be drawn between the groups of items that do have values.

If span-missing-items is true, then a single straight line is drawn between the last chart item before the sequence of non-value items and the first item after the no-value items. If span-missing-items is nil, then no such line is drawn, and lines will connect only contiguous items that all have values.

This property is used only when the draw-lines property is true.

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

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This page was not revised from the 10.0 page.
Created 2019.8.20.