High-Low Displayer

A high-low displayer has the following basic characteristics:

Class	IlvHiLoChartDisplayer
Category	Single
Number of real data sets displayed	2
Can be used with all types of projections	Yes
Items drawn	High-low items

The high-low displayer displays two data sets. The first data set is composed of the low values and the second data set is composed of the high values. A high-low item is drawn between each pair of low-high values, the low values being taken in order from the first data set and the high values being taken in order from the second data set.

The following properties are specific to a high-low displayer:

Property	Methods	Default Value
Width of a High-low Item	getWidth setWidth	IlvChartDisplayerWidth
Width percentage of a High-low Item	getWidthPercent setWidthPercent	100
Rise Palette	getRisePalette setRisePalette	0
Fall Palette	getFallPalette setFallPalette	0

If a width percentage is set, the width of the items is no longer constant but proportional to the zoom level of the chart.

Two palettes are defined: a rise palette and a fall palette. The rise palette is used to draw the high-low items for which the corresponding low value is less than the high value. The fall palette is used to draw the high-low items for which the corresponding low value is greater than the high value.

High-Low Displayers in a Cartesian Chart and in a Polar Chart illustrates the fact that a high-low displayer can be used with all types of projections. Data sets are represented by a high-low displayer in a Cartesian chart (using a Cartesian projection) and in a polar chart (using a polar projection).

High-Low Displayers in a Cartesian Chart and in a Polar Chart

We can use the high-low displayer displaying the green and red high-low items as an example. We can create this displayer by using the following code:

IlvPalette* risePal = dpy->getPalette(dpy->getColor("white"), dpy->getColor("green"),0,0,0,0,2); IlvPalette* fallPal = dpy->getPalette(dpy->getColor("white"), dpy->getColor("red"),0,0,0,0,2); IlvHiLoChartDisplayer* displayer = new IlvHiLoChartDisplayer(IlvChartDisplayerWidth, risePal, fallPal);

Note The Drawn Filled property has no meaning for the high-low displayer. The high-low items are simply drawn with the foreground color of the rise and fall palettes defined.