Crosshair in a chart

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Overview
Implementation
Crosshair in a Chart control
Crosshair in the AAFs (Automatic Application Features)
Modifying the multiple crosshair through programming
Configuring the crosshair options through programming

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Crosshair in a chart

Overview

In a Line chart, it may be difficult to read the value of axes for a point that is far from these axes.

Via the new crosshair included in all charts, the end user precisely knows the pointed value.

All charts with axes automatically benefit from the crosshair.

The user hovers a point in the chart and the crosshair is displayed!

If the vertical crosshair crosses several lines, the value is displayed for each intersection: it is the multiple crosshair.

For a multiple crosshair, the tooltip header can be customized.

Implementation

Crosshair in a Chart control

The crosshair is available by default for all Chart controls created from version 20.

To display a crosshair in a Chart control:

Open the Chart control description window.
In the "Details" tab:
- in the "Zoom and crosshair" area, check "Enable chart crosshair".
  The "Multiple crosshair (stacked lines and columns)" option allows using multiple crosshairs in Line or Column charts.
- in the "Interactivity" area, check (if necessary) "Interactive chart" then check "Enable the chart crosshair".
  The "Multiple crosshair" option allows you to get a multiple crosshair in the Line or Column charts.
  Only the interactive Chart controls are available in PHP.
Validate the control description window.

Remarks:

The crosshair is available for the following types of charts: Area, Bubble, Line, Column, MinMax, Radar and Waterfall.
The crosshair characteristics can be defined in the "Style" tab of Chart control: color, opacity and thickness.

Crosshair in the AAFs (Automatic Application Features)

If the crosshair is not enabled in a chart, it can be enabled by the user via the context menu of chart ("Enable the crosshair").

Modifying the multiple crosshair through programming

By default, the multiple crosshair displays:

in header, the category name.
the content of different tooltips for the points corresponding to the crosshair.

It is possible to modify the header of the crosshair tooltip via grTooltip associated with the grTooltipFormatCrosshairHeader constant.

For example:

grTooltip(CHART_Chart1, grTooltipFormatCrosshairHeader, "Category: [%CATEGORY%]")

Configuring the crosshair options through programming

The crosshair has the following characteristics by default:

color based on the color of gridlines in the Chart control.
thickness: 1 pixel.
opacity: entirely opaque crosshair.

These characteristics can be modified by the following properties:


CrosshairColor	The CrosshairColor property gets and sets the color of the crosshair in a Chart control.
CrosshairOpacity	The CrosshairOpacity property is used to determine and change the opacity of the crosshair in a Chart control.
CrosshairThickness	The CrosshairThickness property is used to determine and change the thickness of the crosshair in a Chart control.

The properties are not available.

Related Examples:

Training (WINDEV): WD Chart

[ + ] This example presents the different uses of the Chart control.
Different types of charts are presented:
- Pie
- Sunburst
- Line
- Scatter
- Column
- Area
- etc.

The main features presented here are the possibility to customize of charts from the code, as well as to fill the chart from an HFSQL data file, or in the editor.