Programming charts (prefix syntax)

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Programming charts (prefix syntax)

Overview

How to program charts?

See also

Programming charts (prefix syntax)

Overview

WINDEV, WEBDEV and WINDEV Mobile include a Chart control (that can be used in the window editor, page editor and report editor) as well as several functions used to create and handle charts.

Using charts in WEBDEV Linux and in WINDEV Linux
To use the charts in Linux, the QT library (Core and GUI) version 5 (or later) must be installed.

In Ubuntu, this library can be installed with the following commands:

sudo apt-get install libqtcore5
sudo apt-get install libqtgui5

How to program charts?

Creating charts through programming

WINDEV, WEBDEV and WINDEV Mobile include several functions for handling charts. These functions allow you to create the charts, to modify them, to change the display options...

The following operations are used to create the charts:

Create the chart with grCreate.
Initialize the chart data with the following functions:
- <Chart>.AddData.
- <Chart>.ScatterAddDataXY for the Scatter charts.
- <Chart>.StockAddData for the Stock charts.
- <Chart>.SurfaceAddData for the Surface charts.
- <Chart>.SunburstAddData for the Sunburst charts.
- <Chart>.HMAddData for the Heatmap charts.
Choose the display destination of the chart with the following functions:
- grDestinationControl: to display the chart in an Image control
- grDestinationWnd: to display the chart in an independent window
  This option is not available.
- grDestinationBMP, grDestinationEMF or grDestinationWMF to save the chart in files in BMP, EMF or WMF format respectively.
- grDestinationImage: to save the chart in an Image variable directly.
Draw the chart with <Chart>.Draw.

Several functions are used to configure and modify the appearance of the chart. You have the ability to display a legend, the title of axes, ... For more details, see the list of functions for chart management.

You cannot create charts through programming. Only Chart controls are available.

Charts and threads

A single chart can be handled in a thread.

Consequences:

Two threads cannot handle the same chart.
A chart created in a thread is automatically destroyed at the end of this thread. The chart exists in the thread that contains the call to grCreate.

Default values of a chart (in a window or in a page)

The default values of a chart are as follows:

Popup menu enabled (can be configured by <Chart>.Menu and <Chart>.MenuOption).
Automatic marks on axes (can be configured by <Chart>.Graduate).
The colors are selected according to a preset order among a set of 13 colors (can be configured by <Chart>.SeriesColor).
The color gradients are available (can be configured by <Chart>.Gradient).
A tooltip is automatically displayed when a chart is hovered (<Chart>.Tooltip).
File size (can be configured by grWndSize).
Window size (can be configured by grWndSize).
No label for the series (can be configured by <Chart>.SeriesLabel).
No caption for the elements (can be configured by <Chart>.CategoryLabel and <Chart>.Label).
No legend (can be configured by <Chart>.Legend).
No title for the chart (can be configured by <Chart>.Title).
No title for the axes (can be configured by <Chart>.AxisTitle).
No gridlines (can be configured by <Chart>.GridLines).
No data (elements can be added by <Chart>.AddData).
No destination (can be configured by grDestinationControl, grDestinationWnd and grDestinationWMF).
No chart display (to draw the chart, use <Chart>.Draw).
No raised effect (can be configured by <Chart>.Raised).
For the pie charts, the starting angle is equal to 0 (can be configured by <Chart>.PieStartAngle).
For the bar charts and the MinMax charts, the spacing between two categories is equal to 10 pixels (can be configured by <Chart>.ColumnSpacing).
For scatter charts, the points are linked and their size is equal to 1 (can be configured by <Chart>.ScatterLinkPoint and <Chart>.ScatterPointSize).