This section of the User Guide describes the interactive capabilities now available in RainPro. These allow you to change many of the chart elements dynamically (for example headings or titles), to implement drill-down capabilities, or to write truly interactive charts where the user can modify data values.

The RainPro workspace includes two examples for you to copy:

• Drill – shows a simple data exploration tool where you can click on pie sectors to see the detail as a barchart
• Edit – shows how to edit the data values on a simple linechart

You can also check out the callbacks in the RawGui function:

Sample
RawGui PG

These illustrate the techniques which you can use to detect the chart elements clicked by the user, modify headings, offer hints on mouse-move etc.

The functions which you may need to call are:

• EnumerateCharts obj – List all charts drawn on this object
• FindInfo – Locate hotspot info by tag (e.g. ‘Heading’)
• GuiId – Return Guiname associated with this chart/tag
• D2L – Convert Device to Logical co-ordinates
• L2D – Convert Logical to Device co-ordinates
• FindHotspot – Hotspot which is pointed to by (x,y) coordinates
• FindSeries – Series data which is within tolerance of the coordinates
• FindPoints – Data points which lie within bounding box
• FindHint – Hint which matches this chart/series/data index
• SetObject – Reset heading or axis captions in-place
• GetPage – Recover updated PostScript source

These are all illustrated by the examples in the RainPro workspace.

N.B. RainPro is shipped with only the data hotspots enabled. FindSeries will work as described, but FindHotspot will not detect any captions, headings and so on. You can only change this setting at initialisation (before you call ch.Set for the first time after you last called ch.Close):

ch.SetDefault 'HO' 2  © all hotspots operative
ch.SetDefault 'HO' 0  © no hotspots at all

This is probably best run in an initialisation function in your workspace.