Math Function Series

[Marcello]

Hi,

 I add in my charts series as trend lines (linear, logarithmic, polynomial,...). All work good but the best solution is show it as annotation that is not depending on a set of datapoints but that is draw on all current visible chart area (as a line annotation).

 Exists a strategy to draw a custom annotation (or other instrument) as a math function instead of a simple line?     

marc.

[Petar Marchev]

Hello Marcello,

If this information is somehow dependent on the horizonta/vertical axis values, this means that they are indeed data-dependent and I think it is a better choice to use a series to render this 'trend line'. Another option you have, but I wouldn't suggest you go with it, is to use the conversion api of the chart (ConvertDataToPoint method) and manually draw some polylines over the chart. These should be on top of the chart as separate UI elements and should not be part of the chart's visual tree. You will need to redraw them every time the size changes, the chart is zoomed and when the axes range change. I hope that you see that the second approach requires a bit more work, this is why I suggest you use a series for this purpose.

Regards,
Petar Marchev
Telerik