You could use the FullExtent rather than the LogicalExtent to define the visible viewport of your scrolling chart. Maybe the attached demo gets close to what you need.
Many thanks. This works for one series. Unfortunately I have 8 different series and the user is free to select which ones to use and when to start them.
But I think the solution is:
- in the ChartToolsetZoomDragTool event "OnAfterMouseUp" one has this code
Extent:= Chart1.GetFullExtent;
Extent.a.x:= Extent.b.x - 20;
Chart1.Extent.FixTo(Extent);
When adding the next time a data point I need to "unfix" the extent. How can this be done?
Regarding your second question I refer to my recent answer (https://forum.lazarus.freepascal.org/index.php/topic,55110.msg409620.html#msg409620). I must confess that writing help files is very boring work, and I always put it away from me...
I always remember my teacher at school: "an undocumented feature will be an unused one". And he was right.
Well, I am an active developer of the program FreeCAD and meanwhile I became a Wiki master to document the features I wrote for FreeCAD. And I can see that the feature will first be used by normal users (non-developers) when it is described in our Wiki. Then questions arise, bugs are reported etc.
my trick is to document whenever I add a feature to avoid to collect to much docs works. When documenting other's work (e.g. at work) my trick is the same - every day a small part and after some weeks it is done without a stress feeling.