How to follow data on graph? (by 10 point interval)

[timurgepard]

Hi guys!

Points of my graph is increasing, and at x axis I have time values.

I want to go only by 10 intervals visible on graph is it possible?

If there is default tool for that?

Like window following graph

[wp]

If you don't want to keep all data delete old data from the beginning of the series until you have at most 10 (or whatever) values:

Code: Pascal  [Select][+][-]

1. procedure TForm1.AddValueToSeries(ASeries: TChartSeries; x, y: Double);
2. const
3.   MAXCOUNT = 10;
4. begin
5.   ASeries.AddXY(x, y);
6.   while ASeries.Count > MAXCOUNT do
7.     ASeries.Listsource.Delete(0);
8. end;

If you want to keep data fix the axis range to show only the recent 10 intervals:

Code: Pascal  [Select][+][-]

1. procedure TForm1.AddValueToSeries(ASeries: TChartSeries; x,y: Double);
2. var
3.   MAXRANGE = .... // max axis range
4. begin
5.   ASeries.AddXY(x, y);
6.   Chart1.BottomAxis.Range.Max := x;
7.   Chart1.BottomAxis.Range.Min := x - MAXRANGE;
8.   Chart1.BottomAxis.Range.UseMax := true;
9.   Chart1.BottomAxis.Range.UseMin := true;
10. end;

 

[timurgepard]

Thank you Sir!

God Bless!

It is little bit hard to find those methods and options in documentation at first (from first glance)
Could you please show me where can I find those methods and options?

[wp]

http://wiki.lazarus.freepascal.org/TAChart_documentation

See also the tutorials:
http://wiki.lazarus.freepascal.org/TAChart#Documentation

There's no list of all methods and properties, though. You must study the sources. Hold the CTRL-Key down while clicking on the identifier "TChart" in your source code - this opens the main TAChart unit and you can navigate through all declarations. Also look at TAChartUtils, TASeries, TCustomSeries. etc.

[timurgepard]

Thank you!

I tried to find "Listsource" function

I looked at TAChart, with no restult
I looked at TASeries, with no restult
Then I decided to click on its own "Listsource" and found it in TACustomSeries.
But there is a problem, if I did not know how the function is called I would never have found it by myself... without your help.