[SOLVED] Troubles with TDataPointDragTool
lazarus / 55-TAChart

----------------------------------------------------------------------
CM630 · 2020-10-02 18:40

I am trying to fix a bug in a component that I have started to
write... 6 or 7 years ago, I have stopped woring on it 5 years ago, at
least.
Well, I tried to create a snippet, but I cannot make
TDataPointDragTool work in a standalone component.
I tried the ..\lazarus\components\tachart\demo\tools.
Dragging works for the two vertical bars, but it does not work for the
Chart1FuncSeries1 (I expect that should be able to move its points).
I have set the AffectedSered of ChartToolset1DataPointDragTool1 to
0,1,2,3 (it was 2,3).
What else should I do?

----------------------------------------------------------------------
wp · 2020-10-02 19:58

ChartFuncSeries1? No, you cannot drag its points, in fact, it does not
even have points, it is defined by a function defined by an event
handler.

----------------------------------------------------------------------
CM630 · 2020-10-04 08:34

Okay, I did:


Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i procedure
TForm1.FormCreate(Sender: TObject);begin  myLineSeries:=
TLineSeries.Create(Chart1) ;  myLineSeries.ShowPoints := True; 
myLineSeries.AddXY (0,-0.5);  chart1.AddSeries(myLineSeries); 
ChartToolset1DataPointDragTool1.AffectedSeries :=
ChartToolset1DataPointDragTool1.AffectedSeries + '0,1,2,3,4,5';end;  
Now I can move the quadrangle, drawn and teh single point of MySeries.


But besides that, sth. seems wrong- I have tried to add a LineSeries
in the GUI mode- the series was shown, but when I run the app it is
gone. (Laz ver etc are in my signature)/.

----------------------------------------------------------------------
wp · 2020-10-04 16:55

Did you add data points to the series? Normally you must do this at
runtime (even if the series is created at designtime -- ok, you could
use a TListChartSource where you can enter values in the DataPoints
property at designtime).

----------------------------------------------------------------------
CM630 · 2020-10-07 08:29

Maybe the image will expain it better than words:
On the left: what is shown in the IDE.
On the right : what happens when the app is executed.


Edit: I have just found sth. odd: When I save and close the project
and reload it- the values in the DataPoints are lost!
No surprise that they are not shown if the compiler does not see them
them saved.

----------------------------------------------------------------------
wp · 2020-10-07 15:42

In fact, I never used the interal listchartsource of a series for this
purpose. I guess the built-in source is not prepared for it, or maybe
there is a Clear somewhere. Debugging designtime code is always hard
stuff, so I am not very much motivated to begin...

What you can do is to add a separate TListChartSource to the form,
attach it to the LineSeries.Source, and add values to the DataPoints
property like you did with the internal ListChartSource. This works,
for sure -- see attachment.

----------------------------------------------------------------------
CM630 · 2020-10-09 12:26

Generally I do not use the design time editor for TAChart, I just
wanted to execute some simple snippet for sth. more complex, which I
have succeeded to fix.
But since you confirm that this is a bug, I will try to create a
report for it, in case that its time comes, or rather to know that
this is not working.

----------------------------------------------------------------------
wp · 2020-10-09 13:54

Quote from: CM630 on October 09, 2020, 02:26:01 pmBut since you
confirm that this is a bug, I will try to create a report for it, in
case that its time comes, or rather to know that this is not working.
Good idea. Assign it to me. Add a demo project and link also to this
discussion.

----------------------------------------------------------------------
CM630 · 2020-10-09 21:32

https://bugs.freepascal.org/view.php?id=37904
I am not sure, that I can assign bugs, currently it is unassigned.