ArrowSeries

[jradke]

Hi!
To plot a time series of wind vectors I use TArrowSeries (see attached sample).
In order to point the arrowhead always to the respective time on the x-axis I draw the arrow inverted:

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AddArrow(x+dx,y+dy,x,y)

Unfortunately the OnGetMarkText event delivers wrong value for ValueIndex because it is related to x+dx instead of x.
My question: Is it possible to draw inverted arrows using AddArrow in the normal form:

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AddArrow(x,y,x+dx,y+dy)

Regards
Jürgen

[jradke]

Ok, meanwhile I have found out, that after creating a series the XValueList is sorted automatically.
By setting

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XValues.Order := loNone

everything works fine.

[Yeray]

Hello,

If I'm understanding you correctly, you can get your ArrowSeries' EndXValues at OnGetMarkText. Ie:

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uses VCLTee.ArrowCha, DateUtils;

procedure TForm1.FormCreate(Sender: TObject);
var x, dx: TDateTime;
    y, dy: double;
begin
  Chart1.View3D:=False;
  Chart1.Legend.Hide;

  x:=IncHour(Today, 10);
  dx:=DateTimeStep[dtOneHour];
  y:=10;
  dy:=1;

  Chart1.Axes.Left.SetMinMax(8, 13);
  Chart1.Axes.Bottom.SetMinMax(IncHour(x,-2), IncHour(x,3));

  with TArrowSeries(Chart1.AddSeries(TArrowSeries)) do
  begin
    AddArrow(x+dx,y+dy,x,y);
    //AddArrow(x,y,x+dx,y+dy);

    OnGetMarkText:=ArrowGetMarkText;
    Marks.Visible:=True;
    Marks.Style:=smsXValue;
  end;
end;

procedure TForm1.ArrowGetMarkText(Sender: TChartSeries; ValueIndex: Integer; var MarkText: string);
begin
  if (ValueIndex>-1) and (Sender is TArrowSeries) then
      MarkText:=FormatDateTime('hh:mm', TArrowSeries(Sender).EndXValues[ValueIndex]);
end;

[jradke]

Hello Yeray,
Thank you for your answer.
Indeed I am using the OnGetMarkText event to display some additional information that is stored in an external data array.
Therefore I needed the correct ValueIndex. By setting XValues.Order to loNone all values will remain at their original positions.

By the way:
How can I format the MarkText? I always get a shadowed silver rectangle with black font color, no matter how I set the Marks property of the series.

Regards.

[Yeray]

Hello,

How can I format the MarkText? I always get a shadowed silver rectangle with black font color, no matter how I set the Marks property of the series.

A simple example seems to work fine for me here:

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uses VCLTee.ArrowCha;

procedure TForm1.FormCreate(Sender: TObject);
begin
  Chart1.View3D:=False;
  Chart1.Legend.Hide;

  with TArrowSeries(Chart1.AddSeries(TArrowSeries)) do
  begin
    FillSampleValues(5);
    Marks.Visible:=True;
    Marks.Transparent:=False;
    Marks.Pen.Show;
    Marks.Pen.Color:=clRed;
    Marks.BackColor:=clGreen;
    Marks.Font.Color:=clWhite;
    Marks.Font.Size:=14;
  end;
end;

Project1_2019-12-10_14-12-48.png (10.49 KiB) Viewed 12436 times

If you still find problems with it, could you please arrange a simple example project we can run as-is to reproduce the problem here?
Thanks in advance.