Labels on TRoseSeries

[peterlepan]

Hi,

I have an TRoseSeries-chart and want to label the segments with labels. How can I position the labels with a larger margin and give them arrows so that every label points to its segment?
Is it possible to have a larger margin from the labels to the chart at the middle of the right and left side of the chart?
If I use Marks instead of the labels, the marks are positioned on my chart, the segments are partially hidden.

TRoseSeries with labels

rose.jpg (257.53 KiB) Viewed 9421 times

marks instead of the labels

marks.jpg (237.79 KiB) Viewed 9408 times

Kind regards

Peter

[Narcís]

Hi Peter,

How can I position the labels with a larger margin and give them arrows so that every label points to its segment?

It's a little bit tricky but possible with custom marks position as shown in the code snippet below. Also find attached the complete example project.

Code: Select all

procedure TForm1.CustomLabelsPosition;
const MarksOffset = 30;
var
  i : Integer;
  P : TPoint;
  Radius  : TPoint;
  Angle : TChartValue;
begin
  Radius:=TeePoint(Rose.XRadius + MarksOffset, Rose.YRadius + MarksOffset);
  
  for i:=0 to Rose.Marks.Positions.Count-1 do
  begin
    Angle:=DegToRad(Rose.AngleValues[i]);

    if Assigned(Rose.Marks.Positions[i]) then
    begin
      Rose.AngleToPos(Angle, Radius.X, Radius.Y, P.X, P.Y);
      Rose.Marks.Positions[i].Custom:=True;
      Rose.Marks.Positions[i].LeftTop.X:=P.X;
      Rose.Marks.Positions[i].LeftTop.Y:=P.Y;
      Rose.Marks.Positions[i].ArrowFrom.X:=P.X;
      Rose.Marks.Positions[i].ArrowFrom.Y:=P.Y;
    end;
  end;

  Rose.Repaint;
  Rose.RefreshSeries;
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
  Rose:=TRoseSeries.Create(Self);
  Rose.FillSampleValues(); 
  Rose.AngleLabels.Visible:=False;
  Rose.Marks.Visible:=True;
  //Rose.Marks.Transparent:=True;
  Rose.Marks.Arrow.Visible:=True;

  Chart1.ClipPoints:=False;
  Chart1.View3D:=False;
  Chart1.AddSeries(Rose);

  Chart1.Draw;
  CustomLabelsPosition;
  Chart1.Draw;
end;

Is it possible to have a larger margin from the labels to the chart at the middle of the right and left side of the chart?

Yes, you can modify that depending on angle values, for example:

Code: Select all

procedure TForm1.CustomLabelsPosition;
const MarksOffset = 30;
var
  i : Integer;
  P : TPoint;
  Radius  : TPoint;
  Angle : TChartValue;
begin
  Radius:=TeePoint(Rose.XRadius + MarksOffset, Rose.YRadius + MarksOffset);

  for i:=0 to Rose.Marks.Positions.Count-1 do
  begin
    Angle:=Rose.AngleValues[i];

    if (Angle<45) or ((Angle>135) and (Angle<225)) or (Angle>315) then
    begin
      Radius.X:=Radius.X + 5;
      Radius.Y:=Radius.Y + 5;
    end;

    Angle:=DegToRad(Angle);

    if Assigned(Rose.Marks.Positions[i]) then
    begin
      Rose.AngleToPos(Angle, Radius.X, Radius.Y, P.X, P.Y);
      Rose.Marks.Positions[i].Custom:=True;
      Rose.Marks.Positions[i].LeftTop.X:=P.X;
      Rose.Marks.Positions[i].LeftTop.Y:=P.Y;
      Rose.Marks.Positions[i].ArrowFrom.X:=P.X;
      Rose.Marks.Positions[i].ArrowFrom.Y:=P.Y;
    end;
  end;

  Rose.Repaint;
  Rose.RefreshSeries;
end;

[peterlepan]

Hi Narcís,
thank you for your answer, but the solutions are really "tricky".
If I use labels and position them with a large margin, the right half of the chart is very nice, but look at the left side! Why are the labels on the left side so confused? Can't they look like the labels on the right side?
Have you an idea for this problem? I wish my labels look like the beams from the sun and the chart is the sun

rose_label.jpg (291.85 KiB) Viewed 9364 times

Sincerely yours

Peter

[Narcís]

Hi Peter,

If I use labels and position them with a large margin, the right half of the chart is very nice, but look at the left side! Why are the labels on the left side so confused? Can't they look like the labels on the right side?
Have you an idea for this problem?

Can you please attach a simple example project we can run "as-is" to reproduce the problem here?

I wish my labels look like the beams from the sun and the chart is the sun

Thanks in advance.

[peterlepan]

Hi Narcís,

my problem was, that some of the labels where too long. Now, we have shorted the labels to three signs and it looks fine. The only caveat now is a little offset on top and bottom of the chart labels. Thats why the label text is left-aligned. Is it possible, to create an ideal cirlce from the labels?

With the new three-signed-labels, I need a legend beside the chart, with the complete label-text for the shortened label. How can I do this with the standard legend? Can I create a new invisible series with the long label texts and the three sign short labes? Or have I to print the legend by myself in the AfterDraw event handler?

Thank you

Peter

[Narcís]

Hi Peter,

Is it possible, to create an ideal cirlce from the labels?

I'm not sure about what you mean here. Could you please attach a simple example project we can run "as-is" to reproduce the problem here?

With the new three-signed-labels, I need a legend beside the chart, with the complete label-text for the shortened label. How can I do this with the standard legend? Can I create a new invisible series with the long label texts and the three sign short labes? Or have I to print the legend by myself in the AfterDraw event handler?

You can have the standard legend with the full text. You could shorten labels in the OnGetMarkText event. Alternatively, you could do something similar in the OnGetLegendText event. Another option is using the Custom Legend tool. You'll find an example at All Features\Welcome!\Tools\Custom Legend in the new features demo, available at TeeChart's program group.