How to have one axis for two series in TMS FNC Charts?

Question

I've built the following Chart that shows temperatures. It shows the lowest and highest temperatures for each day:

The issue I have is that there are two axis on the left and bottom. I want there to only be one left and one bottom.

How can this be achieved?

Let's take the bottom two axis as an example. They're both the exact same. I only need one. How can one be hidden or removed?

This is the code I use to make the chart:


procedure TForm1.Button1Click(Sender: TObject);
const
  CMin: array[1..31] of Double = (
    15, 16, 14, 13, 15, 17, 16, 14, 13, 12,
    15, 16, 18, 17, 16, 14, 15, 18, 19, 17,
    16, 15, 14, 13, 12, 14, 15, 17, 16, 15, 14
  );
  CMax: array[1..31] of Double = (
    28, 29, 30, 27, 26, 31, 32, 29, 28, 27,
    30, 31, 33, 32, 31, 29, 30, 33, 34, 32,
    31, 30, 29, 28, 27, 29, 30, 32, 31, 30, 29
  );
begin
    var lYear := 2025;
    var lMonth := 10;
    var lDaysInMonth := DaysInAMonth(lYear, lMonth);

    TemperatureChart.BeginUpdate;
    try
      TemperatureChart.Series.Clear;

      // Min series
      var sMin := TemperatureChart.Series.Add;
      sMin.LegendText := 'Min (�C)';
      sMin.XValues.MajorUnit := 1;
      sMin.XValues.MajorUnitFormat := '%.0f';
      sMin.YValues.MajorUnitFormat := '%.0f';

      // Max series
      var sMax := TemperatureChart.Series.Add;
      sMax.LegendText := 'Max (�C)';
      sMax.XValues.MajorUnit := 1;
      sMax.XValues.MajorUnitFormat := '%.0f';
      sMax.YValues.MajorUnitFormat := '%.0f';

      // Add points for each day of the selected month
      for var d := 1 to lDaysInMonth do
      begin
        with sMin.Points.Add do
        begin
          XValue := d;
          YValue := CMin[d];
        end;

        with sMax.Points.Add do
        begin
          XValue := d;
          YValue := CMax[d];
        end;
      end;

      // Update chart title
      var lMonthName := FormatDateTime('mmm', EncodeDate(lYear, lMonth, 1));
      TemperatureChart.Title.Text := Format('Temperature (Test Data) - %s %d', [lMonthName, lYear]);
    finally
      TemperatureChart.EndUpdate;
    end;
end;

Since I don't have any experience working with TMS FNC Charts I'm not sure about this. But after reading TMSFMXChartDevGuide I'm guessing this might be due the fact that by default AutoYRange is enabled meaning that the component needs to render two separate Y Axis. Set AutoYRange to arDisabled and then manually set both Y Axis min and max dimensions to match. You can check the example for displaying two chart series on page 30 of the above linked document. — SilverWarior
– SilverWarior, Commented Oct 27 at 16:30

Shaun Roselt · Accepted Answer · 2025-11-05 08:59:19Z

Short answer: You need to let only one series "own" the visible axes, and put both series on common ranges. Give the first series the left/bottom positions, then give the second series no positions so it won’t request extra axes.

You can add the following code to use the same left and bottom axis for both lines:

// Use common ranges and force single left/bottom axis positions
sMin.AutoYRange := arCommonZeroBased;
sMin.AutoXRange := arCommon;
sMin.YValues.Positions := [ypLeft];
sMin.XValues.Positions := [xpBottom];

// Share the same ranges; don't draw extra axes for this series
sMax.AutoYRange := arCommonZeroBased;
sMax.AutoXRange := arCommon;
sMax.YValues.Positions := [];
sMax.XValues.Positions := [];

Screenshot:

Full Fixed code:

procedure TForm1.Button1Click(Sender: TObject);
const
  CMin: array[1..31] of Double = (
    15, 16, 14, 13, 15, 17, 16, 14, 13, 12,
    15, 16, 18, 17, 16, 14, 15, 18, 19, 17,
    16, 15, 14, 13, 12, 14, 15, 17, 16, 15, 14
  );
  CMax: array[1..31] of Double = (
    28, 29, 30, 27, 26, 31, 32, 29, 28, 27,
    30, 31, 33, 32, 31, 29, 30, 33, 34, 32,
    31, 30, 29, 28, 27, 29, 30, 32, 31, 30, 29
  );
begin
    var lYear := 2025;
    var lMonth := 10;
    var lDaysInMonth := DaysInAMonth(lYear, lMonth);

    TemperatureChart.BeginUpdate;
    try
      TemperatureChart.Series.Clear;

      // Min series
      var sMin := TemperatureChart.Series.Add;
      sMin.LegendText := 'Min (°C)';
      sMin.XValues.MajorUnit := 1;
      sMin.XValues.MajorUnitFormat := '%.0f';
      sMin.YValues.MajorUnitFormat := '%.0f';
      // Use common ranges and force single left/bottom axis positions
      sMin.AutoYRange := arCommonZeroBased;
      sMin.AutoXRange := arCommon;
      sMin.YValues.Positions := [ypLeft];
      sMin.XValues.Positions := [xpBottom];

      // Max series
      var sMax := TemperatureChart.Series.Add;
      sMax.LegendText := 'Max (°C)';
      sMax.XValues.MajorUnit := 1;
      sMax.XValues.MajorUnitFormat := '%.0f';
      sMax.YValues.MajorUnitFormat := '%.0f';
      // Share the same ranges; don't draw extra axes for this series
      sMax.AutoYRange := arCommonZeroBased;
      sMax.AutoXRange := arCommon;
      sMax.YValues.Positions := [];
      sMax.XValues.Positions := [];

      // Add points for each day of the selected month
      for var d := 1 to lDaysInMonth do
      begin
        with sMin.Points.Add do
        begin
          XValue := d;
          YValue := CMin[d];
        end;

        with sMax.Points.Add do
        begin
          XValue := d;
          YValue := CMax[d];
        end;
      end;

      // Update chart title
      var lMonthName := FormatDateTime('mmm', EncodeDate(lYear, lMonth, 1));
      TemperatureChart.Title.Text := Format('Temperature (Test Data) - %s %d', [lMonthName, lYear]);
    finally
      TemperatureChart.EndUpdate;
    end;
end;

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