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TeeChart provides comprehensive axis customization capabilities for controlling the appearance, behavior, and positioning of chart axes.

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Overview

Axes are fundamental components that define the coordinate system and scale of your charts. TeeChart supports:
  • Standard axes (Left, Right, Top, Bottom)
  • Custom axes for multi-axis charts
  • Depth axes for 3D charts
  • Automatic and manual scaling
  • Custom labels and formatting

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Key Classes

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TChartAxis

The main axis class that controls all axis properties and behavior. Location: TeEngine.pas Key Properties:
  • Minimum, Maximum - Axis scale range
  • Increment - Distance between labels
  • Visible - Show/hide axis
  • Grid - Grid line properties
  • MinorGrid - Minor grid lines
  • LabelsFont - Label font properties
  • Title - Axis title text and format
  • Automatic - Auto-calculate scale
  • AutomaticMinimum, AutomaticMaximum - Auto-calculate min/max individually

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Basic Axis Configuration

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Setting Axis Scale

// Manual scale
Chart1.LeftAxis.Automatic := False;
Chart1.LeftAxis.Minimum := 0;
Chart1.LeftAxis.Maximum := 100;

// Auto scale with manual minimum
Chart1.LeftAxis.AutomaticMaximum := True;
Chart1.LeftAxis.Minimum := 0;

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Custom Axis Labels

Use the OnGetAxisLabel event to customize axis label text and formatting: 
procedure TForm1.Chart1GetAxisLabel(
  Sender: TChartAxis; 
  Series: TChartSeries; 
  ValueIndex: Integer; 
  var LabelText: String);
var 
  Num: Double;
begin
  Num := StrToFloat(LabelText);
  
  if Sender = Chart1.Axes.Left then
  begin
    if Num > 300 then 
      Sender.LabelsFont.Color := clRed
    else 
      Sender.LabelsFont.Color := clBlue;
  end;
end;
Source: Axis_LabelsFormat.pas:29

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Minor Grid Lines

Display additional grid lines between major ticks: 
Chart1.BottomAxis.MinorGrid.Visible := True;
Chart1.BottomAxis.MinorTickCount := 3;
Source: Axis_MinorGrid.pas:35

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Custom Axes

Create additional axes for multi-scale charts: 
// Access existing custom axes
Chart1.CustomAxes[0].Visible := True;

// Use partner axes for synchronized scaling
Chart1.LeftAxis.UsePartnerAxis := True;
Chart1.LeftAxis.PartnerAxis := Chart1.CustomAxes[1];

Chart1.BottomAxis.UsePartnerAxis := True;
Chart1.BottomAxis.PartnerAxis := Chart1.CustomAxes[0];

// Custom axes can also partner with each other
Chart1.CustomAxes[2].PartnerAxis := Chart1.CustomAxes[3];
Chart1.CustomAxes[3].PartnerAxis := Chart1.CustomAxes[2];
Source: Axis_Custom.pas:48

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Clipping to Axis Area

Restrict series drawing to axis boundaries: 
procedure TForm1.Series1BeforeDrawValues(Sender: TObject);
var 
  Series: TChartSeries;
  Left, Top, Right, Bottom: Double;
  R: TRect;
begin
  Series := TChartSeries(Sender);
  
  Left := Series.GetHorizAxis.Minimum;
  Top := Series.GetVertAxis.Maximum;
  Right := Series.GetHorizAxis.Maximum;
  Bottom := Series.GetVertAxis.Minimum;
  
  R := Rect(
    Series.CalcXPosValue(Left), 
    Series.CalcYPosValue(Top),
    Series.CalcXPosValue(Right),
    Series.CalcYPosValue(Bottom)
  );
  
  Chart1.Canvas.ClipRectangle(R);
end;

procedure TForm1.Series1AfterDrawValues(Sender: TObject);
begin
  Chart1.Canvas.UnClip;
end;
Source: Axis_Custom.pas:74

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Advanced Features

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Grid Band Centering

Center grid lines between data points: 
Chart1.Axes.Left.GridCentered := True;
Source: Axis_GridBandCentered.pas:37

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Logarithmic Axes

Chart1.LeftAxis.Logarithmic := True;
Chart1.LeftAxis.LogarithmicBase := 10;

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DateTime Axes

Chart1.BottomAxis.DateTimeFormat := 'dd/mm/yyyy hh:nn';
Chart1.BottomAxis.LabelStyle := talValue;

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Axis Items

Manually define axis labels: 
Chart1.BottomAxis.Items.Clear;
Chart1.BottomAxis.Items.Add(0, 'January');
Chart1.BottomAxis.Items.Add(1, 'February');
Chart1.BottomAxis.Items.Add(2, 'March');

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Configuration Options

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Label Position

// Position labels
Chart1.LeftAxis.LabelsOnAxis := True;  // Labels on axis line
Chart1.LeftAxis.LabelsSeparation := 10; // Pixels between labels and axis

// Alternate label positions
Chart1.BottomAxis.AlternateLabels := True;

// First and last labels
Chart1.BottomAxis.RoundFirstLabel := False;

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Axis Line Style

// Axis line appearance
Chart1.LeftAxis.Axis.Visible := True;
Chart1.LeftAxis.Axis.Width := 2;
Chart1.LeftAxis.Axis.Color := clBlack;

// Ticks
Chart1.LeftAxis.Ticks.Visible := True;
Chart1.LeftAxis.Ticks.Length := 5;
Chart1.LeftAxis.TicksInner.Visible := True;

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Multi-Line Axis Titles

Chart1.LeftAxis.Title.Caption := 'Temperature' + #13 + '(Celsius)';
Chart1.LeftAxis.Title.Angle := 90; // Vertical text

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Common Use Cases

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Financial Charts (Dual Axes)

Price on left axis, volume on right axis: 
PriceSeries.VertAxis := aLeftAxis;
VolumeSeries.VertAxis := aRightAxis;

Chart1.LeftAxis.Title.Caption := 'Price ($)';
Chart1.RightAxis.Title.Caption := 'Volume';
Chart1.RightAxis.Visible := True;

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Scientific Data (Isometric View)

Maintain equal scaling on both axes: 
Chart1.Axes.IsometricView := True;

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Time Series

Optimize for time-based data: 
Chart1.BottomAxis.DateTimeFormat := 'hh:nn:ss';
Chart1.BottomAxis.Increment := DateTimeStep[dtOneMinute];
Chart1.BottomAxis.ExactDateTime := True;

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Real-Time Charts

Optimize axis calculations for performance: 
// Fast axis calculation mode
Chart1.Axes.FastCalc := True;

// Manual axis range for scrolling
Chart1.BottomAxis.Automatic := False;
Chart1.BottomAxis.SetMinMax(StartTime, EndTime);
Source: FastLine_Realtime.pas:99

Series Types

Different chart series types

Real-Time Data

High-performance real-time charting

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