Real-time charting in TeeChart VCL（VCL TeeChart之实时图表）

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Real-time charting in TeeChart VCL

Choose correct series type

Disable/hide some chart elements

// Prepare chart for maximum speed:
with Chart1 do
begin
ClipPoints := False;
Title.Visible := False;
Legend.Visible := False;
LeftAxis.Axis.Width:=1;
BottomAxis.Axis.Width:=1;
BottomAxis.RoundFirstLabel := False;
View3D := False;
end;

// Number of points we'll be displaying
MaxPoints:=10000;
// Number of points deleted when scrolling chart
ScrollPoints := 5000;

// Prepare series.
// Disable AutoRepaint and X Order

// AutoRepaint=False means "real-time" drawing mode.
// Points are displayed just after adding them,
// without redrawing the whole chart.
Series1.AutoRepaint := False;

// Set Ordering to none, to increment speed when adding points
Series1.XValues.Order := loNone;

// Initialize axis scales
// we're assuming left axis values are within [0,1000]
Chart1.LeftAxis.SetMinMax(0,10000);
Chart1.BottomAxis.SetMinMax(1,MaxPoints);

// Speed tips:

// When using only a single thread, disable locking:
Chart1.Canvas.ReferenceCanvas.Pen.OwnerCriticalSection := nil;
Series1.LinePen.OwnerCriticalSection := nil;

// For Windows NT, 2000 and XP only:
// Speed realtime painting with solid pens of width 1.
Series1.FastPen := True;

// Set axis calculations in "fast mode".
// Note: For Windows Me and 98 might produce bad drawings when
//       chart zoom is very big.
Chart1.Axes.FastCalc := True;

Populate series with data

// Adds a new random point to Series
Procedure RealTimeAdd(Series:TChartSeries);
var XValue,YValue : Double;
begin
if Series.Count=0 then  // First random point
begin
YValue:=Random(10000);
XValue:=1;
end
else
begin
// Next random point
YValue:=Series.YValues.Last+Random(10)-4.5;
XValue:=Series.XValues.Last+1;
end;
// Add new point
Series.AddXY(XValue,YValue);
end;

// When the chart is filled with points, this procedure
// deletes and scrolls points to the left.
Procedure DoScrollPoints(Series: TChartSeries);
var tmp,tmpMin,tmpMax : Double;
begin
// Delete multiple points with a single call.
// Much faster than deleting points using a loop.

Series.Delete(0,ScrollPoints);

// Scroll horizontal bottom axis
tmp := Series.XValues.Last;
Series.GetHorizAxis..SetMinMax(tmp-MaxPoints+ScrollPoints,tmp+ScrollPoints);

// Scroll vertical left axis
tmpMin := Series.YValues.MinValue;
tmpMax = Series.YValues.MaxValue;

Series.GetVertAxis.SetMinMax(tmpMin-tmpMin/5,tmpMax+tmpMax/5);

// Do chart repaint after deleting and scrolling
Application.ProcessMessages;
end;

Var X,Y : Array of Double;   // TChartValues
t   : Integer;
Num : Integer;
begin
{ 1M points }
Num:= 1000000;

{ allocate our custom arrays }
SetLength(X,Num);
SetLength(Y,Num);

{ fill data in our custom arrays }
X[0]:=0;
Y[0]:=Random(10000);
for t:=1 to Num-1 do
begin
X[t]:=t;
Y[t]:=Y[t-1]+Random(101)-50;
end;

{ set our X array }
With Series1.XValues do
begin
Value:=TChartValues(X);  { <-- the array }
Count:=Num;               { <-- number of points }
Modified:=True;           { <-- recalculate min and max }
end;

{ set our Y array }
With Series1.YValues do
begin
Value:=TChartValues(Y);
Count:=Num;
Modified:=True;
end;

{ Show data }
Series1.Repaint;

Conclusion