Question

用Tchart画曲线，想让曲线能动态地显示最新的一段曲线，之前的曲线向左移出。看delphi自带的demo，看不懂

这是自带的demo->Teechart->teebasic的例子，看不懂这一段，能否讲解一二
Function TDemoform.TheChart:TChart;
begin
with NoteBook1 do
result:=(Pages.Objects[PageIndex] as TPage).Controls[0] as TChart;
end;
procedure TDemoForm.Timer1Timer(Sender: TObject);
var t:Longint;
tmpX:Double;
begin
With NoteBook1 do
Case PageIndex of
0,3,4,6: With TheChart do
begin
for t:=0 to SeriesCount-1 do
With Series[t] do
begin
tmpX:=XValues[1]-XValues[0];
Delete(0);
AddXY( XValues.Last+tmpX,
YValues.Last+Random(100)-50,'',clTeeColor);
end;
end;
1,2,8: With TheChart do
begin
if (tmpTimes=-1) then
begin
tmpSeries:=Random(SeriesCount);
tmpIndex :=Random(Series[tmpSeries].Count);
tmpTimes :=Random(10);
tmpRandom:=2*Round(Random(50)-25.0);
end;
if tmpSeries<>-1 then
begin
if PageIndex=8 then
With (Series[tmpSeries] as TBubbleSeries) do
begin
tmpX:=RadiusValues[tmpIndex]+tmpRandom;
if tmpX>=2 then
begin
RadiusValues[tmpIndex]:=tmpX;
if tmpRandom>0 then tmpX:=XValues[tmpIndex]+1
else tmpX:=XValues[tmpIndex]-1;
XValues[tmpIndex]:=tmpX;
if Random(10)<5 then tmpX:=YValues[tmpIndex]+50
else tmpX:=YValues[tmpIndex]-50;
YValues[tmpIndex]:=tmpX;
end
else tmpTimes:=0;
end
else
With Series[tmpSeries].MandatoryValueList do
Value[tmpIndex]:=Value[tmpIndex]+tmpRandom;
Dec(tmpTimes);
Repaint;
end;
end;
5: (TheChart[0] as TPieSeries).Rotate(358);
end;
end;

Answer 1

这个是所有Chart的刷新，你只要看 page0，也就是底下这段。

原理是先删掉曲线第一笔的资料，再从後面插一笔新的，所以X轴数值要一直递增，

如果你要让X轴参数固定，可能先排在阵列里处理过，再餵到series 会比较好作。

  Case PageIndex of
     0,3,4,6:  
         With TheChart do
         begin
            for t:=0 to SeriesCount-1 do
            With Series[t] do         //指定绘制的曲线
            begin
               tmpX:=XValues[1]-XValues[0];  //取得X轴数值间隔
               Delete(0);                    //删除曲线的第一笔数据
               AddXY(                        //插入新的数据，会自动放在最後
                     XValues.Last+tmpX,     //设定X轴数值 
                     YValues.Last+Random(100)-50, //设定Y轴数值
                     '',                          //Label 
                     clTeeColor);                 //曲线颜色  
            end;
        end;
     ...