Finding optimal Min Max Axis after zooming

[Guilz]

Hi,

How can I implement a function to find optimal min max axis after zooming ?
I use SetMinMax function but it does not work, the max value of my serie (for current zoom range) is not on the top of the max axis

Code: Select all

 
Private Sub AxTChart_OnZoom(ByVal sender As Object, ByVal e As System.EventArgs) Handles AxTChart.OnZoom
Dim Min As Double
Dim Max As Double

Min = AxTChart.Series(0).MinVisibleValue(1)
Max = AxTChart.Series(0).MaxVisibleValue(1)
AxTChart.Axis.Left.SetMinMax(Min, Max)
End Sub

zoom00.jpg (101.52 KiB) Viewed 11276 times

zoom01.jpg (77.79 KiB) Viewed 11272 times

Thanks for your help (I did not found any topic about this )

Guilz

[Narcís]

Hi Guilz,

You could do something as the local minimum and maximum example suggested here. You could use series' FirstVisibleIndex and LastVisibleIndex as first and last arguments. This is a TeeChart .NET thread but same should apply to ActiveX version.

Hope this helps.

[Yeray]

Hi Guilz,

Alternatively, you could try forcing a chart repaint before using the MinVisibleValue and MaxVisibleValue functions. Something like:

Code: Select all

AxTChart.Environment.InternalRepaint

[Guilz]

Hi Yeray,

Code: Select all

AxTChart.Environment.InternalRepaint

is working fine with 1 serie but...
let's consider my new example:

zoom02.jpg (225 KiB) Viewed 11269 times

Code: Select all

    Private Sub AxTChart_OnZoom(ByVal sender As Object, ByVal e As System.EventArgs) Handles AxTChart.OnZoom
        Dim Min As Double = 99999999
        Dim Max As Double = -99999999

        AxTChart.Environment.InternalRepaint()
        For i = 0 To AxTChart.SeriesCount - 1
            If AxTChart.Series(i).MinVisibleValue(1) < Min Then
                Min = AxTChart.Series(i).MinVisibleValue(1)
            End If
            If AxTChart.Series(i).MaxVisibleValue(1) > Max Then
                Max = AxTChart.Series(i).MaxVisibleValue(1)
            End If

        Next

        AxTChart.Axis.Left.SetMinMax(Min, Max)
    End Sub

And the result is not correct as bellow...

zoom03.jpg (202.96 KiB) Viewed 11266 times

How can take in account the left and right axis ?

Thanks for your help...

Guilz

[Yeray]

Hi Guliz,

In that case I'm afraid you should control the full zoom manually as in the example Narcis suggested.
If you find problems with it, don't hesitate to let us know.

[Guilz]

Yeray,

I'm afraid Zoomed Event does not exist in Teechart v8....

Could you give us a sample code in VB to do that because the topic is confusing...
(A simple example with 2 differents axis (left and right) and 1 serie associated to right axis and another one to left axis) with the method to fit exactly the 2 series to the zoomed area will be very usefull !

Thanks a lot for us

Guilz

[Yeray]

Hi Guilz,

Finally, it wasn't so trivial...
I've made the example with Point series because it's easier (with Line series you may also want to consider the line segments, not only the points in the area selected)

Code: Select all

Dim MouseDownX, MouseDownY, MouseUpX, MouseUpY As Integer

Private Sub Form_Load()
  TeeCommander1.ChartLink = TChart1.ChartLink
   
  TChart1.Legend.Visible = False
  TChart1.Aspect.View3D = False
  
  Dim i As Integer
  For i = 0 To 1
    TChart1.AddSeries scPoint
    TChart1.Series(i).FillSampleValues 100
    TChart1.Series(i).asPoint.Pointer.VerticalSize = 2
    TChart1.Series(i).asPoint.Pointer.HorizontalSize = 2
    
    If i Mod 2 = 0 Then
      TChart1.Series(i).VerticalAxis = aRightAxis
    End If
  Next i

  TChart1.Axis.Left.GridPen.Visible = False
End Sub

Private Sub TChart1_OnMouseDown(ByVal Button As TeeChart.EMouseButton, ByVal Shift As TeeChart.EShiftState, ByVal X As Long, ByVal Y As Long)
  MouseDownX = X
  MouseDownY = Y
End Sub

Private Sub TChart1_OnMouseUp(ByVal Button As TeeChart.EMouseButton, ByVal Shift As TeeChart.EShiftState, ByVal X As Long, ByVal Y As Long)
  MouseUpX = X
  MouseUpY = Y
End Sub

Private Sub TChart1_OnZoom()
  With TChart1.Axis.Left
    .SetMinMax .CalcPosPoint(MouseUpY), .CalcPosPoint(MouseDownY)
  End With
  With TChart1.Axis.Right
    .SetMinMax .CalcPosPoint(MouseUpY), .CalcPosPoint(MouseDownY)
  End With

  TChart1.Environment.InternalRepaint

  Dim TopPos, BottomPos, tmp, offset As Integer
  offset = 2
  TopPos = -1
  BottomPos = -1
  Dim i, j As Integer
  For i = 0 To TChart1.SeriesCount - 1
    For j = TChart1.Series(i).FirstValueIndex To TChart1.Series(i).LastValueIndex - 1
      tmp = -1
      If TChart1.Series(i).VerticalAxis = aLeftAxis Then
        If TChart1.Series(i).YValues.Value(j) <= TChart1.Axis.Left.Maximum And TChart1.Series(i).YValues.Value(j) >= TChart1.Axis.Left.Minimum Then
          tmp = TChart1.Axis.Left.CalcYPosValue(TChart1.Series(i).YValues.Value(j))
        End If
      ElseIf TChart1.Series(i).VerticalAxis = aRightAxis Then
        If TChart1.Series(i).YValues.Value(j) <= TChart1.Axis.Right.Maximum And TChart1.Series(i).YValues.Value(j) >= TChart1.Axis.Right.Minimum Then
          tmp = TChart1.Axis.Right.CalcYPosValue(TChart1.Series(i).YValues.Value(j))
        End If
      End If
      
      If tmp <> -1 Then
        If TopPos = -1 Or tmp < TopPos Then
          TopPos = tmp
        End If
        If BottomPos = -1 Or tmp > BottomPos Then
          BottomPos = tmp
        End If
      End If
    Next j
  Next i

  If BottomPos <> -1 And TopPos <> -1 Then
    TChart1.Axis.Left.SetMinMax TChart1.Axis.Left.CalcPosPoint(BottomPos + offset), TChart1.Axis.Left.CalcPosPoint(TopPos - offset)
    TChart1.Axis.Right.SetMinMax TChart1.Axis.Right.CalcPosPoint(BottomPos + offset), TChart1.Axis.Right.CalcPosPoint(TopPos - offset)
  End If
End Sub

[Guilz]

Hi Yeray,

Thanks a lot for your reply - it is working like a charm

In my case, I have added the code bellow at the begining of TChart1_OnZoom procedure

Code: Select all

  If TChart1.Zoom.Direction = tzdHorizontal Then
        MouseDownY = TChart1.Axis.Left.IStartPos
        MouseUpY = TChart1.Axis.Left.IEndPos
  End If

to ensure it will be working even if user change the zoom direction property (both->tzdHorizontal)

Regards,

Guilz

[Yeray]

Hi Guilz,

I'm glad to hear that!