Axis scaling and overlapping data

[norman]

Hi,

I've noticed an issue with the display of data when axis min/max's are not set to automatic.

I have added two custom axis to my chart with start and end positions of 100,50 and 50,0 respectively. When the page loads for the first time the axes min and max's are set to automatic (i.e. the scales automatically adjust to the min and max series values - see image1 - the blue series min is 120).

image1

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I have provided the end user with the ability to customize the axes min and max's, i.e. to allow them specify a min and/or max value to which to scale the axis. When the chart is redrawn I get data overlapping between the two series - see image2 - this is what happens when the blue axis min is set to 160. Note the blue series is now overlapping the red series.

image2

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To change the scale I set the blue axis Automatic property to false and then set the axis Minimum property to the desired value e.g. 160, for example:

Code: Select all

axis.AutomaticMinimum = False
axis.Minimum = 160

Is this correct? The desired effect I was expecting was that the first 3 points in the blue series would no longer be visible (see image3 which I edited to illustrate the desired result).

image3

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I’m using version 3.5.3371.26405 (i.e. framework 2.0 build 25th March).

Regards,

Norman

[Yeray]

Hi norman,

Have you seen the demo at All features\Welcome !\Axes\Opaque zones? You should find demos and tutorials at TeeChart programs group.

[norman]

Hi Yeray,

To be honest I hadn't. I expected that the functionality described would have been the default behaviour. I'm not sure in how many cases you'd want overlapping data when you've gone to the trouble of creating individual custom axes and assigning a single series to each.

I'll take a closer look.

Thanks,

Norman

[Yeray]

Hi Norman,

There are many customers who use custom axis, normally with a different distribution than yours, for whose enabling an "opaque zones" by default would broke their expected result.

Maybe it would be possible doing some previous distribution verifications, but every new verification has a little cost in performance.

[norman]

Hi Yeray,

I have manged to prevent the data overlapping using the code in the aforementioned example, thanks, however I have a related problem.

I have annotations attached to some points and if the points are hidden the annotations are still displayed (see below - image1 is before the chart is rescaled, image2 is after the chart is rescaled - note the annotation 'A' is still visible). I'd like to hide such annotations. Can you suggest how best to achieve this? Currently I position the annotations in the charts AfterDraw event after getting the location of the point to which to attach it to, e.g.:

Code: Select all

tmpX = ch(seriesIndex).CalcXPos(pointIndex)
tmpY = ch(seriesIndex).CalcYPos(pointIndex)
With annotation
   .Left = tmpX - (.Width / 2)
   .Top = tmpY - (.Height + 15)
   With .Callout
      .XPosition = tmpX
      .YPosition = tmpY
      .ZPosition = 0
   End With
End With

How can I determine if the annotation and callouts are outside/inside the rectangle formed by the series axes and hide/show them accordingly?

image1

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image2

image2.gif (5.99 KiB) Viewed 8541 times

Thanks,

Norman

[norman]

Hi,

Following my previous post I had a go at the following which seems to work:

Code: Select all

tmpX = ch(seriesIndex).CalcXPos(pointIndex)
tmpY = ch(seriesIndex).CalcYPos(pointIndex)

With annotation
   .Left = tmpX - (.Width / 2)
   .Top = tmpY - (.Height + 15)
   With .Callout
      .XPosition = tmpX
      .YPosition = tmpY
      .ZPosition = 0
   End With
End With

Dim left As Integer = ch.Series(seriesIndex).GetHorizAxis.IStartPos
Dim right As Integer = ch.Series(seriesIndex).GetHorizAxis.IEndPos
Dim top As Integer = ch.Series(seriesIndex).GetVertAxis.IStartPos
Dim bottom As Integer = ch.Series(seriesIndex).GetVertAxis.IEndPos

Dim rect As New Rectangle(left, top, right, bottom)
If Not rect.Contains(tmpX, tmpY) Then
   annotation.Active = False
End If

Can you confirm that this is the correct way to go?

Thanks,

Norman

[Yeray]

Hi Norman,

I can't see any difference between the two codes you posted. Anyway, adding this code in the AfterDraw event should hide your annotation when the point is out of its axis range:

Code: Select all

        If (TChart1(seriesIndex).YValues(pointIndex) < TChart1(seriesIndex).GetVertAxis.Minimum) Or (TChart1(seriesIndex).YValues(pointIndex) > TChart1(seriesIndex).GetVertAxis.Maximum) Then
            annotation.Active = False
        Else
            annotation.Active = True
        End If

[norman]

Hi,

Thanks for the reply.

Original code was:

Code: Select all

tmpX = ch(seriesIndex).CalcXPos(pointIndex)
tmpY = ch(seriesIndex).CalcYPos(pointIndex)

With annotation
   .Left = tmpX - (.Width / 2)
   .Top = tmpY - (.Height + 15)
   With .Callout
      .XPosition = tmpX
      .YPosition = tmpY
      .ZPosition = 0
   End With
End With

Revised code contained these additional lines

Code: Select all

Dim left As Integer = ch.Series(seriesIndex).GetHorizAxis.IStartPos
Dim right As Integer = ch.Series(seriesIndex).GetHorizAxis.IEndPos
Dim top As Integer = ch.Series(seriesIndex).GetVertAxis.IStartPos
Dim bottom As Integer = ch.Series(seriesIndex).GetVertAxis.IEndPos

Dim rect As New Rectangle(left, top, right, bottom)
If Not rect.Contains(tmpX, tmpY) Then
   annotation.Active = False
End If

where tmpX and tmpY are the coords of the point to which the annotation is attached.

Regards,

Norman

[Yeray]

Hi Norman,

Yes, this code looks nice.