Excel macro to fix overlapping data labels in line chart

Question

I am searching/trying to make a macro to fix the position of data labels in a line chart with one or multiple series collections so that they will not overlap each other.

I was thinking of some ways for my macro but when I try to make it I understand that this is way too hard for me and I get headache.

Is there anything that I missed? Do you know about such a macro?

Here's an example chart with overlapped data labels:

Here's an example chart where I manually fixed the data labels:

Answer 1

This task basically breaks down to two steps: access the Chart object to get the Labels, and manipulate the label positions to avoid overlap.

For the sample given all series are plotted on a common X-axis and the X values are sufficiently spread that labels don't overlap in this dimension. Therefore the solution offered only deals with groups of labels for each X point in turn.

Accessing the Labels

This Sub parses the chart and creates an array of Labels for each X point in turn

Sub MoveLabels()
    Dim sh As Worksheet
    Dim ch As Chart
    Dim sers As SeriesCollection
    Dim ser As Series
    Dim i As Long, pt As Long
    Dim dLabels() As DataLabel

    Set sh = ActiveSheet
    Set ch = sh.ChartObjects("Chart 1").Chart
    Set sers = ch.SeriesCollection

    ReDim dLabels(1 To sers.Count)
    For pt = 1 To sers(1).Points.Count
        For i = 1 To sers.Count
            Set dLabels(i) = sers(i).Points(pt).DataLabel
        Next
        AdjustLabels dLabels  ' This Sub is to deal with the overlaps
    Next
End Sub

Detect Overlaps

This calls AdjustLables with an array of Labels. These labels need to be checked for overlap

Sub AdjustLabels(ByRef v() As DataLabel)
    Dim i As Long, j As Long

    For i = LBound(v) To UBound(v) - 1
    For j = LBound(v) + 1 To UBound(v)
        If v(i).Left <= v(j).Left Then
            If v(i).Top <= v(j).Top Then
                If (v(j).Top - v(i).Top) < v(i).Height _
                And (v(j).Left - v(i).Left) < v(i).Width Then
                    ' Overlap!

                End If
            Else
                If (v(i).Top - v(j).Top) < v(j).Height _
                And (v(j).Left - v(i).Left) < v(i).Width Then
                    ' Overlap!

                End If
            End If
        Else
            If v(i).Top <= v(j).Top Then
                If (v(j).Top - v(i).Top) < v(i).Height _
                And (v(i).Left - v(j).Left) < v(j).Width Then
                    ' Overlap!

                End If
            Else
                If (v(i).Top - v(j).Top) < v(j).Height _
                And (v(i).Left - v(j).Left) < v(j).Width Then
                    ' Overlap!

                End If
            End If
        End If
    Next j, i
End Sub

Moving Labels

When an overlap is detected you need a strategy that move one or both labels without creating another overlap.
There are many possibilities here, you havn'e given sufficient details to judge your requirements.

Note about Excel

For this approach to work you need a version of Excel that has DataLabel.Width and DataLabel.Height properties. Version 2003 SP2 (and, presumably, earlier) does not.