VBA: Extracting the RGB value of lines in a chart with default colors

Question

Problem

I would like to know how to read the current RGB value of an automatically assigned color in a chart, even if this entails freezing the colors to their current

Answer 1

So this is interesting. I create a line chart using all defaults, and then I run this procedure:

Sub getLineCOlors()
Dim cht As Chart
Dim srs As Series
Dim colors As String
Dim pt As Point

Set cht = ActiveSheet.ChartObjects(1).Chart

For Each srs In cht.SeriesCollection
    With srs.Format.Line
    colors = colors & vbCrLf & srs.Name & " : " & _
            .ForeColor.RGB
    End With

Next

Debug.Print "Line Colors", colors

End Sub

The Immediate window then displays:

Line Colors   
Series1 : 16777215
Series2 : 16777215
Series3 : 16777215

But this is clearly not the case. It is obvious that they all are different colors. If, instead of .RGB I do .ObjectThemeColor, then I get all 0, which is equally and demonstrably false by observing the chart!

Line Colors   
Series1 : 0
Series2 : 0
Series3 : 0

Now here is where it gets interesting:

If, after having created the chart I change the series colors (or even leave them unchanged, by assigning to the same ThemeColors), then the function shows valid RGBs:

Line Colors   
Series1 : 5066944
Series2 : 12419407
Series3 : 5880731

It is as if Excel (and PowerPoint/etc.) are completely unable to recognize the automatically assigned colors, on Line Charts. Once you assign a color, then it may be able to read the color.

NOTE: Line charts are picky, because you don't have a .Fill, but rather a .Format.Line.ForeColor (and .BackColor) and IIRC there are some other quirks, too, like you can select an individual point and change it's fill color, and then that affects the visual appearance of the preceding line segment, etc...

Is this limited to line charts? Perhaps. My past experience says "probably", although I am not in a position to say that this is a bug, it certainly seems to be a bug.

If I run a similar procedure on a Column Chart -- again using only the default colors that are automatically assigned,

Sub getCOlumnColors()

Dim cht As Chart
Dim srs As Series
Dim colors As String
Dim pt As Point

Set cht = ActiveSheet.ChartObjects(2).Chart

For Each srs In cht.SeriesCollection

    With srs.Format.Fill
    colors = colors & vbCrLf & srs.Name & " : " & _
            .ForeColor.RGB
    End With

Next

Debug.Print "Column Colors", colors

End Sub

Then I get what appear to be valid RGB values:

Column Colors 
Series1 : 12419407
Series2 : 5066944
Series3 : 5880731

HOWEVER: It still doesn't recognize a valid ObjectThemeColor. If I change .RGB then this outputs:

Column Colors 
Series1 : 0
Series2 : 0
Series3 : 0

So based on these observations, there is certainly some inability to access the ObjectThemeColor and/or .RGB property of automatically-assigned color formats.

As Tim Williams confirms, this was a bug as far back as 2005 at least as it pertains to the RGB, and probably that bug carried over in to Excel 2007+ with the ObjectThemeColor, etc... It is not likely to be resolved any time soon then, so we need a hack solution :)

UPDATED SOLUTION

Combine the two methods above! Convert each series from line to xlColumnClustered, then query the color property from the .Fill, and then change the series chart type back to its original state. This may be more reliable than trying to exploit the sequential indexing (which will not be reliable at all if the users have re-ordered the series, e.g., such that "Series1" is at index 3, etc.)

Sub getLineColors()
Dim cht As Chart
Dim chtType As Long
Dim srs As Series
Dim colors As String

Set cht = ActiveSheet.ChartObjects(1).Chart

For Each srs In cht.SeriesCollection
    chtType = srs.ChartType
    'Temporarily turn this in to a column chart:
    srs.ChartType = 51
    colors = colors & vbCrLf & srs.Name & " : " & _
            srs.Format.Fill.ForeColor.RGB
    'reset the chart type to its original state:
    srs.ChartType = chtType
Next

Debug.Print "Line Colors", colors

End Sub