Creating a "color scale" using vba (avoiding conditional formatting)

Question

I'm looking for a way to apply a color scale to a set of cells via VBA code but not by applying some conditional formatting... I want to apply them as static colors (InteriorColor)

I've searched plenty of excel sites, google and stackoverflow and found nothing :(

For my situation if you look at the following picture:

You can see I've given it a color scale, in this example though I have done the color scale via Conditional formatting. I want to create the color scale via VBA but it must avoid using conditional formatting, I want to assign interior colors to the cells so that the colors are static which makes them visible on all mobile excel viewers, faster, won't change if I was to remove any numbers/rows.

Here are some example data Just save it in a csv and open it in excel to see the data in excel :P:

Data 1 (Yes there are blanks),Data 2,Data 3,Data 4,Data 5,Data 6
155.7321504,144.6395913,1,-4,-9.3844,0.255813953
113.0646481,120.1609771,5,-2,-2.5874,0.088082902
126.7759917,125.3691519,2,0,-0.0004,0.107843137
,0,7,,,0.035714286
123.0716084,118.0409686,4,0,0.3236,0.118881119
132.4137536,126.5740362,3,-2,-3.8814,0.090909091
70,105.9874422,6,-1,-0.3234,0.103896104

I do use the following in python but obviously I can't use this code in VBA, the following code successfully assigns hex colors to the numbers from a predefined array of 50 colors so it's pretty accurate.

def mapValues(values):
    nValues = np.asarray(values, dtype="|S8")
    mask = (nValues != '')
    maskedValues = [float(i.split('%')[0]) for i in nValues[mask]]
    colorMap = np.array(['#F8696B', '#F86E6C', '#F8736D', '#F8786E', '#F97E6F', '#F98370', '#F98871', '#FA8E72', '#FA9373', '#FA9874', '#FA9E75', '#FBA376', '#FBA877', '#FBAD78', '#FCB379', '#FCB87A', '#FCBD7B', '#FCC37C', '#FDC87D', '#FDCD7E', '#FDD37F', '#FED880', '#FEDD81', '#FEE382', '#FEE883', '#FCEB84', '#F6E984', '#F0E784', '#E9E583', '#E3E383', '#DCE182', '#D6E082', '#D0DE82', '#C9DC81', '#C3DA81', '#BDD881', '#B6D680', '#B0D580', '#AAD380', '#A3D17F', '#9DCF7F', '#96CD7E', '#90CB7E', '#8ACA7E', '#83C87D', '#7DC67D', '#77C47D', '#70C27C', '#6AC07C', '#63BE7B'])
    _, bins = np.histogram(maskedValues, 49)
    try:
        mapped = np.digitize(maskedValues, bins)
    except:
        mapped = int(0)
    nValues[mask] = colorMap[mapped - 1]
    nValues[~mask] = "#808080"
    return nValues.tolist()

Anyone have any ideas or has anyone done this before with VBA.

Answer 1

The following function CalcColorScale will return a color given any two colors and the scale.The scale is the value of your current data relative to the range of data. e.g. if your data is from 0 to 200 then a data value 100 would be scale 50%(.5)

The image shows the result of scaling between red and blue

Public Sub Test()
    ' Sets cell A1 to background purple
    Sheet1.Range("A1").Interior.Color = CalcColorScale(rgbRed, rgbBlue, 0.5)
End Sub

' color1: The starting color as a long
' color2: The end color as a long
' dScale: This is the percentage in decimal of the color.
Public Function CalcColorScale(color1 As Long, color2 As Long, dScale As    Double) As Long

    ' Convert the colors to red, green, blue components
    Dim r1 As Long, g1 As Long, b1 As Long
    r1 = color1 Mod 256
    g1 = (color1 \ 256) Mod 256
    b1 = (color1 \ 256 \ 256) Mod 256

    Dim r2 As Long, g2 As Long, b2 As Long
    r2 = color2 Mod 256
    g2 = (color2 \ 256) Mod 256
    b2 = (color2 \ 256 \ 256) Mod 256

    CalcColorScale = RGB(CalcColorScaleRGB(r1, r2, dScale) _
                        , CalcColorScaleRGB(g1, g2, dScale) _
                        , CalcColorScaleRGB(b1, b2, dScale))
End Function

' Calculates the R,G or B for a color between two colors based the percentage between them
' e.g .5 would be halfway between the two colors
 Public Function CalcColorScaleRGB(color1 As Long, color2 As Long, dScale As Double) As Long
    If color2 < color1 Then
        CalcColorScaleRGB = color1 - (Abs(color1 - color2) * dScale)
    ElseIf color2 > color1 Then
        CalcColorScaleRGB = color1 + (Abs(color1 - color2) * dScale)
    Else
        CalcColorScaleRGB = color1
    End If
End Function