ACC2000: How to Get Red, Green, Blue Components from RGB Value

• Microsoft Access 2000

SUMMARY

This article shows you how to create a sample user-defined function, GetRGB(), that returns the red, green, or blue component from an RGB color value. Note that this behavior is the opposite of the Visual Basic for Applications function RGB().

MORE INFORMATION

RGB color values are mathematical combinations of red, green, and blue components. The intensities of these components can range from 0 to 255. For example, the RGB color value for white is 16777215, which has component intensities of 255 for red, green, and blue.

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1. Open the sample database Northwind.mdb.



2. Create a module and type the following line in the Declarations section if it is not already there:




Option Explicit 

3. Type the following procedures:




'-----------------------------------------------------------------
'PURPOSE: Returns red/green/blue color from RGB color value.
'
'ACCEPTS: RGB color value as Long, and component number as integer
'         that represents the component color to return (1=red,
'         2=green, 3=blue).
'
'RETURNS: The intensity of the color component (0 - 255) as an
'         integer or -1 indicating that an argument was invalid.
'-----------------------------------------------------------------

Function GetRGB(RGBval As Long, Num As Integer) As Integer
   ' Check if Num, RGBval are valid.
   If Num > 0 And Num < 4 And RGBval > -1 And RGBval < 16777216 Then
     GetRGB = RGBval \ 256 ^ (Num - 1) And 255
   Else
     ' Return True (-1) if Num or RGBval are invalid.
     GetRGB = True
   End If
End Function

'-----------------------------------------------------------------
'PURPOSE: Open the Orders form in Form view, call the GetRGB
'         function, and then switch the Orders form to Design view.
'
'ACCEPTS: RGB color value as Long, and component number as integer
'         that represents the component color to return (1=red,
'         2=green, 3=blue).
'
'RETURNS: Displays a message box with the RGB components
'         of the detail section of the Orders form.
'-----------------------------------------------------------------

Sub TestOrders()

   DoCmd.OpenForm "Orders", acNormal
   
   MsgBox "Red: " & GetRGB(Forms![Orders].Section(0).BackColor, 1) & _
          vbCrLf & _
          "Green: " &  GetRGB(Forms![Orders].Section(0).BackColor, 2) & _
          vbCrLf & _
          "Blue: " &   GetRGB(Forms![Orders].Section(0).BackColor, 3)

   DoCmd.OpenForm "Orders", acDesign
   
End Sub 

4. Save the module as MyUtilities.



5. On the Run menu, click Run Sub/UserForm.



6. From the Database window, click TestOrders, and then click Run.
   
   Note that you can change the BackColor property of the detail section of the Orders form, and then run the macro again to see the results change.

REFERENCES

For more information about the RGB function, in the Visual Basic Editor, click Microsoft Visual Basic Help on the Help menu, type "RGB function" in the Office Assistant or the Answer Wizard, and then click Search to view the topic.

Additional query words: inf video screen

Keywords : kbprg kbdta AccCon KbVBA
Version : WINDOWS:2000
Platform : WINDOWS
Issue type : kbhowto