[RESOLVED] GetPixel/SetPixel Issue

I'm currently working on a user control, and I want to make the control appear transparent on any form is is placed. This line of thought lead me to try to obtain the background color of the form, pass it to the background color of my user control, and be done with it. Since I'm also using gradient coloring/bitmaps on the the form, I can't assume that the color of one location is going to work at a different location on the form. As a result, I figured that I would write a quick test app to try to use GetPixel from the parent.hDC and SetPixel on the usercontrol.

Unfortunately, I always get a CLR_INVALID from Get_Pixel and Set_Pixel regardless of which pixel I try to snag. Any ideas or suggestions for a better solution?

VB Code:

Private Sub UserControl_TestSub()
 
    Dim lhWnd           As Long
    Dim lDC             As Long
    Dim lGetPixel       As Long
    Dim lSetPixel       As Long
    
    lhWnd = GetParent(Me.hwnd)
    lDC = GetDC(lhWnd)
    
    lGetPixel = GetPixel(lDC, 0, 0)
    lSetPixel = SetPixel(Me.hdc, 0, 0, lGetPixel)
    
    Call SetPixel(Me.hdc, 0, 0, GetPixel(lDC, 0, 0))
    
    MsgBox lhWnd & " : " & Me.hwnd & " :: " & lDC & ": " & Me.hdc & " ::: " & lGetPixel & ", " & lSetPixel
End Sub

Quote:

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Originally Posted by Fedhax

Unfortunately, I always get a CLR_INVALID from Get_Pixel and Set_Pixel regardless of which pixel I try to snag. Any ideas or suggestions for a better solution?

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I forgot that GetPixel will only work on visible objects which means it won't work until the form is visible. However, is there any other way for the user control to know what kind of color it should be beside some kind of hack after the form has loaded?

VB Code:

UserCtrl.SetBgColor(GetPixel(Me.hDC,0,0)

why not set the Backstyle property of the usercontrol to transparent?
Then you can use the maskpicture and maskcolor properties if you want to.

Quote:

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Originally Posted by moeur

why not set the Backstyle property of the usercontrol to transparent?
Then you can use the maskpicture and maskcolor properties if you want to.

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Yeah, there was a reason that I wasn't using those properties, but as I thought about it, I simplified my control design so that these properties would work for me.

(And, since I'm still relatively new to creating custom controls, I sometimes forget that this kind of built-in functionality is there. :blush: )