[RESOLVED] Drawing on UserControl with Transparent BackStyle.

I am trying to draw on a UserControl, but I want to have other regions apart from my drawing transparent, so the Background/Controls on the Form should be visible apart from my drawing when the UserControl is over them. As of now when I set the BackStyle Opaque the drawing is visible but when I change it to transparent it is not.

Code:

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Private Sub UserControl_Initialize()
UserControl.BackStyle = 0 '0=Transparent 1=Opaque
Line (200, 200)-(800, 800), RGB(0, 0, 0), BF
End Sub

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Easy enough, but there are limits to what you can do during a UserControl's Initialize event. For one thing the control isn't fully created yet, and even during InitProperties/ReadProperties it is not fully sited yet.

You can trap and do this during the first Show event and often in the Resize event. For example:

Code:

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Option Explicit

Private Sub Draw()
    AutoRedraw = True
    Cls
    FillStyle = vbFSTransparent
    DrawWidth = 1
    DrawStyle = vbDot
    Line (0, 0)-(ScaleWidth - 15, ScaleHeight - 15), vbRed, B
    DrawStyle = vbSolid
    DrawWidth = 3
    Line (180, 180)-(ScaleWidth - 180, ScaleHeight - 180), vbCyan, B
    DrawWidth = 7
    Line (420, 420)-(ScaleWidth - 420, ScaleHeight - 420), vbBlack
    FillStyle = vbDiagonalCross
    FillColor = vbBlue
    DrawWidth = 8
    Line (420, Int(ScaleHeight / 2))-(Int(ScaleWidth / 2), ScaleHeight - 420), vbYellow, B
    AutoRedraw = False
    Set MaskPicture = Image 'Render with mask transparency.
End Sub

Private Sub UserControl_Initialize()
    MaskColor = &HFEFEFE 'Some unique color we don't otherwise use.
    BackColor = MaskColor
End Sub

Private Sub UserControl_Resize()
    Draw
End Sub

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However even at best there are issues with this simple form of transparent rendering, such as interference with ClearType font rendering for many display drivers:

Attachment 158325

This works:

thinBasic Code:

Option Explicit
 
'--- design-time settings
'    UserControl.Windowless = True
'    UserControl.ClipBehaviour = 0-None
 
Private Sub UserControl_Initialize()
    UserControl.BackStyle = 0 '0=Transparent 1=Opaque
End Sub
 
Private Sub UserControl_Paint()
    Line (200, 200)-(800, 800), RGB(0, 0, 0), BF
End Sub
 
Private Sub UserControl_HitTest(X As Single, Y As Single, HitResult As Integer)
    HitResult = vbHitResultHit
End Sub

cheers,
</wqw>

Quote:

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Originally Posted by software07

...Controls on the Form should be visible apart from my drawing when the UserControl is over them. ...

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Quote:

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Originally Posted by wqweto

This works:
...
'--- design-time settings
' UserControl.Windowless = True
...

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I'm pretty sure that a Windowless control can't be drawn over other controls (other than other windowless controls) so doesn't quite work as the OP specified.

Quote:

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Originally Posted by dilettante

Easy enough, but there are limits to what you can do during a UserControl's Initialize event. For one thing the control isn't fully created yet, and even during InitProperties/ReadProperties it is not fully sited yet.

You can trap and do this during the first Show event and often in the Resize event. For example:

Code:

---

Option Explicit

Private Sub Draw()
    AutoRedraw = True
    Cls
    FillStyle = vbFSTransparent
    DrawWidth = 1
    DrawStyle = vbDot
    Line (0, 0)-(ScaleWidth - 15, ScaleHeight - 15), vbRed, B
    DrawStyle = vbSolid
    DrawWidth = 3
    Line (180, 180)-(ScaleWidth - 180, ScaleHeight - 180), vbCyan, B
    DrawWidth = 7
    Line (420, 420)-(ScaleWidth - 420, ScaleHeight - 420), vbBlack
    FillStyle = vbDiagonalCross
    FillColor = vbBlue
    DrawWidth = 8
    Line (420, Int(ScaleHeight / 2))-(Int(ScaleWidth / 2), ScaleHeight - 420), vbYellow, B
    AutoRedraw = False
    Set MaskPicture = Image 'Render with mask transparency.
End Sub

Private Sub UserControl_Initialize()
    MaskColor = &HFEFEFE 'Some unique color we don't otherwise use.
    BackColor = MaskColor
End Sub

Private Sub UserControl_Resize()
    Draw
End Sub

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However even at best there are issues with this simple form of transparent rendering, such as interference with ClearType font rendering for many display drivers:

Attachment 158325

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Thanks it worked perfectly.