Transparent contextmenustrip image margin

Currently the image margin is XP default blue.

any suggestions what is going wrong...

Code:

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Option Strict On

Imports System.Windows.Forms

Public Class ContextMenu
    Inherits ContextMenuStrip

    Public Sub New()
        Me.RenderMode = ToolStripRenderMode.ManagerRenderMode
        Me.Renderer = New Renderer
        Me.SetStyle(ControlStyles.SupportsTransparentBackColor, True)
        Me.BackColor = Color.Transparent
        Me.AllowMerge = True
    End Sub
End Class

Public Class Renderer
    Inherits ToolStripProfessionalRenderer

    Protected Overrides Sub OnRenderToolStripBorder(ByVal e As System.Windows.Forms.ToolStripRenderEventArgs)
        e.Graphics.DrawRectangle(Pens.Gainsboro, e.AffectedBounds)
    End Sub

    Protected Overrides Sub OnRenderMenuItemBackground(ByVal e As ToolStripItemRenderEventArgs)
        If e.Item.Selected Then
            Using sbr As New SolidBrush(Color.FromArgb(50, 0, 120, 255))
                e.Graphics.FillRectangle(sbr, e.Item.ContentRectangle)
            End Using
        End If
    End Sub
End Class

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example

http://gyazo.com/a40ea48e70be3e8f75a0f42759c717ca.png

Any one?

A gentle nudge

Wow why is this so hard? lol VB6 was so easy. Still not resolved. :)

Your code does not explain the problem directly, and the example image is too small on my screen to see exactly what the problem is. However, it looks like there are scruffy edges along the curves and sloping edges of your images. I have no experience with ToolStripProfessionalRenderer, but a quick look in msdn suggest that ImageMargin does not refer to the actual image edge but to a rectangular frame around the image bounds.

Scruffy edges are typically a product of anti-aliasing. It could happen if you use an image which has been anti-aliased against a given background colour. The mixed pixels around the image edge look transparent, but they remain opaque when you make the background color transparent. Even if those pixels really are partially transparent, transparent backgrounds in Windows Forms do not do alpha blending (partial transparency) and the effect will be similar. (I guess that was different in vb6, because I've heard people complain about transparency being "broken" in dotnet.)

However, the Graphics class is able to implement alpha blending in commands such as DrawImage. Assuming your edge pixels really are partially transparent, maybe you could deal with it when you draw the images. This is just guesswork on my part, but maybe you want to look into overriding the ToolStripProfessionalRenderer.OnRenderItemImage method.

BB

Hi BB, sorry the image was an example. When i drag a contexmenu on my form the default XP color sets the image margin blue. I want a context menu i can still add images but leave the image margin transparent.

Surely this can simply be over ridden by using Me.BackColor = Color.Transparent :/ you would of thought any way.

Quote:

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Originally Posted by freeblog

Surely this can simply be over ridden by using Me.BackColor = Color.Transparent :/ you would of thought any way.

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I've never done anything like that so don't really have a clue, I also don't have WinXP, but using Win7 I added this to your class,...

Code:

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Protected Overrides Sub OnRenderImageMargin(e As System.Windows.Forms.ToolStripRenderEventArgs)
    ' by disabling the line below the image margin is now transparent. (Win7 test only)
    'MyBase.OnRenderImageMargin(e)
End Sub

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For testing I did this and attached an image of what my menu looks like.

Code:

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Dim mymenu As New ContxtMenu ' < class name changed due to conflict.
mymenu.BackColor = Color.Coral
mymenu.Items.Add("Testing 123", My.Resources.eventlog.ToBitmap)
mymenu.Items.Add("Testing 456", My.Resources.eventlogInfo.ToBitmap)
mymenu.Items.Add("Testing 789", My.Resources.eventlogWarn.ToBitmap)
Me.ContextMenuStrip = mymenu

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The custom control now freezes VS. Also acts very odd. Clicking properties with the menu selected goes to a different controls properties. Any idea?

Even lead to VS removing a reference to my main user control. Would not appear in the intellisense. Coincidence? Hmm not sure.