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Bitmap.MakeTransparent Method (Color)

Makes the specified color transparent for this Bitmap.

Namespace:  System.Drawing
Assembly:  System.Drawing (in System.Drawing.dll)

'Declaration
Public Sub MakeTransparent ( _
	transparentColor As Color _
)

Parameters

transparentColor
Type: System.Drawing.Color

The Color structure that represents the color to make transparent.

ExceptionCondition
InvalidOperationException

The image format of the Bitmap is an icon format.

Exception

The operation failed.

When you call MakeTransparent, the bitmap will be converted to the Format32bppArgb format, as this format supports an alpha channel.

The following code example is designed for use with Windows Forms, and it requires PaintEventArgs e, which is a parameter of the Paint event handler. The code performs the following actions:

  • Gets the color of a pixel in a Bitmap.

  • Makes that color transparent for the bitmap.

  • Draws the Bitmap to the screen.

Private Sub MakeTransparent_Example2(ByVal e As PaintEventArgs)

    ' Create a Bitmap object from an image file. 
    Dim myBitmap As New Bitmap("Grapes.gif")

    ' Draw myBitmap to the screen.
    e.Graphics.DrawImage(myBitmap, 0, 0, myBitmap.Width, _
        myBitmap.Height)

    ' Get the color of a background pixel. 
    Dim backColor As Color = myBitmap.GetPixel(1, 1)

    ' Make backColor transparent for myBitmap.
    myBitmap.MakeTransparent(backColor)

    ' Draw the transparent bitmap to the screen.
    e.Graphics.DrawImage(myBitmap, myBitmap.Width, 0, myBitmap.Width, _
        myBitmap.Height)
End Sub

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0, 1.1

.NET Framework Client Profile

Supported in: 4, 3.5 SP1
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