Bitmap::MakeTransparent Method
Makes the default transparent color transparent for this Bitmap.
Assembly: System.Drawing (in System.Drawing.dll)
| Exception | Condition |
|---|---|
| InvalidOperationException | The image format of the Bitmap is an icon format. |
| Exception | The operation failed. |
The system palette defines one color as the default transparent, or alpha, color. This method makes the default transparent color transparent for this Bitmap. If no transparent color is specified by the system, LightGray is the transparent color.
When you call [M:System.Drawing.Bitmap.MakeTransparent(System.Drawing.Color]), 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 makes the system default transparent color transparent for myBitmap, and then draws the Bitmap to the screen.
private: void MakeTransparent_Example1( PaintEventArgs^ e ) { // Create a Bitmap object from an image file. Bitmap^ myBitmap = gcnew Bitmap( "Grapes.gif" ); // Draw myBitmap to the screen. e->Graphics->DrawImage( myBitmap, 0, 0, myBitmap->Width, myBitmap->Height ); // Make the default transparent color transparent for myBitmap. myBitmap->MakeTransparent(); // Draw the transparent bitmap to the screen. e->Graphics->DrawImage( myBitmap, myBitmap->Width, 0, myBitmap->Width, myBitmap->Height ); }
Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98
The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.