Public Sub SetOverlayImage( _
   ByVal index As Integer, _
   ByVal overlayImage As RasterImage, _
   ByVal mode As RasterGetSetOverlayImageMode _
) 

Visual Basic (Usage)	Copy Code
Dim instance As RasterImage Dim index As Integer Dim overlayImage As RasterImage Dim mode As RasterGetSetOverlayImageMode   instance.SetOverlayImage(index, overlayImage, mode)

public void SetOverlayImage( 
   int index,
   RasterImage overlayImage,
   RasterGetSetOverlayImageMode mode
)

public:
void SetOverlayImage( 
   int index,
   RasterImage^ overlayImage,
   RasterGetSetOverlayImageMode mode
) 

Parameters

index

The index of the overlay for which to set the image. This index is zero-based and should be less than or equal to MaxOverlays.

overlayImage

The new overlay image. This can be null (Nothing in Visual Basic), in which case the corresponding overlay image will be freed.

mode

Determines how to insert the image, possible values are:

Mode	Description
RasterGetSetOverlayImageMode.Copy	A copy of overlayImage is inserted in the overlay list.
RasterGetSetOverlayImageMode.NoCopy	overlayImage is set into the overlay list without making a copy. You should be careful when modifying overlayImage because you can modify/invalidate the entry in the overlay image list.
RasterGetSetOverlayImageMode.Move	overlayImage is moved into the overlay list. It will also be disposed, so you cannot make changes to it. This is recommended over RasterGetSetOverlayImageMode.NoCopy.

This method is available in the (Document/Medical only) Toolkits.

Calling this method with a valid image set in overlayImage frees the old overlay image at the specified index and sets the overlay image at the index to the new image referenced by overlayImage.

If overlayImage is null (Nothing in Visual Basic), the old overlay image is freed and the size is reset to:

            OverlayWidth = Image.ImageWidth - OverlayImage.Origin.X
            OverlayHeight = Image.ImageHeight - OverlayImage.Origin.Y

If mode is RasterGetSetOverlayImageMode.NoCopy and overlayImage is not null (Nothing), the image is inserted as is into the overlay array. This means whenever you update the data from overlayImage, the overlay image is changed too. Great care should be taken when using this flag because you can invalidate the overlay image stored in the array. For example, if you dispose the overlay image, the data pointed to by the overlay image from the internal array is also freed, but the array does not know that this has happened and thinks the data pointer is still valid. If the overlay image is accessed in some way, a crash will occur. A safer way of quickly setting the data is to use RasterGetSetOverlayImageMode.Move.

If mode is RasterGetSetOverlayImageMode.Move, the data from the overlayImage is copied into the overlay array and then the overlayImage object is disposed. This means that you can do anything with the overlayImage object and the overlay image stored in the array will be unaffected. This is the most efficient way of setting the overlay image, because no copy will take place.

overlayImage must reference an image that is 1-bit, overwise, this method will throw an exception.

For more information, refer to Overlay Overview.

Target Platforms: Silverlight, Windows XP, Windows Server 2003 family, Windows Server 2008 family, Windows Vista, Windows 7, MAC OS/X (Intel Only), Windows Phone 7

Reference