IDCompositionVisual::AddVisual method (dcomp.h)

Adds a new child visual to the children list of this visual.

Syntax

HRESULT AddVisual(
  [in]           IDCompositionVisual *visual,
  [in]           BOOL                insertAbove,
  [in, optional] IDCompositionVisual *referenceVisual
);

Parameters

[in] visual

Type: IDCompositionVisual*

The child visual to add. This parameter must not be NULL.

[in] insertAbove

Type: BOOL

TRUE to place the new child visual in front of the visual specified by the referenceVisual parameter, or FALSE to place it behind referenceVisual.

[in, optional] referenceVisual

Type: IDCompositionVisual*

The existing child visual next to which the new visual should be added.

Return value

Type: HRESULT

If the function succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. See DirectComposition Error Codes for a list of error codes.

Remarks

Child visuals are arranged in an ordered list. The contents of a child visual are drawn in front of (or above) the contents of its parent visual, but behind (or below) the contents of its children.

The referenceVisual parameter must be an existing child of the parent visual, or it must be NULL. The insertAbove parameter indicates whether the new child should be rendered immediately above the reference visual in the Z order, or immediately below it.

If the referenceVisual parameter is NULL, the specified visual is rendered above or below all children of the parent visual, depending on the value of the insertAbove parameter. If insertAbove is TRUE, the new child visual is above no sibling, therefore it is rendered below all of its siblings. Conversely, if insertAbove is FALSE, the visual is below no sibling, therefore it is rendered above all of its siblings.

The visual specified by the visual parameter cannot be either a child of a single other visual, or the root of a visual tree that is associated with a composition target. If visual is already a child of another visual, AddVisual fails. The child visual must be removed from the children list of its previous parent before adding it to the children list of the new parent. If visual is the root of a visual tree, the visual must be dissociated from that visual tree before adding it to the children list of the new parent. To dissociate the visual from a visual tree, call the IDCompositionTarget::SetRoot method and specify either a different visual or NULL as the visual parameter.

A child visual need not have been created by the same IDCompositionDevice interface as its parent. When visuals from different devices are combined in the same visual tree, Microsoft DirectComposition composes the tree as it normally would, except that changes to a particular visual take effect only when IDCompositionDevice::Commit is called on the device object that created the visual. The ability to combine visuals from different devices enables multiple threads to create and manipulate a single visual tree while maintaining independent devices that can be used to commit changes asynchronously

This method fails if visual or referenceVisual is an invalid pointer, or if the visual referenced by the referenceVisual parameter is not a child of the parent visual. These interfaces cannot be custom implementations; only interfaces created by DirectComposition can be used with this method.

Examples

For an example, see How to Build a Simple Visual Tree.

Requirements

See also

IDCompositionDevice::CreateVisual

IDCompositionTarget::SetRoot

IDCompositionVisual

IDCompositionVisual::RemoveAllVisuals

IDCompositionVisual::RemoveVisual