AnnLayer Object

AnnLayer objects can be used to logically group common annotation objects. The AnnContainer object contains a collection of AnnObject's (AnnContainer.Children) and a collection of AnnLayer's (AnnContainer.Layers). The layers are organized in a parent/children tree collection with the main container defined as the root layer. The parent/children relationship controls the z-order of the objects in the layers and the various hit-test methods in the container. Automation takes z-ordering into consideration.

Each AnnObject in the container is also included in a layer in the same container (by default, they are added to the root layer, which is the container itself).

If required, a layer hierarchy can be created inside the container by performing the following steps:

• Use the AnnContainer.Create method to ceeate a new layer and then add it to the AnnContainer.Layers collection. This adds the layer to the default root layer in the container
• Alternatively, you can add the new layer to an existing layer as a child using the AnnLayer.Layers collection.
• Annotation objects that have already been added to the AnnContainer can then be added into any layer in the same container to group them logically using the AnnLayer.Children collection. Note that adding the object to a layer does not remove it from the main container.

After a layer hierarchy is created, use the following methods to manipulate the layers:

• Use AnnLayer.IsVisible to hide or show all of the objects in the layer.
• Use BringToFront and SendToBack to move objects up or down the z-order.

Any container can be designated as the active object in the container using AnnContainer.ActiveLayer. The active container is null by default, denoting the default layer in the container. When new objects in the container are drawn using automation, they are added to the active container.

The layer hierarchy is automatically saved and loaded using AnnCodecs.

For an example, refer to the AnnotationsLayerDemo in your LEADTOOLS setup.

Reference

AnnLayer Members
Leadtools.Annotations.Core Namespace