OOF2: The Manual

4.2. The Layer List
	Chapter 4. The Graphics Window

4.2. The Layer List

The Layer List at the bottom of the Graphics Window contains one line for each Layer in the window. The Layers are listed in the opposite of the order in which they're drawn, so that the layers drawn last are at the top of the list. That is, Layers that are conceptually at the top of the display, obscuring the Layers below them, are listed at the top of the Layer List.

Figure 4.2 illustrates the components of the Layer List. Each line corresponds to a single Layer, and is made up of the following columns:

Show. A check button controlling whether or not the layer is actually drawn. If it's checked, the Layer is drawn on the canvas. If it's not checked, the Layer is invisible. Toggling the button invokes the Hide and Show commands in the Layer menu.
Freeze. When this check button is checked, the layer will not be automatically updated. Use this to display a Mesh at two different times, for example. Toggling the button invokes the Freeze and Unfreeze commands in the Layer menu.
What. The class (Image, Mesh, etc.) and name (in parentheses) of the object being displayed.
How. How the object is being displayed. This is the name of the Layer's DisplayMethod. The amount of extra detail provided for the DisplayMethod depends on the setting of the Long Layer Names entry in the OOF.Graphics_n.Settings menu.

Figure 4.2. The Layer List

Clicking on an entry in the Layer List (but not on one of the buttons in it) selects that Layer for further processing by commands in the Graphics Window's Layer menu. Control-clicking^[7] on a selected Layer will deselect it.

To rearrange the order of the Layers in the list, select a layer and use the Raise and Lower menus in the Layer menu. You can also right-click on a line in the Layer List and use the pop-up menu, which is identical to the Layer menu in the menu bar. The commands and their keyboard shortcuts are:

Raise
- One_Level (ctrl-R)
- To Top (ctrl-T)
- By
Lower
- One_Level (ctrl-L)
- To Top (ctrl-B)
- By

In normal operation, the Layer List actually doesn't show all of the Layers that are being displayed on the Canvas. This is because there are a lot of auxiliary Layers, for showing selections and other decorations, that would just clutter up the list. These Layers are called unlisted layers, and are indicated by thin nearly invisible horizontal lines in the list. The List All Layers command in the Settings menu governs whether or not the auxiliary Layers are listed.

The auxiliary layers are (from top to bottom in their standard order):

SkeletonNodeSelectionDisplay — selected Nodes
PinnedNodesDisplay — pinned nodes.
MoveNodeDisplay — Nodes being moved manually.
PixelInfoDisplay — the pixel being interrogated by the Pixel Info Toolbox.
SkeletonSegmentSelectionDisplay — selected Segments.
SkeletonIllegalElementDisplay — illegal Elements.
SkeletonInfoDisplay — the Node, Segment or Element being interrogated by the Skeleton Info Toolbox.
SelectedSkeletonBoundaryDisplay — the Skeleton boundary selected in the Skeleton Boundaries page.
MeshCrossSectionDisplay — cross sections for data output.
SkeletonElementSelectionDisplay — selected Elements.
A bitmap overlay for selected pixels.
A bitmap overlay for Active Areas.

^[7]Maybe command clicking. This seems to be system dependent.


Chapter 4. The Graphics Window		4.3. The Contour Map