By default only one overlay is created for each snapshot. To add more overlays,
the user must first open the Snapshot Window. To open the Snapshot window the
user can either double-click on the desired snapshot or can single-click to
select a snapshot and then select 'Open Selected' from the
'Snapshots' menu item.
After the Snapshot Window is open, the user can create an overlay by
pressing the 'New Overlay' button. Figure 2.3.1.3a illustrates
pressing the 'New Overlay' button.
Figure 2.4.1.3a: Creating an overlay
Newly created overlays are placed by default at the head of the overlay list.
The z-order can be changed after being created, described in section
2.4.1.4.1. Figure 2.3.1.3b displays
a newly created overlay.
Figure 2.4.1.3b: A newly created overlay
Once a user creates a new overlay, permissions for that overlay may need
to be set depending on its purpose. Permissions consist of viewing permissions,
who is allowed to see this overaly, and editing permission, who is allowed
to edit this overlay. By default only the user who created the overlay is
allowed to view and edit an overlay.
To change the permissions the user must first open the 'Edit Permissions'
dialog by selecting the desired overlay in the Snapshot Window and then pressing
the 'Edit Permissions' button. Figure 2.4.1.3c shows the initial dialog.
Figure 2.4.1.3c: Initial Edit Permissions Dialog
The current user and owner of the overlay is Student E and therefor is
not displayed in either of the classlists, as he will always have permissions
for both functions. To allow more users to view the overlay, the user first
selects the desired users from the view classlist, seen in Figure 2.4.1.3d.
To add the selected users the 'Left Arrow' button must then be pressed,
which will add the users to the 'View List', seen in Figure 2.4.1.3e.
Figure 2.4.1.3d: Selecting users from the classlist
Figure 2.4.1.3e: Users added to the View list
To allow other users to edit the overlay, the owner must include those users
to the 'Edit List'. The process is the same as the 'View List',
first select the desired users and then press the 'Left Arrow' button.
Figure 2.4.1.3f illustrates selecting users to give editing permission and
Figure 2.4.1.3g displays the 'Edit List' after the selected users
have been added.
Figure 2.4.1.3f: Selecting users from the classlist
Figure 2.4.1.3g: Users added to the Edit list
To remove user permissions the opposite technique can be used. To remove
view permissions the user first selects the desired users from the
'View List', seen in Figure 2.4.1.3h. The user then presses the
'Right Arrow' button, moving the users back to the classlist. The
result of the action can be seen in Figure 2.4.1.3i. The same actions can
be used to remove permissions for editting an overlay.
Figure 2.4.1.3h: Selecting users from the View list
