imakeb(3G)

NAME
     imakeb - registers the screen background process

FORTRAN 77 SPECIFICATION
     subroutine imakeb

PARAMETERS
     none

DESCRIPTION
     imakeb registers a process that maintains the screen background.  Call it
     before winope.  The process should redraw the screen background each time
     it receives a REDRAW event.

     There is only one background so only one imakeb process can run at a
     time. Any existing imakeb process is killed when a new one is started.

     Because the X Window System's inability to change the mode (called the
     visual in xspeak) of a window conflicts with the GL's freedom to change
     modes at any time, imakebackground imakeb processes cannot paint on the
     real background (called the root window in xspeak).  Instead a new window
     is created with the correct visual. This window is kept at the bottom of
     the stack of windows just above the screen background. This
     imakebackground imakeb window works better when it is what in xspeak is
     called an override-redirect window. In simple terms this means the window
     is not managed by the window manager.

     A window that is managed is likely to be given borders by the window
     manager.  Currently only 4Dwm(1X) and mwm(1X) understand the request to
     turn off the borders. Also the window manager will post the usual window
     menu for a managed window. You cannot access the root menu.  A managed
     window is useful, however, when the imakebackground imakeb process is
     running in color map mode (see cmode(3G)). The window manager is the only
     process that can install the GL color map according to its own color map
     management policies so that the window is displayed correctly at the
     expected times.

     Because of this dichotomy, there is an X resource that controls whether
     or not the imakebackground imakeb window is managed.  The full resource
     class is

          Name.GL.GLBackground.Manage

     Name is the name of the window taken from the argument to winope The
     resource can have the values true or false. The default is false. In
     other words if the resource isn't specified the imakebackground imakeb
     window is not managed. We recommend using managed windows for cmode(3g)
     processes and non-managed windows for RGBmode(3g) processes. For example
     the following entries in the X resource database
          *GLBackground.Manage: false
          texback*GLBackground.Manage: true

     cause background windows to be unmanaged except for a background program
     called texback which is known to be a cmode(3g) program.

SEE ALSO
     winope

NOTE
     This routine is available only in immediate mode.