FvwmBacker(1) Fvwm Modules FvwmBacker(1)

NAME

FvwmBacker - the fvwm background changer module

SYNOPSIS

Module FvwmBacker

FvwmBacker can only be invoked by fvwm. Command line invocation of
the FvwmBacker module will not work.

DESCRIPTION

The FvwmBacker module provides functionality to change the background
when changing desktops. Any command can be executed to change the
backgrounds. Actually, any arbitrary command can be sent to fvwm to
execute, so you could also do things such as changing window border
colors, etc.

COPYRIGHTS

The FvwmBacker module is the original work of Mike Finger.

Copyright 1994, Mike Finger. The author makes no guarantees or
warranties of any kind about the use of this module. Use this module
at your own risk. You may freely use this module or any portion of
it for any purpose as long as the copyright is kept intact.

INITIALIZATION

During initialization, FvwmBacker gets config info from fvwm's module
configuration database (see fvwm(1), section MODULE COMMANDS).
Available options are discussed in a later section.

INVOCATION

FvwmBacker can be invoked by fvwm during initialization by inserting
the line

AddToFunc StartFunction I Module FvwmBacker

in the .fvwm2rc file.

FvwmBacker can be started using a 'Module FvwmBacker' command or
stopped using a 'KillModule FvwmBacker' command at any time when fvwm
is running.

FvwmBacker must reside in a directory that is listed in the
ModulePath option of fvwm for it to be executed by fvwm.

CONFIGURATION OPTIONS

The following options can be placed in the .fvwm2rc file


*FvwmBacker: Command (Desk d, Page x y) command
Specifies the command to execute when the viewport matches the
arguments for the desk d, page x coordinate and y coordinate.
Any or all of these three numeric arguments can be replaced
with an asterisk (*) to indicate that any value matches, in
this case Desk or Page parts can be skipped.

If either the Desk or the Page parts are omitted, the command
is not executed if only the desk or the page is switched. If
neither is given, the command is executed only once when the
module is started. This is not the same as using asterisks
for the numeric arguments: if asterisks are used, the command
is always executed when only the desk or page changes, if the
corresponding part is omitted, the command is never executed
when only the desk or page changes.

If the command is -solid FvwmBacker uses the next argument as
a color in the X database and sets the background to that
color without generating a system call to xsetroot (only
single word color names may be used).

If the command is colorset FvwmBacker uses the background
specified in colorset n for the given desk. Please refer to
the fvwm man page for details about colorsets.

Otherwise the command is sent to fvwm to execute.


*FvwmBacker: RetainPixmap
Causes FvwmBacker to retain and publish the Pixmap with which
the background has been set. This works only for the -solid or
colorset commands. This is useful for applications which want
to use the root Pixmap on the background to simulate
transparency (for example, Eterm and Aterm use this method).
This option should also be used for the RootTransparent
colorset option. Note: with a colorset background this
command may add a lot of memory to the X server. For example,
this adds the pixmap width times height bytes with a
TiledPixmap image, screen_width times screen_height bytes with
a Pixmap image or a C,B,D,R,S or Y Gradient and screen_width
bytes with a VGradient or screen height bytes with an
HGradient.


*FvwmBacker: DoNotRetainPixmap
Cancels the effect of the previous option. This is the
default.


RUN-TIME CONFIGURATION
It it possible to replace FvwmBacker's configuration at run-time,
although it is not yet possible to remove existing configuration
lines. This is done by simply removing the old configuration from
within fvwm and then read a new one. This can be done in many ways,
for example by using an fvwm function or one of the modules
FvwmCommand or FvwmConsole.

Example:


DestroyModuleConfig FvwmBacker*
*FvwmBacker: Command (Desk 0) -solid black
*FvwmBacker: Command (Desk 1) -solid blue


OLD-STYLE OPTIONS
There is continued support for the now deprecated option:


*FvwmBacker: Desk d command

It is functionally equivalent to omitting the page coordinates
with *FvwmBacker: Command:


*FvwmBacker: Command (Desk Id) command

SAMPLE CONFIGURATION

The following are excerpts from an .fvwm2rc file which describe
FvwmBacker initialization commands:


####
# Set Up Backgrounds for different desktop pages (2 desks, 3x2 pages).
####
*FvwmBacker: Command (Page 2 *) -solid steelblue
*FvwmBacker: Command (Desk 0, Page 0 0) Exec fvwm-root $[HOME]/bg2.xpm
*FvwmBacker: Command (Desk 0, Page 0 1) -solid midnightblue
*FvwmBacker: Command (Desk 0, Page 1 *) -solid yellow
*FvwmBacker: Command (Desk 1, Page * 0) -solid navy
*FvwmBacker: Command (Desk 1, Page * 1) Colorset 5

AUTHOR

Mike Finger (mfinger@mermaid.micro.umn.edu)
(Mike_Finger@atk.com)
(doodman on IRC, check the #linux channel)

Modified by
Andrew Davison (davison@cs.monash.edu.au)

Michael Han (mikehan@best.com)

Mikhael Goikhman (migo@homemail.com)

3rd Berkeley Distribution 19 October 2022 (2.7.0) FvwmBacker(1)