FvwmMFL - the Fvwm3 front-loader module
FvwmMFL can only be invoked by Fvwm3. Command line invocation of the
FvwmMFL will not work.
This module has no command-line options.
The
FvwmMFL module provides access to Fvwm events over a unix-domain
socket. This module is intended to provide externally-written programs
(clients) the ability to receive information from Fvwm and to perform an
action on that event.
The information from Fvwm3 is in the form of JSON packets. Each JSON packet has
different fields, depending on the type requested.
The default unix-domain socket for
FvwmMFL is
$TMPDIR/fvwm_mfl.sock, although this can be overridden via an
environment variable
FVWMMFL_SOCKET.
Commands can be sent to
FvwmMFL to control which information is sent the
client. The
set command is used for this. The table below shows which
events can be subscribed to.
| Event |
Description |
| new_window |
Fired when a new window is mapped and visible. |
| map |
Fired when a window is mapped. |
| configure_window |
Fired when a window is moved or resized. |
| destroy_window |
Fired when a window is closed. |
| new_page |
Fired when a new page is switched to. |
| new_desk |
Fired when a new desk is switched to. |
| raise_window |
Fired when a window is raised (or changes layer). |
| lower_window |
Fired when a window is lowered (or changed layer). |
| focus_change |
Fired when a window loses/gains focus. |
| enter_window |
Fired when a window has the pointer moved into it. |
| leave_Window |
Fired when a window has pointer moved out of it. |
| window_shade |
Fired when a window is shaded. |
| window_unshade |
Fired when a window is unshaded. |
| window_name |
Fired when the window name changes. |
| visible_name |
Fired when the visible window name changes. |
| res_class |
Fired when the class of the window is set. |
| res_name |
Fired when the resource of the window is set. |
| iconify |
Fired when a window is iconified. |
| deiconify |
Fired when a window is deiconified. |
| icon_name |
Fired when the icon name changes. |
| visible_icon_name |
Fired when the icon’s visible name changes. |
| icon_file |
Fired when the path to the icon changes. |
| icon_location |
Fired when the icon location changes. |
| restack |
Fired when the window stacking order changes. |
| echo |
Fired when Fvwm receives an Echo command. |
For example, to register an interest in
new_window and
focus_change, the following commands would be set via the socket:
set new_window
set focus_change
To remove interest in an event, use the
unset command:
Each packet sent to a client is in plain JSON. The information contained in each
packet varies depending on the event.
TODO: document each JSON structure.
The following example shows how to monitor for
focus_change events at the
shell, printing the JSON returned:
echo set focus_change | nc -U /tmp/fvwm_mfl.sock 2>&1 | jq --unbuffered
Outputs:
{ "focus_change": { "window": "0x5400022", "type": 0, "hilight": {
"text_colour": 16777215, "bg_colour": 32767 } } }
This module first appeared in 2020.