[fbpanel] hide on click

[Daniel G. <da...@ms...>]

Thanks very much for the auto-hide feature!

It occurred to me that sometimes it is also helpful to have panel hiding 
triggered by a mouse click. (The panel in KDE allows either autohiding 
or clicking on the sides of the panel to trigger hiding, for example.) I 
don't want to seem ungrateful for the work that went into fbpanel's 
autohide! So rather than just asking for hide-on-click to be added to 
fbpanel, I thought it would be proper to offer a workaround that can be 
used in the meantime to accomplish the same goal.

Here's a simple way to accomplish this with fbpanel:

This is based on wmctrl, "a UNIX/Linux command line tool to interact 
with an EWMH/NetWM compatible X Window Manager."  
(http://www.sweb.cz/tripie/utils/wmctrl/)

wmctrl can resize a window from the command line or from within a 
script. On my system, for example, the following command slides fbpanel 
almost completely off the screen to the left, leaving only a small 
region visible on the left of the screen: "wmctrl -r panel -e 
0,-1,-1,26,-1". (The "-r panel" identifies the fbpanel window by the 
title assigned to it by the window manager, while the "-e 0,-1,-1,26-1" 
indicates the new dimensions when the window is mostly hidden.) 
Similarly, the following command slides the fbpanel window back across 
the screen, making it fully visible: "wmctrl -r panel -e 
0,-1,-1,1305,26". I place each of these commands in their own files, 
labeled fbpanel_hide and fbpanel_show respectively. Of course these 
exact dimension may not work for you, depending on screen resolution, 
etc. You will have to experiment with the "wmctrl -e" parameters to find 
what works. ("man wmctrl" is helpful.)

The next step is to add two launchbar plugins to the ~/.fbpanel/default 
file. I place one launchbar plugin early in my default config file, so 
that the image associated with this plugin will appear on the leftmost 
portion of my panel. (So in my case I place my launchbar before the menu 
plugin.) Here's what it looks like

Plugin {
    type = launchbar
    config {
        button {
            image = ~/image_files/left_arrow.png
            tooltip = hide
            action = ~/fbpanel_hide
        }
    }
}

The second launchbar plugin needs to be near the end of the file, so 
that the image associated with it will be placed on the rightmost part 
of the panel:

 Plugin {
    type = launchbar
    config {
        button {
            image = ~/image-files/right_arrow.png
            tooltip = show
            action = ~/fbpanel_show
        }
    }
}

When you click on the left arrow ("hide"), wmctrl slides the panel all 
the way to the left, leaving only the right arrow visible. (The right 
arrow appears in the left corner of the screen.) Click the right arrow 
("show") and the panel is restored again. A nice touch is to make sure 
that when you restore the panel, the right arrow moves all the way off 
the right edge of the screen. This ensures that the "show" button will 
only appear when the panel is hidden.

All this works pretty well, but there is a complication that should be 
mentioned: On startup, fbpanel assigns the title "panel" to its window. 
When wmctrl resizes a window it does so by looking for the first window 
with a title that includes the string "panel." If some window other than 
fbpanel's has a title that includes "panel" then it may get resized when 
you press the hide or show buttons. I found this out when I was editing 
my ~/fbpanel/default file. I pressed the "hide" arrow on my panel and my 
xterm window disappeared! Why? Because I had the name of my current 
directory included in the window title for each of my xterms. Since my 
xterm window title -  "~/fbpanel" - includes the string "panel" it got 
resized instead of fbpanel's window.

There are a couple ways to deal with this problem. 

1) wmctrl lets you change the name of a window to something unique that 
is unlikely to be included in any other window title. E.g., "wmctrl -r 
panel -T use_a_unique_string_here" will allow you to direct the wmctrl 
window resize commands to a window called "use_a_unique_string_here." If 
you change "panel" to something unique right after fbpanel starts, then 
you can ensure that your window show and window hide commands always go 
to this unique window. 

2) A simpler and more direct approach is to modify the two lines in 
fbpanel's panel.c code that sets the window title to "panel."

    line 389: gtk_window_set_wmclass(GTK_WINDOW(p->topgwin), "panel", 
"fbpanel");
    line 390: gtk_window_set_title(GTK_WINDOW(p->topgwin), "panel");

Replace "panel" with your unique string, recompile fbpanel, and then you 
can direct your wmctrl resize commands to this unique window title 
without having to use wmctrl to rename the window.