Merge pull request #28 from fvwmorg/ta/switchwindow

Cookbook/AltTab: SwitchWindow to use infostore

Wiki/CookBook/AltTab/index.md

@@ -8,27 +8,26 @@ tags:
 description: |
   Alt-Tab is a common key binding to switch between windows. In Fvwm
   there are lots of different variations on how to do this.
-
 ---
 
-## Switching focus between windows. (Alt-Tab)
+# Alt-Tab: Switching focus between windows.
 
-The default-config Alt-Tab binding in Fvwm looks like
+The default-config Alt-Tab binding in fvwm looks like:
 
 {% highlight fvwm %}
-Key Tab A M WindowList Root c c NoDeskSort, SelectOnRelease Meta_L
+Key Tab A M WindowList Root c c NoDeskSort, SelectOnRelease Meta_L, CurrentAtEnd
 {% endhighlight %}
 
-When Alt-Tab is hit a Menu appears that lists all the windows. As long
+When Alt-Tab is hit a menu appears that lists all the windows. As long
 as you hold down the Alt key, you can keep pressing tab to cycle through
-this Menu to select the window you want then release Alt to switch to that
-menu.
+this menu to select the window you want, then release Alt to switch to that
+window.
 
-Although WindowList can be configured a bit, not everyone
-wants a Menu to appear when one hits Alt-Tab. One
-simple solution to that is just use the Next and Prev conditionals
+Although `WindowList` can be configured a bit, not everyone
+wants a menu to appear when one hits Alt-Tab. One
+simple solution to that is just use the `Next` and `Prev` conditionals
 to switch between windows. For example if one wanted to switch between
-windows on the current Desktop, the following keybindings would work.
+windows on the current desktop, the following keybindings would work.
 
 {% highlight fvwm %}
 Key Tab A M Next (CurrentDesk, AcceptsFocus) Focus
@@ -38,10 +37,10 @@ Key Tab A SM Prev (CurrentDesk, AcceptsFocus) Focus
 This simple solution works but it may not completely achieve the affect you
 want. For example if you hit Alt-Tab again do you want to go back to your
 previous window or not? Do you want to move the pointer to the window
-that is selected? Do you want to DeIconify the window or Raise it? The Focus
-command only gives the window Focus, it doesn't alter the window list order,
-DeIconfiy, Raise, or even move the mouse pointer. All of this can be achieved
-with a more complex function:
+that is selected? Do you want to `DeIconify` the window or `Raise` it? The
+`Focus` command only gives the window focus, it doesn't alter the window
+list order, deiconify, raise, or even move the mouse pointer. All of this
+can be achieved with a more complex function:
 
 {% highlight fvwm %}
 # Custom Focus Function
@@ -62,40 +61,45 @@ that is more like you want. Next is another example that someone used
 because even this did not achieve the desired Alt-Tab experience the user
 wanted.
 
-## Another Alt-Tab Function
+# Another Alt-Tab Function
 
-I don't like the default behavior of FVWM's Alt-Tab key combination -- yes,
-the WindowList is useful, but it's not what I want to see when I want to
+I don't like the default behavior of fvwm's Alt-Tab key combination -- yes,
+the `WindowList` is useful, but it's not what I want to see when I want to
 focus other windows --- I prefer (dare I say it) functionality similar to
 MS-Windows.  I'd much rather be able to cycle windows. There's some
-suggestions in the main FVWM_FAQ about how to do this, although that still
-didn't quite emulate what I was after --- indeed, none of the solutions
+suggestions in the main fvwm FAQ about how to do this, although that still
+didn't quite emulate what I was after -- indeed, none of the solutions
 cycled back round to the first window. So, here's my solution to it.
 
 {% highlight fvwm %}
-SetEnv DIR Next
+InfoStoreAdd TabDir Next
 
-AddToFunc FocusRaiseAndStuff
+DestroyFunc FocusRaiseAndStuff
+AddToFunc   FocusRaiseAndStuff
 + I Iconify off
 + I Focus
 + I Raise
 
-AddToFunc SwitchWindow
-+ I $[DIR] (CurrentPage, !Iconic, !Sticky) FocusRaiseAndStuff
+DestroyFunc SwitchDirection
+AddToFunc   SwitchDirection
++ I Test (EnvMatch infostore.TabDir Next) InfoStoreAdd TabDir Prev
++ I TestRc (NoMatch) InfoStoreAdd TabDir Next
+
+DestroyFunc SwitchWindow
+AddToFunc   SwitchWindow
++ I $[infostore.TabDir] (CurrentPage, !Iconic, !Sticky) FocusRaiseAndStuff
 + I Deschedule 134000
-+ I PipeRead `[ "$[DIR]" == "Prev" ] && \
-    echo 'SetEnv NDIR Next' || \
-    echo 'SetEnv NDIR Prev'`
-+ I Schedule 700 134000 SetEnv DIR $[NDIR]
++ I Schedule 700 134000 SwitchDirection
 
 Key Tab A M  SwitchWindow
 {% endhighlight %}
 
-The SwitchWindow function does all the work. It might look elaborate, but all
-it is doing is flipping the value of Next and Prev into the DIR environment
-variable, so that if the last window is reached, it goes back to the first.
-The schedule command is used because without it, the focusing of windows
-gets confused -- so the delay via the Schedule commands ensures this isn't
-the case.  The caveat being that switching windows can be ever so slightly
-slow.
-
+This might look elaborate, but all it is doing is saving the direction
+conditional `Next` or `Prev` in the `InfoStore` variable TabDir. Then
+the SwitchWindow function cycles through the windows in the saved direction
+and starts a 700 millisecond timer via the `Schedule` command. If Alt-Tab
+is hit again before the timer goes of, the direction remains the same,
+the timer is stopped via the `Deschedule` command, and a new timer is started.
+Once the timer goes off, the SwitchDirection function changes which direction
+is saved in the TabDir variable, reversing the direction next time Alt-Tab
+is pressed.