New module: XMonad.Hooks.BorderPerWindow

CHANGES.md

@@ -16,6 +16,11 @@
     Put XMonad actions in the queue to be executed every time the
     `logHook` (or, alternatively, a hook of your choice) runs.
 
+  * `XMonad.Hooks.BorderPerWindow`
+
+    While XMonad provides config to set all window borders at the same
+    width, this extension defines and sets border width for each window.
+
 ### Bug Fixes and Minor Changes
 
   * `XMonad.Prompt`

XMonad/Hooks/BorderPerWindow.hs

@@ -0,0 +1,78 @@
+-----------------------------------------------------------------------------
+-- |
+-- Module      :  XMonad.Hooks.BorderPerWindow
+-- Description :  Set border width for each window in all layouts.
+-- Copyright   :  (c) 2021 Xiaokui Shu
+-- License     :  BSD-style (see LICENSE)
+--
+-- Maintainer  :  subbyte@gmail.com
+-- Stability   :  unstable
+-- Portability :  unportable
+--
+-- Want to customize border width, for each window on all layouts? Want
+-- specific window have no border on all layouts? Try this.
+-----------------------------------------------------------------------------
+
+module XMonad.Hooks.BorderPerWindow ( -- * Usage
+                                      -- $usage
+                                      defineBorderWidth
+                                    , actionQueue
+
+                                      -- * Design Considerations
+                                      -- $design
+                                    ) where
+
+
+import Graphics.X11.Xlib (Dimension)
+import XMonad
+import XMonad.Util.ActionQueue (enqueue, actionQueue)
+
+-- $usage
+--
+-- To use this module, first import it
+--
+-- > import XMonad.Hooks.BorderPerWindow (defineBorderWidth, actionQueue)
+--
+-- Then specify which window to customize the border of in your
+-- @manageHook@:
+--
+-- > myManageHook :: ManageHook
+-- > myManageHook = composeAll
+-- >     [ className =? "firefox"  --> defineWindowWidth 0
+-- >     , className =? "Chromium" --> defineWindowWidth 0
+-- >     , isDialog                --> defineWindowWidth 8
+-- >     ]
+--
+-- Finally, add the 'actionQueue' combinator and @myManageHook@ to your
+-- config:
+--
+-- > main = xmonad $ actionQueue $ def
+-- >     { ...
+-- >     , manageHook = myManageHook
+-- >     , ...
+-- >     }
+--
+-- Note that this module is incompatible with other ways of changing
+-- borders, like "XMonad.Layout.NoBorders".  This is because we are
+-- changing the border exactly /once/ (when the window first appears)
+-- and not every time some condition is satisfied.
+
+-- $design
+--
+-- 1. Keep it simple. Since the extension does not aim to change border setting
+--    when layout changes, only execute the border setting function once to
+--    avoid potential window flashing/jumping/scaling.
+--
+-- 2. The 'ManageHook' eDSL is a nice language for specifying windows. Let's
+--    build on top of it and use it to specify window to define border.
+
+defineBorderWidth :: Dimension -> ManageHook
+defineBorderWidth bw = do
+    w <- ask
+    liftX . enqueue $ updateBorderWidth w bw
+    idHook
+
+updateBorderWidth :: Window -> Dimension -> X ()
+updateBorderWidth w bw = do
+    withDisplay $ \d -> io $ setWindowBorderWidth d w bw
+    refresh

xmonad-contrib.cabal

@@ -168,6 +168,7 @@ library
                         XMonad.Doc.Configuring
                         XMonad.Doc.Developing
                         XMonad.Doc.Extending
+                        XMonad.Hooks.BorderPerWindow
                         XMonad.Hooks.CurrentWorkspaceOnTop
                         XMonad.Hooks.DebugEvents
                         XMonad.Hooks.DebugKeyEvents