Add gaps to my stumpwm configuration

I had to copy in and redefine the ‘stumpwm::maximize-window’ function from the
‘swm-gaps’ package because for some reason ‘(frame-width ...)’ returns a ratio
on my machine (is it because high-dpi, or ultra-wide? I don't know) and not an
integer, which screws up the ‘(setf (xlib:drawable-width ...) ...)’ call.

oni/home/services/stumpwm.scm

@@ -2,9 +2,12 @@
   #:use-module ((gnu services configuration)
                 #:select (serialize-package
                           define-configuration))
+  #:use-module ((gnu packages lisp)
+                #:select (sbcl))
   #:use-module ((gnu packages wm)
                 #:select (stumpwm
-                          stumpish))
+                          stumpish
+                          sbcl-stumpwm-swm-gaps))
   #:use-module ((gnu home services)
                 #:select (service-type
                           service-extension
@@ -25,13 +28,19 @@
   (package
     (package stumpwm)
     "Package to use for setting Stumpwm")
+  (gaps-package
+   (package sbcl-stumpwm-swm-gaps)
+   "Package to use for setting Stumpwm Gaps")
   (stumpish-package
    (package stumpish)
    "Package to use for setting Stumpish"))
 
 (define (add-stumpwm-packages config)
-  (list (home-stumpwm-configuration-package config)
+  (list sbcl
-        (home-stumpwm-configuration-stumpish-package config)))
+        (home-stumpwm-configuration-package config)
+        (list stumpwm "lib")
+        (home-stumpwm-configuration-stumpish-package config)
+        (home-stumpwm-configuration-gaps-package config)))
 
 (define (home-stumpwm-config-files config)
   `(("stumpwm/config" ,(local-file "stumpwm/config"))))

oni/home/services/stumpwm/config

@@ -2,6 +2,7 @@
 (in-package :stumpwm-user)
 
 (require 'swank)
+(require 'swm-gaps)
 
 (set-prefix-key (kbd "s-x"))
 
@@ -76,6 +77,70 @@ after it has been unlocked."
             "%d "))
 (mode-line)
 
+;;; Redefine this function again because for some reason on my system
+;;; `(frame-width ...)' returns a ratio, not an integer, which is not accepted
+;;; by `xlib:drawable-width'.
+(defun stumpwm::maximize-window (win)
+  "Redefined gaps aware maximize function."
+  (multiple-value-bind (x y wx wy width height border stick)
+      (stumpwm::geometry-hints win)
+
+    (let ((ox 0) (oy 0) (ow 0) (oh 0)
+          (frame (stumpwm::window-frame win)))
+      (if (swm-gaps::apply-gaps-p win)
+          (multiple-value-setq (ox oy ow oh) (swm-gaps::gaps-offsets win)))
+
+      ;; Only do width or height subtraction if result will be positive,
+      ;; otherwise stumpwm will crash. Also, only modify window dimensions
+      ;; if needed (i.e. window at least fills frame minus gap).
+      (when (and (< ow width)
+                 (>= width (- (frame-width frame) ow)))
+        (setf width (- width ow)))
+      (when (and (< oh height)
+                 (>= height (- (frame-height frame) oh)))
+        (setf height (- height oh)))
+
+      (setf x (+ x ox)
+            y (+ y oy))
+
+      ;; This is the only place a window's geometry should change
+      (set-window-geometry win :x wx :y wy :width width :height height :border-width 0)
+      (xlib:with-state ((window-parent win))
+        ;; FIXME: updating the border doesn't need to be run everytime
+        ;; the window is maximized, but only when the border style or
+        ;; window type changes. The overhead is probably minimal,
+        ;; though.
+        (setf (xlib:drawable-x (window-parent win)) x
+              (xlib:drawable-y (window-parent win)) y
+              (xlib:drawable-border-width (window-parent win)) border)
+        ;; the parent window should stick to the size of the window
+        ;; unless it isn't being maximized to fill the frame.
+        (if (or stick
+                (find *window-border-style* '(:tight :none)))
+            (setf (xlib:drawable-width (window-parent win)) (window-width win)
+                  (xlib:drawable-height (window-parent win)) (window-height win))
+            (let ((frame (stumpwm::window-frame win)))
+              (setf (xlib:drawable-width (window-parent win)) (- (round (frame-width frame))
+                                                                 (* 2 (xlib:drawable-border-width (window-parent win)))
+                                                                 ow)
+                    (xlib:drawable-height (window-parent win)) (- (stumpwm::frame-display-height (window-group win) frame)
+                                                                  (* 2 (xlib:drawable-border-width (window-parent win)))
+                                                                  oh))))
+        ;; update the "extents"
+        (xlib:change-property (window-xwin win) :_NET_FRAME_EXTENTS
+                              (list wx
+                                    (- (xlib:drawable-width (window-parent win)) width wx)
+                                    wy
+                                    (- (xlib:drawable-height (window-parent win)) height wy))
+                              :cardinal 32))
+      (update-configuration win))))
+
+(setf swm-gaps:*head-gaps-size* 0)
+(setf swm-gaps:*inner-gaps-size* 15)
+(setf swm-gaps:*outer-gaps-size* 15)
+
+(swm-gaps:toggle-gaps-on)
+
 (restore-from-file "default")
 
 (define-frame-preference "Default"