Helm: Add custom helm-split-window-preferred-function

.emacs.d/lisp/init-evil-leader.el

@@ -24,6 +24,7 @@
   (evil-leader/set-key
    "p" 'emms-pause
    "n" 'emms-next))
+
 (with-eval-after-load 'init-helm
   (evil-leader/set-key
    "b" 'helm-mini

.emacs.d/lisp/init-exwm.el

@@ -10,7 +10,7 @@
 
 ;;; TODO: Pressing "s-a" ('emms-smart-browse) loses the cursor.
 ;;; Sometimes waiting helps.  Calling emms-smart-browse manually does not trigger the issue.
-;;; TODO: Spawn select programs in floating mode. (E.g. mpv, mupen64plus, mplayer, qemu, steam, .exe (wine).)
+;;; TODO: Spawn select programs in floating mode? (E.g. mpv, mupen64plus, mplayer, qemu, steam, .exe (wine).)
 ;;; TODO: Separate EXWM buffers and Emacs buffers in `helm-mini'?
 
 ;;; TODO: Rendering issue with Qutebrowser
@@ -98,7 +98,7 @@
 
 ;;; Web browser
 (with-eval-after-load 'helm
-  ;; TODO: When follow-mode is one, multiselection is broken.
+  ;; TODO: When follow-mode is on, multiselection is broken.
   ;; TODO: Default value should be last browser window.
   ;; TODO: kill-persistent is not persistent.
   (defvar exwm/helm-browser-map

.emacs.d/lisp/init-helm.el

@@ -54,6 +54,49 @@
  helm-window-show-buffers-function 'helm-window-mosaic-fn
  helm-window-prefer-horizontal-split t)
 
+;;; REVIEW: Windowing configuration is way complicated.  See
+;;; https://github.com/emacs-helm/helm/issues/1902.
+(defun helm-custom-display-buffer (buffer)
+  "Custom function to display `helm-buffer' BUFFER."
+  (display-buffer
+   buffer `(nil . ((window-height . ,helm-display-buffer-default-height)
+                   (window-width  . ,helm-display-buffer-default-width))))
+  (helm-log-run-hook 'helm-window-configuration-hook))
+(defun helm-split-window-combined-fn (window)
+  "Helm window splitting that combined most standard features.
+
+- With C-u, split inside. With C-u C-u, use same window.
+- Else use biggest other window when available.
+- Else split horizontally if width>height, vertically otherwise."
+  (cond
+   ((or (minibufferp helm-current-buffer)
+        (and
+         (not (one-window-p t))
+         (not (equal current-prefix-arg '(4)))
+         (not (equal current-prefix-arg '(16)))))
+    ;; Find biggest window.
+    (let (biggest (maxarea 0))
+      (dolist (w (window-list))
+        (unless (eq w (selected-window))
+          (let ((area (* (window-pixel-width w) (window-pixel-height w))))
+            (when (> area maxarea)
+              (setq maxarea area
+                    biggest w)))))
+      biggest))
+   ((equal current-prefix-arg '(16))
+    ;; Same window.
+    (selected-window))
+   (t
+    ;; If split inside or if unique window.
+    (split-window (selected-window) nil
+                  (if (> (window-pixel-width) (window-pixel-height))
+                      'right
+                    'below)))))
+(setq helm-display-function 'helm-custom-display-buffer
+      helm-split-window-preferred-function 'helm-split-window-combined-fn)
+
+
+
 ;;; From https://github.com/emacs-helm/helm/issues/362.
 ;;; This is not perfect with evil mode as the cursor type is not right in the
 ;;; header line and the evil cursor remains in the minibuffer.