Provides function 'ads/maximize-window-vertically', plus a suggested key binding.

dot-emacs-snippet-maximize-window-vertically.el

;; SPDX-FileCopyrightText: <text> © 1985, 1989, 1992-1994, 2000-2020 Free Software Foundation, Inc.
;;     © 2020 Alan D. Salewski <ads@salewski.email> </text>
;;
;; SPDX-License-Identifier: GPL-3.0-or-later

;; This file IS NOT part of GNU Emacs, but it is derived from the function
;; `maximize-window', which IS part of GNU Emacs. At the time of writing
;; (2020-08-27) the `maximize-window' function is defined in the Emacs file
;; 'window.el':
;;
;;     https://git.savannah.gnu.org/cgit/emacs.git/tree/lisp/window.el
;;     Search for "(defun maximize-window "

;; Shamelessly borrowed (butchered?) from `maximize-window'; this is just like
;; it, but constrains its activity to the vertical dimension.
;;
(defun ads/maximize-window-vertically (&optional window)
  "Maximize WINDOW, only in the vertical dimension.
Make WINDOW as tall as possible without deleting any windows.
WINDOW must be a valid window and defaults to the selected one.

If the option `window-resize-pixelwise' is non-nil maximize
WINDOW pixelwise."
  (interactive)
  (setq window (window-normalize-window window))
  (window-resize window
                 (window-max-delta window nil nil nil nil nil window-resize-pixelwise)
                 nil ;; HORIZONTAL?
                 nil window-resize-pixelwise))

(global-set-key [?\C-c ?^] 'ads/maximize-window-vertically)