├── LICENSE ├── README.org ├── screenshots ├── demo.gif ├── with-overlay.png └── without-overlay.png ├── window-stool-window.el └── window-stool.el /LICENSE: -------------------------------------------------------------------------------- 1 | GNU GENERAL PUBLIC LICENSE 2 | Version 3, 29 June 2007 3 | 4 | Copyright (C) 2007 Free Software Foundation, Inc. 5 | Everyone is permitted to copy and distribute verbatim copies 6 | of this license document, but changing it is not allowed. 7 | 8 | Preamble 9 | 10 | The GNU General Public License is a free, copyleft license for 11 | software and other kinds of works. 12 | 13 | The licenses for most software and other practical works are designed 14 | to take away your freedom to share and change the works. By contrast, 15 | the GNU General Public License is intended to guarantee your freedom to 16 | share and change all versions of a program--to make sure it remains free 17 | software for all its users. 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It is safest 630 | to attach them to the start of each source file to most effectively 631 | state the exclusion of warranty; and each file should have at least 632 | the "copyright" line and a pointer to where the full notice is found. 633 | 634 | 635 | Copyright (C) 636 | 637 | This program is free software: you can redistribute it and/or modify 638 | it under the terms of the GNU General Public License as published by 639 | the Free Software Foundation, either version 3 of the License, or 640 | (at your option) any later version. 641 | 642 | This program is distributed in the hope that it will be useful, 643 | but WITHOUT ANY WARRANTY; without even the implied warranty of 644 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 645 | GNU General Public License for more details. 646 | 647 | You should have received a copy of the GNU General Public License 648 | along with this program. If not, see . 649 | 650 | Also add information on how to contact you by electronic and paper mail. 651 | 652 | If the program does terminal interaction, make it output a short 653 | notice like this when it starts in an interactive mode: 654 | 655 | Copyright (C) 656 | This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'. 657 | This is free software, and you are welcome to redistribute it 658 | under certain conditions; type `show c' for details. 659 | 660 | The hypothetical commands `show w' and `show c' should show the appropriate 661 | parts of the General Public License. Of course, your program's commands 662 | might be different; for a GUI interface, you would use an "about box". 663 | 664 | You should also get your employer (if you work as a programmer) or school, 665 | if any, to sign a "copyright disclaimer" for the program, if necessary. 666 | For more information on this, and how to apply and follow the GNU GPL, see 667 | . 668 | 669 | The GNU General Public License does not permit incorporating your program 670 | into proprietary programs. If your program is a subroutine library, you 671 | may consider it more useful to permit linking proprietary applications with 672 | the library. If this is what you want to do, use the GNU Lesser General 673 | Public License instead of this License. But first, please read 674 | . 675 | -------------------------------------------------------------------------------- /README.org: -------------------------------------------------------------------------------- 1 | * window-stool-mode 2 | A minor mode to show code context for code above the window similar to the excellent context.vim plugin. 3 | Like a little stool for your window that you can use to view stuff in the buffer above the window. 4 | 5 | Using only indentation means we can use this in non treesitter based modes as well, but I'm not 6 | against adding some treesitter support (I just need to find time to dig into the treesitter api) 7 | 8 | It can be a little janky at times, since I had to do some hacky things with overlays since headerline doesn't 9 | support multiple lines. Essentially on every scroll, we have to move the overlay to go back to the top of the 10 | screen so it acts like a pseudo multi-line header-line. 11 | It works pretty well with my usage of mostly golang and elisp. 12 | 13 | Also has some support for org mode as well. 14 | 15 | Primarily tested on emacs29 with doom and with vanilla. 16 | 17 | ** Motivation 18 | I really liked context.vim when I was using vim and I couldn't really find something that fit exactly. 19 | 20 | I used some of the other packages like the breadcrumb headerline of lsp mode, which-function-mode and 21 | topsy, but they weren't quite the same. 22 | 23 | * Installation 24 | 25 | With emacs 29 we have built in package-vc-install 26 | #+begin_src elisp 27 | (package-vc-install "https://github.com/JasZhe/window-stool") 28 | #+end_src 29 | 30 | With straight: 31 | #+begin_src elisp 32 | (straight-use-package 33 | '(window-stool :type git :host github :repo "jaszhe/window-stool")) 34 | #+end_src 35 | 36 | With doom: 37 | #+begin_src elisp 38 | (package! window-stool :recipe (:host github :repo "jaszhe/window-stool" :files ("*.el"))) 39 | #+end_src 40 | 41 | Add a hook to prog-mode (or any other mode) with a use-package config 42 | #+begin_src elisp 43 | (use-package window-stool 44 | :config 45 | (add-hook 'prog-mode-hook #'window-stool-mode)) 46 | #+end_src 47 | 48 | * Customization options 49 | =window-stool-face= - the overlay will inherit this face if you want to change from the default =fringe= inheritance with =:extend t= 50 | 51 | =window-stool-n-from-top= and =window-stool-n-from-bottom= - optionally limit the amount of context to show. The default is to take the first context line from the outer most context, (this is usually the function signature, for example) and then 2 lines of the inner most context (like the most recent if statement you just passed by) 52 | 53 | =window-stool-major-mode-functions-alist= - a list of (major-mode . function) for specific context rules outside of the basic indentation based one. An org one is provided as an example (although feel free to change it). 54 | Note: I would still classify this as somewhat experimental. I do think the current contract for this makes sense (it just returns a list of strings) but there is a small chance this might change if I get some feedback about it. 55 | 56 | =window-stool-valid-indentation-ctx-regex= - an alist of (major-mode . regex) to match "useful" lines based on the current major mode. The default, if major mode isn't found, is any line with at least 2 alphanumeric characters. 57 | This only affects the default indentation based context function. Context functions provided above will not inherit this. 58 | This way we avoid taking lines of only opening braces like in this example: 59 | #+begin_src c 60 | if condition 61 | { 62 | blah 63 | } 64 | #+end_src 65 | When we're inside the block, we want to see the if statement instead of just "{" as the outermost context. 66 | 67 | Another thing that's useful if you want the window-stool to appear with consult previews is to add 68 | #+begin_src elisp 69 | (add-to-list 'consult-preview-allowed-hooks #'window-stool-mode) 70 | #+end_src 71 | 72 | 73 | * Screenshot/Video 74 | [[file:screenshots/without-overlay.png]] 75 | 76 | [[file:screenshots/with-overlay.png]] 77 | 78 | [[file:screenshots/demo.gif]] 79 | 80 | (theme is [[https://protesilaos.com/emacs/modus-themes][modus-operandi]] built into emacs 29) 81 | 82 | * Related packages 83 | Most of the alternatives use a single line via the header-line, but they're also probably much more performant than this package. 84 | This package also takes up more screen real estate than the single header-line ones. 85 | 86 | This package also behaves more like topsy/org-sticky-header in that it starts the context search from the 87 | beginning of the window rather than at point itself like the other packages. 88 | 89 | - [[https://github.com/zbelial/treesitter-context.el][treesitter-context]] 90 | - [[https://github.com/alphapapa/topsy.el][topsy]] 91 | - [[https://github.com/alphapapa/org-sticky-header][org-sticky-header]] 92 | - [[https://emacs-lsp.github.io/lsp-mode/page/settings/headerline/][lsp-mode-headerline]] 93 | - [[https://github.com/joaotavora/breadcrumb][breadcrumb-mode]] 94 | 95 | * Contributing 96 | Any feedback via the issues tab would be appreciated :) 97 | -------------------------------------------------------------------------------- /screenshots/demo.gif: -------------------------------------------------------------------------------- https://raw.githubusercontent.com/JasZhe/window-stool/b647d70e4ec429920a186c188bc80e50cede11fb/screenshots/demo.gif -------------------------------------------------------------------------------- /screenshots/with-overlay.png: -------------------------------------------------------------------------------- https://raw.githubusercontent.com/JasZhe/window-stool/b647d70e4ec429920a186c188bc80e50cede11fb/screenshots/with-overlay.png -------------------------------------------------------------------------------- /screenshots/without-overlay.png: -------------------------------------------------------------------------------- https://raw.githubusercontent.com/JasZhe/window-stool/b647d70e4ec429920a186c188bc80e50cede11fb/screenshots/without-overlay.png -------------------------------------------------------------------------------- /window-stool-window.el: -------------------------------------------------------------------------------- 1 | ;;; window-stool-window.el --- Description -*- lexical-binding: t; -*- 2 | ;; 3 | ;; Copyright (C) 2023 Jason Zhen 4 | ;; 5 | ;; Author: Jason Zhen 6 | ;; Maintainer: Jason Zhen 7 | ;; Created: December 19, 2023 8 | ;; Modified: December 19, 2023 9 | ;; Version: 0.0.1 10 | ;; Package-Requires: ((emacs "27.1")) 11 | ;; Keywords: context window 12 | ;; Homepage: https://github.com/jasonzhen/window-stool 13 | ;; 14 | ;; This file is not part of GNU Emacs. 15 | ;; 16 | ;;; Commentary: 17 | ;; Sort of experimental, I much prefer the overlays but I played around with having a "dedicated" window 18 | ;; for this in my head. 19 | ;; 20 | ;;; Description: 21 | ;; Window stool using an actual window instead of overlays with some convenience advice 22 | ;; to various window switching functions to allow "skipping" the window stool 23 | ;; if, for example, we have two real windows on top of each other. 24 | ;; 25 | ;;; Code: 26 | 27 | (setq window-stool-window nil) 28 | (setq window-stool-window--buffer-name " *Window Stool*") 29 | 30 | (defun window-stool-window--create (&rest _) 31 | "Create a code context window above the currently selected window." 32 | 33 | ;; Fixes issue with window stool window sometimes sticking around after #'delete-window 34 | ;; if the next selected window was a non file visiting buffer. 35 | ;; Needs post-command-hook attached to this to be non-local 36 | (when (overlayp window-stool-overlay) (delete-overlay window-stool-overlay)) 37 | (window-stool-window--delete) 38 | ;; only in file visiting buffers 39 | (when (and (buffer-file-name) (not (eq window-stool-fn #'ignore))) 40 | (let* ((ctx-1 (window-stool--truncate-context (save-excursion (funcall window-stool-fn (window-start))))) 41 | (ctx (if (not (eq major-mode 'org-mode)) (cl-subseq ctx-1 0 (1- (length ctx-1))) ctx-1)) 42 | (buf-name window-stool-window--buffer-name) 43 | (buf (get-buffer-create buf-name)) 44 | (win (display-buffer-in-direction buf '((direction . above))))) 45 | 46 | (set-window-dedicated-p win t) 47 | (with-current-buffer buf 48 | (setq mode-line-format nil) 49 | (set-window-parameter win 'no-other-window t) 50 | (erase-buffer) 51 | (when ctx (insert (cl-reduce (lambda (acc str) (concat acc str)) ctx))) 52 | (add-face-text-property (point-min) (point-max) '(:inherit window-stool-face) t) 53 | (fit-window-to-buffer win))))) 54 | 55 | 56 | (defun window-stool-window--create-ad (&rest _) (window-stool-window--create)) 57 | 58 | (defun window-stool-window--windmove-up-advice () 59 | "Advice to move 'past the context window if there's another window above. 60 | If there isn't (when \"windmove-up\" signals an error), move back down to the original window." 61 | (when (string= (buffer-name) window-stool-window--buffer-name) 62 | (condition-case nil 63 | (windmove-up) 64 | (error (windmove-down))))) 65 | 66 | (defun window-stool-window--windmove-down-advice () 67 | "Similar to \"window-stool-window--windmove-up-advice\". 68 | Doesn't need to move back to the original window on error,since context window is always on top." 69 | (when (string= (buffer-name) window-stool-window--buffer-name) 70 | (windmove-down))) 71 | 72 | (defun window-stool-window--delete (&rest _) 73 | "Find the window containing the context buffer, and delete it." 74 | (let ((win (get-buffer-window window-stool-window--buffer-name))) 75 | (when win (delete-window win)))) 76 | 77 | (defun window-stool-window--fit-to-buffer () 78 | "Find the window containing the context buffer, and fit the window to its contents." 79 | (let ((win (get-buffer-window window-stool-window--buffer-name))) 80 | (when win (fit-window-to-buffer win)))) 81 | 82 | (defun window-stool-window--balance-advice-after (&rest _) 83 | (window-stool-window--fit-to-buffer)) 84 | 85 | (defun window-stool-window--balance-advice-before (&rest _) 86 | (window-stool-window--fit-to-buffer)) 87 | 88 | (defun window-stool-window--advise-window-functions () 89 | "Advise a variety of window and buffer functions for interoperability with the context window." 90 | 91 | ;; When quitting magit on a split frame in doom, the window rebalancing 92 | ;; would be thrown off because of the window-stool-window. 93 | ;; 94 | ;; Killing the window, prior to showing the magit buffer via an advice to 95 | ;; display-buffer seemed to fix it and should hopefully fix it for other 96 | ;; issues as well. 97 | (advice-add 'display-buffer :before #'window-stool-window--delete) 98 | 99 | ;; ensure window stool window doesn't get resized from rebalancing 100 | ;; odd case where balancing windows on a window with a non window-stool 101 | ;; buffer displayed, will equalize the other window that does have the 102 | ;; window-stool-window. 103 | (advice-add 'balance-windows :before #'window-stool-window--balance-advice-before) 104 | (advice-add 'balance-windows :after #'window-stool-window--balance-advice-after) 105 | 106 | ;; delete the window and then re-add so we don't affect window enlargement/shrinkage 107 | (advice-add 'shrink-window :before #'window-stool-window--delete) 108 | (advice-add 'shrink-window :after #'window-stool-window--create-ad) 109 | (advice-add 'enlarge-window :before #'window-stool-window--delete) 110 | (advice-add 'enlarge-window :after #'window-stool-window--create-ad) 111 | 112 | (advice-add 'windmove-up :after #'window-stool-window--windmove-up-advice) 113 | (advice-add 'windmove-down :after #'window-stool-window--windmove-down-advice)) 114 | 115 | (defun window-stool-window--remove-window-function-advice () 116 | (advice-remove 'display-buffer #'window-stool-window--delete) 117 | 118 | (advice-remove 'balance-windows #'window-stool-window--balance-advice-before) 119 | (advice-remove 'balance-windows #'window-stool-window--balance-advice-after) 120 | 121 | (advice-remove 'shrink-window #'window-stool-window--delete) 122 | (advice-remove 'shrink-window #'window-stool-window--create) 123 | (advice-remove 'enlarge-window #'window-stool-window--delete) 124 | (advice-remove 'enlarge-window #'window-stool-window--create-ad) 125 | 126 | (advice-remove 'windmove-up #'window-stool-window--windmove-up-advice) 127 | (advice-remove 'windmove-down #'window-stool-window--windmove-down-advice)) 128 | 129 | (provide 'window-stool-window) 130 | ;;; window-stool-window.el ends here 131 | -------------------------------------------------------------------------------- /window-stool.el: -------------------------------------------------------------------------------- 1 | ;;; window-stool.el --- Description -*- lexical-binding: t; -*- 2 | ;; 3 | ;; Copyright (C) 2023 Jason Zhen 4 | ;; 5 | ;; Author: Jason Zhen 6 | ;; Maintainer: Jason Zhen 7 | ;; Created: December 16, 2023 8 | ;; Modified: December 16, 2023 9 | ;; Version: 0.0.1 10 | ;; Keywords: context overlay 11 | ;; Homepage: https://github.com/jasonzhen/window-stool 12 | ;; Package-Requires: ((emacs "27.1")) 13 | ;; 14 | ;; This file is not part of GNU Emacs. 15 | ;; 16 | ;;; Commentary: 17 | ;; Like a little "stool" for your window viewing needs 18 | ;; 19 | ;; Description 20 | ;; Uses an overlay that moves when the window is scrolled to take over the first 21 | ;; two lines (one line gets a little buggy when it comes to scrolling) to show 22 | ;; indentation based (default but can define other methods) buffer context 23 | ;; 24 | ;; Works best if you have some sort of scroll margin, cause editing the overlay text 25 | ;; can get wonky. 26 | ;; 27 | ;; Will definitely affect scrolling performance. 28 | ;; 29 | ;;; Code: 30 | ;;; 31 | (require 'cl-lib) 32 | (require 'org) 33 | (require 'timer) 34 | 35 | (defgroup window-stool nil 36 | "A minor mode for providing some additional buffer context via overlays." 37 | :group 'tools) 38 | 39 | (defface window-stool-face 40 | '((t (:inherit fringe :extend t))) 41 | "Face for window stool overlay background. 42 | This will be ADDED to the context string's existing buffer font locking." 43 | :group 'window-stool) 44 | 45 | (defcustom window-stool-n-from-top 1 46 | "Number of lines of context to keep from the outermost context list. 47 | i.e. suppose we have 48 | \(defun foo \(\) 49 | \(progn ;; one 50 | \(progn ;; two 51 | \(progn ;; three\)\)\)\) 52 | 53 | Setting this to 2, would take the defun and the first progn. 54 | Similar behavior for \"window-stool-n-from-bottom\". 55 | Except we take from the end (the second and third progn). 56 | Setting both of these to zero keeps all context. 57 | 58 | This needs to be increased to one more than what you would have 59 | normally for the non overlay version." 60 | :type '(natnum)) 61 | 62 | (defcustom window-stool-n-from-bottom 2 63 | "Number of lines of context to keep from the innermost context list. 64 | See: \"window-stool-n-from-top\"." 65 | :type '(natnum)) 66 | 67 | (defcustom window-stool-major-mode-functions-alist 68 | '((org-mode . window-stool-get-org-header-context) 69 | (nil . window-stool-get-indentation-context-from)) 70 | "A list of (major-mode . function). 71 | Each function should take one argument, the point to search from. 72 | Each function should return a list of strings. 73 | Each string will be displayed in the overlay from top to bottom. 74 | Strings should end with newlines. 75 | Defaults to indentation based context function." 76 | :type '(alist :key-type symbol :value-type function)) 77 | 78 | 79 | (defcustom window-stool-major-mode-valid-indentation-ctx-regex '((nil .".*[[:alnum:]][[:alnum:]].*")) 80 | "Alist of major-modes to regex for valid context lines. 81 | Intended to be used for the default indentation based context defun. 82 | The default is any string with at least two alphanumeric characters. 83 | This way, we avoid showing lines of only symbols like parentheses. 84 | Example in SQL: 85 | 86 | CREATE TABLE xyz 87 | ( 88 | blah... 89 | 90 | We want to show \"CREATE TABLE xyz\" instead of ( as the upper context here." 91 | :type '(alist :key-type symbol :value-type regexp)) 92 | 93 | (defvar-local window-stool-valid-indentation-ctx-regex "" 94 | "Valid context regex for the current buffer") 95 | 96 | (defvar window-stool-fn #'ignore 97 | "Function that returns the context in a buffer from point.") 98 | 99 | (defconst window-stool--min-height 20 100 | "Minimum height (arbitrarily chosen) that a window needs to have for context to be displayed. 101 | This is a hack to prevent some issues with resizing a window causing Emacs to freeze in the redisplay code.") 102 | 103 | (defconst window-stool--min-width 50 104 | "Minimum width (arbitrarily chosen) that a window needs to have for context to be displayed. 105 | This is a hack to prevent some issues with resizing a window causing Emacs to freeze in the redisplay code.") 106 | 107 | (defun window-stool-get-org-header-context (pos) 108 | "Get org header contexts from POS. 109 | Will move point so caller should call \"save-excursion\"." 110 | (goto-char pos) 111 | (when (not (org-before-first-heading-p)) 112 | 113 | (outline-back-to-heading) 114 | 115 | ;; When indent mode is on, display-start for the overlay is indented. The issue is then 116 | ;; the first line of the context will match the indent level of org, but the rest of the 117 | ;; headings will have their normal indents. 118 | ;; Instead we propertize manually by grabbing the org-level-faces manually 119 | (let* ((ctx '()) 120 | (ctx-fn (lambda () 121 | (concat 122 | (buffer-substring-no-properties 123 | (line-beginning-position) 124 | (line-end-position)) 125 | "\n"))) 126 | (ctx-str (propertize 127 | (funcall ctx-fn) 128 | 'face 129 | (nth (1- (nth 0 (org-heading-components))) org-level-faces)))) 130 | (cl-pushnew ctx-str ctx) 131 | (while (> (org-current-level) 1) 132 | (outline-up-heading 1) 133 | (let ((ctx-str (propertize 134 | (funcall ctx-fn) 135 | 'face 136 | (nth (1- (nth 0 (org-heading-components))) org-level-faces)))) 137 | (cl-pushnew ctx-str ctx))) 138 | ctx))) 139 | 140 | (defun window-stool-find-prev-non-empty-line () 141 | "Find non-empty line above from point." 142 | ;; keep going back even further until we hit a "useful" line for context: at least 2 alphanumeric characters 143 | ;; empty body cause we basically just do the re-search-backward as part of the loop 144 | (while (and (or (looking-at-p (rx-to-string `(: (* blank) eol))) 145 | (not (looking-at-p (cdr (or (assq major-mode window-stool-major-mode-valid-indentation-ctx-regex) 146 | (assq nil window-stool-major-mode-valid-indentation-ctx-regex)))))) 147 | (re-search-backward (rx-to-string `(: bol (+ any))) nil t)))) 148 | 149 | (defun window-stool-get-indentation-context-from (pos) 150 | "Get indentation based context from POS. 151 | Returns a list of fontified strings with newlines at the end. 152 | Strings will also inherit props of \"window-stool-face\". 153 | Will move point so caller should call \"save-excursion\"." 154 | (goto-char pos) 155 | (window-stool-find-prev-non-empty-line) 156 | (let* ((ctx '()) 157 | (prev-indentation (current-indentation)) 158 | (ctx-fn (lambda () 159 | (concat 160 | (buffer-substring 161 | (line-beginning-position) 162 | (line-end-position)) 163 | "\n"))) 164 | (ctx-str (funcall ctx-fn))) 165 | ;; Need to add the current line that pos is on as well cause there's some weird issues 166 | ;; if we have an empty context 167 | (cl-pushnew ctx-str ctx) 168 | (while (and (> (current-indentation) 0) (not (bobp))) 169 | (forward-line -1) 170 | (window-stool-find-prev-non-empty-line) 171 | (when (< (current-indentation) prev-indentation) 172 | (setq prev-indentation (current-indentation)) 173 | (let ((ctx-str (funcall ctx-fn))) 174 | (cl-pushnew ctx-str ctx)) 175 | ) 176 | ) 177 | ;; need the forward char so we ensure we go back to the beg of current defun 178 | ;; and not previous defun 179 | (when (fboundp 'beginning-of-defun) 180 | (forward-line) 181 | (beginning-of-defun) 182 | (let ((ctx-str (funcall ctx-fn))) 183 | (when (not (string-equal ctx-str (cl-first ctx))) 184 | (cl-pushnew ctx-str ctx)))) 185 | ctx)) 186 | 187 | (defun window-stool--truncate-context (ctx) 188 | "Truncates CTX. 189 | See: doc for \"window-stool-n-from-top\". 190 | Just returns CTX if both are 0." 191 | (if (or (> window-stool-n-from-top 0) (> window-stool-n-from-bottom 0)) 192 | (let* ((from-top (min (length ctx) window-stool-n-from-top)) 193 | (top-ctx (cl-subseq ctx 0 from-top)) 194 | (ctx-1 (nthcdr from-top ctx)) 195 | (from-bottom (min (length ctx-1) window-stool-n-from-bottom)) 196 | (bottom-ctx (when (> from-bottom 0) (cl-subseq ctx-1 (- from-bottom))))) 197 | (append top-ctx bottom-ctx)) 198 | ctx)) 199 | 200 | (defvar-local window-stool--prev-window-start nil 201 | "The previous window-start. So we don't run the overlay creation unnecessarily.") 202 | 203 | (defvar-local window-stool--prev-ctx nil) 204 | (defvar-local window-stool--prev-indentation 0) 205 | 206 | (defvar-local window-stool-overlays '() 207 | "Alist of windows to overlays for the current buffer. 208 | Most of the time this is just a single element, unless the buffer is shown in 209 | multiple windows,in which case we need an overlay for each window.") 210 | 211 | (defcustom window-stool-ignore-buffer-regexps nil 212 | "List of buffer regexps to disable window-stool overlay on. 213 | Different from `window-stool-ignore-file-regexps'" 214 | :type '(repeat regexp)) 215 | 216 | ;; Some git operations i.e. commit/rebase open up a buffer that we can edit 217 | ;; which is based a temporary file in the .git directory. 218 | ;; Most of the time I don't really want the overlay in those buffers so 219 | ;; I've opted to disable them here via regexps. 220 | (defcustom window-stool-ignore-file-regexps '("\\.git") 221 | "List of file name regexps to disable window-stool overlay on. 222 | Different from `window-stool-ignore-buffer-regexps'" 223 | :type '(repeat regexp)) 224 | 225 | (defun window-stool-single-overlay (window display-start) 226 | "Create/move an overlay to show buffer context above DISPLAY-START. 227 | Single overlay per buffer. 228 | Contents of the overlay is based on the results of \"window-stool-fn\"." 229 | ;; Issue with having multiple windows displaying the same buffer since now 230 | ;; there's multiple "window starts" which make it difficult to deal with. 231 | ;; Simpler to temporarily delete the overlays until only a single window shows the buffer for now. 232 | (when (and window (with-current-buffer (window-buffer window) window-stool-mode)) 233 | (let ((ov (or (alist-get window window-stool-overlays nil nil #'equal) 234 | (make-overlay 1 1)))) 235 | (overlay-put ov 'type 'window-stool--buffer-overlay) 236 | (overlay-put ov 'window window) 237 | (overlay-put ov 'priority 0) 238 | 239 | (setf (alist-get window window-stool-overlays nil nil #'equal) ov) 240 | 241 | (if (or (<= (window-size window) window-stool--min-height) 242 | (<= (window-size window t) window-stool--min-width) 243 | (eq display-start (point-min))) 244 | (delete-overlay ov) 245 | (progn 246 | ;; Some git operations i.e. commit/rebase open up a buffer that we can edit which is based a temporary file in the .git directory. 247 | ;; Most of the time I don't really want the overlay in those buffers so I've opted to disable them here via this simple heuristic. 248 | (when (and (not (or 249 | (cl-find-if (lambda (r) (and buffer-file-name (string-match r buffer-file-name))) 250 | window-stool-ignore-file-regexps) 251 | (cl-find-if (lambda (r) (string-match r (buffer-name))) 252 | window-stool-ignore-file-regexps)))) 253 | (let* ((ctx-1 (save-excursion (funcall window-stool-fn display-start))) 254 | (ctx (window-stool--truncate-context ctx-1))) 255 | (let* ((ol-beg-pos display-start) 256 | (ol-end-pos (save-excursion 257 | (goto-char display-start) 258 | (forward-visible-line 1) 259 | (line-end-position))) 260 | ;; There's some bugginess if we don't have end-pos be on the next line, 261 | ;; cause depending on the order of operations we might scroll past our overlay after redisplay. 262 | ;; The solution here is to make the overlay 2 lines and just show 263 | ;; the "covered" second line as part of the overlay 264 | (covered-line (save-excursion 265 | (goto-char display-start) 266 | (forward-visible-line 1) 267 | (buffer-substring 268 | (line-beginning-position) 269 | (line-end-position)))) 270 | (context-str-1 (when ctx (cl-reduce (lambda (acc str) 271 | (let* ((truncated (truncate-string-to-width str (1- (window-size window t)) 0 nil "\n")) 272 | (truncated-respecting-word-boundaries 273 | (if (string= truncated str) ;; this means we didn't need to truncate 274 | truncated 275 | (truncate-string-to-width truncated 276 | (- (length truncated) (1+ (string-match "[[:space:]]" (reverse truncated)))) 277 | 0 nil "\n")))) 278 | (concat acc truncated-respecting-word-boundaries))) 279 | ctx))) 280 | 281 | (context-str (progn 282 | (add-face-text-property 0 (length context-str-1) '(:inherit window-stool-face) t context-str-1) 283 | (concat context-str-1 covered-line)))) 284 | 285 | (move-overlay ov ol-beg-pos ol-end-pos) 286 | (overlay-put ov 'display context-str) 287 | ) 288 | (setq window-stool--prev-ctx ctx))))) 289 | ) 290 | ) 291 | (setq-local window-stool--prev-window-start (window-start))) 292 | 293 | (defun window-stool--pre-command-hook () 294 | "Fixes an issue with scrolling down a single line by simply deleting the overlay. 295 | The idea is that the scrolling redisplay logic can then properly calculate where the 296 | next scroll position should be without our multiline overlay getting in the way. 297 | Then, `window-stool-single-overlay' will generate the new overlay afterwards since `window-scroll-functions' 298 | runs after the pre-command hook. 299 | This fixes the issue with multiple windows showing the same buffer." 300 | (let* ((win (selected-window)) 301 | (ov (alist-get win window-stool-overlays nil nil #'equal))) 302 | (when (and ov (or (eq this-command 'evil-scroll-line-down) 303 | (eq this-command 'viper-scroll-up-one) 304 | (eq this-command 'scroll-up-line))) 305 | (delete-overlay ov)))) 306 | 307 | (defun window-stool--scroll-overlay-into-position () 308 | "Fixes some bugginess with scrolling getting stuck when the overlay large." 309 | (let* ((win (selected-window)) 310 | (ov (alist-get win window-stool-overlays nil nil #'equal))) 311 | (when (and ov 312 | (overlay-buffer ov) 313 | (> (window-size (selected-window)) window-stool--min-height) 314 | (> (window-size (selected-window) t) window-stool--min-width) 315 | (not (eq (window-start) window-stool--prev-window-start)) (buffer-file-name)) 316 | (let* ((ctx-1 (save-excursion (funcall window-stool-fn (window-start)))) 317 | (ctx (window-stool--truncate-context ctx-1))) 318 | (ignore-errors 319 | (when (and ctx (or (eq last-command 'evil-scroll-line-up) 320 | (eq last-command 'viper-scroll-down-one) 321 | (eq last-command 'scroll-down-line))) 322 | (forward-visible-line (- (1+ (min (- (length ctx) (length window-stool--prev-ctx)) 0)))) 323 | 324 | ;; So we don't need to double scroll when window start is in the middle of a visual line split 325 | (when (= (save-excursion 326 | (goto-char (window-start)) 327 | (line-beginning-position)) 328 | (save-excursion 329 | (goto-char (window-start)) 330 | (line-move-visual -1 t) 331 | (line-beginning-position))) 332 | (scroll-down-line)))))))) 333 | 334 | (defun window-stool--scroll-function (window display-start) 335 | "Convenience wrapper for `window-scroll-functions'." 336 | (when (and (buffer-file-name) 337 | (or (not (boundp 'git-commit-mode)) 338 | (not git-commit-mode))) 339 | 340 | ;; for org mode we can't use the exact display-start passed via window-scroll-functions 341 | ;; if org-hide-emphasis-markers is set, for instance: 342 | ;; *This is bold* then display-start would point to the "T" instead of 343 | ;; the first "*" and (scroll-down 1) would complain about beginning of buffer 344 | (window-stool-single-overlay window (save-excursion (goto-char display-start) (line-beginning-position))))) 345 | 346 | (defun window-stool--state-change-function (window) 347 | "Convenience wrapper for `window-state-change-functions' " 348 | (when (and (buffer-file-name) 349 | (or (not (boundp 'git-commit-mode)) 350 | (not git-commit-mode))) 351 | 352 | ;; for org mode, if we hide the font decoration symbols for instance: 353 | ;; *This is bold* then display-start would point to the "T" instead of 354 | ;; the first "*" and (scroll-down 1) would complain about beginning of buffer 355 | (window-stool-single-overlay window (window-start window)))) 356 | 357 | (defun window-stool--selection-change-function (frame-or-window) 358 | (if (and (windowp frame-or-window) (window-live-p frame-or-window)) 359 | (save-window-excursion 360 | (select-window frame-or-window) 361 | (window-stool--scroll-function frame-or-window (window-start frame-or-window))) 362 | (let ((prev-window (and (framep frame-or-window) (frame-old-selected-window frame-or-window)))) 363 | (when (and prev-window (window-live-p prev-window)) 364 | (save-window-excursion 365 | (select-window prev-window) 366 | (when (not (eq window-stool-fn #'ignore)) 367 | (window-stool--scroll-function prev-window (window-start prev-window)))))))) 368 | 369 | (defvar window-stool-timer nil 370 | "Idle timer used to reset the window-stool overlay if for some reason, it gets out of position 371 | and the normal mechanism for repositioning it doesn't run (via \"window-scroll-functions\").") 372 | 373 | (defvar window-stool-buffer-list '() 374 | "List of buffers, window-stool is enabled in.") 375 | 376 | (defun window-stool-idle-fn () 377 | "Function to be used in an idle timer. 378 | Re-positions the window-stool overlay if it gets out of position. 379 | 380 | Cancels \"window-stool-timer\" if \"window-stool-buffer-list\" is empty." 381 | (save-window-excursion 382 | (dolist (win (window-list)) 383 | (select-window win t) 384 | (when (and (boundp 'window-stool-mode) 385 | window-stool-mode 386 | (not (eq window-stool-fn #'ignore)) 387 | (not (cl-remove-if-not 388 | (lambda (o) (eq (overlay-get o 'type) 'window-stool--buffer-overlay)) 389 | (overlays-at (window-start))))) 390 | (window-stool--scroll-function nil (window-start))))) 391 | (when (= (length window-stool-buffer-list) 0) 392 | (cancel-timer window-stool-timer) 393 | (setq window-stool-timer nil))) 394 | 395 | (defun window-stool--window-resize-before-advice (&rest _) 396 | "Advice to prevent a Emacs hanging when windows are resized with the window stool overlay." 397 | (dolist (win (window-list)) 398 | (with-current-buffer (window-buffer win) 399 | (let ((ov (alist-get win window-stool-overlays nil nil #'equal))) 400 | (ignore-errors (delete-overlay ov)))))) 401 | 402 | (defun window-stool--window-resize-after-advice (&rest _) 403 | "Advice to rebuild the overlays after window resizing." 404 | (dolist (window (window-list)) 405 | (with-current-buffer (window-buffer window) 406 | (when (and (boundp 'window-stool-mode) 407 | window-stool-mode 408 | (not (eq window-stool-fn #'ignore))) 409 | (window-stool-single-overlay window (save-excursion (goto-char (window-start window)) (line-beginning-position))))))) 410 | 411 | ;;;###autoload 412 | (define-minor-mode window-stool-mode 413 | "Minor mode to show buffer context. 414 | Get a glimpse of the buffer contents above your current window position. 415 | Like a stool to peek a little higher than you could normally. 416 | 417 | Uses overlays by default and attaches to \"post-command-hook\". 418 | CAUTION: This can have some major performance impact on scrolling." 419 | :lighter " WinStool" 420 | :group 'window-stool 421 | (if window-stool-mode 422 | (progn (setq-local window-stool--prev-ctx nil) 423 | (setq-local window-stool--prev-window-start (window-start)) 424 | (remove-overlays (point-min) (point-max) 'type 'window-stool--buffer-overlay) 425 | 426 | (setq-local window-stool-fn 427 | (cdr (or (assq major-mode window-stool-major-mode-functions-alist) 428 | (assq nil window-stool-major-mode-functions-alist)))) 429 | (setq-local window-stool-valid-indentation-ctx-regex 430 | (cdr (or (assq major-mode window-stool-major-mode-valid-indentation-ctx-regex) 431 | (assq nil window-stool-major-mode-valid-indentation-ctx-regex)))) 432 | 433 | ;; set buffer local scroll margin to avoid strange behavior when putting point into the overlay itself 434 | ;; since the overlay encompasses a lot less real text than the virtual text it actually shows 435 | (when (< scroll-margin (+ window-stool-n-from-top window-stool-n-from-bottom)) 436 | (setq-local scroll-margin (+ 1 window-stool-n-from-top window-stool-n-from-bottom))) 437 | 438 | (advice-add #'window-resize :before #'window-stool--window-resize-before-advice) 439 | (advice-add #'window-resize :after #'window-stool--window-resize-after-advice) 440 | 441 | (add-hook 'post-command-hook #'window-stool--scroll-overlay-into-position nil t) 442 | (add-hook 'pre-command-hook #'window-stool--pre-command-hook nil t) 443 | 444 | ;; little hack to redisplay the overlay after a delay in the cases where 445 | ;; the overlay ends up in an odd position/not displayed and window-scroll-functions don't run 446 | ;; like when changing tabs 447 | (unless (timerp window-stool-timer) 448 | (setq window-stool-timer (run-with-idle-timer 0.5 t #'window-stool-idle-fn))) 449 | 450 | (when (buffer-file-name) 451 | (cl-pushnew (current-buffer) window-stool-buffer-list)) 452 | 453 | ;; remove from window-stool-buffer-list if buffer iskilled 454 | (add-hook 'kill-buffer-hook (lambda () (cl-remove (current-buffer) window-stool-buffer-list)) nil t) 455 | 456 | ;; prevents a (void-function: nil) error when we switch to a non-hooked mode i.e. in fundamental mode, 457 | ;; which will break the global window-scroll-functions' window-stool--scroll-function 458 | ;; therefore breaking window-stool for all other buffers 459 | (add-hook 'window-scroll-functions #'window-stool--scroll-function nil t) 460 | (add-hook 'window-state-change-functions #'window-stool--state-change-function nil t)) 461 | 462 | ;; clean up overlay stuff 463 | (progn (remove-overlays (point-min) (point-max) 'type 'window-stool--buffer-overlay) 464 | (advice-remove #'window-resize #'window-stool--window-resize-before-advice) 465 | (advice-remove #'window-resize #'window-stool--window-resize-after-advice) 466 | 467 | (remove-hook 'pre-command-hook #'window-stool--pre-command-hook t) 468 | (remove-hook 'post-command-hook #'window-stool--scroll-overlay-into-position t) 469 | 470 | (remove-hook 'window-scroll-functions #'window-stool--scroll-function t) 471 | (remove-hook 'window-state-change-functions #'window-stool--state-change-function t) 472 | 473 | (setq window-stool-buffer-list (cl-remove (current-buffer) window-stool-buffer-list)) 474 | (kill-local-variable 'scroll-margin) 475 | 476 | (when (boundp 'window-stool--prev-window-min-height) (setq window-min-height window-stool--prev-window-min-height))))) 477 | 478 | (provide 'window-stool) 479 | ;;; window-stool.el ends here 480 | --------------------------------------------------------------------------------