Adding window-tool-bar package (bug#68765).

* lisp/window-tool-bar.el: New file.

lisp/window-tool-bar.el

@@ -0,0 +1,491 @@
+;;; window-tool-bar.el --- Add tool bars inside windows -*- lexical-binding: t -*-
+
+;; Copyright (C) 2023-2024 Free Software Foundation, Inc.
+
+;; Author: Jared Finder <jared@finder.org>
+;; Created: Nov 21, 2023
+;; Version: 0.2
+;; Keywords: mouse
+;; Package-Requires: ((emacs "29.1"))
+
+;; This is a GNU ELPA :core package.  Avoid adding functionality that
+;; is not available in the version of Emacs recorded above or any of
+;; the package dependencies.
+
+;; This file is part of GNU Emacs.
+
+;; GNU Emacs is free software; you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation, either version 3 of the License, or
+;; (at your option) any later version.
+
+;; GNU Emacs is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.
+
+;;; Commentary:
+;;
+;; This package puts a tool bar in each window.  This allows you to see
+;; multiple tool bars simultaneously directly next to the buffer it
+;; acts on which feels much more intuitive.  Emacs "browsing" modes
+;; generally have sensible tool bars, for example: *info*, *help*, and
+;; *eww* have them.
+;;
+;; It does this while being mindful of screen real estate.  Most modes
+;; do not provide a custom tool bar, and this package does not show the
+;; default tool bar.  This means that for most buffers there will be no
+;; space taken up.  Furthermore, you can put this tool bar in the mode
+;; line or tab line if you want to share it with existing content.
+;;
+;; To get the default behavior, run (global-window-tool-bar-mode 1) or
+;; enable via M-x customize-group RET window-tool-bar RET.  This uses
+;; the per-window tab line to show the tool bar.
+;;
+;; If you want to share space with an existing tab line, mode line, or
+;; header line, add (:eval (window-tool-bar-string)) to
+;; `tab-line-format', `mode-line-format', or `header-line-format'.
+
+;;; Known issues:
+;;
+;; On GNU Emacs 29.1, terminals dragging to resize windows will error
+;; with message "<tab-line> <mouse-movement> is undefined".  This is a
+;; bug in GNU Emacs,
+;; <https://debbugs.gnu.org/cgi/bugreport.cgi?bug=67457>.
+;;
+;; On GNU Emacs 29, performance in terminals is lower than on
+;; graphical frames.  This is due to a workaround, see "Workaround for
+;; https://debbugs.gnu.org/cgi/bugreport.cgi?bug=68334", below.
+
+;;; Todo:
+;;
+;; Not all features planned are implemented yet.  Eventually I would
+;; like to also generally make tool bars better.
+;;
+;; Targeting 0.3:
+;; * Properly support reamining less frequently used tool bar item specs.  From
+;;   `parse_tool_bar_item':
+;;     * :visible
+;;     * :filter
+;;     * :button
+;;     * :wrap
+;; * Add display customization similar to `tool-bar-style'.
+;;
+;; Targeting 1.0:
+;;
+;; * Clean up Emacs tool bars
+;;     * Default: Remove default tool-bar entirely
+;;     * grep, vc: Remove default tool-bar inherited
+;;     * info: Remove Next / Prev / Up, which is already in the header
+;;     * smerge: Add tool bar for next/prev
+;;
+;; Post 1.0 work:
+;;
+;; * Show keyboard shortcut on help text.
+;;
+;; * Add a bit more documentation.
+;; * Add customization option: ignore-default-tool-bar-map
+;; * Make tab-line dragging resize the window
+
+;;; Code:
+
+(require 'mwheel)
+(require 'tab-line)
+(require 'tool-bar)
+
+;;; Benchmarking code
+;;
+;; Refreshing the tool bar is computationally simple, but generates a
+;; lot of garbage.  So this benchmarking focuses on garbage
+;; generation.  Since it has to run after most commands, generating
+;; significantly more garbage will cause noticeable performance
+;; degration.
+;;
+;; The refresh has two steps:
+;;
+;; Step 1: Look up the <tool-bar> map.
+;; Step 2: Generate a Lisp string using text properties for the tool
+;; bar string.
+;;
+;; Additionally, we keep track of the percentage of commands that
+;; acutally created a refresh.
+(defvar window-tool-bar--memory-use-delta-step1 (make-list 7 0)
+  "Absolute delta of memory use counters during step 1.
+This is a list in the same structure as `memory-use-counts'.")
+(defvar window-tool-bar--memory-use-delta-step2 (make-list 7 0)
+  "Absolute delta of memory use counters during step 2.
+This is a list in the same structure as `memory-use-counts'.")
+(defvar window-tool-bar--refresh-done-count 0
+  "Number of tool bar string refreshes run.
+The total number of requests is the sum of this and
+`window-tool-bar--refresh-skipped-count'.")
+(defvar window-tool-bar--refresh-skipped-count 0
+  "Number of tool bar string refreshes that were skipped.
+The total number of requests is the sum of this and
+`window-tool-bar--refresh-done-count'.")
+
+(defun window-tool-bar--memory-use-avg-step1 ()
+  "Return average memory use delta during step 1."
+  (mapcar (lambda (elt) (/ (float elt) window-tool-bar--refresh-done-count))
+          window-tool-bar--memory-use-delta-step1))
+
+(defun window-tool-bar--memory-use-avg-step2 ()
+  "Return average memory use delta during step 2."
+  (mapcar (lambda (elt) (/ (float elt) window-tool-bar--refresh-done-count))
+          window-tool-bar--memory-use-delta-step2))
+
+(declare-function time-stamp-string "time-stamp")
+
+(defun window-tool-bar-debug-show-memory-use ()
+  "Development-only command to show memory used by `window-tool-bar-string'."
+  (interactive)
+  (require 'time-stamp)
+  (save-selected-window
+    (pop-to-buffer "*WTB Memory Report*")
+    (unless (derived-mode-p 'special-mode)
+      (special-mode))
+
+    (goto-char (point-max))
+    (let ((inhibit-read-only t))
+      (insert (propertize (concat "Function: window-tool-bar-string "
+                                  (time-stamp-string))
+                          'face 'underline 'font-lock-face 'underline)
+              "\n\n")
+      (window-tool-bar--insert-memory-use
+       "Step 1" (window-tool-bar--memory-use-avg-step1))
+      (window-tool-bar--insert-memory-use
+       "Step 2" (window-tool-bar--memory-use-avg-step2))
+      (insert (format "Refresh count  %d\n" window-tool-bar--refresh-done-count)
+              (format "Refresh executed percent %.2f\n"
+                      (/ (float window-tool-bar--refresh-done-count)
+                         (+ window-tool-bar--refresh-done-count
+                            window-tool-bar--refresh-skipped-count)))
+              "\n"))))
+
+(defun window-tool-bar--insert-memory-use (label avg-memory-use)
+  "Insert memory use into current buffer.
+
+LABEL is a prefix string to be in front of the data.
+AVG-MEMORY-USE is a list of averages, with the same meaning as
+`memory-use-counts'."
+  (let* ((label-len (length label))
+         (padding (make-string label-len ?\s)))
+    (cl-loop for usage in avg-memory-use
+             for usage-label in '("Conses" "Floats" "Vector cells" "Symbols"
+                                  "String chars" "Intervals" "Strings")
+             for idx from 0
+             do (insert (format "%s  %8.2f %s\n"
+                                (if (= idx 0) label padding)
+                                usage
+                                usage-label)))))
+
+(defgroup window-tool-bar nil
+  "Tool bars per-window."
+  :group 'convenience
+  :prefix "window-tool-bar-")
+
+(defvar-keymap window-tool-bar--button-keymap
+  :doc "Keymap used by `window-tool-bar--keymap-entry-to-string'."
+  "<follow-link>" 'mouse-face
+  ;; Follow link on all clicks of mouse-1 and mouse-2 since the tool
+  ;; bar is not a place the point can travel to.
+  "<tab-line> <mouse-1>" #'window-tool-bar--call-button
+  "<tab-line> <double-mouse-1>" #'window-tool-bar--call-button
+  "<tab-line> <triple-mouse-1>" #'window-tool-bar--call-button
+  "<tab-line> <mouse-2>" #'window-tool-bar--call-button
+  "<tab-line> <double-mouse-2>" #'window-tool-bar--call-button
+  "<tab-line> <triple-mouse-2>" #'window-tool-bar--call-button
+
+  ;; Mouse down events do nothing.  A binding is needed so isearch
+  ;; does not exit when the tab bar is clicked.
+  "<tab-line> <down-mouse-1>" #'window-tool-bar--ignore
+  "<tab-line> <double-down-mouse-1>" #'window-tool-bar--ignore
+  "<tab-line> <triple-down-mouse-1>" #'window-tool-bar--ignore
+  "<tab-line> <down-mouse-2>" #'window-tool-bar--ignore
+  "<tab-line> <double-down-mouse-2>" #'window-tool-bar--ignore
+  "<tab-line> <triple-down-mouse-2>" #'window-tool-bar--ignore)
+(fset 'window-tool-bar--button-keymap window-tool-bar--button-keymap) ; So it can be a keymap property
+
+;; Register bindings that stay in isearch.  Technically, these
+;; commands don't pop up a menu but they act very similar in that they
+;; are caused by mouse input and may call commands via
+;; `call-interactively'.
+(push 'window-tool-bar--call-button isearch-menu-bar-commands)
+(push 'window-tool-bar--ignore isearch-menu-bar-commands)
+
+(defvar-local window-tool-bar-string--cache nil
+  "Cache for previous result of `window-tool-bar-string'.")
+
+;;;###autoload
+(defun window-tool-bar-string ()
+  "Return a (propertized) string for the tool bar.
+
+This is for when you want more customizations than
+`window-tool-bar-mode' provides.  Commonly added to the variable
+`tab-line-format', `header-line-format', or `mode-line-format'"
+  (if (or (null window-tool-bar-string--cache)
+          (window-tool-bar--last-command-triggers-refresh-p))
+      (let* ((mem0 (memory-use-counts))
+             (toolbar-menu (window-tool-bar--get-keymap))
+             (mem1 (memory-use-counts))
+             (result (mapconcat #'window-tool-bar--keymap-entry-to-string
+                                (cdr toolbar-menu) ;Skip 'keymap
+                                ;; Without spaces between the text, hovering
+                                ;; highlights all adjacent buttons.
+                                (if (window-tool-bar--use-images)
+                                    (propertize " " 'invisible t)
+                                  " ")))
+             (mem2 (memory-use-counts)))
+        (cl-mapl (lambda (l-init l0 l1)
+                   (cl-incf (car l-init) (- (car l1) (car l0))))
+                 window-tool-bar--memory-use-delta-step1 mem0 mem1)
+        (cl-mapl (lambda (l-init l1 l2)
+                   (cl-incf (car l-init) (- (car l2) (car l1))))
+                 window-tool-bar--memory-use-delta-step2 mem1 mem2)
+
+        (setf window-tool-bar-string--cache
+              (concat
+               ;; The tool bar face by default puts boxes around the
+               ;; buttons.  However, this box is not displayed if the
+               ;; box starts at the leftmost pixel of the tab-line.
+               ;; Add a single space in this case so the box displays
+               ;; correctly.
+               (and (display-supports-face-attributes-p
+                     '(:box (line-width 1)))
+                    (propertize " " 'display '(space :width (1))))
+               result))
+        (cl-incf window-tool-bar--refresh-done-count))
+    (cl-incf window-tool-bar--refresh-skipped-count))
+
+  window-tool-bar-string--cache)
+
+(defconst window-tool-bar--graphical-separator
+  (concat
+   (propertize " " 'display '(space :width (4)))
+   (propertize " " 'display '(space :width (1) face (:inverse-video t)))
+   (propertize " " 'display '(space :width (4)))))
+
+(defun window-tool-bar--keymap-entry-to-string (menu-item)
+  "Convert MENU-ITEM into a (propertized) string representation.
+
+MENU-ITEM is a menu item to convert.  See info node (elisp)Tool Bar."
+  (pcase-exhaustive menu-item
+    ;; Separators
+    ((or `(,_ "--")
+         `(,_ menu-item ,(and (pred stringp)
+                              (pred (string-prefix-p "--")))))
+     (if (window-tool-bar--use-images)
+         window-tool-bar--graphical-separator
+       "|"))
+
+    ;; Menu item, turn into propertized string button
+    (`(,key menu-item ,name-expr ,binding . ,plist)
+     (when binding      ; If no binding exists, then button is hidden.
+       (let* ((name (eval name-expr))
+              (str (upcase-initials (or (plist-get plist :label)
+                                        (string-trim-right name "\\.+"))))
+              (len (length str))
+              (enable-form (plist-get plist :enable))
+              (enabled (or (not enable-form)
+                           (eval enable-form))))
+         (if enabled
+             (add-text-properties 0 len
+                                  '(mouse-face window-tool-bar-button-hover
+                                    keymap window-tool-bar--button-keymap
+                                    face window-tool-bar-button)
+                                  str)
+           (put-text-property 0 len
+                              'face
+                              'window-tool-bar-button-disabled
+                              str))
+         (when-let ((spec (and (window-tool-bar--use-images)
+                               (plist-get menu-item :image))))
+           (put-text-property 0 len
+                              'display
+                              (append spec
+                                      (if enabled '(:margin 2 :ascent center)
+                                        '(:margin 2 :ascent center
+                                          :conversion disabled)))
+                              str))
+         (put-text-property 0 len
+                            'help-echo
+                            (or (plist-get plist :help) name)
+                            str)
+         (put-text-property 0 len 'tool-bar-key key str)
+         str)))))
+
+(defun window-tool-bar--call-button ()
+  "Call the button that was clicked on in the tab line."
+  (interactive)
+  (when (mouse-event-p last-command-event)
+    (let ((posn (event-start last-command-event)))
+      ;; Commands need to execute with the right buffer and window
+      ;; selected.  The selection needs to be permanent for isearch.
+      (select-window (posn-window posn))
+      (let* ((str (posn-string posn))
+             (key (get-text-property (cdr str) 'tool-bar-key (car str)))
+             (cmd (lookup-key (window-tool-bar--get-keymap) (vector key))))
+        (call-interactively cmd)))))
+
+(defun window-tool-bar--ignore ()
+  "Internal command so isearch does not exit on button-down events."
+  (interactive)
+  nil)
+
+(defvar window-tool-bar--ignored-event-types
+  (let ((list (list 'mouse-movement 'pinch
+                    'wheel-down 'wheel-up 'wheel-left 'wheel-right
+                    mouse-wheel-down-event mouse-wheel-up-event
+                    mouse-wheel-left-event mouse-wheel-right-event
+                    (bound-and-true-p mouse-wheel-down-alternate-event)
+                    (bound-and-true-p mouse-wheel-up-alternate-event)
+                    (bound-and-true-p mouse-wheel-left-alternate-event)
+                    (bound-and-true-p mouse-wheel-right-alternate-event))))
+    (delete-dups (delete nil list)))
+  "Cache for `window-tool-bar--last-command-triggers-refresh-p'.")
+
+(defun window-tool-bar--last-command-triggers-refresh-p ()
+  "Test if the recent command or event should trigger a tool bar refresh."
+  (let ((type (event-basic-type last-command-event)))
+    (and
+     ;; Assume that key presses and button presses are the only user
+     ;; interactions that can alter the tool bar.  Specifically, this
+     ;; excludes mouse movement, mouse wheel scroll, and pinch.
+     (not (member type window-tool-bar--ignored-event-types))
+     ;; Assume that any command that triggers shift select can't alter
+     ;; the tool bar.  This excludes pure navigation commands.
+     (not (window-tool-bar--command-triggers-shift-select-p last-command))
+     ;; Assume that self-insert-command won't alter the tool bar.
+     ;; This is the most commonly executed command.
+     (not (eq last-command 'self-insert-command)))))
+
+(defun window-tool-bar--command-triggers-shift-select-p (command)
+  "Test if COMMAND would trigger shift select."
+  (let* ((form (interactive-form command))
+         (spec (car-safe (cdr-safe form))))
+    (and (eq (car-safe form) 'interactive)
+         (stringp spec)
+         (seq-position spec ?^))))
+
+;;;###autoload
+(define-minor-mode window-tool-bar-mode
+  "Toggle display of the tool bar in the tab line of the current buffer."
+  :global nil
+  (let ((should-display (and window-tool-bar-mode
+                             (not (eq tool-bar-map
+                                      (default-value 'tool-bar-map)))))
+        (default-value '(:eval (window-tool-bar-string))))
+
+    ;; Preserve existing tab-line set outside of this mode
+    (if (or (null tab-line-format)
+	    (equal tab-line-format default-value))
+        (if should-display
+            (setq tab-line-format default-value)
+          (setq tab-line-format nil))
+      (message
+       "tab-line-format set outside of window-tool-bar-mode, currently `%S'"
+       tab-line-format))))
+
+;;;###autoload
+(define-globalized-minor-mode global-window-tool-bar-mode
+  window-tool-bar-mode window-tool-bar--turn-on
+  :group 'window-tool-bar
+  (add-hook 'isearch-mode-hook #'window-tool-bar--turn-on)
+  (add-hook 'isearch-mode-end-hook #'window-tool-bar--turn-on))
+
+(defvar window-tool-bar--allow-images t
+  "Internal debug flag to force text mode.")
+
+(defun window-tool-bar--use-images ()
+  "Internal function.
+Respects `window-tool-bar--allow-images' as well as frame
+capabilities."
+  (and window-tool-bar--allow-images
+       (display-images-p)))
+
+;;; Display styling:
+(defface window-tool-bar-button
+  '((default
+     :inherit tab-line)
+    (((class color) (min-colors 88) (supports :box t))
+     :box (:line-width -1 :style released-button)
+     :background "grey85")
+    ;; If the box is not supported, dim the button background a bit.
+    (((class color) (min-colors 88))
+     :background "grey70")
+    (t
+     :inverse-video t))
+  "Face used for buttons when the mouse is not hovering over the button."
+  :group 'window-tool-bar)
+
+(defface window-tool-bar-button-hover
+  '((default
+     :inherit tab-line)
+    (((class color) (min-colors 88))
+     :box (:line-width -1 :style released-button)
+     :background "grey95")
+    (t
+     :inverse-video t))
+  "Face used for buttons when the mouse is hovering over the button."
+  :group 'window-tool-bar)
+
+(defface window-tool-bar-button-disabled
+  '((default
+     :inherit tab-line)
+    (((class color) (min-colors 88))
+     :box (:line-width -1 :style released-button)
+     :background "grey50"
+     :foreground "grey70")
+    (t
+     :inverse-video t
+     :background "brightblack"))
+  "Face used for buttons when the button is disabled."
+  :group 'window-tool-bar)
+
+;;; Workaround for https://debbugs.gnu.org/cgi/bugreport.cgi?bug=68334.
+(defun window-tool-bar--get-keymap ()
+  "Return the tool bar keymap."
+  (let ((tool-bar-always-show-default nil))
+    (if (and (version< emacs-version "30")
+             (not (window-tool-bar--use-images)))
+        ;; This code path is a less efficient workaround.
+        (window-tool-bar--make-keymap-1)
+      (keymap-global-lookup "<tool-bar>"))))
+
+(declare-function image-mask-p "image.c" (spec &optional frame))
+
+(defun window-tool-bar--make-keymap-1 ()
+  "Patched copy of `tool-bar-make-keymap-1'."
+  (mapcar (lambda (bind)
+            (let (image-exp plist)
+              (when (and (eq (car-safe (cdr-safe bind)) 'menu-item)
+                         ;; For the format of menu-items, see node
+                         ;; `Extended Menu Items' in the Elisp manual.
+                         (setq plist (nthcdr (if (consp (nth 4 bind)) 5 4)
+                                             bind))
+                         (setq image-exp (plist-get plist :image))
+                         (consp image-exp)
+                         (not (eq (car image-exp) 'image))
+                         (fboundp (car image-exp)))
+                (let ((image (and (display-images-p)
+                                  (eval image-exp))))
+                  (unless (and image (image-mask-p image))
+                    (setq image (append image '(:mask heuristic))))
+                  (setq bind (copy-sequence bind)
+                        plist (nthcdr (if (consp (nth 4 bind)) 5 4)
+                                      bind))
+                  (plist-put plist :image image)))
+              bind))
+          tool-bar-map))
+
+(defun window-tool-bar--turn-on ()
+  "Internal function called by `global-window-tool-bar-mode'."
+  (when global-window-tool-bar-mode
+    (window-tool-bar-mode 1)))
+
+(provide 'window-tool-bar)
+
+;;; window-tool-bar.el ends here