| 1 | ;;; follow.el --- synchronize windows showing the same buffer |
| 2 | |
| 3 | ;; Copyright (C) 1995-1997, 1999, 2001-2014 Free Software Foundation, |
| 4 | ;; Inc. |
| 5 | |
| 6 | ;; Author: Anders Lindgren <andersl@andersl.com> |
| 7 | ;; Maintainer: emacs-devel@gnu.org (Anders' email bounces, Sep 2005) |
| 8 | ;; Created: 1995-05-25 |
| 9 | ;; Keywords: display, window, minor-mode, convenience |
| 10 | |
| 11 | ;; This file is part of GNU Emacs. |
| 12 | |
| 13 | ;; GNU Emacs is free software: you can redistribute it and/or modify |
| 14 | ;; it under the terms of the GNU General Public License as published by |
| 15 | ;; the Free Software Foundation, either version 3 of the License, or |
| 16 | ;; (at your option) any later version. |
| 17 | |
| 18 | ;; GNU Emacs is distributed in the hope that it will be useful, |
| 19 | ;; but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 20 | ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 21 | ;; GNU General Public License for more details. |
| 22 | |
| 23 | ;; You should have received a copy of the GNU General Public License |
| 24 | ;; along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>. |
| 25 | |
| 26 | ;;; Commentary: |
| 27 | |
| 28 | ;; `Follow mode' is a minor mode for Emacs and XEmacs that |
| 29 | ;; combines windows into one tall virtual window. |
| 30 | ;; |
| 31 | ;; The feeling of a "virtual window" has been accomplished by the use |
| 32 | ;; of two major techniques: |
| 33 | ;; |
| 34 | ;; * The windows always display adjacent sections of the buffer. |
| 35 | ;; This means that whenever one window is moved, all the |
| 36 | ;; others will follow. (Hence the name Follow mode.) |
| 37 | ;; |
| 38 | ;; * Should point (cursor) end up outside a window, another |
| 39 | ;; window displaying that point is selected, if possible. This |
| 40 | ;; makes it possible to walk between windows using normal cursor |
| 41 | ;; movement commands. |
| 42 | ;; |
| 43 | ;; Follow mode comes to its prime when a large screen and two |
| 44 | ;; side-by-side window are used. The user can, with the help of Follow |
| 45 | ;; mode, use two full-height windows as though they are one. |
| 46 | ;; Imagine yourself editing a large function, or section of text, |
| 47 | ;; and being able to use 144 lines instead of the normal 72... (your |
| 48 | ;; mileage may vary). |
| 49 | |
| 50 | ;; To test this package, make sure `follow' is loaded, or will be |
| 51 | ;; autoloaded when activated (see below). Then do the following: |
| 52 | ;; |
| 53 | ;; * Find your favorite file (preferably a long one). |
| 54 | ;; |
| 55 | ;; * Resize Emacs so that it will be wide enough for two full size |
| 56 | ;; columns. Delete the other windows and split the window with |
| 57 | ;; the commands `C-x 1 C-x 3'. |
| 58 | ;; |
| 59 | ;; * Give the command: |
| 60 | ;; M-x follow-mode <RETURN> |
| 61 | ;; |
| 62 | ;; * Now the display should look something like (assuming the text "71" |
| 63 | ;; is on line 71): |
| 64 | ;; |
| 65 | ;; +----------+----------+ |
| 66 | ;; |1 |73 | |
| 67 | ;; |2 |74 | |
| 68 | ;; |3 |75 | |
| 69 | ;; ... ... |
| 70 | ;; |71 |143 | |
| 71 | ;; |72 |144 | |
| 72 | ;; +----------+----------+ |
| 73 | ;; |
| 74 | ;; As you can see, the right-hand window starts at line 73, the line |
| 75 | ;; immediately below the end of the left-hand window. As long as |
| 76 | ;; `follow-mode' is active, the two windows will follow each other! |
| 77 | ;; |
| 78 | ;; * Play around and enjoy! Scroll one window and watch the other. |
| 79 | ;; Jump to the beginning or end. Press `Cursor down' at the last |
| 80 | ;; line of the left-hand window. Enter new lines into the |
| 81 | ;; text. Enter long lines spanning several lines, or several |
| 82 | ;; windows. |
| 83 | ;; |
| 84 | ;; * Should you find `Follow' mode annoying, just type |
| 85 | ;; M-x follow-mode <RETURN> |
| 86 | ;; to turn it off. |
| 87 | |
| 88 | |
| 89 | ;; The command `follow-delete-other-windows-and-split' maximizes the |
| 90 | ;; visible area of the current buffer. |
| 91 | ;; |
| 92 | ;; I recommend adding it, and `follow-mode', to hotkeys in the global |
| 93 | ;; key map. To do so, add the following lines (replacing `[f7]' and |
| 94 | ;; `[f8]' with your favorite keys) to the init file: |
| 95 | ;; |
| 96 | ;; (global-set-key [f8] 'follow-mode) |
| 97 | ;; (global-set-key [f7] 'follow-delete-other-windows-and-split) |
| 98 | |
| 99 | |
| 100 | ;; There exist two system variables that control the appearance of |
| 101 | ;; lines wider than the window containing them. The default is to |
| 102 | ;; truncate long lines whenever a window isn't as wide as the frame. |
| 103 | ;; |
| 104 | ;; To make sure lines are never truncated, please place the following |
| 105 | ;; lines in your init file: |
| 106 | ;; |
| 107 | ;; (setq truncate-lines nil) |
| 108 | ;; (setq truncate-partial-width-windows nil) |
| 109 | |
| 110 | |
| 111 | ;; The correct way to configure Follow mode, or any other mode for |
| 112 | ;; that matter, is to create one or more functions that do |
| 113 | ;; whatever you would like to do. These functions are then added to |
| 114 | ;; a hook. |
| 115 | ;; |
| 116 | ;; The keymap `follow-key-map' contains key bindings activated by |
| 117 | ;; `follow-mode'. |
| 118 | ;; |
| 119 | ;; Example: |
| 120 | ;; (add-hook 'follow-mode-hook 'my-follow-mode-hook) |
| 121 | ;; |
| 122 | ;; (defun my-follow-mode-hook () |
| 123 | ;; (define-key follow-mode-map "\C-ca" 'your-favorite-function) |
| 124 | ;; (define-key follow-mode-map "\C-cb" 'another-function)) |
| 125 | |
| 126 | |
| 127 | ;; Usage: |
| 128 | ;; |
| 129 | ;; To activate, issue the command "M-x follow-mode" |
| 130 | ;; and press Return. To deactivate, do it again. |
| 131 | ;; |
| 132 | ;; The following is a list of commands useful when follow-mode is active. |
| 133 | ;; |
| 134 | ;; follow-scroll-up C-c . C-v |
| 135 | ;; Scroll text in a Follow mode window chain up. |
| 136 | ;; |
| 137 | ;; follow-scroll-down C-c . v |
| 138 | ;; Like `follow-scroll-up', but in the other direction. |
| 139 | ;; |
| 140 | ;; follow-delete-other-windows-and-split C-c . 1 |
| 141 | ;; Maximize the visible area of the current buffer, |
| 142 | ;; and enter Follow mode. This is a very convenient |
| 143 | ;; way to start Follow mode, hence we recommend that |
| 144 | ;; this command be added to the global keymap. |
| 145 | ;; |
| 146 | ;; follow-recenter C-c . C-l |
| 147 | ;; Place point in the center of the middle window, |
| 148 | ;; or a specified number of lines from either top or bottom. |
| 149 | ;; |
| 150 | ;; follow-switch-to-buffer C-c . b |
| 151 | ;; Switch buffer in all windows displaying the current buffer |
| 152 | ;; in this frame. |
| 153 | ;; |
| 154 | ;; follow-switch-to-buffer-all C-c . C-b |
| 155 | ;; Switch buffer in all windows in the selected frame. |
| 156 | ;; |
| 157 | ;; follow-switch-to-current-buffer-all |
| 158 | ;; Show the current buffer in all windows on the current |
| 159 | ;; frame and turn on `follow-mode'. |
| 160 | ;; |
| 161 | ;; follow-first-window C-c . < |
| 162 | ;; Select the first window in the frame showing the same buffer. |
| 163 | ;; |
| 164 | ;; follow-last-window C-c . > |
| 165 | ;; Select the last window in the frame showing the same buffer. |
| 166 | ;; |
| 167 | ;; follow-next-window C-c . n |
| 168 | ;; Select the next window in the frame showing the same buffer. |
| 169 | ;; |
| 170 | ;; follow-previous-window C-c . p |
| 171 | ;; Select the previous window showing the same buffer. |
| 172 | |
| 173 | |
| 174 | ;; Well, it seems ok, but what if I really want to look at two different |
| 175 | ;; positions in the text? Here are two simple methods to use: |
| 176 | ;; |
| 177 | ;; 1) Use multiple frames; `follow' mode only affects windows displayed |
| 178 | ;; in the same frame. (My apologies to you who can't use frames.) |
| 179 | ;; |
| 180 | ;; 2) Bind `follow-mode' to key so you can turn it off whenever |
| 181 | ;; you want to view two locations. Of course, `follow' mode can |
| 182 | ;; be reactivated by hitting the same key again. |
| 183 | ;; |
| 184 | ;; Example from my ~/.emacs: |
| 185 | ;; (global-set-key [f8] 'follow-mode) |
| 186 | |
| 187 | ;; Implementation: |
| 188 | ;; |
| 189 | ;; The main method by which Follow mode aligns windows is via the |
| 190 | ;; function `follow-post-command-hook', which is run after each |
| 191 | ;; command. This "fixes up" the alignment of other windows which are |
| 192 | ;; showing the same Follow mode buffer, on the same frame as the |
| 193 | ;; selected window. It does not try to deal with buffers other than |
| 194 | ;; the buffer of the selected frame, or windows on other frames. |
| 195 | ;; |
| 196 | ;; Comint mode specially calls `follow-comint-scroll-to-bottom' on |
| 197 | ;; Follow mode buffers. This function scrolls the bottom-most window |
| 198 | ;; in a window chain and aligns the other windows accordingly. Follow |
| 199 | ;; mode adds a function to `compilation-filter-hook' to align |
| 200 | ;; compilation buffers. |
| 201 | |
| 202 | ;;; Code: |
| 203 | |
| 204 | (require 'easymenu) |
| 205 | (eval-when-compile (require 'cl-lib)) |
| 206 | |
| 207 | ;;; Variables |
| 208 | |
| 209 | (defgroup follow nil |
| 210 | "Synchronize windows showing the same buffer." |
| 211 | :group 'windows |
| 212 | :group 'convenience) |
| 213 | |
| 214 | (defcustom follow-mode-hook nil |
| 215 | "Normal hook run by `follow-mode'." |
| 216 | :type 'hook |
| 217 | :group 'follow) |
| 218 | |
| 219 | ;;; Keymap/Menu |
| 220 | |
| 221 | ;; Define keys for the follow-mode minor mode map and replace some |
| 222 | ;; functions in the global map. All Follow mode special functions can |
| 223 | ;; be found on the `C-c .' prefix key. |
| 224 | ;; |
| 225 | ;; To change the prefix, redefine `follow-mode-prefix' before `follow' |
| 226 | ;; is loaded, or see the section on `follow-mode-hook' above for an |
| 227 | ;; example of how to bind the keys the way you like. |
| 228 | |
| 229 | (defcustom follow-mode-prefix "\C-c." |
| 230 | "Prefix key to use for follow commands in Follow mode. |
| 231 | The value of this variable is checked as part of loading Follow mode. |
| 232 | After that, changing the prefix key requires manipulating keymaps." |
| 233 | :type 'string |
| 234 | :group 'follow) |
| 235 | |
| 236 | (defvar follow-mode-map |
| 237 | (let ((mainmap (make-sparse-keymap)) |
| 238 | (map (make-sparse-keymap))) |
| 239 | (define-key map "\C-v" 'follow-scroll-up) |
| 240 | (define-key map "\M-v" 'follow-scroll-down) |
| 241 | (define-key map "v" 'follow-scroll-down) |
| 242 | (define-key map "1" 'follow-delete-other-windows-and-split) |
| 243 | (define-key map "b" 'follow-switch-to-buffer) |
| 244 | (define-key map "\C-b" 'follow-switch-to-buffer-all) |
| 245 | (define-key map "\C-l" 'follow-recenter) |
| 246 | (define-key map "<" 'follow-first-window) |
| 247 | (define-key map ">" 'follow-last-window) |
| 248 | (define-key map "n" 'follow-next-window) |
| 249 | (define-key map "p" 'follow-previous-window) |
| 250 | |
| 251 | (define-key mainmap follow-mode-prefix map) |
| 252 | |
| 253 | ;; Replace the standard `end-of-buffer', when in Follow mode. (I |
| 254 | ;; don't see the point in trying to replace every function that |
| 255 | ;; could be enhanced in Follow mode. End-of-buffer is a special |
| 256 | ;; case since it is very simple to define and it greatly enhances |
| 257 | ;; the look and feel of Follow mode.) |
| 258 | (define-key mainmap [remap end-of-buffer] 'follow-end-of-buffer) |
| 259 | |
| 260 | (define-key mainmap [remap scroll-bar-toolkit-scroll] 'follow-scroll-bar-toolkit-scroll) |
| 261 | (define-key mainmap [remap scroll-bar-drag] 'follow-scroll-bar-drag) |
| 262 | (define-key mainmap [remap scroll-bar-scroll-up] 'follow-scroll-bar-scroll-up) |
| 263 | (define-key mainmap [remap scroll-bar-scroll-down] 'follow-scroll-bar-scroll-down) |
| 264 | (define-key mainmap [remap mwheel-scroll] 'follow-mwheel-scroll) |
| 265 | |
| 266 | mainmap) |
| 267 | "Minor mode keymap for Follow mode.") |
| 268 | |
| 269 | ;; When the mode is not activated, only one item is visible to activate |
| 270 | ;; the mode. |
| 271 | (defun follow-menu-filter (menu) |
| 272 | (if (bound-and-true-p follow-mode) |
| 273 | menu |
| 274 | '(["Follow mode" follow-mode |
| 275 | :style toggle :selected follow-mode]))) |
| 276 | |
| 277 | (easy-menu-add-item nil '("Tools") |
| 278 | '("Follow" |
| 279 | :filter follow-menu-filter |
| 280 | ["Scroll Up" follow-scroll-up follow-mode] |
| 281 | ["Scroll Down" follow-scroll-down follow-mode] |
| 282 | "--" |
| 283 | ["Delete Other Windows and Split" follow-delete-other-windows-and-split follow-mode] |
| 284 | "--" |
| 285 | ["Switch To Buffer" follow-switch-to-buffer follow-mode] |
| 286 | ["Switch To Buffer (all windows)" follow-switch-to-buffer-all follow-mode] |
| 287 | "--" |
| 288 | ["First Window" follow-first-window follow-mode] |
| 289 | ["Last Window" follow-last-window follow-mode] |
| 290 | ["Next Window" follow-next-window follow-mode] |
| 291 | ["Previous Window" follow-previous-window follow-mode] |
| 292 | "--" |
| 293 | ["Recenter" follow-recenter follow-mode] |
| 294 | "--" |
| 295 | ["Follow mode" follow-mode :style toggle :selected follow-mode])) |
| 296 | |
| 297 | (defcustom follow-mode-line-text " Follow" |
| 298 | "Text shown in the mode line when Follow mode is active. |
| 299 | Defaults to \" Follow\". Examples of other values |
| 300 | are \" Fw\", or simply \"\"." |
| 301 | :type 'string |
| 302 | :group 'follow) |
| 303 | |
| 304 | (defcustom follow-auto nil |
| 305 | "Non-nil activates Follow mode whenever a file is loaded." |
| 306 | :type 'boolean |
| 307 | :group 'follow |
| 308 | :set (lambda (symbol value) |
| 309 | (if value |
| 310 | (add-hook 'find-file-hook 'follow-find-file-hook t) |
| 311 | (remove-hook 'find-file-hook 'follow-find-file-hook)) |
| 312 | (set-default symbol value))) |
| 313 | |
| 314 | (defvar follow-cache-command-list |
| 315 | '(next-line previous-line forward-char backward-char right-char left-char) |
| 316 | "List of commands that don't require recalculation. |
| 317 | |
| 318 | In order to be able to use the cache, a command should not change the |
| 319 | contents of the buffer, nor should it change selected window or current |
| 320 | buffer. |
| 321 | |
| 322 | The commands in this list are checked at load time. |
| 323 | |
| 324 | To mark other commands as suitable for caching, set the symbol |
| 325 | property `follow-mode-use-cache' to non-nil.") |
| 326 | |
| 327 | (defcustom follow-debug nil |
| 328 | "If non-nil, emit Follow mode debugging messages." |
| 329 | :type 'boolean |
| 330 | :group 'follow) |
| 331 | |
| 332 | ;; Internal variables: |
| 333 | |
| 334 | (defvar follow-internal-force-redisplay nil |
| 335 | "True when Follow mode should redisplay the windows.") |
| 336 | |
| 337 | (defvar follow-active-menu nil |
| 338 | "The menu visible when Follow mode is active.") |
| 339 | |
| 340 | (defvar follow-inactive-menu nil |
| 341 | "The menu visible when Follow mode is inactive.") |
| 342 | |
| 343 | (defvar follow-inside-post-command-hook nil |
| 344 | "Non-nil when inside Follow modes `post-command-hook'. |
| 345 | Used by `follow-window-size-change'.") |
| 346 | |
| 347 | (defvar follow-windows-start-end-cache nil |
| 348 | "Cache used by `follow-window-start-end'.") |
| 349 | |
| 350 | ;;; Debug messages |
| 351 | |
| 352 | ;; This inline function must be as small as possible! |
| 353 | ;; Maybe we should define a macro that expands to nil if |
| 354 | ;; the variable is not set. |
| 355 | |
| 356 | (defsubst follow-debug-message (&rest args) |
| 357 | "Like `message', but only active when `follow-debug' is non-nil." |
| 358 | (if (and (boundp 'follow-debug) follow-debug) |
| 359 | (apply 'message args))) |
| 360 | |
| 361 | ;;; Cache |
| 362 | |
| 363 | (dolist (cmd follow-cache-command-list) |
| 364 | (put cmd 'follow-mode-use-cache t)) |
| 365 | |
| 366 | ;;; The mode |
| 367 | |
| 368 | ;;;###autoload |
| 369 | (defun turn-on-follow-mode () |
| 370 | "Turn on Follow mode. Please see the function `follow-mode'." |
| 371 | (follow-mode 1)) |
| 372 | |
| 373 | |
| 374 | ;;;###autoload |
| 375 | (defun turn-off-follow-mode () |
| 376 | "Turn off Follow mode. Please see the function `follow-mode'." |
| 377 | (follow-mode -1)) |
| 378 | |
| 379 | (put 'follow-mode 'permanent-local t) |
| 380 | ;;;###autoload |
| 381 | (define-minor-mode follow-mode |
| 382 | "Toggle Follow mode. |
| 383 | With a prefix argument ARG, enable Follow mode if ARG is |
| 384 | positive, and disable it otherwise. If called from Lisp, enable |
| 385 | the mode if ARG is omitted or nil. |
| 386 | |
| 387 | Follow mode is a minor mode that combines windows into one tall |
| 388 | virtual window. This is accomplished by two main techniques: |
| 389 | |
| 390 | * The windows always displays adjacent sections of the buffer. |
| 391 | This means that whenever one window is moved, all the |
| 392 | others will follow. (Hence the name Follow mode.) |
| 393 | |
| 394 | * Should point (cursor) end up outside a window, another |
| 395 | window displaying that point is selected, if possible. This |
| 396 | makes it possible to walk between windows using normal cursor |
| 397 | movement commands. |
| 398 | |
| 399 | Follow mode comes to its prime when used on a large screen and two |
| 400 | side-by-side windows are used. The user can, with the help of Follow |
| 401 | mode, use two full-height windows as though they would have been |
| 402 | one. Imagine yourself editing a large function, or section of text, |
| 403 | and being able to use 144 lines instead of the normal 72... (your |
| 404 | mileage may vary). |
| 405 | |
| 406 | To split one large window into two side-by-side windows, the commands |
| 407 | `\\[split-window-right]' or \ |
| 408 | `M-x follow-delete-other-windows-and-split' can be used. |
| 409 | |
| 410 | Only windows displayed in the same frame follow each other. |
| 411 | |
| 412 | This command runs the normal hook `follow-mode-hook'. |
| 413 | |
| 414 | Keys specific to Follow mode: |
| 415 | \\{follow-mode-map}" |
| 416 | :keymap follow-mode-map |
| 417 | (if follow-mode |
| 418 | (progn |
| 419 | (add-hook 'compilation-filter-hook 'follow-align-compilation-windows t t) |
| 420 | (add-hook 'post-command-hook 'follow-post-command-hook t) |
| 421 | (add-hook 'window-size-change-functions 'follow-window-size-change t)) |
| 422 | ;; Remove globally-installed hook functions only if there is no |
| 423 | ;; other Follow mode buffer. |
| 424 | (let ((buffers (buffer-list)) |
| 425 | following) |
| 426 | (while (and (not following) buffers) |
| 427 | (setq following (buffer-local-value 'follow-mode (car buffers)) |
| 428 | buffers (cdr buffers))) |
| 429 | (unless following |
| 430 | (remove-hook 'post-command-hook 'follow-post-command-hook) |
| 431 | (remove-hook 'window-size-change-functions 'follow-window-size-change))) |
| 432 | (remove-hook 'compilation-filter-hook 'follow-align-compilation-windows t))) |
| 433 | |
| 434 | (defun follow-find-file-hook () |
| 435 | "Find-file hook for Follow mode. See the variable `follow-auto'." |
| 436 | (if follow-auto (follow-mode 1))) |
| 437 | |
| 438 | ;;; User functions |
| 439 | |
| 440 | ;;; Scroll |
| 441 | |
| 442 | ;; `scroll-up' and `-down', but for windows in Follow mode. |
| 443 | ;; |
| 444 | ;; Almost like the real thing, except when the cursor ends up outside |
| 445 | ;; the top or bottom... In our case however, we end up outside the |
| 446 | ;; window and hence we are recentered. Should we let `recenter' handle |
| 447 | ;; the point position we would never leave the selected window. To do |
| 448 | ;; it ourselves we would need to do our own redisplay, which is easier |
| 449 | ;; said than done. (Why didn't I do a real display abstraction from |
| 450 | ;; the beginning?) |
| 451 | ;; |
| 452 | ;; We must sometimes set `follow-internal-force-redisplay', otherwise |
| 453 | ;; our post-command-hook will move our windows back into the old |
| 454 | ;; position... (This would also be corrected if we would have had a |
| 455 | ;; good redisplay abstraction.) |
| 456 | |
| 457 | (defun follow-scroll-up (&optional arg) |
| 458 | "Scroll text in a Follow mode window chain up. |
| 459 | |
| 460 | If called with no ARG, the `next-screen-context-lines' last lines of |
| 461 | the bottom window in the chain will be visible in the top window. |
| 462 | |
| 463 | If called with an argument, scroll ARG lines up. |
| 464 | Negative ARG means scroll downward. |
| 465 | |
| 466 | Works like `scroll-up' when not in Follow mode." |
| 467 | (interactive "P") |
| 468 | (cond ((not follow-mode) |
| 469 | (scroll-up arg)) |
| 470 | (arg |
| 471 | (save-excursion (scroll-up arg)) |
| 472 | (setq follow-internal-force-redisplay t)) |
| 473 | (t |
| 474 | (let* ((windows (follow-all-followers)) |
| 475 | (end (window-end (car (reverse windows))))) |
| 476 | (if (eq end (point-max)) |
| 477 | (signal 'end-of-buffer nil) |
| 478 | (select-window (car windows)) |
| 479 | ;; `window-end' might return nil. |
| 480 | (if end |
| 481 | (goto-char end)) |
| 482 | (vertical-motion (- next-screen-context-lines)) |
| 483 | (set-window-start (car windows) (point))))))) |
| 484 | |
| 485 | |
| 486 | (defun follow-scroll-down (&optional arg) |
| 487 | "Scroll text in a Follow mode window chain down. |
| 488 | |
| 489 | If called with no ARG, the `next-screen-context-lines' top lines of |
| 490 | the top window in the chain will be visible in the bottom window. |
| 491 | |
| 492 | If called with an argument, scroll ARG lines down. |
| 493 | Negative ARG means scroll upward. |
| 494 | |
| 495 | Works like `scroll-up' when not in Follow mode." |
| 496 | (interactive "P") |
| 497 | (cond ((not follow-mode) |
| 498 | (scroll-up arg)) |
| 499 | (arg |
| 500 | (save-excursion (scroll-down arg))) |
| 501 | (t |
| 502 | (let* ((windows (follow-all-followers)) |
| 503 | (win (car (reverse windows))) |
| 504 | (start (window-start (car windows)))) |
| 505 | (if (eq start (point-min)) |
| 506 | (signal 'beginning-of-buffer nil) |
| 507 | (select-window win) |
| 508 | (goto-char start) |
| 509 | (vertical-motion (- (- (window-height win) |
| 510 | (if header-line-format 2 1) |
| 511 | next-screen-context-lines))) |
| 512 | (set-window-start win (point)) |
| 513 | (goto-char start) |
| 514 | (vertical-motion (- next-screen-context-lines 1)) |
| 515 | (setq follow-internal-force-redisplay t)))))) |
| 516 | |
| 517 | (declare-function comint-adjust-point "comint" (window)) |
| 518 | (defvar comint-scroll-show-maximum-output) |
| 519 | |
| 520 | (defun follow-comint-scroll-to-bottom (&optional _window) |
| 521 | "Scroll the bottom-most window in the current Follow chain. |
| 522 | This is to be called by `comint-postoutput-scroll-to-bottom'." |
| 523 | (let* ((buffer (current-buffer)) |
| 524 | (selected (selected-window)) |
| 525 | (is-selected (eq (window-buffer) buffer)) |
| 526 | some-window) |
| 527 | (when (or is-selected |
| 528 | (setq some-window (get-buffer-window))) |
| 529 | (let* ((pos (progn (comint-adjust-point nil) (point))) |
| 530 | (win (if is-selected |
| 531 | selected |
| 532 | (car (last (follow-all-followers some-window)))))) |
| 533 | (select-window win) |
| 534 | (goto-char pos) |
| 535 | (setq follow-windows-start-end-cache nil) |
| 536 | (follow-adjust-window win) |
| 537 | (unless is-selected |
| 538 | (select-window selected) |
| 539 | (set-buffer buffer)))))) |
| 540 | |
| 541 | (defun follow-align-compilation-windows () |
| 542 | "Align the windows of the current Follow mode buffer. |
| 543 | This is to be called from `compilation-filter-hook'." |
| 544 | (let ((buffer (current-buffer)) |
| 545 | (win (get-buffer-window)) |
| 546 | (selected (selected-window))) |
| 547 | (when (and follow-mode (waiting-for-user-input-p) win) |
| 548 | (let ((windows (follow-all-followers win))) |
| 549 | (unless (eq (window-buffer selected) buffer) |
| 550 | (setq win (car windows)) |
| 551 | (select-window win)) |
| 552 | (follow-redisplay windows win t) |
| 553 | (setq follow-windows-start-end-cache nil) |
| 554 | (unless (eq selected win) |
| 555 | (select-window selected) |
| 556 | (set-buffer buffer)))))) |
| 557 | |
| 558 | ;;; Buffer |
| 559 | |
| 560 | ;;;###autoload |
| 561 | (defun follow-delete-other-windows-and-split (&optional arg) |
| 562 | "Create two side by side windows and enter Follow mode. |
| 563 | |
| 564 | Execute this command to display as much as possible of the text |
| 565 | in the selected window. All other windows, in the current |
| 566 | frame, are deleted and the selected window is split in two |
| 567 | side-by-side windows. Follow mode is activated, hence the |
| 568 | two windows always will display two successive pages. |
| 569 | \(If one window is moved, the other one will follow.) |
| 570 | |
| 571 | If ARG is positive, the leftmost window is selected. If negative, |
| 572 | the rightmost is selected. If ARG is nil, the leftmost window is |
| 573 | selected if the original window is the first one in the frame." |
| 574 | (interactive "P") |
| 575 | (let ((other (or (and (null arg) |
| 576 | (not (eq (selected-window) |
| 577 | (frame-first-window)))) |
| 578 | (and arg |
| 579 | (< (prefix-numeric-value arg) 0)))) |
| 580 | (start (window-start))) |
| 581 | (delete-other-windows) |
| 582 | (split-window-right) |
| 583 | (if other |
| 584 | (progn |
| 585 | (other-window 1) |
| 586 | (set-window-start (selected-window) start) |
| 587 | (setq follow-internal-force-redisplay t))) |
| 588 | (follow-mode 1))) |
| 589 | |
| 590 | (defun follow-switch-to-buffer (buffer) |
| 591 | "Show BUFFER in all windows in the current Follow mode window chain." |
| 592 | (interactive "BSwitch to Buffer: ") |
| 593 | (let ((orig-window (selected-window)) |
| 594 | (windows (follow-all-followers))) |
| 595 | (while windows |
| 596 | (select-window (car windows)) |
| 597 | (switch-to-buffer buffer) |
| 598 | (setq windows (cdr windows))) |
| 599 | (select-window orig-window))) |
| 600 | |
| 601 | |
| 602 | (defun follow-switch-to-buffer-all (&optional buffer) |
| 603 | "Show BUFFER in all windows on this frame. |
| 604 | Defaults to current buffer." |
| 605 | (interactive (list (read-buffer "Switch to Buffer: " |
| 606 | (current-buffer)))) |
| 607 | (or buffer (setq buffer (current-buffer))) |
| 608 | (let ((orig-window (selected-window))) |
| 609 | (walk-windows (lambda (win) |
| 610 | (select-window win) |
| 611 | (switch-to-buffer buffer)) |
| 612 | 'no-minibuf) |
| 613 | (select-window orig-window) |
| 614 | (follow-redisplay))) |
| 615 | |
| 616 | |
| 617 | (defun follow-switch-to-current-buffer-all () |
| 618 | "Show current buffer in all windows on this frame, and enter Follow mode." |
| 619 | (interactive) |
| 620 | (unless follow-mode |
| 621 | (follow-mode 1)) |
| 622 | (follow-switch-to-buffer-all)) |
| 623 | |
| 624 | ;;; Movement |
| 625 | |
| 626 | ;; Note, these functions are not very useful, at least not unless you |
| 627 | ;; rebind the rather cumbersome key sequence `C-c . p'. |
| 628 | |
| 629 | (defun follow-next-window () |
| 630 | "Select the next window showing the same buffer." |
| 631 | (interactive) |
| 632 | (let ((succ (cdr (follow-split-followers (follow-all-followers))))) |
| 633 | (if succ |
| 634 | (select-window (car succ)) |
| 635 | (error "%s" "No more windows")))) |
| 636 | |
| 637 | |
| 638 | (defun follow-previous-window () |
| 639 | "Select the previous window showing the same buffer." |
| 640 | (interactive) |
| 641 | (let ((pred (car (follow-split-followers (follow-all-followers))))) |
| 642 | (if pred |
| 643 | (select-window (car pred)) |
| 644 | (error "%s" "No more windows")))) |
| 645 | |
| 646 | |
| 647 | (defun follow-first-window () |
| 648 | "Select the first window in the frame showing the same buffer." |
| 649 | (interactive) |
| 650 | (select-window (car (follow-all-followers)))) |
| 651 | |
| 652 | |
| 653 | (defun follow-last-window () |
| 654 | "Select the last window in the frame showing the same buffer." |
| 655 | (interactive) |
| 656 | (select-window (car (reverse (follow-all-followers))))) |
| 657 | |
| 658 | ;;; Redraw |
| 659 | |
| 660 | (defun follow-recenter (&optional arg) |
| 661 | "Recenter the middle window around point. |
| 662 | Rearrange all other windows around the middle window. |
| 663 | |
| 664 | With a positive argument, place the current line ARG lines |
| 665 | from the top. With a negative argument, place it -ARG lines |
| 666 | from the bottom." |
| 667 | (interactive "P") |
| 668 | (if arg |
| 669 | (let ((p (point)) |
| 670 | (arg (prefix-numeric-value arg))) |
| 671 | (if (>= arg 0) |
| 672 | ;; Recenter relative to the top. |
| 673 | (progn |
| 674 | (follow-first-window) |
| 675 | (goto-char p) |
| 676 | (recenter arg)) |
| 677 | ;; Recenter relative to the bottom. |
| 678 | (follow-last-window) |
| 679 | (goto-char p) |
| 680 | (recenter arg) |
| 681 | ;; Otherwise, our post-command-hook will move the window |
| 682 | ;; right back. |
| 683 | (setq follow-internal-force-redisplay t))) |
| 684 | ;; Recenter in the middle. |
| 685 | (let* ((dest (point)) |
| 686 | (windows (follow-all-followers)) |
| 687 | (win (nth (/ (- (length windows) 1) 2) windows))) |
| 688 | (select-window win) |
| 689 | (goto-char dest) |
| 690 | (recenter)))) |
| 691 | |
| 692 | |
| 693 | (defun follow-redraw () |
| 694 | "Arrange windows displaying the same buffer in successor order. |
| 695 | This function can be called even if the buffer is not in Follow mode. |
| 696 | |
| 697 | Hopefully, there should be no reason to call this function when in |
| 698 | Follow mode since the windows should always be aligned." |
| 699 | (interactive) |
| 700 | (sit-for 0) |
| 701 | (follow-redisplay)) |
| 702 | |
| 703 | ;;; End of buffer |
| 704 | |
| 705 | (defun follow-end-of-buffer (&optional arg) |
| 706 | "Move point to the end of the buffer, Follow mode style. |
| 707 | |
| 708 | If the end is not visible, it will be displayed in the last possible |
| 709 | window in the Follow mode window chain. |
| 710 | |
| 711 | The mark is left at the previous position. With arg N, put point N/10 |
| 712 | of the way from the true end." |
| 713 | (interactive "P") |
| 714 | (let ((followers (follow-all-followers)) |
| 715 | (pos (point))) |
| 716 | (cond (arg |
| 717 | (select-window (car (reverse followers)))) |
| 718 | ((follow-select-if-end-visible |
| 719 | (follow-windows-start-end followers))) |
| 720 | (t |
| 721 | (select-window (car (reverse followers))))) |
| 722 | (goto-char pos) |
| 723 | (with-no-warnings |
| 724 | (end-of-buffer arg)))) |
| 725 | |
| 726 | ;;; Display |
| 727 | |
| 728 | (defun follow--window-sorter (w1 w2) |
| 729 | "Sorting function for W1 and W2 based on their positions. |
| 730 | Return non-nil if W1 is above W2; if their top-lines |
| 731 | are at the same position, return non-nil if W1 is to the |
| 732 | left of W2." |
| 733 | (let* ((edge-1 (window-pixel-edges w1)) |
| 734 | (edge-2 (window-pixel-edges w2)) |
| 735 | (y1 (nth 1 edge-1)) |
| 736 | (y2 (nth 1 edge-2))) |
| 737 | (if (= y1 y2) |
| 738 | (< (car edge-1) (car edge-2)) |
| 739 | (< y1 y2)))) |
| 740 | |
| 741 | (defun follow-all-followers (&optional win) |
| 742 | "Return all windows displaying the same buffer as the WIN. |
| 743 | The list is sorted with topmost and leftmost windows first, and |
| 744 | contains only windows in the same frame as WIN. If WIN is nil, |
| 745 | it defaults to the selected window." |
| 746 | (unless (window-live-p win) |
| 747 | (setq win (selected-window))) |
| 748 | (let ((windows (get-buffer-window-list |
| 749 | (window-buffer win) 'no-minibuf (window-frame win)))) |
| 750 | (sort windows #'follow--window-sorter))) |
| 751 | |
| 752 | (defun follow-split-followers (windows &optional win) |
| 753 | "Split WINDOWS into two sets: predecessors and successors. |
| 754 | Return `(PRED . SUCC)' where `PRED' and `SUCC' are ordered starting |
| 755 | from the selected window." |
| 756 | (or win |
| 757 | (setq win (selected-window))) |
| 758 | (let ((pred '())) |
| 759 | (while (not (eq (car windows) win)) |
| 760 | (setq pred (cons (car windows) pred)) |
| 761 | (setq windows (cdr windows))) |
| 762 | (cons pred (cdr windows)))) |
| 763 | |
| 764 | (defun follow-calc-win-end (&optional win) |
| 765 | "Calculate the end position for window WIN. |
| 766 | Return (END-POS END-OF-BUFFER). |
| 767 | |
| 768 | Actually, the position returned is the start of the line after |
| 769 | the last fully-visible line in WIN. If WIN is nil, the selected |
| 770 | window is used." |
| 771 | (let* ((win (or win (selected-window))) |
| 772 | (edges (window-inside-pixel-edges win)) |
| 773 | (ht (- (nth 3 edges) (nth 1 edges))) |
| 774 | (last-line-pos (posn-point (posn-at-x-y 0 (1- ht) win)))) |
| 775 | (if (pos-visible-in-window-p last-line-pos win) |
| 776 | (let ((end (window-end win t))) |
| 777 | (list end (= end (point-max)))) |
| 778 | (list last-line-pos nil)))) |
| 779 | |
| 780 | (defun follow-calc-win-start (windows pos win) |
| 781 | "Determine the start of window WIN in a Follow mode window chain. |
| 782 | WINDOWS is a list of chained windows, and POS is the starting |
| 783 | position for the first window in the list. If WIN is nil, return |
| 784 | the point below all windows." |
| 785 | (while (and windows (not (eq (car windows) win))) |
| 786 | (let ((old-start (window-start (car windows)))) |
| 787 | ;; Can't use `save-window-excursion' since it triggers a redraw. |
| 788 | (set-window-start (car windows) pos 'noforce) |
| 789 | (setq pos (car (follow-calc-win-end (car windows)))) |
| 790 | (set-window-start (car windows) old-start 'noforce) |
| 791 | (setq windows (cdr windows)))) |
| 792 | pos) |
| 793 | |
| 794 | ;; The result from `follow-windows-start-end' is cached when using |
| 795 | ;; a handful simple commands, like cursor movement commands. |
| 796 | |
| 797 | (defsubst follow-cache-valid-p (windows) |
| 798 | "Test if the cached value of `follow-windows-start-end' can be used. |
| 799 | Note that this handles the case when the cache has been set to nil." |
| 800 | (let ((res t) |
| 801 | (cache follow-windows-start-end-cache)) |
| 802 | (while (and res windows cache) |
| 803 | (setq res (and (eq (car windows) |
| 804 | (car (car cache))) |
| 805 | (eq (window-start (car windows)) |
| 806 | (car (cdr (car cache)))))) |
| 807 | (setq windows (cdr windows)) |
| 808 | (setq cache (cdr cache))) |
| 809 | (and res (null windows) (null cache)))) |
| 810 | |
| 811 | (defun follow-windows-start-end (windows) |
| 812 | "Return a list of (WIN START END BUFFER-END-P) for window list WINDOWS." |
| 813 | (if (follow-cache-valid-p windows) |
| 814 | follow-windows-start-end-cache |
| 815 | (let ((orig-win (selected-window)) |
| 816 | win-start-end) |
| 817 | (dolist (w windows) |
| 818 | (select-window w) |
| 819 | (push (cons w (cons (window-start) (follow-calc-win-end))) |
| 820 | win-start-end)) |
| 821 | (select-window orig-win) |
| 822 | (setq follow-windows-start-end-cache (nreverse win-start-end))))) |
| 823 | |
| 824 | (defsubst follow-pos-visible (pos win win-start-end) |
| 825 | "Non-nil when POS is visible in WIN." |
| 826 | (let ((wstart-wend-bend (cdr (assq win win-start-end)))) |
| 827 | (and (>= pos (car wstart-wend-bend)) |
| 828 | (or (< pos (cadr wstart-wend-bend)) |
| 829 | (nth 2 wstart-wend-bend))))) |
| 830 | |
| 831 | |
| 832 | ;; By `aligned' we mean that for all adjacent windows, the end of the |
| 833 | ;; first is equal with the start of the successor. The first window |
| 834 | ;; should start at a full screen line. |
| 835 | |
| 836 | (defsubst follow-windows-aligned-p (win-start-end) |
| 837 | "Non-nil if the follower windows are aligned. |
| 838 | The argument, WIN-START-END, should be a list of the form |
| 839 | returned by `follow-windows-start-end'." |
| 840 | (let ((result t)) |
| 841 | (while (and win-start-end result) |
| 842 | (if (cdr win-start-end) |
| 843 | (setq result (eq (nth 2 (car win-start-end)) |
| 844 | (nth 1 (cadr win-start-end))))) |
| 845 | (setq win-start-end (cdr win-start-end))) |
| 846 | result)) |
| 847 | |
| 848 | ;; Check if point is visible in all windows. (So that |
| 849 | ;; no one will be recentered.) |
| 850 | |
| 851 | (defun follow-point-visible-all-windows-p (win-start-end) |
| 852 | "Non-nil when the `window-point' is visible in all windows." |
| 853 | (let ((res t)) |
| 854 | (while (and res win-start-end) |
| 855 | (setq res (follow-pos-visible (window-point (car (car win-start-end))) |
| 856 | (car (car win-start-end)) |
| 857 | win-start-end)) |
| 858 | (setq win-start-end (cdr win-start-end))) |
| 859 | res)) |
| 860 | |
| 861 | |
| 862 | ;; Make sure WIN always starts at the beginning of a whole screen |
| 863 | ;; line. If WIN is not aligned the start is updated which probably |
| 864 | ;; will lead to a redisplay of the screen later on. |
| 865 | ;; |
| 866 | ;; This is used with the first window in a follow chain. The reason |
| 867 | ;; is that we want to detect that point is outside the window. |
| 868 | ;; (Without the update, the start of the window will move as the |
| 869 | ;; user presses BackSpace, and the other window redisplay routines |
| 870 | ;; will move the start of the window in the wrong direction.) |
| 871 | |
| 872 | (defun follow-update-window-start (win) |
| 873 | "Make sure that the start of WIN starts at a full screen line." |
| 874 | (save-excursion |
| 875 | (goto-char (window-start win)) |
| 876 | (unless (bolp) |
| 877 | (vertical-motion 0 win) |
| 878 | (unless (eq (point) (window-start win)) |
| 879 | (vertical-motion 1 win) |
| 880 | (set-window-start win (point) 'noforce))))) |
| 881 | |
| 882 | (defun follow-select-if-visible (dest win-start-end) |
| 883 | "Select and return a window, if DEST is visible in it. |
| 884 | Return the selected window." |
| 885 | (let (win wse) |
| 886 | (while (and (not win) win-start-end) |
| 887 | ;; Don't select a window that was just moved. This makes it |
| 888 | ;; possible to later select the last window after a |
| 889 | ;; `end-of-buffer' command. |
| 890 | (setq wse (car win-start-end)) |
| 891 | (when (follow-pos-visible dest (car wse) win-start-end) |
| 892 | (setq win (car wse)) |
| 893 | (select-window win)) |
| 894 | (setq win-start-end (cdr win-start-end))) |
| 895 | win)) |
| 896 | |
| 897 | ;; Lets select a window showing the end. Make sure we only select it if |
| 898 | ;; it wasn't just moved here. (I.e. M-> shall not unconditionally place |
| 899 | ;; point in the selected window.) |
| 900 | ;; |
| 901 | ;; (Compatibility kludge: in Emacs `window-end' is equal to `point-max'; |
| 902 | ;; in XEmacs, it is equal to `point-max + 1'. Should I really bother |
| 903 | ;; checking `window-end' now when I check `end-of-buffer' explicitly?) |
| 904 | |
| 905 | (defun follow-select-if-end-visible (win-start-end) |
| 906 | "Select and return a window, if end is visible in it." |
| 907 | (let ((win nil)) |
| 908 | (while (and (not win) win-start-end) |
| 909 | ;; Don't select a window that was just moved. This makes it |
| 910 | ;; possible to later select the last window after a `end-of-buffer' |
| 911 | ;; command. |
| 912 | (if (and (eq (point-max) (nth 2 (car win-start-end))) |
| 913 | (nth 3 (car win-start-end)) |
| 914 | ;; `window-end' might return nil. |
| 915 | (let ((end (window-end (car (car win-start-end))))) |
| 916 | (and end |
| 917 | (eq (point-max) (min (point-max) end))))) |
| 918 | (progn |
| 919 | (setq win (car (car win-start-end))) |
| 920 | (select-window win))) |
| 921 | (setq win-start-end (cdr win-start-end))) |
| 922 | win)) |
| 923 | |
| 924 | |
| 925 | ;; Select a window that will display point if the windows would |
| 926 | ;; be redisplayed with the first window fixed. This is useful for |
| 927 | ;; example when the user has pressed return at the bottom of a window |
| 928 | ;; as point is not visible in any window. |
| 929 | |
| 930 | (defun follow-select-if-visible-from-first (dest windows) |
| 931 | "Try to select one of WINDOWS without repositioning the topmost window. |
| 932 | If one of the windows in WINDOWS contains DEST, select it, call |
| 933 | `follow-redisplay', move point to DEST, and return that window. |
| 934 | Otherwise, return nil." |
| 935 | (let (win end-pos-end-p) |
| 936 | (save-excursion |
| 937 | (goto-char (window-start (car windows))) |
| 938 | ;; Make sure the line start in the beginning of a real screen |
| 939 | ;; line. |
| 940 | (vertical-motion 0 (car windows)) |
| 941 | (when (>= dest (point)) |
| 942 | ;; At or below the start. Check the windows. |
| 943 | (save-window-excursion |
| 944 | (let ((windows windows)) |
| 945 | (while (and (not win) windows) |
| 946 | (set-window-start (car windows) (point) 'noforce) |
| 947 | (setq end-pos-end-p (follow-calc-win-end (car windows))) |
| 948 | (goto-char (car end-pos-end-p)) |
| 949 | ;; Visible, if dest above end, or if eob is visible |
| 950 | ;; inside the window. |
| 951 | (if (or (car (cdr end-pos-end-p)) |
| 952 | (< dest (point))) |
| 953 | (setq win (car windows)) |
| 954 | (setq windows (cdr windows)))))))) |
| 955 | (when win |
| 956 | (select-window win) |
| 957 | (follow-redisplay windows (car windows)) |
| 958 | (goto-char dest)) |
| 959 | win)) |
| 960 | |
| 961 | ;;; Redisplay |
| 962 | |
| 963 | ;; Redraw all the windows on the screen, starting with the top window. |
| 964 | ;; The window used as as marker is WIN, or the selected window if WIN |
| 965 | ;; is nil. Start every window directly after the end of the previous |
| 966 | ;; window, to make sure long lines are displayed correctly. |
| 967 | |
| 968 | (defun follow-redisplay (&optional windows win preserve-win) |
| 969 | "Reposition the WINDOWS around WIN. |
| 970 | Should point be too close to the roof we redisplay everything |
| 971 | from the top. WINDOWS should contain a list of windows to |
| 972 | redisplay; it is assumed that WIN is a member of the list. |
| 973 | Should WINDOWS be nil, the windows displaying the |
| 974 | same buffer as WIN, in the current frame, are used. |
| 975 | Should WIN be nil, the selected window is used. |
| 976 | If PRESERVE-WIN is non-nil, keep WIN itself unchanged while |
| 977 | repositioning the other windows." |
| 978 | (or win (setq win (selected-window))) |
| 979 | (or windows (setq windows (follow-all-followers win))) |
| 980 | ;; Calculate the start of the first window. |
| 981 | (let* ((old-win-start (window-start win)) |
| 982 | (try-first-start (follow-estimate-first-window-start |
| 983 | windows win old-win-start)) |
| 984 | (try-win-start (follow-calc-win-start |
| 985 | windows try-first-start win)) |
| 986 | (start (cond ((= try-win-start old-win-start) |
| 987 | (follow-debug-message "exact") |
| 988 | try-first-start) |
| 989 | ((< try-win-start old-win-start) |
| 990 | (follow-debug-message "above") |
| 991 | (follow-calculate-first-window-start-from-above |
| 992 | windows try-first-start win old-win-start)) |
| 993 | (t |
| 994 | (follow-debug-message "below") |
| 995 | (follow-calculate-first-window-start-from-below |
| 996 | windows try-first-start win old-win-start))))) |
| 997 | (dolist (w windows) |
| 998 | (unless (and preserve-win (eq w win)) |
| 999 | (set-window-start w start)) |
| 1000 | (setq start (car (follow-calc-win-end w)))))) |
| 1001 | |
| 1002 | (defun follow-estimate-first-window-start (windows win start) |
| 1003 | "Estimate the position of the first window. |
| 1004 | The estimate is computed by assuming that the window WIN, which |
| 1005 | should be a member of WINDOWS, starts at position START." |
| 1006 | (let ((windows-before (car (follow-split-followers windows win)))) |
| 1007 | (save-excursion |
| 1008 | (goto-char start) |
| 1009 | (vertical-motion 0 win) |
| 1010 | (dolist (w windows-before) |
| 1011 | (vertical-motion (- 1 (window-text-height w)) w)) |
| 1012 | (point)))) |
| 1013 | |
| 1014 | |
| 1015 | ;; Find the starting point, start at GUESS and search downward. |
| 1016 | ;; The returned point is always a point below GUESS. |
| 1017 | |
| 1018 | (defun follow-calculate-first-window-start-from-above |
| 1019 | (windows guess win start) |
| 1020 | (save-excursion |
| 1021 | (let ((done nil) |
| 1022 | win-start |
| 1023 | res) |
| 1024 | (goto-char guess) |
| 1025 | (while (not done) |
| 1026 | (if (not (= (vertical-motion 1 (car windows)) 1)) |
| 1027 | ;; Hit bottom! (Can we really do this?) |
| 1028 | ;; We'll keep it, since it ensures termination. |
| 1029 | (progn |
| 1030 | (setq done t) |
| 1031 | (setq res (point-max))) |
| 1032 | (setq win-start (follow-calc-win-start windows (point) win)) |
| 1033 | (if (>= win-start start) |
| 1034 | (setq done t res (point))))) |
| 1035 | res))) |
| 1036 | |
| 1037 | |
| 1038 | ;; Find the starting point, start at GUESS and search upward. Return |
| 1039 | ;; a point on the same line as GUESS, or above. |
| 1040 | |
| 1041 | (defun follow-calculate-first-window-start-from-below |
| 1042 | (windows guess &optional win start) |
| 1043 | (setq win (or win (selected-window))) |
| 1044 | (setq start (or start (window-start win))) |
| 1045 | (save-excursion |
| 1046 | (let (done win-start res opoint) |
| 1047 | ;; Always calculate what happens when no line is displayed in the first |
| 1048 | ;; window. (The `previous' res is needed below!) |
| 1049 | (goto-char guess) |
| 1050 | (vertical-motion 0 (car windows)) |
| 1051 | (setq res (point)) |
| 1052 | (while (not done) |
| 1053 | (setq opoint (point)) |
| 1054 | (if (not (= (vertical-motion -1 (car windows)) -1)) |
| 1055 | ;; Hit roof! |
| 1056 | (setq done t res (point-min)) |
| 1057 | (setq win-start (follow-calc-win-start windows (point) win)) |
| 1058 | (cond ((>= (point) opoint) |
| 1059 | ;; In some pathological cases, vertical-motion may |
| 1060 | ;; return -1 even though point has not decreased. In |
| 1061 | ;; that case, avoid looping forever. |
| 1062 | (setq done t res (point))) |
| 1063 | ((= win-start start) ; Perfect match, use this value |
| 1064 | (setq done t res (point))) |
| 1065 | ((< win-start start) ; Walked to far, use previous result |
| 1066 | (setq done t)) |
| 1067 | (t ; Store result for next iteration |
| 1068 | (setq res (point)))))) |
| 1069 | res))) |
| 1070 | |
| 1071 | ;;; Avoid tail recenter |
| 1072 | |
| 1073 | ;; This sets the window internal flag `force_start'. The effect is |
| 1074 | ;; that windows only displaying the tail aren't recentered. |
| 1075 | ;; |
| 1076 | ;; A window displaying only the tail, is a window whose window-start |
| 1077 | ;; position is equal to (point-max) of the buffer it displays. |
| 1078 | |
| 1079 | (defun follow-avoid-tail-recenter (&rest _rest) |
| 1080 | "Make sure windows displaying the end of a buffer aren't recentered. |
| 1081 | This is done by reading and rewriting the start position of |
| 1082 | non-first windows in Follow mode." |
| 1083 | (let* ((orig-buffer (current-buffer)) |
| 1084 | (top (frame-first-window)) |
| 1085 | (win top) |
| 1086 | who) ; list of (buffer . frame) |
| 1087 | ;; If the only window in the frame is a minibuffer |
| 1088 | ;; window, `next-window' will never find it again... |
| 1089 | (unless (window-minibuffer-p top) |
| 1090 | (while ;; look, no body! |
| 1091 | (let ((start (window-start win)) |
| 1092 | (pair (cons (window-buffer win) (window-frame win)))) |
| 1093 | (set-buffer (window-buffer win)) |
| 1094 | (cond ((null (member pair who)) |
| 1095 | (setq who (cons pair who))) |
| 1096 | ((and follow-mode (eq (point-max) start)) |
| 1097 | ;; Write the same window start back, but don't |
| 1098 | ;; set the NOFORCE flag. |
| 1099 | (set-window-start win start))) |
| 1100 | (setq win (next-window win 'not t)) |
| 1101 | (not (eq win top)))) ;; Loop while this is true. |
| 1102 | (set-buffer orig-buffer)))) |
| 1103 | |
| 1104 | ;;; Post Command Hook |
| 1105 | |
| 1106 | ;; The magic little box. This function is called after every command. |
| 1107 | |
| 1108 | ;; This is not as complicated as it seems. It is simply a list of common |
| 1109 | ;; display situations and the actions to take, plus commands for redrawing |
| 1110 | ;; the screen if it should be unaligned. |
| 1111 | ;; |
| 1112 | ;; We divide the check into two parts; whether we are at the end or not. |
| 1113 | ;; This is due to the fact that the end can actually be visible |
| 1114 | ;; in several window even though they are aligned. |
| 1115 | |
| 1116 | (defun follow-post-command-hook () |
| 1117 | "Ensure that the windows in Follow mode are adjacent after each command." |
| 1118 | (unless (input-pending-p) |
| 1119 | (let ((follow-inside-post-command-hook t) |
| 1120 | (win (selected-window))) |
| 1121 | ;; Work in the selected window, not in the current buffer. |
| 1122 | (with-current-buffer (window-buffer win) |
| 1123 | (unless (and (symbolp this-command) |
| 1124 | (get this-command 'follow-mode-use-cache)) |
| 1125 | (setq follow-windows-start-end-cache nil)) |
| 1126 | (follow-adjust-window win))))) |
| 1127 | |
| 1128 | (defun follow-adjust-window (win) |
| 1129 | ;; Adjust the window WIN and its followers. |
| 1130 | (cl-assert (eq (window-buffer win) (current-buffer))) |
| 1131 | (when (and follow-mode |
| 1132 | (not (window-minibuffer-p win))) |
| 1133 | (let* ((dest (point)) |
| 1134 | (windows (follow-all-followers win)) |
| 1135 | (win-start-end (progn |
| 1136 | (follow-update-window-start (car windows)) |
| 1137 | (follow-windows-start-end windows))) |
| 1138 | (aligned (follow-windows-aligned-p win-start-end)) |
| 1139 | (visible (follow-pos-visible dest win win-start-end)) |
| 1140 | selected-window-up-to-date) |
| 1141 | (unless (and aligned visible) |
| 1142 | (setq follow-windows-start-end-cache nil)) |
| 1143 | |
| 1144 | ;; Select a window to display point. |
| 1145 | (unless follow-internal-force-redisplay |
| 1146 | (if (eq dest (point-max)) |
| 1147 | ;; Be careful at point-max: the display can be aligned |
| 1148 | ;; while DEST can be visible in several windows. |
| 1149 | (cond |
| 1150 | ;; Select the current window, but only when the display |
| 1151 | ;; is correct. (When inserting characters in a tail |
| 1152 | ;; window, the display is not correct, as they are |
| 1153 | ;; shown twice.) |
| 1154 | ;; |
| 1155 | ;; Never stick to the current window after a deletion. |
| 1156 | ;; Otherwise, when typing `DEL' in a window showing |
| 1157 | ;; only the end of the file, a character would be |
| 1158 | ;; removed from the window above, which is very |
| 1159 | ;; unintuitive. |
| 1160 | ((and visible |
| 1161 | aligned |
| 1162 | (not (memq this-command |
| 1163 | '(backward-delete-char |
| 1164 | delete-backward-char |
| 1165 | backward-delete-char-untabify |
| 1166 | kill-region)))) |
| 1167 | (follow-debug-message "Max: same")) |
| 1168 | ;; If the end is visible, and the window doesn't |
| 1169 | ;; seems like it just has been moved, select it. |
| 1170 | ((follow-select-if-end-visible win-start-end) |
| 1171 | (follow-debug-message "Max: end visible") |
| 1172 | (setq visible t aligned nil) |
| 1173 | (goto-char dest)) |
| 1174 | ;; Just show the end... |
| 1175 | (t |
| 1176 | (follow-debug-message "Max: default") |
| 1177 | (select-window (car (last windows))) |
| 1178 | (goto-char dest) |
| 1179 | (setq visible nil aligned nil))) |
| 1180 | |
| 1181 | ;; We're not at the end, here life is much simpler. |
| 1182 | (cond |
| 1183 | ;; This is the normal case! |
| 1184 | ;; It should be optimized for speed. |
| 1185 | ((and visible aligned) |
| 1186 | (follow-debug-message "same")) |
| 1187 | ;; Pick a position in any window. If the display is ok, |
| 1188 | ;; this picks the `correct' window. |
| 1189 | ((follow-select-if-visible dest win-start-end) |
| 1190 | (follow-debug-message "visible") |
| 1191 | (goto-char dest) |
| 1192 | ;; Perform redisplay, in case line is partially visible. |
| 1193 | (setq visible nil)) |
| 1194 | ;; Not visible anywhere else, lets pick this one. |
| 1195 | (visible |
| 1196 | (follow-debug-message "visible in selected.")) |
| 1197 | ;; If DEST is before the first window start, select the |
| 1198 | ;; first window. |
| 1199 | ((< dest (nth 1 (car win-start-end))) |
| 1200 | (follow-debug-message "before first") |
| 1201 | (select-window (car windows)) |
| 1202 | (goto-char dest) |
| 1203 | (setq visible nil aligned nil)) |
| 1204 | ;; If we can position the cursor without moving the first |
| 1205 | ;; window, do it. This is the case that catches `RET' at |
| 1206 | ;; the bottom of a window. |
| 1207 | ((follow-select-if-visible-from-first dest windows) |
| 1208 | (follow-debug-message "Below first") |
| 1209 | (setq visible t aligned t)) |
| 1210 | ;; None of the above. Stick to the selected window. |
| 1211 | (t |
| 1212 | (follow-debug-message "None") |
| 1213 | (setq visible nil aligned nil)))) |
| 1214 | |
| 1215 | ;; If a new window was selected, make sure that the old is |
| 1216 | ;; not scrolled when point is outside the window. |
| 1217 | (unless (eq win (selected-window)) |
| 1218 | (let ((p (window-point win))) |
| 1219 | (set-window-start win (window-start win) nil) |
| 1220 | (set-window-point win p)))) |
| 1221 | |
| 1222 | (unless visible |
| 1223 | ;; If point may not be visible in the selected window, |
| 1224 | ;; perform a redisplay; this ensures scrolling. |
| 1225 | (let ((opoint (point))) |
| 1226 | (redisplay) |
| 1227 | ;; If this `redisplay' moved point, we got clobbered by a |
| 1228 | ;; previous call to `set-window-start'. Try again. |
| 1229 | (when (/= (point) opoint) |
| 1230 | (goto-char opoint) |
| 1231 | (redisplay))) |
| 1232 | |
| 1233 | (setq selected-window-up-to-date t) |
| 1234 | (follow-avoid-tail-recenter) |
| 1235 | (setq win-start-end (follow-windows-start-end windows) |
| 1236 | follow-windows-start-end-cache nil |
| 1237 | aligned nil)) |
| 1238 | |
| 1239 | ;; Now redraw the windows around the selected window. |
| 1240 | (unless (and (not follow-internal-force-redisplay) |
| 1241 | (or aligned |
| 1242 | (follow-windows-aligned-p win-start-end)) |
| 1243 | (follow-point-visible-all-windows-p win-start-end)) |
| 1244 | (setq follow-internal-force-redisplay nil) |
| 1245 | (follow-redisplay windows (selected-window) |
| 1246 | selected-window-up-to-date) |
| 1247 | (setq win-start-end (follow-windows-start-end windows) |
| 1248 | follow-windows-start-end-cache nil) |
| 1249 | ;; Point can end up in another window when DEST is at |
| 1250 | ;; the beginning of the buffer and the selected window is |
| 1251 | ;; not the first. It can also happen when long lines are |
| 1252 | ;; used and there is a big difference between the width of |
| 1253 | ;; the windows. (When scrolling one line in a wide window |
| 1254 | ;; which will cause a move larger that an entire small |
| 1255 | ;; window.) |
| 1256 | (unless (follow-pos-visible dest win win-start-end) |
| 1257 | (follow-select-if-visible dest win-start-end) |
| 1258 | (goto-char dest))) |
| 1259 | |
| 1260 | ;; If the region is visible, make it look good when spanning |
| 1261 | ;; multiple windows. |
| 1262 | (when (region-active-p) |
| 1263 | (follow-maximize-region |
| 1264 | (selected-window) windows win-start-end))) |
| 1265 | |
| 1266 | ;; Whether or not the buffer was in follow mode, update windows |
| 1267 | ;; displaying the tail so that Emacs won't recenter them. |
| 1268 | (follow-avoid-tail-recenter))) |
| 1269 | |
| 1270 | ;;; The region |
| 1271 | |
| 1272 | ;; Tries to make the highlighted area representing the region look |
| 1273 | ;; good when spanning several windows. |
| 1274 | ;; |
| 1275 | ;; Not perfect, as point can't be placed at window end, only at |
| 1276 | ;; end-1. This will highlight a little bit in windows above |
| 1277 | ;; the current. |
| 1278 | |
| 1279 | (defun follow-maximize-region (win windows win-start-end) |
| 1280 | "Make a highlighted region stretching multiple windows look good." |
| 1281 | (let* ((all (follow-split-followers windows win)) |
| 1282 | (pred (car all)) |
| 1283 | (succ (cdr all)) |
| 1284 | data) |
| 1285 | (while pred |
| 1286 | (setq data (assq (car pred) win-start-end)) |
| 1287 | (set-window-point (car pred) (max (nth 1 data) (- (nth 2 data) 1))) |
| 1288 | (setq pred (cdr pred))) |
| 1289 | (while succ |
| 1290 | (set-window-point (car succ) (nth 1 (assq (car succ) win-start-end))) |
| 1291 | (setq succ (cdr succ))))) |
| 1292 | |
| 1293 | ;;; Scroll bar |
| 1294 | |
| 1295 | ;;;; Scroll-bar support code. |
| 1296 | |
| 1297 | ;; This handles the case where the user drags the scroll bar of a |
| 1298 | ;; non-selected window whose buffer is in Follow mode. |
| 1299 | |
| 1300 | (declare-function scroll-bar-toolkit-scroll "scroll-bar" (event)) |
| 1301 | (declare-function scroll-bar-drag "scroll-bar" (event)) |
| 1302 | (declare-function scroll-bar-scroll-up "scroll-bar" (event)) |
| 1303 | (declare-function scroll-bar-scroll-down "scroll-bar" (event)) |
| 1304 | (declare-function mwheel-scroll "mwheel" (event)) |
| 1305 | |
| 1306 | (defun follow-scroll-bar-toolkit-scroll (event) |
| 1307 | (interactive "e") |
| 1308 | (scroll-bar-toolkit-scroll event) |
| 1309 | (follow-redraw-after-event event)) |
| 1310 | |
| 1311 | (defun follow-scroll-bar-drag (event) |
| 1312 | (interactive "e") |
| 1313 | (scroll-bar-drag event) |
| 1314 | (follow-redraw-after-event event)) |
| 1315 | |
| 1316 | (defun follow-scroll-bar-scroll-up (event) |
| 1317 | (interactive "e") |
| 1318 | (scroll-bar-scroll-up event) |
| 1319 | (follow-redraw-after-event event)) |
| 1320 | |
| 1321 | (defun follow-scroll-bar-scroll-down (event) |
| 1322 | (interactive "e") |
| 1323 | (scroll-bar-scroll-down event) |
| 1324 | (follow-redraw-after-event event)) |
| 1325 | |
| 1326 | (defun follow-mwheel-scroll (event) |
| 1327 | (interactive "e") |
| 1328 | (mwheel-scroll event) |
| 1329 | (follow-redraw-after-event event)) |
| 1330 | |
| 1331 | (defun follow-redraw-after-event (event) |
| 1332 | "Re-align the Follow mode windows affected by EVENT." |
| 1333 | (let* ((window (nth 0 (event-end event))) |
| 1334 | (buffer (window-buffer window)) |
| 1335 | (orig-win (selected-window))) |
| 1336 | (when (and (buffer-local-value 'follow-mode buffer) |
| 1337 | ;; Ignore the case where we scroll the selected window; |
| 1338 | ;; that is handled by the post-command hook function. |
| 1339 | (not (eq window (selected-window)))) |
| 1340 | (select-window window) |
| 1341 | (follow-redisplay) |
| 1342 | (unless (eq (window-buffer orig-win) buffer) |
| 1343 | (select-window orig-win))))) |
| 1344 | |
| 1345 | ;;; Window size change |
| 1346 | |
| 1347 | ;; The functions in `window-size-change-functions' are called every |
| 1348 | ;; time a window in a frame changes size, most notably after the frame |
| 1349 | ;; has been resized. We call `follow-post-command-hook' for every |
| 1350 | ;; Follow mode buffer visible in any window in the resized frame. |
| 1351 | ;; |
| 1352 | ;; Since `follow-window-size-change' can be called indirectly from |
| 1353 | ;; `follow-post-command-hook' we have a potential infinite loop. To |
| 1354 | ;; avoid this, we simply do not do anything in this situation. The |
| 1355 | ;; variable `follow-inside-post-command-hook' contains information |
| 1356 | ;; about whether the execution actually is inside the |
| 1357 | ;; post-command-hook or not. |
| 1358 | |
| 1359 | (defun follow-window-size-change (frame) |
| 1360 | "Redraw all windows in FRAME, when in Follow mode." |
| 1361 | ;; Below, we call `post-command-hook'. Avoid an infloop. |
| 1362 | (unless follow-inside-post-command-hook |
| 1363 | (let ((buffers '()) |
| 1364 | (orig-window (selected-window)) |
| 1365 | (orig-buffer (current-buffer)) |
| 1366 | (orig-frame (selected-frame)) |
| 1367 | windows |
| 1368 | buf) |
| 1369 | (select-frame frame) |
| 1370 | (unwind-protect |
| 1371 | (walk-windows |
| 1372 | (lambda (win) |
| 1373 | (setq buf (window-buffer win)) |
| 1374 | (unless (memq buf buffers) |
| 1375 | (set-buffer buf) |
| 1376 | (when follow-mode |
| 1377 | (setq windows (follow-all-followers win)) |
| 1378 | (if (not (memq orig-window windows)) |
| 1379 | (follow-redisplay windows win) |
| 1380 | ;; Make sure we're redrawing around the selected |
| 1381 | ;; window. |
| 1382 | (select-window orig-window) |
| 1383 | (follow-post-command-hook) |
| 1384 | (setq orig-window (selected-window))) |
| 1385 | (setq buffers (cons buf buffers))))) |
| 1386 | 'no-minibuf) |
| 1387 | (select-frame orig-frame) |
| 1388 | (set-buffer orig-buffer) |
| 1389 | (select-window orig-window))))) |
| 1390 | |
| 1391 | (add-hook 'window-scroll-functions 'follow-avoid-tail-recenter t) |
| 1392 | |
| 1393 | ;;; Profile support |
| 1394 | |
| 1395 | ;; The following (non-evaluated) section can be used to |
| 1396 | ;; profile this package using `elp'. |
| 1397 | ;; |
| 1398 | ;; Invalid indentation on purpose! |
| 1399 | |
| 1400 | ;; (setq elp-function-list |
| 1401 | ;; '(window-end |
| 1402 | ;; vertical-motion |
| 1403 | ;; follow-mode |
| 1404 | ;; follow-all-followers |
| 1405 | ;; follow-split-followers |
| 1406 | ;; follow-redisplay |
| 1407 | ;; follow-estimate-first-window-start |
| 1408 | ;; follow-calculate-first-window-start-from-above |
| 1409 | ;; follow-calculate-first-window-start-from-below |
| 1410 | ;; follow-calc-win-end |
| 1411 | ;; follow-calc-win-start |
| 1412 | ;; follow-pos-visible |
| 1413 | ;; follow-windows-start-end |
| 1414 | ;; follow-cache-valid-p |
| 1415 | ;; follow-select-if-visible |
| 1416 | ;; follow-select-if-visible-from-first |
| 1417 | ;; follow-windows-aligned-p |
| 1418 | ;; follow-point-visible-all-windows-p |
| 1419 | ;; follow-avoid-tail-recenter |
| 1420 | ;; follow-update-window-start |
| 1421 | ;; follow-post-command-hook)) |
| 1422 | |
| 1423 | (provide 'follow) |
| 1424 | |
| 1425 | ;; /------------------------------------------------------------------------\ |
| 1426 | ;; | "I [..] am rarely happier then when spending an entire day programming | |
| 1427 | ;; | my computer to perform automatically a task that it would otherwise | |
| 1428 | ;; | take me a good ten seconds to do by hand. Ten seconds, I tell myself, | |
| 1429 | ;; | is ten seconds. Time is valuable and ten seconds' worth of it is well | |
| 1430 | ;; | worth the investment of a day's happy activity working out a way to | |
| 1431 | ;; | save it". -- Douglas Adams, "Last Chance to See" | |
| 1432 | ;; \------------------------------------------------------------------------/ |
| 1433 | |
| 1434 | ;;; follow.el ends here |