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;;; fit-frame.el --- Resize a frame.  In particular, fit a frame to its buffers.
;; Filename: fit-frame.el
;; Description: Resize a frame.  In particular, fit a frame to its buffers.
;; Author: Drew Adams
;; Maintainer: Drew Adams (concat "drew.adams" "@" "oracle" ".com")
;; Copyright (C) 2000-2018, Drew Adams, all rights reserved.
;; Created: Thu Dec  7 09:32:12 2000
;; Version: 0
;; Package-Requires: ()
;; Last-Updated: Sun Apr  1 20:10:02 2018 (-0700)
;;           By: dradams
;;     Update #: 1392
;; URL:
;; Doc URL:
;; Doc URL:
;; Keywords: internal, extensions, convenience, local
;; Compatibility: GNU Emacs: 20.x, 21.x, 22.x, 23.x, 24.x, 25.x, 26.x
;; Features that might be required by this library:
;;   None
;;; Commentary:
;;    Resize a frame.  In particular, fit a frame to its buffers.
;;  Commands and user options (variables) are provided here to resize
;;  (shrink-wrap) a frame to fit its displayed buffers, its selected
;;  buffer, or the `fill-column' width.
;;  The command to fit a frame is `fit-frame'.  The main user options
;;  for this command are `fit-frame-inhibit-fitting-flag' and
;;  `fit-frame-max-*[-percent]'.  You can use a prefix argument to
;;  control the behavior of command `fit-frame'.
;;  To take full advantage of the functionality provided here, load
;;  the companion library `autofit-frame.el', to modify primitives
;;  `display-buffer' and `switch-to-buffer' so they automatically fit
;;  all frames that have a single window.  Library `autofit-frame.el'
;;  loads library `fit-frame.el'.
;;  Put this in your initialization file (`~/.emacs'):
;;    (require 'fit-frame)
;;    (add-hook 'after-make-frame-functions 'fit-frame)
;;  The second line here causes newly created frames to be fitted to
;;  their buffer.  Even if you load library `autofit-frame.el', you
;;  will still need to do this, because `display-buffer' and
;;  `switch-to-buffer' are not called when a new frame is created.
;;  Command `fit-frame' does *not* take the following into account,
;;  when determining the proper frame size:
;;   - font sizes, other than the default frame font
;;   - characters that have special widths
;;  NOTE: If you also use library `frame-cmds.el', and you are on MS
;;  Windows, then load that library after `fit-frame.el'.  This is
;;  because the commands `maximize-frame' and `restore-frame' defined
;;  there are more general and non-Windows-specific.
;;  Suggested key bindings:
;;   (global-set-key [(control ?x) (control ?_)] 'fit-frame)
;;   (global-set-key [vertical-line down-mouse-1]
;;                   'fit-frame-or-mouse-drag-vertical-line)
;;  Customize the menu-bar.  Uncomment this to try it out.
;;   (defvar menu-bar-frames-menu (make-sparse-keymap "Frames"))
;;   (define-key global-map [menu-bar frames]
;;     (cons "Frames" menu-bar-frames-menu)))
;;   (define-key menu-bar-frames-menu [fit-frame]
;;     '("Fit This Frame" . fit-frame))
;;  Commands defined here:
;;    `fit-frame', `fit-frame-or-mouse-drag-vertical-line',
;;    `fit-frame-maximize-frame', `fit-frame-minimize-frame',
;;    `fit-frame-restore-frame', `fit-frame-to-image',
;;    `maximize-frame', `minimize-frame', `restore-frame',
;;  User options (variables) defined here:
;;    `fit-frame-crop-end-blank-flag', `fit-frame-empty-height',
;;    `fit-frame-empty-special-display-height',
;;    `fit-frame-empty-special-display-width',
;;    `fit-frame-empty-width', `fit-frame-fill-column-margin',
;;    `fit-frame-inhibit-fitting-flag', `fit-frame-max-height',
;;    `fit-frame-max-height-percent', `fit-frame-max-width',
;;    `fit-frame-max-width-percent', `fit-frame-min-height',
;;    `fit-frame-min-width', `fit-frame-skip-header-lines-alist'.
;;  Non-interactive functions defined here:
;;    `fit-frame-fringe-width', `fit-frame-max-frame-size',
;;    `fit-frame-max-height', `fit-frame-max-width',
;;    `fit-frame-max-window-size', `fit-frame-same-column-windows',
;;    `fit-frame-same-row-windows', `fit-frame-thumbnail-factor'.
;;  See also these files for other frame commands:
;;     `autofit-frame.el' - See above.
;;     `frame-cmds.el' - Various frame and window commands, including
;;                       commands to incrementally resize frames and
;;                       better, non-Windows-specific commands to
;;                       maximize and restore frames.
;;     `doremi-frm.el' - Incrementally adjust frame properties
;;                       using arrow keys and/or mouse wheel.
;;  This file was formerly called `shrink-fit.el', then
;;  `resize-frame.el', and command `fit-frame' was formerly called
;;  `shrink-frame-to-fit', then `resize-frame'.
;;  TO DO:
;;  Emacs needs a command similar to `fit-frame' for windows, that is,
;;  a command that will fit the existing windows of a frame to their
;;  buffers, as well as possible.  That could be then be used in
;;  combination with `fit-frame'.
;;; Change Log:
;; 2018/04/01 dadams
;;     fit-frame-max-height-percent: Change default value to 80 for Emacs 26+.
;; 2016/10/02 dadams
;;     Added: fit-frame-to-non-image.
;;     fit-frame:
;;       Added optional arg INTERACTIVEP.
;;       If image and not interactive, ignore errors in call to fit-frame-to-image.
;;       Factored out non-image case as fit-frame-to-non-image - just call it if no image.
;;     fit-frame-to-image: If not interactive then call message, not error.
;;                         Return non-nil if not no-op.
;; 2013/06/30 dadams
;;     fit-frame: Respect fit-frame-inhibit-fitting-flag for image-fitting also.
;; 2013/06/10 dadams
;;     fit-frame, fit-frame-to-image: No-op if Emacs not running in a graphic display.
;;     fit-frame: Ensure one-window-p before calling fit-frame-to-image.
;; 2013/03/12 dadams
;;     Do not defalias if a function with the alias name already exists.
;; 2012/11/01 dadams
;;     fit-frame-skip-header-lines-alist: Use 3 for Dired (1 for wildcards line).
;; 2011/03/04 dadams
;;     fit-frame-to-image: Fixed for Emacs 23, which doesn't yet have image-display-size.
;; 2011/01/04 dadams
;;     Removed autoload cookies from non def* sexps.
;; 2010/12/24 dadams
;;     Added: fit-frame-to-image.
;;     fit-frame: Call fit-frame-to-image if frame is in an image mode.
;; 2010/08/27 dadams
;;     Added: fit-frame-fringe-width.
;;     fit-frame-max-frame-size: Increase width by fit-frame-fringe-width.
;; 2009/05/17 dadams
;;     Updated to reflect thumb-frm.el name changes.
;; 2009/05/15 dadams
;;     Added: fit-frame-crop-end-blank-flag.
;;     fit-frame-min-width: Initalize to window-min-width, not to 20.
;;     fit-frame: Include menu-bar-lines, and assume menu-bar wraps once.
;;     fit-frame-max-window-size:
;;       Don't increase if at eob (can't move forward).
;;       Respect fit-frame-crop-end-blank-flag.
;;       Add 1 for mode-line.
;;       Header line count was 1 too many.
;; 2009/04/26 dadams
;;     fit-frame-max-window-size: Bind inhibit-field-text-motion, for end-of-line.
;; 2008/03/11 dadams
;;     fit-frame-same-(row|column)-windows: cadddr etc. -> non Common-Lisp versions.
;; 2007/12/30 dadams
;;     fit-frame: Forgot to set extra-lines for Emacs 20.
;; 2007/12/29 dadams
;;     fit-frame:
;;       Put init of empty-buf-p and specbuf-p back inside window excursion.
;;       Compute computed-max-frame-size before call set-frame-size.
;;     fit-frame-same-(row|column)-windows: Replace FRAME arg with WINS.
;; 2007/12/28 dadams
;;     fit-frame-same-(row|column)-windows: Use dolist instead of walk-windows.
;;     fit-frame: Compute empty-buf-p and specbuf-p in let binding.
;;     Misc. doc string and comment rephrasing.
;; 2007/12/18 dadams
;;     fit-frame-max-(width|height): Applied patch from David Reitter for Apple (Mac).
;; 2007/11/27 dadams
;;     fit-frame: Use read-number, if available.
;; 2007/11/21 dadams
;;     fit-frame: extra-lines:
;;       Don't add 1 for standalone minibuffer.
;;       Removed extra 2-line tweak factor for Emacs 21+.
;; 2007/11/01 dadams
;;     RMS request: Simplified fit-frame doc string.
;; 2007/07/22 dadams
;;     RMS requests:
;;       Lowercased group name.
;;       Renamed to use prefix fit-frame-: (maximize|minimize|restore)-frame,
;;         create-empty(-special-display)-frame-(height|width),
;;         fill-column-frame-margin, frame-max-(height|width)(-percent),
;;         frame-min-(height|width), inhibit-fit-frame-flag,  max-(frame|window)-size,
;;         same-(column|row)-windows, thumbnail-factor.
;;     Added aliases: maximize-frame, minimize-frame, restore-frame.
;; 2007/07/21 dadams
;;     fit-frame: Added optional all-windows-p arg.
;;     Added: max-frame-size, max-window-size, same-column-windows, same-row-windows.
;;     Removed: show-frame, get-a-frame, get-frame-name, (set-)minibuffer-empty-p.
;;     Removed require of frame-cmds.el.
;;     Renamed: create-frame-(min|max)-(width|height)(-percent) to
;;              frame-(min|max)-(width|height)(-percent).
;; 2007/03/11 dadams
;;     fit-frame: Deal with header lines that wrap more than once.
;;     fit-frame-skip-header-lines-alist: 2 lines for Dired.
;; 2006/03/13 dadams
;;     fit-frame: Treat nil tool-bar-lines as zero.  (Thx to Sebastian Luque.)
;; 2006/01/07 dadams
;;     Added :link for sending bug report.
;; 2006/01/06 dadams
;;     Added :link.  Capitalized group name.
;;     Added ;;;###autoload.
;; 2005/12/30 dadams
;;     Added: thumbnail-factor.
;;     create-frame-max-height: Use thumbnail-factor.
;; 2005/11/15 dadams
;;     create-frame-max-* functions: Added optional frame arg.
;;     Minor bug fix: Call create-frame-max-* with frame arg, so use correct char size.
;; 2005/07/31 dadams
;;     Removed require of strings.el.
;; 2005/07/04 dadams
;;     fit-frame: Bug fix: Added (set-buffer (window-buffer))
;; 2005/05/30 dadams
;;     Added: fit-frame-skip-header-lines-alist.
;;     fit-frame:
;;       Use fit-frame-skip-header-lines-alist to ignore width of header lines.
;; 2005/05/29 dadams
;;     Moved enlarge-frame* and shrink-frame* to frame-cmds.el.
;; 2005/05/25 dadams
;;     string-to-int -> string-to-number everywhere.
;; 2005/03/18 dadams
;;     Added: maximize-frame, restore-frame, minimize-frame.
;; 2004/12/18 dadams
;;     Updated Commentary to clarify use of after-make-frame-functions.
;; 2004/10/13 dadams
;;     Use special-display-p instead of special-display-buffer-p.
;; 2004/10/09 dadams
;;     Per request by RMS:
;;       Removed fit-1-window-frames-on (moved to compile-.el).
;;       Removed ;;;#autoload's.
;;       Renamed resize-* to fit-*.
;;       Changed defvar to defcustom.
;; 2004/10/02 dadams
;;     Per request by RMS:
;;       Renamed grow-frame-height and grow-frame-width to enlarge-frame
;;         and enlarge-frame-horizontally, respectively.
;;       Added shrink-frame and shrink-frame-horizontally.
;; 2004/08/26 dadams
;;     Added enlarge-frame and enlarge-frame-horizontally
;; 2004/06/01 dadams
;;     1. Removed making-frame-msg and making-frame-done-msg.
;;     2. Renamed shrink-* to resize-*. Renamed file.
;;     3. Renamed and reversed enable-* to inhibit-*.
;; 2004/05/07 dadams
;;     Updated to work with Emacs 21 and to work standalone.
;; 2004/04/06 dadams
;;     Removed nframe. make-frame is defined without it in Emacs 20.7.
;; 2001/01/05 dadams
;;     Protected show-frame via fboundp.
;; 2000/12/08 dadams
;;     Clarified doc strings: create-empty-frame-*, create-empty-special-*.
;; This program 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, or (at your option)
;; any later version.

;; This program is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License
;; along with this program; see the file COPYING.  If not, write to
;; the Free Software Foundation, Inc., 51 Franklin Street, Fifth
;; Floor, Boston, MA 02110-1301, USA.
;;; Code:

(eval-when-compile (when (< emacs-major-version 21) (require 'cl))) ;; dolist

;; Quiet the byte compiler.
(defvar image-minor-mode)

;;; User options ---------------------------------------------------

(defgroup fit-frame nil
  "Resize a frame to fit its buffers."
  :group 'frames :group 'convenience
  :link `(url-link :tag "Send Bug Report"
          ,(concat "mailto:" "drew.adams" "@" "oracle" ".com?subject=\
fit-frame.el bug: \
&body=Describe bug here, starting with `emacs -q'.  \
Don't forget to mention your Emacs and library versions."))
  :link '(url-link :tag "Other Libraries by Drew"
  :link '(url-link :tag "Download"
  :link '(url-link :tag "Description"
  :link '(emacs-commentary-link :tag "Commentary" "fit-frame"))

(defcustom fit-frame-inhibit-fitting-flag nil
  "*Non-nil means command `fit-frame' does nothing.
You can bind this to non-`nil' to temporarily inhibit frame fitting:
    (let ((fit-frame-inhibit-fitting-flag  t))...)"
  :type 'boolean :group 'fit-frame)

(defcustom fit-frame-crop-end-blank-flag nil
  "*Non-nil means `fit-frame' doesn't count blank lines at end of buffer.
If nil, then fitting leaves room for such blank lines."
  :type 'boolean :group 'fit-frame)

(defcustom fit-frame-min-width window-min-width
  "*Minimum width, in characters, that `fit-frame' gives to a frame.
The actual minimum is at least the greater of this and `window-min-width'."
  :type 'integer :group 'fit-frame)

(defcustom fit-frame-max-width nil
  "*Maximum width, in characters, that `fit-frame' gives to a frame.
If nil, then the function `fit-frame-max-width' is used instead."
  :type '(choice (const :tag "Use `fit-frame-max-width-percent' instead" nil)
  :group 'fit-frame)

(defcustom fit-frame-max-width-percent 94
  "*Maximum percent of display width that `fit-frame' gives to a frame'.
See function `fit-frame-max-width'.
Not used unless `fit-frame-max-width' is nil."
  :type 'integer :group 'fit-frame)

(defcustom fit-frame-min-height window-min-height
  "*Minimum height, in lines, that `fit-frame' gives to a frame.
The actual minimum is at least the greater of this and `window-min-height'."
  :type 'integer :group 'fit-frame)

(defcustom fit-frame-max-height nil
  "*Maximum height, in lines, that `fit-frame' gives to a frame.
If nil, then the function `fit-frame-max-height' is used instead."
  :type '(choice (const :tag "Use `fit-frame-max-height-percent' instead" nil)
  :group 'fit-frame)

(defcustom fit-frame-max-height-percent (if (> emacs-major-version 25) 80 82)
  "*Maximum percent of display height that `fit-frame' gives to a frame.
See function `fit-frame-max-height'.
Not used unless `fit-frame-max-height' is nil."
  :type 'integer :group 'fit-frame)

(defcustom fit-frame-empty-width (or (cdr (assq 'width default-frame-alist))  80)
  "*Width, in characters, that `fit-frame' gives to an empty frame."
  :type 'integer :group 'fit-frame)

(defcustom fit-frame-empty-height (or (cdr (assq 'height default-frame-alist))  35)
  "*Height, in lines, that `fit-frame' gives to an empty frame."
  :type 'integer :group 'fit-frame)

(defcustom fit-frame-empty-special-display-width 80
  "*Width, in chars, that `fit-frame' gives to an empty special-display frame.
If this is nil, it is ignored."
  :type 'integer :group 'fit-frame)

(defcustom fit-frame-empty-special-display-height 9
  "*Height, in lines, that `fit-frame' gives to an empty special-display frame.
If this is nil, it is ignored."
  :type 'integer :group 'fit-frame)

(defcustom fit-frame-fill-column-margin 7
  "*Difference between `fill-column' and frame width after fitting a frame.
Used when `fit-frame' fits a frame, if the prefix arg is negative.
Depending on the average word length of the language used in the
selected window, you might want different values for this.  This
variable is buffer-local."
  :type 'integer :group 'fit-frame)

(make-variable-buffer-local 'fit-frame-fill-column-margin)

(defcustom fit-frame-skip-header-lines-alist
  '((Info-mode . 1) (dired-mode . 3) (compilation-mode . 2))
  "*Alist of major-modes and header lines to ignore.
When `fit-frame' calculates the width of the current buffer, it can
first skip some lines at the buffer beginning, ignoring their
widths.  For example, Info, Dired, and compilation buffers sometimes
have a long header line at the top.  You can use this alist to tell
`fit-frame' to ignore the width of these header lines.

Each item in the alist is of form (MODE . LINES).
 MODE is a major-mode name.
 LINES is the number of lines to skip at the beginning of the buffer."
  :type '(repeat (cons :format "%v" (symbol :tag "Major Mode")
                       (integer :tag "Header Lines to Ignore")))
  :group 'fit-frame)
;;; Commands ---------------------------------------------------

(defun fit-frame (&optional frame width height all-windows-p interactivep)
  "Resize FRAME to fit its buffer(s).
Does nothing if `fit-frame-inhibit-fitting-flag' is non-nil.

FRAME defaults to the current (i.e. selected) frame.

If non-nil, WIDTH and HEIGHT specify the frame width and height.  To
define them interactively, use a non-negative prefix arg (e.g. `C-9').

To set the width to `fill-column' + `fit-frame-fill-column-margin',
use a negative prefix arg (e.g. `M--').

To fit the frame to all of its displayed buffers, use no prefix arg.
To fit it to just the current buffer, use a plain prefix arg (`C-u').

Fitting a non-empty buffer means resizing the frame to the smallest
size such that the following are both true:

 * The width is at least `fit-frame-min-width' and `window-min-width'.
   The width is at most `fit-frame-max-width(-percent)' and the
   longest line length.

   (However, extra width is allowed for fringe, if shown.)

 * The height is at least `fit-frame-min-height' and
   `window-min-height'.  The height is at most
   `fit-frame-max-height(-percent)' and the number of lines.

You can thus use those user variables to control the maximum and
minimum frame sizes.  The `*-percent' options let you specify the
maximum as a percentage of your display size.

See also options `fit-frame-skip-header-lines-alist' and

The following user options control how an empty frame is fit.
An empty frame is a one-window frame displaying an empty buffer.

 * `fit-frame-empty-width', `fit-frame-empty-height' (normal buffer)
 * `fit-frame-empty-special-display-width',
   `fit-frame-empty-special-display-height' (special-display buffer)

Note: `fit-frame' does not take into account wrapping of a menu-bar
line.  There is no easy way to calculate the number of display lines
from such wrapping."
   (let ((option  (prefix-numeric-value current-prefix-arg)))
     (list nil
           ;; Plain `C-u' means WIDTH, HEIGHT, and ALL-WINDOWS-P are all nil.
           ;; Non-negative prefix arg means prompt user for WIDTH and HEIGHT.
           ;; Negative prefix arg means use
           ;;   `fill-column' + `fit-frame-fill-column-margin'
           ;;   for WIDTH, and use current frame height for HEIGHT.
           (and current-prefix-arg  (atom current-prefix-arg)
                (if (fboundp 'display-graphic-p) (display-graphic-p) window-system)
                (if (natnump option)
                    (floor (if (fboundp 'read-number)
                               (read-number "New width: ")
                             (string-to-number (read-string "New width: "))))
                  (+ fill-column fit-frame-fill-column-margin)))
           (and current-prefix-arg  (atom current-prefix-arg)
                (if (fboundp 'display-graphic-p) (display-graphic-p) window-system)
                (if (natnump option)
                    (floor (if (fboundp 'read-number)
                               (read-number "New height: ")
                             (string-to-number (read-string "New height: "))))
           (atom current-prefix-arg)
  (and (if (fboundp 'display-graphic-p) (display-graphic-p) window-system) ; No-op if not.
       (if (and (fboundp 'image-mode-fit-frame) ; Emacs 23+
                (if (or (null frame)  (eq frame (selected-frame)))
                    (or (eq major-mode 'image-mode)  image-minor-mode)
                    (select-frame frame)
                    (one-window-p)      ; `fit-frame-to-image' requires it.
                    (or (eq major-mode 'image-mode)  image-minor-mode))))
           (unless fit-frame-inhibit-fitting-flag
             (if interactivep
                 (fit-frame-to-image t frame)
               (or (condition-case nil (fit-frame-to-image nil frame))
                   (fit-frame-to-image t frame))))
         (fit-frame-to-non-image frame width height all-windows-p))))

(defun fit-frame-to-non-image (&optional frame width height all-windows-p)
  "Fit FRAME (default: selected frame) to buffer contents.
FRAME has more than one window or the window is not showing an image."
  (setq frame  (or frame  (selected-frame)))
  (unless fit-frame-inhibit-fitting-flag
    (let ((extra-lines  0)
          computed-max-frame-size empty-buf-p specbuf-p)
        (select-frame frame)
        (setq empty-buf-p  (and (= (point-min) (point-max))
                                (one-window-p (selected-window)))
              specbuf-p    (and empty-buf-p
                                (special-display-p (buffer-name (window-buffer))))))
      ;; `extra-lines' for minimum frame height.  Starting with Emacs 21+,
      ;; `set-frame-size' includes the tool-bar and the minibuffer.  For Emacs
      ;; without a toolkit, the one-line menu-bar is also included - add 1 line
      ;; for that.  Add 1 line for the minibuffer, unless it is standalone.
      ;; Perhaps we should also take into account a possible horizontal scroll
      ;; bar, but we don't do that.
      (let* ((fparams     (frame-parameters frame))
             (menu-lines  (or (cdr (assq 'menu-bar-lines fparams))  0)))
        (when (> emacs-major-version 20)
          (setq extra-lines  (or (cdr (assq 'tool-bar-lines fparams))  0))
          (when (and (not (eq system-type 'windows-nt))  (not (featurep 'x-toolkit)))
            (setq extra-lines  (1+ extra-lines))))
        ;; We can't really know whether menu-bar gets wrapped.  Assume it wraps once.
        (when (> menu-lines 0)
          (setq extra-lines  (+ extra-lines (1+ menu-lines))))
        (when (and (cdr (assq 'minibuffer fparams)) ; Frame has a minibuffer, but
                   (save-window-excursion (select-frame frame) ; it's not standalone.
                                          (not (one-window-p nil 'selected-frame))))
          (setq extra-lines  (1+ extra-lines))))
      (unless (or empty-buf-p  (and width  height))
        (setq computed-max-frame-size  (fit-frame-max-frame-size frame all-windows-p)))
       ;; Frame
       ;; Columns
       (or width
           (and empty-buf-p  (if specbuf-p
           (max fit-frame-min-width window-min-width
                (min (or fit-frame-max-width  (fit-frame-max-width frame))
                     (1+ (car computed-max-frame-size)))))
       ;; Rows
       (or height
           (and empty-buf-p  (if specbuf-p
           (max fit-frame-min-height window-min-height
                (min (or fit-frame-max-height  (fit-frame-max-height frame))
                     (+ (cdr computed-max-frame-size) extra-lines))))))))

;; Similar to `image-mode-fit-frame'.
;; 1. Adds the optional arg FRAME.
;; 2. Does not toggle between original size and fit size unless interactive.
;;    When called from code it always fits.
(defun fit-frame-to-image (interactivep &optional frame)
  "Fit FRAME to the current image.
If FRAME is not the selected frame, fit it to its first image.
Interactively, if frame has already been fit to the image, then
 restore the size from before it was fit.
This function assumes that FRAME has only one window."
  ;; Vanilla Emacs FIXME: This does not take into account decorations
  ;; like mode-line, minibuffer, header-line, ...
  (interactive "p")
  (unless (fboundp 'image-mode-fit-frame)
    (funcall (if interactivep #'error #'message)
             "This command requires the image support of Emacs 23 or later"))
  (and (if (fboundp 'display-graphic-p) (display-graphic-p) window-system) ; No-op if not.
       (let* ((saved    (frame-parameter frame 'image-mode-saved-size))
              (display  (if (or (null frame)  (equal frame (selected-frame)))
                          (save-selected-window (select-frame frame)
              (size     (if (fboundp 'image-display-size) ; Emacs 24+.
                            (image-display-size display nil frame)
                          (image-size display nil frame))))
         (setq frame  (or frame  (selected-frame)))
         (if (and interactivep  saved
                  (eq (caar saved) (frame-width frame))
                  (eq (cdar saved) (frame-height frame)))
             (progn                     ; Restore previous size, before it was fit.
               (set-frame-parameter frame 'image-mode-saved-size nil)
               (setq size  (cdr saved)))
           ;; Round up size, and save current size so we can toggle back to it.
           (setcar size (ceiling (car size)))
           (setcdr size (ceiling (cdr size)))
            frame 'image-mode-saved-size
            (cons size (cons (frame-width frame) (frame-height frame)))))
         (set-frame-size frame (car size) (cdr size))
         t)))                           ; Return non-nil if not no-op.

(defun fit-frame-or-mouse-drag-vertical-line (start-event)
  "If only window in frame, `fit-frame'; else `mouse-drag-vertical-line'."
  (interactive "e")
  (if (one-window-p t) (fit-frame) (mouse-drag-vertical-line start-event)))

;; Note that in Windows you can also just double-click the title bar
;; of a frame to alternately maximize and restore it.
(when (eq window-system 'w32)
  (unless (fboundp 'restore-frame) (defalias 'restore-frame 'fit-frame-restore-frame))
  (defun fit-frame-restore-frame (&optional frame)
    "Restore FRAME to previous size (default: current frame)."
    (w32-send-sys-command 61728 frame)))

(when (eq window-system 'w32)
  (unless (fboundp 'maximize-frame) (defalias 'maximize-frame 'fit-frame-maximize-frame))
  (defun fit-frame-maximize-frame (&optional frame)
    "Maximize FRAME (default: current frame)."
    (w32-send-sys-command 61488 frame)))

(when (eq window-system 'w32)
  (unless (fboundp 'minimize-frame) (defalias 'minimize-frame 'fit-frame-minimize-frame))
  (defalias 'fit-frame-minimize-frame
      (if (fboundp 'thumfr-really-iconify-frame)
;;; Non-Interactive Functions -------------------------------------------

(defun fit-frame-max-width (&optional frame)
  "Returns the maximum width, in chars, for a new frame that was fit.
If option `fit-frame-max-width' is non-nil, then this is not used.

The value is relative to your display size and FRAME's character
size, and depends on the value of `fit-frame-max-width-percent':

  (/ (* fit-frame-max-width-percent (x-display-pixel-width))
     (* 100 (frame-char-width FRAME)))"
  (setq frame  (or frame  (selected-frame)))
  (/ (* fit-frame-max-width-percent
        (if (fboundp 'winmgr-display-available-pixel-bounds) ; For MacIntosh.
 	    (nth 2 (winmgr-display-available-pixel-bounds))
     (* 100 (frame-char-width frame))))

(defun fit-frame-max-height (&optional frame)
  "Returns the maximum height, in lines, for a new frame that was fit.
If option `fit-frame-max-height' is non-nil, then this is not used.

The value is relative to your display size and FRAME's character
size, and depends on the value of `fit-frame-max-height-percent':

  (/ (* fit-frame-max-height-percent (x-display-pixel-height))
     (* 100 (frame-char-height FRAME)))"
  (setq frame  (or frame  (selected-frame)))
  (/ (* fit-frame-max-height-percent
        (if (fboundp 'winmgr-display-available-pixel-bounds) ; For MacIntosh.
 	    (nth 3 (winmgr-display-available-pixel-bounds))
     (* 100 (frame-char-height frame)
        ;; When fitting a thumbnail frame, we don't want the height to use the
        ;; whole display height.  So, we apply a fudge factor:
        ;; `fit-frame-thumbnail-factor'.  We could also use it in
        ;; `fit-frame-max-width', in addition to `fit-frame-max-height',
        ;; but we don't need to.
        (fit-frame-thumbnail-factor frame))))

(defun fit-frame-max-frame-size (frame all-windows-p)
  "Return maximum size of frame FRAME as a cons: (MAX-WIDTH . MAX-HEIGHT).
If ALL-WINDOWS-P is non-nil, then consider all buffers shown in FRAME.
Otherwise, consider only the selected buffer."
    (select-frame frame)
    (if (not all-windows-p)
        (let ((win-cons  (fit-frame-max-window-size (selected-window))))
          (cons (+ (car win-cons) (fit-frame-fringe-width frame))
                (cdr win-cons)))
      (let* ((wins         ())
             (marked-wins  ())           ; Windows whose size was already considered.
             (max-width    0)
             (max-height   0))
        (walk-windows (lambda (w) (push w wins)) 'no-mini 'this-frame)
        (setq wins  (sort wins (lambda (w1 w2) ; Top to bottom, left to right.
                                 (let ((edges1  (window-edges w1))
                                       (edges2  (window-edges w2)))
                                   (or (< (cadr edges1) (cadr edges2)) ; top
                                       (and (= (cadr edges1) (cadr edges2))
                                            (<= (car edges1) (car edges2)))))))) ; left
        ;; Iterate over all windows in frame.
        ;; For each, check all windows in the same row, and all in the same column.
        ;; When checking those in the same row:
        ;;   1. Increase MAX-HEIGHT to the max buffer height of the row windows.
        ;;   2. Increase MAX-WIDTH to the sum of the buffer widths of the row windows.
        ;; When checking those in the same column:
        ;;   1. Increase MAX-WIDTH to the max buffer width of the column windows.
        ;;   2. Increase MAX-HEIGHT to the sum of the buffer heights of the col windows.
        ;; After examining a window in the frame, exclude it from further examination
        ;;  by adding it to MARKED-WINS.
        (dolist (win wins)
          (unless (memq win marked-wins)
            (let* ((win-edges  (window-edges win))
                   (win-top    (cadr win-edges))
                   (win-left   (car win-edges)))
              ;; Add widths of buffers in the same row.  Max the heights of the buffers.
              (dolist (row-win (fit-frame-same-row-windows wins win marked-wins))
                ;; Add ROW-WIN to exclusion list for subsequent iterations.
                (setq marked-wins  (cons row-win marked-wins))
                (let* ((win-size        (fit-frame-max-window-size row-win))
                       (max-win-width   (car win-size))
                       (max-win-height  (cdr win-size)))
                  (unless (> (cadr (window-edges row-win)) win-top) ; Use only first.
                    (setq max-width  (+ max-width max-win-width)))
                  (setq max-height  (max max-height max-win-height))))
              ;; Add heights of buffers in the same column.  Max the buffer widths.
              (dolist (col-win (fit-frame-same-column-windows wins win marked-wins))
                ;; Add COL-WIN to exclusion list for subsequent iterations.
                (setq marked-wins  (cons col-win marked-wins))
                (let* ((win-size        (fit-frame-max-window-size col-win))
                       (max-win-width   (car win-size))
                       (max-win-height  (cdr win-size)))
                  (unless (> (car (window-edges col-win)) win-left) ; Use only first.
                    (setq max-height  (+ max-height max-win-height)))
                  (setq max-width  (max max-width max-win-width)))))))
        (cons (+ max-width (fit-frame-fringe-width frame)) max-height)))))

(defun fit-frame-fringe-width (&optional frame)
  "Width to allow for fringes on FRAME."
  ;; Ignore differences between frame parameter values and round-up actual widths.
  (let ((fringe        (+ (abs (or (frame-parameter frame 'left-fringe)   0))
                          (abs (or (frame-parameter frame 'right-fringe)  0))))
        (char-width    (frame-char-width frame))
        (fringe-width  0))
    (when (and (boundp 'fringe-mode)  fringe  (not (zerop fringe)))
      ;; Round the integer division using: 1 + (x-1)/y
      (setq fringe-width  (+ fringe-width 1 (/ (1- fringe) char-width))))

(defun fit-frame-same-row-windows (wins window exclude)
  "Returns the windows in WINS that are in the same row as window WINDOW.
This the list of windows in WINS whose top edge is above the bottom
 edge of WINDOW.
Windows that are in list EXCLUDE are excluded from the result."
  (let ((ref-bottom  (cadr (cddr (window-edges window))))
        (row-wins    ()))
    (dolist (win wins)
      (when (and (not (memq win exclude))  (< (cadr (window-edges win)) ref-bottom))
        (push win row-wins)))

(defun fit-frame-same-column-windows (wins window exclude)
  "Returns the windows in WINS that are in the same column as window WINDOW.
This the list of windows in WINS whose left edge is to the left of the
 right edge of WINDOW.
Windows that are in list EXCLUDE are excluded from the result."
  (let ((ref-right  (car (cddr (window-edges window))))
        (col-wins   ()))
    (dolist (win wins)
      (when (and (not (memq win exclude))  (< (car (window-edges win)) ref-right))
        (push win col-wins)))

(defun fit-frame-max-window-size (window)
  "Maximum size that would be needed to display the buffer in WINDOW.
Returned as a cons: (MAX-WIDTH . MAX-HEIGHT), where:
 MAX-WIDTH is the maximum width, in default characters.
 MAX-HEIGHT is the maximum height, in lines."
  (select-window window)
  (let ((hdr-lines                  (cdr (assq major-mode
        (hdr-widths                 ())
        (max-win-width              0)
        (max-win-height             1)
        (inhibit-field-text-motion  t)) ; So `end-of-line' will do what it says.
      (set-buffer (window-buffer))
      (goto-char (point-min))
      ;; Do not count header lines for width calculation.
      ;; FIXME. This does not work well if header lines have intangible text etc.
      ;; E.g. Does not work for Emacs 20-22 in Dired with wildcard showing only 1 file.
      (while (and hdr-lines  (> hdr-lines 0))
        (setq hdr-widths  (cons (current-column) hdr-widths)
              hdr-lines   (1- hdr-lines))
        (when (zerop (forward-line 1))  ; Don't increase if can't move forward.
          (setq max-win-height  (1+ max-win-height))))
      ;; Calculate maximum line width and number of lines.
      (while (not (eobp))
        (setq max-win-width  (max (current-column) max-win-width))
        (when (zerop (forward-line 1))  ; Don't increase if can't move forward.
          (setq max-win-height  (1+ max-win-height))))
      ;; No need to count lines at buffer end.
      (when fit-frame-crop-end-blank-flag
          (while (and (looking-at "^\\s-*$")  (not (bobp)))
            (setq max-win-height  (1- max-win-height))
            (forward-line -1)))
        (setq max-win-height  (max 0 max-win-height))))
    ;; Add mode-line.
    (when (cdr (assq 'modeline (frame-parameters (window-frame window))))
      (setq max-win-height  (1+ max-win-height)))
    ;; Add height for any wrap-around header lines.
    (while hdr-widths
      (when (> (car hdr-widths) max-win-width)
        (if (zerop max-win-width)
            (setq max-win-height  (1+ max-win-height))
          (let ((nb-wraps   (1- (/ (car hdr-widths) max-win-width)))
                (remainder  (% (car hdr-widths) max-win-width)))
            (unless (zerop remainder) (setq nb-wraps  (1+ nb-wraps)))
            (setq max-win-height  (+ max-win-height nb-wraps)))))
      (setq hdr-widths  (cdr hdr-widths)))
    (cons max-win-width max-win-height)))

(defun fit-frame-thumbnail-factor (frame)
  "Shrink factor for thumbnail frames.  See `thumb-frm.el'.
FRAME is the frame to apply factor to."
  (let ((char-height  (frame-char-height frame)))
    (if (and (fboundp 'thumfr-thumbnail-frame-p) ; Defined in `thumb-frm.el'
             (thumfr-thumbnail-frame-p frame))
        ;; Need integer result for `set-frame-size'.  1+ because of integer round-off.
        (1+ (/ (+ char-height thumfr-font-difference) char-height))


(provide 'fit-frame)

;;; fit-frame.el ends here