我正在尝试在Emacs中使用文档视图来阅读PDF，但是我不知道如何使其行为类似于许多PDF阅读器具有的"适合宽度"命令。有没有内部方法可以做到这一点？
以下代码片段定义了一个新的次要模式doc-view-autofit-mode，我在下面使用 doc-view-mode-hook 激活了它。它在 Ubuntu 24.3 上的 Emacs 14.04 上对我有用，甚至可以在我调整窗口大小时调整缩放大小！
(由于doc-view-autofit-timer-start，通常会有短暂的大小调整延迟，但我很高兴接受这一点。
我不相信解决方案;我在 emacs-devel 邮件列表中找到了这段代码。
(require 'cl)
;;;; Automatic fitting minor mode
(defcustom doc-view-autofit-timer-start 1.0
"Initial value (seconds) for the timer that delays the fitting when
`doc-view-autofit-fit' is called (Which is when a window
configuration change occurs and a document needs to be fitted)."
:type 'number
:group 'doc-view)
(defcustom doc-view-autofit-timer-inc 0.02
"Value to increase (seconds) the timer (see `doc-view-autofit-timer-start')
by, if there is another window configuration change occuring, before
it runs out."
:type 'number
:group 'doc-view)
(defcustom doc-view-autofit-default-fit 'width
"The fitting type initially used when mode is enabled.
Valid values are: width, height, page."
:type 'symbol
:group 'doc-view)
(defvar doc-view-autofit-mode-map
(let ((map (make-sparse-keymap)))
(define-key map (kbd "C-c W") 'doc-view-autofit-width)
(define-key map (kbd "C-c H") 'doc-view-autofit-height)
(define-key map (kbd "C-c P") 'doc-view-autofit-page)
map)
"Keymap used by `doc-view-autofit-mode'.")
(defun doc-view-autofit-set (type)
"Set autofitting to TYPE for current buffer."
(when doc-view-autofit-mode
(setq doc-view-autofit-type type)
(doc-view-autofit-fit)))
(defun doc-view-autofit-width ()
"Set autofitting to width for current buffer."
(interactive) (doc-view-autofit-set 'width))
(defun doc-view-autofit-height ()
"Set autofitting to height for current buffer."
(interactive) (doc-view-autofit-set 'height))
(defun doc-view-autofit-page ()
"Set autofitting to page for current buffer."
(interactive) (doc-view-autofit-set 'page))
(defun doc-view-autofit-fit ()
"Fits the document in the selected window's buffer
delayed with a timer, so multiple calls in succession
don't cause as much overhead."
(lexical-let
((window (selected-window)))
(if (equal doc-view-autofit-timer nil)
(setq doc-view-autofit-timer
(run-with-timer
doc-view-autofit-timer-start nil
(lambda ()
(if (window-live-p window)
(save-selected-window
(select-window window)
(cancel-timer doc-view-autofit-timer)
(setq doc-view-autofit-timer nil)
(cond
((equal 'width doc-view-autofit-type)
(doc-view-fit-width-to-window))
((equal 'height doc-view-autofit-type)
(doc-view-fit-height-to-window))
((equal 'page doc-view-autofit-type)
(doc-view-fit-page-to-window))))))))
(timer-inc-time doc-view-autofit-timer doc-view-autofit-timer-inc))))
(define-minor-mode doc-view-autofit-mode
"Minor mode for automatic (timer based) fitting in DocView."
:lighter " AFit" :keymap doc-view-autofit-mode-map :group 'doc-view
(when doc-view-autofit-mode
(set (make-local-variable 'doc-view-autofit-type)
doc-view-autofit-default-fit)
(set (make-local-variable 'doc-view-autofit-timer) nil)
(add-hook 'window-configuration-change-hook
'doc-view-autofit-fit nil t)
(doc-view-autofit-fit))
(when (not doc-view-autofit-mode)
(remove-hook 'window-configuration-change-hook
'doc-view-autofit-fit t)
(when doc-view-autofit-timer
(cancel-timer doc-view-autofit-timer)
(setq doc-view-autofit-timer nil))
(setq doc-view-autofit-type nil)))
(add-hook 'doc-view-mode-hook 'doc-view-autofit-mode)
它对我有用：
(add-hook 'doc-view-mode-hook 'doc-view-fit-width-to-window)
更新：如果转换(转换为 png 或其他内容(仍在进行(首次打开文档(，则无法正常工作。还有另一种更可靠的方法可以处理这种特殊情况(它根本不使用钩子，而是使用建议(：
(defadvice doc-view-display (after fit-width activate)
(doc-view-fit-width-to-window))
以下是 Chris 对答案的轻微修改——它提供了与find-file-other-window等函数的兼容性——例如，当selected-window与显示*.pdf文件不同的功能时。
(defvar last-displayed-doc-view-buffer nil)
(defun get-last-displayed-doc-view-buffer ()
(setq last-displayed-doc-view-buffer (current-buffer)))
(add-hook 'doc-view-mode-hook 'get-last-displayed-doc-view-buffer)
(defun doc-view-autofit-fit ()
"Fits the document in the selected window's buffer
delayed with a timer, so multiple calls in succession
don't cause as much overhead."
(if (null doc-view-autofit-timer)
(setq doc-view-autofit-timer
(run-with-timer doc-view-autofit-timer-start nil (lambda ()
(let* (
(selected-window
(cond
((eq major-mode 'doc-view-mode)
(selected-window))
(t
(get-buffer-window last-displayed-doc-view-buffer))))
(current-buffer
(cond
((eq major-mode 'doc-view-mode)
(current-buffer))
(t
(get-buffer last-displayed-doc-view-buffer))))
(selected-fit
(when (buffer-live-p (get-buffer current-buffer))
(with-current-buffer (get-buffer current-buffer)
doc-view-autofit-type))) )
(when (window-live-p selected-window)
(with-selected-window selected-window
(when doc-view-autofit-timer (cancel-timer doc-view-autofit-timer))
(setq doc-view-autofit-timer nil)
(cond
((eq 'width selected-fit)
(doc-view-fit-width-to-window))
((eq 'height selected-fit)
(doc-view-fit-height-to-window))
((eq 'page selected-fit)
(doc-view-fit-page-to-window)))))))))
(timer-inc-time doc-view-autofit-timer doc-view-autofit-timer-inc)))
而且，正如我之前对Chris的回答的评论中所指出的，以下变量需要定义：
(defvar doc-view-autofit-timer nil)
(defvar doc-view-autofit-type nil)
因为上面的修改在doc-view-mode-hook中增加了一个新函数来获取函数current-buffer，这是函数doc-view-autofit-fit所需要的，所以需要保证后一个函数追加到doc-view-mode-hook的末尾。 所以更改看起来像这样 - 即，我们为追加参数添加一个t：
(add-hook 'doc-view-mode-hook 'doc-view-autofit-mode t)
Chris的回答中尚未被上述修改取代的其他所有内容仍然有效。
要做：
- 创建一个测试以在滚动时检查每个页面，以确保视图与
autofit-type一致。 目前，处理长*.pdf文件时页面大小会出现错误。
只是注意：(需要'cl(已经过时了。从 emacs-24.3 开始，它应该是
(require ‘cl-lib)
请参阅 http://www.emacswiki.org/emacs/CommonLispForEmacs