Variable: lazy-lock-defer-on-scrolling

lazy-lock-defer-on-scrolling is a customizable variable defined in lazy-lock.el.gz.

Value

nil

Documentation

If non-nil, means fontification after a scroll should be deferred.

If nil, means demand-driven fontification is performed. This means when scrolling into unfontified areas of the buffer, those areas are immediately fontified. Thus scrolling never presents unfontified areas. However, since fontification occurs during scrolling, scrolling may be slow. If t, means defer-driven fontification is performed. This means fontification of those areas is deferred. Thus scrolling may present momentarily unfontified areas. However, since fontification does not occur during scrolling, scrolling will be faster than demand-driven fontification. If any other value, e.g., eventually, means demand-driven fontification is performed until the buffer is fontified, then buffer fontification becomes defer-driven. Thus scrolling never presents unfontified areas until the buffer is first fontified, after which subsequent scrolling may present future buffer insertions momentarily unfontified. However, since fontification does not occur during scrolling after the buffer is first fontified, scrolling will become faster. (But, since contextual changes continually occur, such a value makes little sense if lazy-lock-defer-contextually is non-nil.)

The value of this variable is used when Lazy Lock mode is turned on.

Probably introduced at or before Emacs version 20.1.

Source Code

;; Defined in /usr/src/emacs/lisp/obsolete/lazy-lock.el.gz
(defcustom lazy-lock-defer-on-scrolling nil
  "If non-nil, means fontification after a scroll should be deferred.
If nil, means demand-driven fontification is performed.  This means when
scrolling into unfontified areas of the buffer, those areas are immediately
fontified.  Thus scrolling never presents unfontified areas.  However, since
fontification occurs during scrolling, scrolling may be slow.
If t, means defer-driven fontification is performed.  This means fontification
of those areas is deferred.  Thus scrolling may present momentarily unfontified
areas.  However, since fontification does not occur during scrolling, scrolling
will be faster than demand-driven fontification.
If any other value, e.g., `eventually', means demand-driven fontification is
performed until the buffer is fontified, then buffer fontification becomes
defer-driven.  Thus scrolling never presents unfontified areas until the buffer
is first fontified, after which subsequent scrolling may present future buffer
insertions momentarily unfontified.  However, since fontification does not
occur during scrolling after the buffer is first fontified, scrolling will
become faster.  (But, since contextual changes continually occur, such a value
makes little sense if `lazy-lock-defer-contextually' is non-nil.)

The value of this variable is used when Lazy Lock mode is turned on."
  :type '(choice (const :tag "never" nil)
		 (const :tag "always" t)
		 (other :tag "eventually" eventually)))