diff options
Diffstat (limited to 'lisp/jit-lock.el')
| -rw-r--r-- | lisp/jit-lock.el | 17 |
1 files changed, 13 insertions, 4 deletions
diff --git a/lisp/jit-lock.el b/lisp/jit-lock.el index a1287926eb9..bb2df2b1ffa 100644 --- a/lisp/jit-lock.el +++ b/lisp/jit-lock.el @@ -44,10 +44,13 @@ Preserves the `buffer-modified-p' state of the current buffer." :version "21.1" :group 'font-lock) -(defcustom jit-lock-chunk-size 500 +(defcustom jit-lock-chunk-size 1500 "Jit-lock fontifies chunks of at most this many characters at a time. -This variable controls both display-time and stealth fontification." +This variable controls both `display-time' and stealth fontification. + +The optimum value is a little over the typical number of buffer +characters which fit in a typical window." :type 'integer) @@ -150,7 +153,10 @@ If 0, then fontification is only deferred while there is input pending." (defvar jit-lock-functions nil "Special hook run to do the actual fontification. The functions are called with two arguments: -the START and END of the region to fontify.") +the START and END of the region to fontify. +Each function can return a list of the form (jit-lock-bounds BEG . END), +to indicate the bounds of the region it actually fontified; +JIT font-lock will use this information to optimize redisplay cycles.") (defvar-local jit-lock-context-unfontify-pos nil "Consider text after this position as contextually unfontified. @@ -332,7 +338,10 @@ like `debug-on-error' and Edebug can be used." "Register FUN as a fontification function to be called in this buffer. FUN will be called with two arguments START and END indicating the region that needs to be (re)fontified. -If non-nil, CONTEXTUAL means that a contextual fontification would be useful." +If non-nil, CONTEXTUAL means that a contextual fontification would be useful. +FUN can return a list of the form (jit-lock-bounds BEG . END), +to indicate the bounds of the region it actually fontified; JIT +font-lock will use this information to optimize redisplay cycles." (add-hook 'jit-lock-functions fun nil t) (when (and contextual jit-lock-contextually) (setq-local jit-lock-contextually t)) |