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Add new functions for computing default font dimensions

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lisp/window.el (window-font-width, window-font-height)
 (window-max-chars-per-line): New functions.
 lisp/simple.el (default-font-height): Doc fix.
 (default-font-width): New function.

 etc/NEWS: Mention `default-font-width', `window-font-height',
 `window-font-width', and `window-max-chars-per-line'.
This commit is contained in:
Titus von der Malsburg 2015-03-21 12:31:29 +02:00 • committed by Eli Zaretskii
parent 70565a2176
commit 4a50af936e
5 changed files with 109 additions and 1 deletions
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5
etc/ChangeLog
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@ -1,3 +1,8 @@
2015-03-21 Titus von der Malsburg <malsburg@posteo.de>
* NEWS: Mention `default-font-width', `window-font-height',
`window-font-width', and `window-max-chars-per-line'.
2015-03-03 Kelvin White <kwhite@gnu.org>
* NEWS.24: Add section to include ERC changes.

18
etc/NEWS
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@ -173,6 +173,24 @@ possible inaccuracies in the end position.
In particular, it now returns the average width of the font's
characters, which can be used for geometry-related calculations.
** A new function `default-font-width' returns the average width of a
character in the current buffer's default font. If the default face
is remapped (see `face-remapping-alist'), the value for the remapped
face is returned. This function complements the existing function
`default-font-height'.
** New functions `window-font-height' and `window-font-width' return
the height and average width of characters in a specified face and
window. If FACE is remapped (see `face-remapping-alist'), the
function returns the information for the remapped face.
** A new function `window-max-chars-per-line' returns the maximal
number of characters that can be displayed on one line. If a face
and/or window are provided, these values are used for the
calculation. This function is different from `window-body-width' in
that it accounts for (i) continuation glyphs, (ii) the size of the
font, and (iii) the specified window.
* Editing Changes in Emacs 25.1

8
lisp/ChangeLog
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@ -1,3 +1,11 @@
2015-03-21 Titus von der Malsburg <malsburg@posteo.de>
* window.el (window-font-width, window-font-height)
(window-max-chars-per-line): New functions.
* simple.el (default-font-height): Doc fix.
(default-font-width): New function.
2015-03-21 Tassilo Horn <tsdh@gnu.org>
* emacs-lisp/lisp-mode.el (lisp-el-font-lock-keywords-1): Also

24
lisp/simple.el
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@ -5409,7 +5409,10 @@ lines."
(declare-function font-info "font.c" (name &optional frame))
(defun default-font-height ()
"Return the height in pixels of the current buffer's default face font."
"Return the height in pixels of the current buffer's default face font.
If the default font is remapped (see `face-remapping-alist'), the
function returns the height of the remapped face."
(let ((default-font (face-font 'default)))
(cond
((and (display-multi-font-p)
@ -5420,6 +5423,25 @@ lines."
(aref (font-info default-font) 3))
(t (frame-char-height)))))
(defun default-font-width ()
"Return the width in pixels of the current buffer's default face font.
If the default font is remapped (see `face-remapping-alist'), the
function returns the width of the remapped face."
(let ((default-font (face-font 'default)))
(cond
((and (display-multi-font-p)
;; Avoid calling font-info if the frame's default font was
;; not changed since the frame was created. That's because
;; font-info is expensive for some fonts, see bug #14838.
(not (string= (frame-parameter nil 'font) default-font)))
(let* ((info (font-info (face-font 'default)))
(width (aref info 11)))
(if (> width 0)
width
(aref info 10))))
(t (frame-char-width)))))
(defun default-line-height ()
"Return the pixel height of current buffer's default-face text line.

55
lisp/window.el
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@ -1835,6 +1835,61 @@ optional argument PIXELWISE is passed to the functions."
(window-body-width window pixelwise)
(window-body-height window pixelwise)))
(defun window-font-width (&optional window face)
"Return average character width for the font of FACE used in WINDOW.
WINDOW must be a live window and defaults to the selected one.
If FACE is nil or omitted, the default face is used. If FACE is
remapped (see `face-remapping-alist'), the function returns the
information for the remapped face."
(with-selected-window (window-normalize-window window t)
(if (display-multi-font-p)
(let* ((face (if face face 'default))
(info (font-info (face-font face)))
(width (aref info 11)))
(if (> width 0)
width
(aref info 10)))
(frame-char-width))))
(defun window-font-height (&optional window face)
"Return character height for the font of FACE used in WINDOW.
WINDOW must be a live window and defaults to the selected one.
If FACE is nil or omitted, the default face is used. If FACE is
remapped (see `face-remapping-alist'), the function returns the
information for the remapped face."
(with-selected-window (window-normalize-window window t)
(if (display-multi-font-p)
(let* ((face (if face face 'default))
(info (font-info (face-font face))))
(aref info 3))
(frame-char-height))))
(defun window-max-chars-per-line (&optional window face)
"Return the number of characters that can be displayed on one line in WINDOW.
WINDOW must be a live window and defaults to the selected one.
The character width of FACE is used for the calculation. If FACE
is nil or omitted, the default face is used. If FACE is
remapped (see `face-remapping-alist'), the function uses the
remapped face.
This function is different from `window-body-width' in two
ways. First, it accounts for the portions of the line reserved
for the continuation glyph. Second, it accounts for the size of
the font."
(with-selected-window (window-normalize-window window t)
(let* ((window-width (window-body-width window t))
(font-width (window-font-width window face))
(ncols (/ window-width font-width)))
(if (and (display-graphic-p)
overflow-newline-into-fringe
(/= (frame-parameter nil 'left-fringe) 0)
(/= (frame-parameter nil 'right-fringe) 0))
ncols
(1- ncols)))))
(defun window-current-scroll-bars (&optional window)
"Return the current scroll bar types for WINDOW.
WINDOW must be a live window and defaults to the selected one.