lisp/dynamic-setting.el

   1 ;;; dynamic-setting.el --- Support dynamic changes
   2
   3 ;; Copyright (C) 2009-2017 Free Software Foundation, Inc.
   4
   5 ;; Author: Jan Djärv <jan.h.d@swipnet.se>
   6 ;; Maintainer: emacs-devel@gnu.org
   7 ;; Keywords: font, system-font, tool-bar-style
   8 ;; Package: emacs
   9
  10 ;; This file is part of GNU Emacs.
  11
  12 ;; GNU Emacs is free software: you can redistribute it and/or modify
  13 ;; it under the terms of the GNU General Public License as published by
  14 ;; the Free Software Foundation, either version 3 of the License, or
  15 ;; (at your option) any later version.
  16
  17 ;; GNU Emacs is distributed in the hope that it will be useful,
  18 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  19 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20 ;; GNU General Public License for more details.
  21
  22 ;; You should have received a copy of the GNU General Public License
  23 ;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.
  24
  25 ;;; Commentary:
  26
  27 ;; This file provides the lisp part of the GConf and XSetting code in
  28 ;; xsetting.c.  But it is nothing that prevents it from being used by
  29 ;; other configuration schemes.
  30
  31 ;;; Code:
  32
  33 ;;; Customizable variables
  34
  35 (declare-function font-get-system-font "xsettings.c" ())
  36
  37 (defvar font-use-system-font)
  38
  39 (defun font-setting-change-default-font (display-or-frame set-font)
  40   "Change font and/or font settings for frames on display DISPLAY-OR-FRAME.
  41 If DISPLAY-OR-FRAME is a frame, the display is the one for that frame.
  42
  43 If SET-FONT is non-nil, change the font for frames.  Otherwise re-apply the
  44 current form for the frame (i.e. hinting or somesuch changed)."
  45   (let ((new-font (and (fboundp 'font-get-system-font)
  46                        (font-get-system-font)))
  47         (frame-list (frames-on-display-list display-or-frame)))
  48     (when (and new-font (display-graphic-p display-or-frame))
  49       (clear-font-cache)
  50       (if set-font
  51           ;; Set the font on all current and future frames, as though
  52           ;; the `default' face had been "set for this session":
  53           (set-frame-font new-font nil frame-list)
  54         ;; Just redraw the existing fonts on all frames:
  55         (dolist (f frame-list)
  56           (let ((frame-font
  57                  (or (font-get (face-attribute 'default :font f 'default)
  58                                :user-spec)
  59                      (frame-parameter f 'font-parameter))))
  60             (when frame-font
  61               (set-frame-parameter f 'font-parameter frame-font)
  62               (set-face-attribute 'default f
  63                                   :width 'normal
  64                                   :weight 'normal
  65                                   :slant 'normal
  66                                   :font frame-font))))))))
  67
  68 (defun dynamic-setting-handle-config-changed-event (event)
  69   "Handle config-changed-event on the display in EVENT.
  70 Changes can be
  71   The monospace font. If `font-use-system-font' is nil, the font
  72     is not changed.
  73   The normal font.
  74   Xft parameters, like DPI and hinting.
  75   The Gtk+ theme name.
  76   The tool bar style."
  77   (interactive "e")
  78   (let ((type (nth 1 event))
  79         (display-name (nth 2 event)))
  80     (cond ((and (eq type 'monospace-font-name) font-use-system-font)
  81            (font-setting-change-default-font display-name t))
  82
  83           ((eq type 'font-render)
  84            (font-setting-change-default-font display-name nil))
  85
  86           ;; This is a bit heavy, ideally we would just clear faces
  87           ;; on the affected display, and perhaps only the relevant
  88           ;; faces.  Oh well.
  89           ((eq type 'theme-name) (clear-face-cache))
  90
  91           ((eq type 'tool-bar-style) (force-mode-line-update t)))))
  92
  93 (define-key special-event-map [config-changed-event]
  94   'dynamic-setting-handle-config-changed-event)
  95