Info Catalog elisp: Window Systems elisp: Display elisp: Bidirectional Display

elisp: Tooltips

 
 37.25 Tooltips
 ==============
 
 “Tooltips” are special frames (Frames) that are used to display
 helpful hints (a.k.a. “tips”) related to the current position of the
 mouse pointer.  Emacs uses tooltips to display help strings about active
 portions of text (Special Properties) and about various UI
 elements, such as menu items (Extended Menu Items) and tool-bar
 buttons (Tool Bar).
 
  -- Function: tooltip-mode
      Tooltip Mode is a minor mode that enables display of tooltips.
      Turning off this mode causes the tooltips be displayed in the echo
      area.  On text-mode (a.k.a. “TTY”) frames, tooltips are always
      displayed in the echo area.
 
    When Emacs is built with GTK+ support, it by default displays
 tooltips using GTK+ functions, and the appearance of the tooltips is
 then controlled by GTK+ settings.  GTK+ tooltips can be disabled by
 changing the value of the variable ‘x-gtk-use-system-tooltips’ to ‘nil’.
 The rest of this subsection describes how to control non-GTK+ tooltips,
 which are presented by Emacs itself.
 
    Since tooltips are special frames, they have their frame parameters
 (Frame Parameters).  Unlike other frames, the frame parameters
 for tooltips are stored in a special variable.
 
  -- Variable: tooltip-frame-parameters
      This customizable option holds the frame parameters used for
      displaying tooltips.  Any font and color parameters are ignored,
      and the corresponding attributes of the ‘tooltip’ face are used
      instead.  If ‘left’ or ‘top’ parameters are included, they are used
      as absolute frame-relative coordinates where the tooltip should be
      shown.  (Mouse-relative position of the tooltip can be customized
      using the variables described in (emacs)Tooltips.)  Note
      that the ‘left’ and ‘top’ parameters, if present, override the
      values of mouse-relative offsets.
 
    The ‘tooltip’ face determines the appearance of text shown in
 tooltips.  It should generally use a variable-pitch font of size that is
 preferably smaller than the default frame font.
 
  -- Variable: tooltip-functions
      This abnormal hook is a list of functions to call when Emacs needs
      to display a tooltip.  Each function is called with a single
      argument EVENT which is a copy of the last mouse movement event.
      If a function on this list actually displays the tooltip, it should
      return non-‘nil’, and then the rest of the functions will not be
      called.  The default value of this variable is a single function
      ‘tooltip-help-tips’.
 
    If you write your own function to be put on the ‘tooltip-functions’
 list, you may need to know the buffer of the mouse event that triggered
 the tooltip display.  The following function provides that information.
 
  -- Function: tooltip-event-buffer event
      This function returns the buffer over which EVENT occurred.  Call
      it with the argument of the function from ‘tooltip-functions’ to
      obtain the buffer whose text triggered the tooltip.  Note that the
      event might occur not over a buffer (e.g., over the tool bar), in
      which case this function will return ‘nil’.
 
    Other aspects of tooltip display are controlled by several
 customizable settings; see (emacs)Tooltips.
 

Info Catalog elisp: Window Systems elisp: Display elisp: Bidirectional Display