Info Catalog elisp: Active Display Table elisp: Character Display elisp: Glyphless Chars

elisp: Glyphs

 
 37.22.4 Glyphs
 --------------
 
 A “glyph” is a graphical symbol which occupies a single character
 position on the screen.  Each glyph is represented in Lisp as a “glyph
 code”, which specifies a character and optionally a face to display it
 in (Faces).  The main use of glyph codes is as the entries of
 display tables (Display Tables).  The following functions are
 used to manipulate glyph codes:
 
  -- Function: make-glyph-code char &optional face
      This function returns a glyph code representing char CHAR with face
      FACE.  If FACE is omitted or ‘nil’, the glyph uses the default
      face; in that case, the glyph code is an integer.  If FACE is
      non-‘nil’, the glyph code is not necessarily an integer object.
 
  -- Function: glyph-char glyph
      This function returns the character of glyph code GLYPH.
 
  -- Function: glyph-face glyph
      This function returns face of glyph code GLYPH, or ‘nil’ if GLYPH
      uses the default face.
 
    You can set up a “glyph table” to change how glyph codes are actually
 displayed on text terminals.  This feature is semi-obsolete; use
 ‘glyphless-char-display’ instead (Glyphless Chars).
 
  -- Variable: glyph-table
      The value of this variable, if non-‘nil’, is the current glyph
      table.  It takes effect only on character terminals; on graphical
      displays, all glyphs are displayed literally.  The glyph table
      should be a vector whose Gth element specifies how to display glyph
      code G, where G is the glyph code for a glyph whose face is
      unspecified.  Each element should be one of the following:
 
      ‘nil’
           Display this glyph literally.
 
      a string
           Display this glyph by sending the specified string to the
           terminal.
 
      a glyph code
           Display the specified glyph code instead.
 
      Any integer glyph code greater than or equal to the length of the
      glyph table is displayed literally.
 

Info Catalog elisp: Active Display Table elisp: Character Display elisp: Glyphless Chars