Info Catalog elisp: Properties in Mode elisp: Mode Line Format elisp: Emulating Mode Line

elisp: Header Lines

 
 22.4.7 Window Header Lines
 --------------------------
 
 A window can have a “header line” at the top, just as it can have a mode
 line at the bottom.  The header line feature works just like the mode
 line feature, except that it’s controlled by ‘header-line-format’:
 
  -- Variable: header-line-format
      This variable, local in every buffer, specifies how to display the
      header line, for windows displaying the buffer.  The format of the
      value is the same as for ‘mode-line-format’ (Mode Line
      Data).  It is normally ‘nil’, so that ordinary buffers have no
      header line.
 
  -- Function: window-header-line-height &optional window
      This function returns the height in pixels of WINDOW’s header line.
      WINDOW must be a live window, and defaults to the selected window.
 
    A window that is just one line tall never displays a header line.  A
 window that is two lines tall cannot display both a mode line and a
 header line at once; if it has a mode line, then it does not display a
 header line.
 

Info Catalog elisp: Properties in Mode elisp: Mode Line Format elisp: Emulating Mode Line