HORIZONTAL SCAN LINEs

Ilya Zakharevich nospam-abuse at ilyaz.org
Wed Apr 2 13:36:45 CDT 2014


The current version (and 7.0.0-tobe) describe them as:

    @   	    Scan lines for terminal graphics
    @+	    	 The scan line numbers here refer to old,
     low-resolution technology for terminals, with only 9 scan lines per
     fixed-size character glyph. Even-numbered scan lines are unified with
     box-drawing graphics.
    23BA	    HORIZONTAL SCAN LINE-1
    23BB	    HORIZONTAL SCAN LINE-3
    23BC	    HORIZONTAL SCAN LINE-7
    23BD	    HORIZONTAL SCAN LINE-9

Is not it a complete BS?  Was not this intended to be written similar to:

  Glyphs for even-numbered scan lines were never defined.  The 5th
  scan line is unified with U+2500 (from box-drawing graphic).

Please note that even well-researched fonts (like Symbola) treat them
wrongly.  Should not another comment (or two) be better added:

  Line-1 was the top line of the character box, and Line-9 was at the bottom.
  These characters were intended to connect on the sides, and with

  	23B8	LEFT VERTICAL BOX LINE
	23B9	RIGHT VERTICAL BOX LINE

Thanks,
Ilya

P.S.  The references I found are

      http://lists.freedesktop.org/archives/wayland-devel/2012-May/003687.html
      http://invisible-island.net/vttest/images/VTTEST-VT100%20character%20sets.png
	illustrating	http://invisible-island.net/vttest/
      http://www.unicode.org/mail-arch/unicode-ml/y2001-m09/0037.html
      5-9 in  ftp://kermit.columbia.edu/kermit/ucsterminal/ucsterminal.txt
      http://paulbourke.net/dataformats/ascii/	(search for: control-backspace)



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