RE: Terminal Graphics Proposal

From: Frank da Cruz (
Date: Fri Oct 16 1998 - 14:44:55 EDT

> Ahem. I would like someone to help me understand the purpose of this
> proposal. Apparently many folks want a fuller set of terminal emulator
> control pictures. It is not clear to me how these are very useful. If one
> wishes to be in the mode of displaying all charaters in a datastream,
> controls and all, how are these control pictures used? Is a control code
> mapped to the control picture and then mapped to a value in a font?

> How is this a big advantage? Is it the hope that if the control pictures are
> encoded, a fuller and more standard set of glyphs will be developed?
Yes. This is explained at some length in the proposal:

Real terminals show these glyphs, and so it would be good if a
Unicode-based terminal emulator could show them too. Otherwise converting
from real terminals to PC-based emulators will be a step down. But then
to avoid this, makers of emulators will develop a panoply of incompatible
extensions to show these characters, which is not in anybody's best

The usefulness of these glyphs is not limited to terminal emulators.
Control characters -- and data streams containing them -- are something
that people write about, not only in computer manuals, but also in
textbooks, email, and newsgroup postings. Thus these glyphs can be used
in many applications.

Unicode already includes control pictures, but only for the C0 (ASCII)
control set. The proposal suggests that the control-picture domain be
expanded to include the C1 set as well as the sets used in the EBCDIC and
3270 arena, and possibly even the Unicode set (Zero-Width Joiners, etc).

Control pictures are only one part of the proposal. The most important
part (to me) are the extensible math characters and additional
line/box/block drawing characters used by a wide variety of real
terminals, but that are not in Unicode.

A third draft of the proposal will be available next week, after some
clarifications on certain glyphs are received from their makers, or I time
out waiting for them, in which case they will simply be removed from the

- Frank

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