Re: Unicode WYSIWYG - WYSIWYS campaign
Re: Unicode WYSIWYG - WYSIWYS campaign
- Subject: Re: Unicode WYSIWYG - WYSIWYS campaign
- From: Henrik Holmegaard <email@hidden>
- Date: Sat, 13 Mar 2004 16:04:17 +0100
In the following character refers to the abstract semantic signs
required in a writing system and glyph refers to the PS or TT outline
that represents the character(s).
Markup Language (ML) versus Page Description Language (PDL), which is
the better approach to repurposing of text strings?
In theory Markup Languages record character co-ordinates in logical
order and for this reason the text string is ideally suitable for
repurposing.
In practice Markup Languages record the result of the keyboard
operator's glyph selections rendered on the monitor.
Human beings don't proof read abstract character co-ordinates any more
than they color proof abstract CIE co-ordinates, obviously.
As glyph selections may as well map to semantically correct as to
semantically incorrect characters, MLs are unsafe for professional text
repurposing.
On the PDL side there is always the rendered glyph order which is
visually searchable, even if it may not be electronically searchable.
So does the PDL approach have an absolute answer to repurposing of
electronic text, given that it has an absolute answer to repurposing of
rendered glyph orders?
The white papers by Apple and Adobe suggest that the PDL is also the
better approach when the text string is correct to begin with.
If text strings are left intact and can be copied and pasted correctly,
how then does one ensure that the glyph order is rendered the same
across applications?
The Apple white paper makes the GX argument for OS level default table
processing mechanisms, in this case the text-to-type Line Layout
Manager.
GX glyph ordering was managed at the OS level which meant that
applications would order glyphs alike and could take advantage of new
OS level typographic features without themselves being updated, but
they had to surrender their text engines.
OpenType allows glyph ordering at the application level (though
Uniscribe, the equivalent of OS/X ATSUI, lets developers plug into
Windows text services).
In the world of OpenType text engines may not order glyphs quite the
same when using the same Unicode text string, so if a correct text
string is repurposed the glyph ordering as rendered by a known text
engine such as Adobe Cooltype still needs to be visually represented.
Which as far as I can see means that text repurposing is in practice
inseparable from a PDL (: PDF) which captures the output of a text
engine and represents it in device independent form.
Thanks,
Henrik
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