Re: FT2 design question

[Stefan Seefeld]

Werner LEMBERG wrote:

> If line breaks aren't an issue, why bothering with ligatures at all?
> This is a typographical issue, usually completely hidden to the end
> user -- you specify the font, have an input character string and get a
> glyph string back.

right. The point is that all the scene graph knows about is the characters
plus some attached requirement information so I can pick individual characters
with the mouse and edit them. The Glyph string is a representation cached
inside the renderer and the mapping between them is done when the drawing
happens.

> WYSIWYG only works if you use the same font for the screen and
> printing IMHO.

Ok, I probably used 'font' in a wrong way. What I mean is that the scene
graph contains the information about the font (in terms of family, point size,
weight etc.) but the font renderer/rasterizer which is associated with it
depends on with which DrawingKit you render it. And there is the problem:
I can't know just from inspecting the font attributes how a particular
renderer mapps the characters to glyphs. Ligature information and kerning
etc. are all optional ! So while I'll cache some default requirements inside
the scene graph (I could for example put glues with negative sizes to
represent kerning between characters...) I can't really be sure that the
exact glyph metrics are preserved among DrawingKits. The point is really to
*try* to use the same font on both, screen and printer, as much as possible.
But without inspecting the DrawingKits this can't be guaranteed.

> I think I haven't understood you completely (but I have read the very
> interesting paper to which you've given a pointer).  Can you give a
> real example of the problem you have?

Well, for me this is all still quite theoretical. I'm doing the main 
architecture
of berlin and I realize some potential problems just from looking at the 
dependencies 
between the different modules (kits). May be we should continue this discussion
once we have a more complete implementation of the TextKit. It's the TextKit 
which
constructs entities representing lines, paragraphs, columns, pages etc. (It's 
really 
a continuation of Fresco/InterViews so the paper should reflect the overal 
design 
pretty well...)

Best regards,   Stefan

_______________________________________________________              
              
Stefan Seefeld
Departement de Physique
Universite de Montreal
email: address@hidden

_______________________________________________________

      ...ich hab' noch einen Koffer in Berlin...