Re: XFree86 4.0

[Juliusz Chroboczek]

Hi Joerg, hello everyone.

JP> Well, I can't speek for Juliusz, but he indicated more than once
JP> that he will integrate Freetype 2.0 into XFree86 once it is ready.

I'm very keen on doing a FreeType 2-based backend.  I just need to
find a bit of quiet.

I also need convenient access to all the TrueType tables and Type 1
entries I need.  In particular, I want the head, hmtx, OS/2 and post
tables.  I also want to be able to use Type 1 glyphs by name.  I don't
know whether FreeType 2 satisfies these conditions yet, I haven't
checked since beta 4.

JP> As for anti-aliasing: This is nothing new in Freetype
JP> 2.0. Freetype-1.x could do anti-aliasing almost from the
JP> beginning. This feature is not used in X because the X protocol
JP> does not allow for this.

Correct again.  Basically, the problem is that all X requests take a
drawable and a GC.  This is not always enough to determine the visual
(pixmaps aren't associated to a particular visual, they only have a
depth), and never enough to determine a colormap.

Core X may therefore manipulate pixel values, but has no way of
mapping them to colours.  Without knowing the mapping between pixels
and colours, there is no way to do the blending required to implement
anti-aliased text.

(We're not speaking of image text here, the kind that overwrites the
background.  If we implement anti-aliased text, we also implement
ordinary text.)

JP> So after a lot of heated discussion

After some constructive exchange of ideas performed in an atmosphere
of proactive synergy.

JP> it was decided that anti-aliasing is not a sensible option for the
JP> current X rendering model.

Yes.  Implementing anti-aliasing basically requires designing a new
rendering model.  If we do such a big job, we might as well do it
right, with alpha buffers and all.

JP> Keith Packard is working on a new one
JP> that will contain a completely new font handling scheme. It is
JP> supposed to support anti-aliased character rendering. For more
JP> information read:
JP> http://www.xfree86.org/~keithp/talks/usenix2000/render.html

Yep.

Keith is one of the authors of the comprehensive rewrite of the SI
that happened with X11R4.  He's also the author of the new scheduler
in XFree86 4.0, and coincidentally of the ``silken mouse'' trick.  I
think the best thing to do is to wait for his design, which is very
likely to be what we need.

But for now, I'll point you to my pet project.

  http://dps.sourceforge.net

Regards,

                                        Juliusz Chroboczek