On 21 Dec, Soeren Sandmann wrote:
> [EMAIL PROTECTED] writes:
> 
>>  - usable, fast text using non-AA fonts over 50/25 kbps with o(10)ms
>>    round trip.  (I'm using client/server transmit speed notation.  50/25
>>    could be a 56K modem or a low power wireless data.)
>>  - borderline, sluggish text using AA fonts over 50/25.
>>  - usable, fast text using AA fonts over 768/128 (e.g. DSL, cable, wireless)
>>  - immediate text, OK graphics and images over 10,000/10,000
>>  - immediate text, fast graphics and images over 100,000/100,000.
> 
> I am obviously missing something, so please enlighten me. 
> 
> Why should antialiasing make a difference with respect to bandwidth? I
> thought Render cached glyphs on the server, and that a glyph was an
> ARGB image. If that's the case, the client should only have to
> transmit the index of the glyph is wants drawn, and this would also be
> the case for non-antialiased text, so I don't see why there would be
> any difference.
> 

It does, but there are two effects that need to be controlled:
 1) Cache management.  You still need to initially populate the cache
  for new fonts and sizes.  You have cache removal for unreferenced
  fonts so you may need to repopulate.  For a non-AA font glyphs are
  1-bit per pixel. For AA and color AA glyphs are 8 or 32 bits per
  pixel.
 2) References to glyph indices still consume several times more bits
  per character than strings using the old style.

Since X is already just barely usable over 50/25 links, I reduced the
performance goal.  (xterm is fine over 50/25, Netscape gives new meaning
to the term "badly behaved", most applications are somewhere in
between.) Better performance is great, but I would accept a reduced
performance over a slow link like that.

R Horn

_______________________________________________
Render mailing list
[EMAIL PROTECTED]
http://XFree86.Org/mailman/listinfo/render

Reply via email to