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From: rws@expo.lcs.mit.EDU (Bob Scheifler)
Newsgroups: comp.windows.x
Subject: Re: X server speed
Message-ID: <9106042200.AA22663@expire.lcs.mit.edu>
Date: 4 Jun 91 22:00:27 GMT
References: <7413@acorn.co.uk>
Sender: daemon@athena.mit.edu (Mr Background)
Organization: The Internet
Lines: 27


    Although the X protocol is unclear on the effect of line width on *arc*
    (as opposed to line) drawing

Although there are some ambiguities, for the most part the effect is rather
clear, some would say too clear.

    This is particularly important for servers with
    graphics accelerators which support circle drawing - this circle drawing
    will almost certainly *not* conform to the protocol (you can't do the
    protocol efficiently in hardware as far as I know :-).

You obviously haven't done your homework.  Pixelating the boundaries of wide
circles is not a problem.  The problem is pixelating the boundaries of wide
ellipses.

    On my server (Acorn R260, about 75% the speed
    of a 1+ with no accelerator?) I get 8.1 circles/sec for line width 1 and
    317 circles/sec for line width 0.  (gbench, diameter 100 pixels, no complex
    raster ops, not that it makes any difference, FillSolid).

You poor thing. :-)  On a lowly Sun 3/60 with an 8-bit frame buffer, I can
get about 200 such circles per second for line width 1.

    Probably there are better ways of doing this

Yes, use a little math. :-)