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From: scott@graft.Berkeley.EDU (Scott Silvey)
Newsgroups: comp.windows.x
Subject: Re: XPutImage() vs XDrawPoints() performance
Message-ID: <26261@pasteur.Berkeley.EDU>
Date: 17 Jul 90 01:36:23 GMT
Sender: news@pasteur.Berkeley.EDU
Reply-To: scott@xcf.berkeley.edu
Organization: UC Berkeley Experimental Computing Facility
Lines: 29
X-Local-Date: 16 Jul 90 18:36:23 PDT


 
Ok, I've learned something here.  I didn't realize that XGetImage
  actually made a local copy of the pixmap.  That is very good to
  know.  I thought XGet/PutPixel() did and X operation each time,
  but I just wasn't thinking.

So here is a summary of the responses at this point:
 
If you have more than 30000 points to draw, XGet/PutImage() along with 
  XGet/PutPixel() is much better becuase you muck around with the 
  actual data locally and you blast the finished image over to the 
  server when you are done.

XDrawPoints() does an X operation each time which is slower if you 
  have to do several of these (bunches of 30000 points).  However,
  it is faster if you only need to do one batch or if your pixmap
  is huge.



Am I correct in my understanding of these issues that people have
  presented?  

Does having a huge image cause XGet/PutImage() to slow down 
  significantly so that XDrawPoints() becomes an attractive 
  alternative?

Scott