From kde-devel  Mon Apr 03 19:50:32 2000
From: Werner Trobin <wtrobin () carinthia ! com>
Date: Mon, 03 Apr 2000 19:50:32 +0000
To: kde-devel
Subject: Masked QPixmap, bitBlt,...?
X-MARC-Message: https://marc.info/?l=kde-devel&m=95479228928801

Hi!

I know that there is no "do-it-that-way-and-everything-
will-be-magnificent" answer to my following questions,
but I hope you can at least give me some basic information
based on your experience or on deeper knowledge of the
Qt drawing code / X server stuff.
To be honest I'm asking because I'm too lazy to implement
lots of "benchmarks" which don't represent the "reality."
(lack of time :)

* Is there any "golden-rule" when to draw things directly
  and when to use cached QPixmaps & bitBlt()? (e.g. a few
  lines and polygons vs. complex drawings with lots of
  filled polygons, ellipses,...)

* What about non rectangular pieces (i.e. masked QPixmaps)?
  How does the above "limit" change if the area has to be
  masked (with QBitmaps)?

* Is there any measurable speed advantage when "optimizing"
  QPixmaps? How high is the mem penalty?

I know that this is the old "trade memory for speed" issue,
but I hope you can give me a few hints :)

Thank you in advance,
Werner