[REBOL] Re: deceleration !
From: greggirwin:mindspring at: 11-Oct-2002 11:32
<<...i'm really surprise by the result of my test and i can't believe that
drawing a simple circle (just one!) is so consequent. Or i must understand
that in rebol drawing a circle is very complex and requiere a lot of compute
that slow down performances.
Maybe someone have another explanation to solve this question. >>
There are some underlying conceptual issues, perhaps, and some other things
First, in many drawing apps, the things you draw become just "bits on a
background", which is fast and easy to display. In more capable apps, you
may have lots of drawing objects which can be arbitrarily moved between
layers (i.e. Z-ordered), etc. They tend to be highly optimized, and are the
subject of an enormous amount of effort to keep their performance high.
REBOL faces are very general and powerful. Every face uses the compositing
engine and can have its own set of effects. The DRAW effect (as I understand
it) has to be re-interpreted every time you show the face, which can be very
slow, especially where fills and things are concerned. The little paint app
I've seen holds its own pretty well, but I haven't seen Olivier's to see how
it works or performs.
Two things that affect face redrawing performance are 1) the size of the
face, and 2) any other effects you have applied to it. Large faces are slow
to paint, and other effects have to be re-rendered each time as well, which
can bring things to a crawl if you're not careful. Their performance is
good, but real-time, 24-bit compositing is a lot of work no matter how you
look at it.