nanogui: Cyrix CS5330 and frame buffer
Subject:
Re: [nanogui] Cyrix CS5330 and frame buffer
From:
"John Zulauf" ####@####.####
Date:
25 Jun 2001 15:45:13 -0000
Message-Id: <3B375AC9.BE7199C0@ia.nsc.com>
Also, from the name of the routine "DrawImageToFit" it sounds like this
routine is doing image scaling. If that's correct then you *certainly*
want to use pixmap such that the image is scaled ONCE to the pixmap and
copied thereafter. Better would be to prescale the image. Resampling
an image per refresh is a very processor intense (i.e. inefficient,
slower) way to draw.
Beyond the pure performance issue is a power issue. In wireless or
cordless devices, the amount of work you ask from a
well-power-managemed-device will effect battery life. Typically
browsing is an 80% idle (or more) activity typically. Code which drives
the processor to the extent that performance is preceptably affected
means that the machine is running full-out. Potenially 4-5x the power
draw of well coded refresh (for the period of the refresh).
John Zulauf
National Semiconductor
Jordan Crouse wrote:
>
> Can you be a little more specific? Were you running Microwindows in
> framebuffer mode or in X11 mode? How big was your image? What type of image
> was it?
>
> What was the context? Were you just trying to draw one image every once in a
> while (like an icon) or were you drawing many times very fast (like in a
> game)?
>
> Have you tried using a offscreen pixmap? You could draw the image on the
> offscreen buffer, and then copy it over as needed (copying is always cheaper
> than drawing images).
>
> Jordan
>
> On Monday 25 June 2001 07:02, ####@####.#### mentioned:
> > Hi there.
> >
> > I set up nano-X on an embedded platform equipped
> > with a geode microprocessor, a Cyrix CS5330 based video
> > controller, running Linux 2.2.19 with frame buffer support.
> >
> > All worked fine, but I experienced slowness in image rendering
> > ( GrDrawImageToFit() ).
> >
> > Is this due to microwindows or what?
> >
> > Thanks in advance.
> >
> >
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