[directfb-users] Re: Initial image

[Denis Oliver Kropp <dok@directfb.org>]

Quoting Jan Ekholm:
> On Wed, 28 Apr 2004, Denis Oliver Kropp wrote:
> 
> >Quoting Andreas Kotes:
> >> Heya,
> >>
> >> * Jan Ekholm <chakie@infa.abo.fi> [20040428 08:46]:
> >> > Is it possible to set some kind of "initial image" that would be set after
> >> > the framebuffer has been initialized? I always just see garbage, quite
> >> > often something from before the last reboot. Warm reboots don't seem to
> >> > clear the framebuffer, and I'd like to have something else there, such as
> >> > a DirectFB logo or similar.
> >> >
> >> > I can of course do it using a custom app or DFBSee, but they have to be
> >> > left running, as soon as I kill them the image becomes garbage that
> >> > slightly resembles what the original image was. What I'm looking for is
> >> > thus an app or "thing" that sets an image to the framebuffer and then
> >> > exits, leaving the framebuffer free for the main application that will be
> >> > started once the system is fully up and running.
> >> >
> >> > I hope my ramblings make any sense?
> >>
> >> sure does. how about pure ignorance:
> >>
> >> cat /dev/fb0 > your_file.raw
> >>
> >> .. with what you want on screen .. and:
> >>
> >> cat your_file.raw > /dev/fb0
> >>
> >> .. to show it on boot.
> >
> >dd if=/dev/fb0 of=your_file.raw bs=1024k count=2
> >
> >and
> >
> >dd if=/dev/fb0 of=your_file.raw bs=1024k count=2
> 
> Seriously, should the image be 33M big? This is for a mode:

No, using the dd command lines above you have 2 MB.

You can adjust the bs and count arguments to match your mode:

dd if=/dev/fb0 of=your_file.raw bs=1620k count=1

>     LineLength  : 1440
> 
> I'd expect it to be more like 1658880 bytes (720*576*4), or something like

You have to take care of the LineLength. In most cases it matches Width*Bpp,
but sometimes it's higher (alignment for hardware).

> that. Or did it dump the whole darn thing as seen from the size attribute?

When using "cat", yes ;)

> I don't think I grok this size thing well enough to know why it is that
> big. Shouldn't it just be a raw buffer big enough to hold one or two
> frames?
> 
> Anyway, a screenshot this big is a bit too expensive (and thus slow) to
> put onto flash or a USB memory card... :)

;)

-- 
Best regards,
  Denis Oliver Kropp

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