In lists.linux.video4linux, you wrote:
> On 15 Oct 2002, Gerd Knorr wrote:
> > > If I have an application like xawtv and I want to set the WM
> > > properies on the X window so that the window can be resized between
> > > the min/max size the hardware supports, how would I do this?
> >
> > Don't do that (IMHO). You can't assume that the hardware can freely
> > scale between given min and max sizes. Most usb cams have a few fixed
> > sizes they can handle for example.
>
> What would you do? make the window unresizeable? That's hardly very usable.
Don't limit the size at all. Maybe have a "make window size fit" menu
entry and/or hotkey.
> Anyway to get this information about what fixed sizes a card supports, other
> than some kind of guessing game?
No. It is next to impossible to find some scheme to pass this
information which works for all hardware out there. There are
simply to much possible dependences.
And you don't need to play the guessing game. If the user resized the
window you simply pass the new size down to the driver to see what it
can do about that.
> Is there any information on v4l2_cropcap? The v4l2 document on thedirks.org
> just says:
The pixel aspect ratio and the default image rectangle is in there.
Currently looks like this:
struct v4l2_cropcap {
struct v4l2_rect bounds;
struct v4l2_rect defrect;
struct v4l2_fract pixelaspect;
};
See Michaels comments on this list for more on this. Michael is working
on the v4l2 specs, but there is nothing on the web yet.
Gerd
--
You can't please everybody. And usually if you _try_ to please
everybody, the end result is one big mess.
-- Linus Torvalds, 2002-04-20
