Quoting Ville Syrj�l�:
> On Tue, Jun 15, 2004 at 12:51:03AM +0200, Stefan Lucke wrote:
> > On Dienstag, 15. Juni 2004 00:15, Ville Syrj�l� wrote:
> > > On Tue, Jun 15, 2004 at 12:01:59AM +0200, Stefan Lucke wrote:
> > > > I've a question how to realize some sort of cropping
> > > > with SetScreenLocation ( .. ).
> > > > 
> > > > My test stream has a 4:3 frame encoded as 16:9 anamorphic mpeg2 frame.
> > > > To display this correct on a 4:3 or 5:4 display, a center out operation has to 
> > > > be
> > > > done.
> > > > 
> > > > Is such a operation possible with SetScreenLocation ?
> > > 
> > > I'm not exactly sure what you mean. 
> > 
> > Let's say the decoded picture is of size 720x576. It is anamorphic 16:9.
> > But I know (AFD descriptors tell that) the active area is of 4:3 format. So
> > only this area should be drawn on a 4:3 screen in full size. Without doing
> > that I would get black bars on top and bottom due to 16:9 scaling and
> > black bars left and right, since the active area is 4:3.
> > 
> > > Do you want to resize the image so 
> > > that parts of it go outside the visible screen?
> > 
> > No (virtual yes). I want to draw a part of picture so that it fills the screen.
> > With Xv output it is easy. There I can specify source x and y offsets and
> > source width and height witch should be drawn at a given destination area.
> > With Xv-X11 this works with matrox and radeon and I think with others too.
> 
> DirectFB doesn't have any method of specifying source cropping for layers. 
> It would be a useful thing to add though.

It's already prepared to being added easily, at least the driver API covers
source AND destination rectangles.

> But you since you're looking to fill the entire screen you don't actually 
> need source cropping. SetScreenLocation() will suffice provided that the 
> driver crops things properly. You just have to calculate the coordinates 
> and size accordingly.

Or you configure the layer to have the pixel size of the active area and
copy only those pixels to the surface.

-- 
Best regards,
  Denis Oliver Kropp

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