[haiku-appserver] Re: clipping
- From: "DarkWyrm" <bpmagic@xxxxxxxxxxxxxxx>
- To: haiku-appserver@xxxxxxxxxxxxx
- Date: Fri, 25 Mar 2005 12:57:18 -0500 EST
> Hi,
>
> while I'm still cleaning up and shuffling arround code, could someone
> explain to me how clipping is supposed to work in app_server? The
> clipping region is passed in the DrawData object, but what coordinate
> space is this supposed to be in, screen space? Why is there a
Everything which takes place in the DisplayDriver is in screen
coordinates. I _think_ that the region objects kept in Layer are
relative to the layer itself, if not, then they are relative to the
parent. Adi?
> DrawBitmap call, that takes an additional clipping region? It seems
> to
> be the only DrawBitmap call in actual use (by ServerWindow), while
> the
> other one has neither a DisplayDriver nor ViewDriver implementation
> (but DirectDriver and BitmapDriver implement it, but those are not in
> regular use, are they?). PicturePlayer uses the second form of
The unused one is probably cruft. PicturePlayer is so old and crusty
that it actually has mold growing on it. :P
> DrawBitmap(), the one which isn't actually implemented. In which
> coordinate space is the clipreg member of PicturePlayer?
> Do all drawing commands allways get the screen coordinate system?
> What
> about scaled and scrolled BViews, is that taken into account already?
> If so, where is the origin of the scale supposed to be then?
All drawing commands get screen coordinates. Quite literally the idea
is that the DisplayDriver does no coodinate conversion whatsoever --
all that stuff is handled by the caller, better known as What You Call
Is What You Get. :D
--DW
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