Re: [XaraXtreme-dev] Cairo Port

[Jonas Diemer <diemer@xxxxxx>]

Hi,

again, thanks for replying. Didn't expect such immediate feedback since 
the list had been mute for a month or so :-)

Alex Bligh schrieb:
> --On 07 May 2007 22:08 +0200 Jonas Diemer <diemer@xxxxxx> wrote:
>
> > 1. Carl created stubs for function calls to CDraw functions, which 
> > are to
> > be replaced by Cairo functions. Wouldn't it be easier to derive a new
> > GDrawContext instead? This has been done originally with GDrawAsm as a
> > C++ wrapper for the assemblerfunctions in GDRAW.DLL. I think this would
> > at least save passing around contexts, and would be more object 
> > oriented,
> > too.
>
> Yes and no. Yes, in that creating a derived context class is desirable,
> so one can do both from the same binary, and no in that you will need
> to do some (possibly conditional) stubbing out in order to avoid 
> unresolved
> references when linking without CDraw.
True unless I replace GDrawAsm, which I was originally thinking about. 
But you are right, it might be nice to switch at run time (for testing 
etc.). I might as well continue the way Carl started for now, but then 
there's this context passing which I don't fully understand yet.

What is actually passed in the GCONTEXT struct? Esp., what's in the Data 
field?

Should Valid actually be set toC90FDAA2 as it says in gconsts.h:238?

> You will also, I think, need to look carefully at whether you need to
> derive an alternate render region class from GRenderRegion; ideally you
> won't (as you'll have to change all sorts of instances where these are
> created); perhaps you can use the render region capabilities system
> (RRCAPS).

Hmm, haven't thought about those details yet. This is what Carl was 
refering to where GDRAW etc. paint to, right?

But using stubs or deriving a GDrawContext should be irelevant for this 
matter, right?

> I possess complementary skills to Carl, in that I know very little about
> Cairo, but a little more about Xara internals than most, though the
> Xara guys know more, obviously.

Great, then I have two experts I can refer to with problems :-)

Jonas.