Re: [XaraXtreme-dev] EPS export

[Alex Bligh <alex@xxxxxxxxxxx>]

Gerry Iles wrote:
> Errr, what is full of virtuals?  I presume you mean wxDC.

pure virtuals, yes, wxDC.

> Well, under
> MFC, CDC is the class that simply wraps a Win32 HDC so there are no
> virtuals involved.  Unfortunately, in wxWidgets, there is a class
> hierarchy of DCs (similar to our CCDC hierarchy) but to link the two
> hierarchies together is not really possible.  This is why CCPaintDC was
> changed to derive from wxPaintDC rather than CCDC (as it requires the
> functionality in wxPaintDC).

Sure.

> You may have to make similar changes for
> the printing and/or export DCs if this is compatible with how the DCs
> get created during printing or export (e.g. derive ExportDC from one of
> the derived wxDC classes if it is possible for the app to create its own
> DC for the print job).  However, I suspect that wx will actually create
> the relevant type of DC and the just has to use it so it might be
> necessary to reorganise things a bit (e.g. make CCDC contain a wxDC*
> rather than be derived from it).  I think this will be a large amount of
> work.
>
> The plugin filter stuff doesn't export in the same way.  The "rendering"
> that it does is either simple rendering into bitmaps or uses a
> specialised render region that does not output anything to a "device"
> and hence does not need a DC (of any sort) to render into.

OK I think I can assume that as CCDC has pure virtuals too, no instance
of it is ever currently created then!

I'm trying to work out which bits of wxDC CCDC (and thus EPSExportDC
etc.) actually need. If the only thing CDC did was wrap an m_hDC
I'm guessing the answer is "none". Or is CDC more complex than that?

Alex