Re: [XaraXtreme-dev] RE: Bitmap storage format [Was: Debugging View::RenderOptimalView - request for assistance]

[Alex Bligh <alex@xxxxxxxxxxx>]

Phil Martin wrote:
> CWxBitmap doesn't seem to have much connection to wxWidgets at all, no.
> The only thing is a function called MakewxImage which runs through the
> bitmap pixel by pixel anyway and so may as well swap the RGB byte order
> there if need be.
>
> BUT, for some reason its RGB byte order on Linux is different than on
> Windows and so it's probably not correct to call that "DIB format"...

Well I think that is probably the bug! I don't know /why/ the bitmap
format is not in straight DIB format (at least for architectures
of the same endianness).

> Maybe the reason is that blitting the CDraw output bitmap requires a
> different RGB byte order on Linux and the byte order percolates back
> from there?

I'm not sure why that would be. At least on the current plotting
route (USE_wxBITMAP == 0) we process Gavin's output buffer word
by word anyway (we OR in 0xff00000 as GTK expects ff for an
alpha value). We could just as easily swap R and B if they are
the other way around in a DIB from GTK (I'm not sure they are).
My point is that the Linux RGB byte order does not (certainly
need not) drive it. The only thing I can see might need to
change is the CONVHINT stuff which seems to presume a fixed
RGB order in the final output format.

I would have thought the least bug ridden way forward would be
"use DIB format everywhere". How would people feel about that?

Alex