[mapguide-internals] Patch: Remove usage of DbXml private header

[Traian Stanev]

As far as I remember, two of the changes to gd are definitely not
suitable.

One of them adds a return array to the gdImageStringFTEx function that
gets filled with floating point kerning pair information. This helps us
position path labels correctly. This is a breaking change to the gd API,
but I guess it could be added as an overload to the current gd string
drawing function.

The other change was to comment out line clipping from a certain
algorithm, since clipping was making lines look discontinuous across map
tiles. This would negatively affect performance in cases where
continuity across images is not needed.

Also, Walt rewrote the line anti-aliasing function from scratch, so that
piece would not be a  minor patch either. The old anti-aliasing function
did incorrect alpha-blending and I think (not positive) had crashes due
to illegal memory access.

If you have specific questions about this code, post them here.

Traian



-----Original Message-----
From: Helio Chissini de Castro [mailto:helio at kde.org] 
Sent: Friday, May 11, 2007 4:07 PM
To: mapguide-internals at lists.osgeo.org
Cc: Traian Stanev
Subject: Re: [mapguide-internals] Patch: Remove usage of DbXml private
header

Em ven 11 mai 2007, Traian Stanev escreveu:
> > Is there something really special inside mapguide gd that i miss ?
>
> Yes.
>
> With the external gd, you will find that labeling of polylines will
not
> work. Text in general may not draw at all. Also, if you use tiled
maps,
> there will be discontinuities across tile boundaries. I am not sure if
> the other bug we fixed was also fixed in the main gd stream, it had to
> do with crashes because pixels outside the image were accessed by the
> antialiased line drawing algorithm. There was also a bug in GIF output
> that I am not sure was fixed in the main stream. I guess I should
check
> up on that, but considering how little time I have it probably won't
> happen soon...

Good to know, i will see the diffs and probably will try apply it
Mandriva 
official package, if suitable.

>
> When I last tried an x64 build, the MapGuide server would crash on
> startup. Have you seen such problems?

Yes, and i'm tracking this as a font cache issue. As i finish build with
beta1 
here, i can produce a valid bt and confirm if this is really the cause.

[]'s

-- 
Helio Chissini de Castro
KDE Project South America Primary Contact
Curitiba - Brasil