MapGuide fork of AGG

thomas bonfort thomas.bonfort at GMAIL.COM
Tue Oct 23 04:06:20 EDT 2007

On 10/23/07, Paul Spencer <pspencer at> wrote:
> Steve, Daniel, I encourage you to voice your opinions on the mapguide
> internals list ... the more the better.  I would love to see some
> collaboration between mapguide and mapserver at this level.  It seems
> like easy common ground to get started talking together.

hi all,

I've been thinking about the pros and cons of having an osgeo fork of
AGG, from a mapserver point of view but I think most of it applies to
mapguide too.

* the agg build process is a pain for the users, as the agg makefiles
need some modifications before some of the mapscript components can
run. I see two issues that have to be fixed in this field:
- the freetype font manager isn't included in the default built. This
is by design and not a bug, so any fixes on this end will never be
backported to the official 2.4+ agg branches ( at least imho )
- makefiles and configure logic should include the ability to build
position independant code (-fPIC). I don't think fixes for this would
be included in the official agg releases, as I think the aim is to
have agg build by just typing 'make' and not having to configure

this could push us to have an osgeo tarball of agg 2.4 , with these
few glitches fixed. I don't know if we can call that a fork, but this
at least allows us to keep a bsd compatible version secure whatever
happens on the agg side, and a place to point the endusers at if/when
they encounter build problems.

* do any folks at osgeo have the incentive and/or knowledge to
continue on agg development? backporting fixes should be easy to do
(for the time being this is useless as maxim of agg is still
maintaining 2.4 - this might not last for long though), but keeping up
with features of 2.5+ (when and if they come) seems unfeasible for non
specialist people (without resorting to blindly backporting agg
trunk's changes which seems a rather lame thing to do given maxim's
wish in change of license)
* this is mapserver specific, and I may be completely wrong here, but
it seems to me that the agg license change isn't a deal breaker for
us. folks can continue "using" an agg-gpl enabled mapserver, and the
businesses who are reselling modified/bundled/etc versions of
mapserver can either continue with the gd-only version, or pay up for
a commercial agg license. I didn't follow the discussions when pdf
support was added, but pdflib is far more constraining than agg in the
sense you have to pay a license for /any/ commercial use.

> In particular, I think mapserver could benefit from Traian's
> modifications for rendering into a different buffer to solve the
> alpha problems and for the rendering on transparent background thing.
after sorting this out off-list with Traian, it turns out that there
is no bug in the agg blending functions, just a mixup in which
blenders to use and what ouptut they are supposed to generate

just my .02€


> On 22-Oct-07, at 2:12 PM, Steve Lime wrote:
> > This should be a nice mess, especially if there is a broader
> > community fork of AGG 2.4. I'm curious
> > why a fork is even necessary? The RFC doesn't go into any detail.
> > The one piece of code mentioned
> > in the thread certainly doesn't necessitate a fork.
> >
> > Steve
> >
> >>>> On 10/20/2007 at 12:11 PM, in message <471A36AC.
> >>>> 8090403 at>, Daniel
> > Morissette <dmorissette at MAPGEARS.COM> wrote:
> >> MapServer Dev's
> >>
> >> This is just a heads up that MapGuide has a RFC open right now about
> >> adding support for AGG rendering, and as part of that they plan to
> >> fork
> >> AGG 2.4 and make some improvements to it:
> >>
> >>
> >> A few people have already suggested on the mapguide-internals list
> >> that
> >> they do that in a way that other OSGeo projects such as MapServer can
> >> benefit from the improved version. Interested parties can review the
> >> thread in the archives at
> >>
> >> 001922.html
> >>
> >> Daniel
> +-----------------------------------------------------------------+
> |Paul Spencer                          pspencer at    |
> +-----------------------------------------------------------------+
> |Chief Technology Officer                                         |
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