Subject: [ggl] Efficient rotation about a point
From: Mateusz Loskot (mateusz)
Date: 2009-12-01 14:07:14
Barend Gehrels wrote:
>>>> Barend, since GGL transformers aren't composable, wouldn't it be
>>>> right for GGL to provide some type of transformer taking a matrix as
>>>> its constructor parameter?
>>> Yes, I think that is a good idea. Will be solved (either done, or
>>> maybe they should be composable).
>> I was thinking about it yesterday.
>> For now, wouldn't it be sufficient to use ublas_transformer
>> and enable compositions  with a simple custom matrix  in similar
>> manner as Boost.GIL does it.
>>  http://www.boost.org/doc/libs/1_41_0/libs/gil/example/affine.cpp
> Interesting! I didn't know that GIL defined its own matrix. That the
> link is broken, it refers to extensions not being there (so therefore
> ). Which shows the potential fragility of extensions.
I've attached affine.hpp file.
It comes from numeric extension available here:
but it looks the numeric.zip file vanished there too.
Anyway, i found this file, probably older version, at koders.com.
> It is a good idea but I don't think we can or should copy this exactly
> because we cannot rely on external sources. Anyway, we can implement it
> using an uBlas matrix, or include it as an example (actually, that *is*
> the way GIL does it.... So right...)
That's right, we can just copy, refine and provide it for users who
need it now, as an extension or example, whatever.
-- Mateusz Loskot, http://mateusz.loskot.net -------------- next part -------------- A non-text attachment was scrubbed... Name: affine.hpp Type: text/x-c++hdr Size: 3885 bytes Desc: not available Url : http://lists.osgeo.org/pipermail/ggl/attachments/20091201/17373154/affine.bin
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