Re: imagemagick support on W32

[Christoph <cschol2112@googlemail.com>]

On 10/1/2010 4:37 AM, Juanma Barranquero wrote:

> In theory, you could statically link any library to Emacs, but IMO in
> this case is much better to stick to using the DLLs. The library is
> big, unneeded when you start with -nw or in -batch mode, and it's
> easier to update as DLLs than recompiling/relinking Emacs (which the
> common, non-developer user cannot do).

That makes much sense.

> It shouldn't be difficult, but there are a few tricky details, I
> think. If ImageMagick is loaded,
> image-library-alist/init-image-library will have to act as if every
> image type supported by ImageMagick is loaded (or there is a way to
> ask ImageMagick for a list of the formats it support?) But even if
> Emacs is compiled with ImageMagick support, a given instance could be
> unable to load the libraries (not found in the path, or whatever), and
> in this case, the other libraries could be loaded. Assuming, of
> course, that compiling with ImageMagick support does not deactivate
> (at compile time) the other image libraries' stuff. Does it?

I guess Joakim answered this in his email. I will have a look at at 
that. Thanks.

> Eli's question is very relevant. I had trouble in the past mixing
> MSVC-compiled Emacs and MinGW-compiled image libraries; perhaps you're
> seeing just the opposite. Both runtimes are not compatible; in fact,
> if the library uses stdio facilities to access files you'll get all
> kind of havoc. It'd be easier if you can compile ImageMagick with
> MinGW.

I will answer Eli's question here. AFAIK, the libraries from 
ImageMagick's website are compiled with MSVC. I had read somewhere that 
MSVC/mingw libraries are mostly incompatible but figured I'd give it 
shot anyway, since my original problem was Emacs not finding the 
libraries during linking.

Now, I have tried compiling ImageMagick with mingw but that turned out 
to be a huge pita. I installed all necessary GnuWin32 libs, and even 
MSYS, and ./configure would fail with lots of problems still. It says it 
can't find some components of the different packages (jpeg, png etc.) 
and basically disabled the support for those. I do have all the GnuWin32 
dev packages installed and it finds most of the headers.

Sounds like I will have to sort that out after all and get some mingw 
dll's compiled first before going on.

Thanks,
Christoph