Re: imagemagick support on W32

[Juanma Barranquero <lekktu@gmail.com>]

On Fri, Oct 1, 2010 at 06:16, Christoph <cschol2112@googlemail.com> wrote:

> For now, I will go on with the dlls. On a side note: would Emacs require to
> use the .dlls or could the library also be statically linked in?

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).

> I assumed that that was the intention of the inclusion of the ImageMagick
> branch in the first place.

OK.

> Thanks for the image-library-alist hint.

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?

> Right now, everything compiles fine (with the addition of my own
> init_imagemagick_functions function, but when I run
> (imagemagick-register-types) Emacs crashes.

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.

    Juanma