how to resolve namespace issues between imagemagick and gif libraries?

how to resolve namespace issues between imagemagick and gif libraries?

[joakim]

I've made a patch that makes it possible to load an image file using
the imagemagick library. However, I cant compile in imagemagick and gif
support at the same time due to namespace collisions.

When compiling image.c:

gcc -c -D_BSD_SOURCE   -Demacs -DHAVE_CONFIG_H  -I. -I/mnt/data/build/emacsnew/emacs/src -D_BSD_SOURCE -I/usr/include/gtk-2.0 -I/usr/lib/gtk-2.0/include -I/usr/include/atk-1.0 -I/usr/include/cairo -I/usr/include/pango-1.0 -I/usr/include/glib-2.0 -I/usr/lib/glib-2.0/include -I/usr/include/pixman-1 -I/usr/include/freetype2 -I/usr/include/libpng12 -I/usr/include/freetype2 -I/usr/include/alsa -I/usr/include/librsvg-2 -I/usr/include/glib-2.0 -I/usr/lib/glib-2.0/include -I/usr/include/gtk-2.0 -I/usr/include/cairo -I/usr/include/pixman-1 -I/usr/include/freetype2 -I/usr/include/libpng12 -fopenmp -I/usr/include/ImageMagick -I/usr/include/dbus-1.0 -I/usr/lib/dbus-1.0/include -g -O2 -Wno-pointer-sign   image.c
In file included from /usr/include/ImageMagick/wand/deprecate.h:28,
                 from /usr/include/ImageMagick/wand/MagickWand.h:154,
                 from image.c:7865:
/usr/include/ImageMagick/wand/drawing-wand.h:172: error: conflicting types for ‘DrawRectangle’
/usr/include/gif_lib.h:324: note: previous declaration of ‘DrawRectangle’ was here
make[1]: *** [image.o] Error 1
make[1]: Leaving directory `/mnt/data/build/emacsnew/emacs/src'
make: *** [src] Error 2

If I leave out gif support it compiles and works well enough to load a
djvu file in emacs like this:

(insert-image (create-image "/tmp/tst.djvu" 'imagemagick) )

Any hints how to fix this in a manner acceptable for Emacs code?

-- 
Joakim Verona

Re: how to resolve namespace issues between imagemagick and gif libraries?

[Eli Zaretskii]

> From: joakim@verona.se
> Date: Fri, 31 Jul 2009 20:02:32 +0200
> 
> In file included from /usr/include/ImageMagick/wand/deprecate.h:28,
>                  from /usr/include/ImageMagick/wand/MagickWand.h:154,
>                  from image.c:7865:
> /usr/include/ImageMagick/wand/drawing-wand.h:172: error: conflicting types for ‘DrawRectangle’
> /usr/include/gif_lib.h:324: note: previous declaration of ‘DrawRectangle’ was here
> make[1]: *** [image.o] Error 1
> make[1]: Leaving directory `/mnt/data/build/emacsnew/emacs/src'
> make: *** [src] Error 2

Can you show here the prototype of DrawRectangle from Imagemagick?

Is that the only conflict?  If not, please show the others as well.

> Any hints how to fix this in a manner acceptable for Emacs code?

Does Emacs use DrawRectangle, from any or both these libraries?  I
guess at most one is used, or else you'd have problems in the Emacs
sources as well, not just in the headers.  If we don't need to use
both, you should be able to rename one of them with #define.

A better solution would be to lobby the maintainers of Imagemagick to
use names specific to the package.

Re: how to resolve namespace issues between imagemagick and gif libraries?

[joakim]

Eli Zaretskii <eliz@gnu.org> writes:

>> From: joakim@verona.se
>> Date: Fri, 31 Jul 2009 20:02:32 +0200
>> 
>> In file included from /usr/include/ImageMagick/wand/deprecate.h:28,
>>                  from /usr/include/ImageMagick/wand/MagickWand.h:154,
>>                  from image.c:7865:
>> /usr/include/ImageMagick/wand/drawing-wand.h:172: error: conflicting types for ‘DrawRectangle’
>> /usr/include/gif_lib.h:324: note: previous declaration of ‘DrawRectangle’ was here
>> make[1]: *** [image.o] Error 1
>> make[1]: Leaving directory `/mnt/data/build/emacsnew/emacs/src'
>> make: *** [src] Error 2
>
> Can you show here the prototype of DrawRectangle from Imagemagick?

DrawRectangle(DrawingWand *,const double,const double,const double,
    const double)
    
> Is that the only conflict?  If not, please show the others as well.
>
>> Any hints how to fix this in a manner acceptable for Emacs code?
>
> Does Emacs use DrawRectangle, from any or both these libraries?  I
> guess at most one is used, or else you'd have problems in the Emacs
> sources as well, not just in the headers.  If we don't need to use
> both, you should be able to rename one of them with #define.

Emacs doesnt use the gif DrawRectangle AFAICS, and I dont plan to use
the one in the imagemagick library either.

> A better solution would be to lobby the maintainers of Imagemagick to
> use names specific to the package.
-- 
Joakim Verona

Re: how to resolve namespace issues between imagemagick and gif libraries?

[Eli Zaretskii]

> From: joakim@verona.se
> Cc: emacs-devel@gnu.org
> Date: Sat, 01 Aug 2009 18:57:31 +0200
> 
> > Does Emacs use DrawRectangle, from any or both these libraries?  I
> > guess at most one is used, or else you'd have problems in the Emacs
> > sources as well, not just in the headers.  If we don't need to use
> > both, you should be able to rename one of them with #define.
> 
> Emacs doesnt use the gif DrawRectangle AFAICS, and I dont plan to use
> the one in the imagemagick library either.

Then I guess #define is the way to go.  Unless there are objections
from Stefan or Yidong, that is.

Re: how to resolve namespace issues between imagemagick and gif libraries?

[Chong Yidong]

Eli Zaretskii <eliz@gnu.org> writes:

>> Emacs doesnt use the gif DrawRectangle AFAICS, and I dont plan to use
>> the one in the imagemagick library either.
>
> Then I guess #define is the way to go.  Unless there are objections
> from Stefan or Yidong, that is.

Fine by me.

Re: how to resolve namespace issues between imagemagick and gif libraries?

[Stefan Monnier]

>>> Emacs doesnt use the gif DrawRectangle AFAICS, and I dont plan to use
>>> the one in the imagemagick library either.
>> Then I guess #define is the way to go.  Unless there are objections
>> from Stefan or Yidong, that is.
> Fine by me.

Fine by me as well, but please please pretty please, report the
problem(s) to the library maintainers (I guess to both the Gif and the
ImageMagick library maintainers).


        Stefan