Re: imagemmagick patch 5

[joakim@verona.se]

Juri Linkov <juri@jurta.org> writes:

>> The Imagemagick patch allows Emacs to use the Imagemagick libraries to
>> load images. This support can be used in parallell with the existing
>> image loading support. There is support for asking your imagemagick
>> installation which image types it supports, and registering them in
>> Emacs selectively.
>
> Great!
>
>> I use this patch a lot for viewing scanned djvu packages. I also have a
>> emacs scanner frontend called "emsane" I'm using together with this
>> patch.
>
> I wonder how do you plan to handle multi-page djvu?  Is it something
> that doc-view has to do when ImageMagick support will be incorporated
> into the core?

I've added some interfaces in the display spec for various imagemagick
operations like scaling and rotation of the image. I've also added an
index interface so a particular subimage inside a multipage djvu can be
viewed. This is the same interface already present for the gif support
in emacs, since gifs also can be image bundles. Imagemagick support a
number of image bundle formats such as pdf, djvu, tif, etc.

My experience is, though, that imagemagick handles image bundles
oddly. It seems to render the entire bundle in ram before rendering the
single indexed page. Most image bundle formats are not designed for that
to be necessary, so I'm not sure why imagemagick does that.

Until this area of imagemagick improves, I would say its doc-views
responsibility to handle image bundles, in the same way it already
does. If this problem is in someway solved, doc-view can take advantage
of the imagemagick library. I'm planning at having a go at this for
the case of directories with image files.

-- 
Joakim Verona