Image formats support

Image formats support

[Fabrice Popineau]

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Maybe a stupid question but if emacs is compiled with ImageMagick support,
what is the point in asking JPEG, PNG, etc support at the same time from
independent libraries ?
Shouldn't configure made those options to be exclusive ?

Also what is (are) the drawback(s) of ImageMagick support vs the other
libraries ?

Fabrice

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Re: Image formats support

[Andreas Politz]

Fabrice Popineau <fabrice.popineau@gmail.com> writes:

> Maybe a stupid question but if emacs is compiled with ImageMagick support, 
> what is the point in asking JPEG, PNG, etc support at the same time from independent libraries ?
> Shouldn't configure made those options to be exclusive ?

Imagemagick is handled like an image type, so png and imagemagick are
two different types.  One uses libpng as backend and the other
libmagick.

> Also what is (are) the drawback(s) of ImageMagick support vs the other libraries ?

In my experience, libpng is faster then imagemagick.

-ap

Re: Image formats support

[joakim]

Fabrice Popineau <fabrice.popineau@gmail.com> writes:

> Maybe a stupid question but if emacs is compiled with ImageMagick support, 
> what is the point in asking JPEG, PNG, etc support at the same time from independent libraries ?
> Shouldn't configure made those options to be exclusive ?
>
> Also what is (are) the drawback(s) of ImageMagick support vs the other libraries ?

As I remember it I was a bit unsure if Imagemagick was as good as the
other libraries. So I wanted to support both sets of libraries, to keep
the options open. But that was a number of years ago, so things have
surely changed.



>
> Fabrice
>
-- 
Joakim Verona
joakim@verona.se

Re: Image formats support

[Clément Pit-Claudel]

On 2017-03-18 09:38, Fabrice Popineau wrote:
> Maybe a stupid question but if emacs is compiled with ImageMagick support, 
> what is the point in asking JPEG, PNG, etc support at the same time from independent libraries ?
> Shouldn't configure made those options to be exclusive ?
> 
> Also what is (are) the drawback(s) of ImageMagick support vs the other libraries ?

There's also the security aspect.  The individual JPEG and PNG libraries have a better track record than ImageMagick.

Re: Image formats support

[Fabrice Popineau]

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2017-03-18 15:27 GMT+01:00 Andreas Politz <politza@hochschule-trier.de>:

> Fabrice Popineau <fabrice.popineau@gmail.com> writes:
>
> > Maybe a stupid question but if emacs is compiled with ImageMagick
> support,
> > what is the point in asking JPEG, PNG, etc support at the same time from
> independent libraries ?
> > Shouldn't configure made those options to be exclusive ?
>
> Imagemagick is handled like an image type, so png and imagemagick are
> two different types.  One uses libpng as backend and the other
> libmagick.


My point is that only one of imagemagick and libpng will handle png files
at a time.
When ImageMagick is available, it supersedes png, jpeg and anything it
handles (AFAICS).
If you want to let libpng handle png files, you need to change some
defaults
(imagemagick-filter-types, etc.)


> > Also what is (are) the drawback(s) of ImageMagick support vs the other
> libraries ?
>
> In my experience, libpng is faster then imagemagick.


Ok, that is understandable.

Fabrice

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Re: Image formats support

[Andreas Politz]

Fabrice Popineau <fabrice.popineau@gmail.com> writes:

> My point is that only one of imagemagick and libpng will handle png
> files at a time.  When ImageMagick is available, it supersedes png,
> jpeg and anything it handles (AFAICS).

No, the used library depends on the image-type, i.e.

(create-image "foo.png" 'imagemagick)

    vs.

(create-image "foo.png" 'png)

-ap

Re: Image formats support

[Fabrice Popineau]

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2017-03-18 16:44 GMT+01:00 Andreas Politz <politza@hochschule-trier.de>:

> Fabrice Popineau <fabrice.popineau@gmail.com> writes:
>
> > My point is that only one of imagemagick and libpng will handle png
> > files at a time.  When ImageMagick is available, it supersedes png,
> > jpeg and anything it handles (AFAICS).
>
> No, the used library depends on the image-type, i.e.
>
> (create-image "foo.png" 'imagemagick)
>
>     vs.
>
> (create-image "foo.png" 'png)
>
>
That is when you program, but when you merely use emacs to browse files
with dired, or when some package generates and load images (preview-latex),
defaults are used. And the default is that imagemagick supersedes png and
jpeg.

Fabrice

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Re: Image formats support

[Andreas Politz]

Fabrice Popineau <fabrice.popineau@gmail.com> writes:

> That is when you program, but when you merely use emacs [...]

Who does that ?

-ap

Re: Image formats support

[Andreas Politz]

Is there a down-side to this, apart from the exe becoming a little bigger
?

a-p

Re: Image formats support

[Fabrice Popineau]

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2017-03-18 22:57 GMT+01:00 Andreas Politz <politza@hochschule-trier.de>:

>
> Is there a down-side to this, apart from the exe becoming a little bigger
> ?


I run Windows so the exe is not bigger because the dlls are dynamically
loaded.
My problem is rather  about emacs configuration. Various packages are able
to generate
preview images on the fly. How a normal user will know that ImageMagick or
libpng
will render those images ? How to switch from one to the other if needed ?
Or should ImageMagick supersede everything else when it is available ?

Also some packages call mogrify to resize images. If emacs is compiled with
ImageMagick support, surely the cost of calling an external program can be
spared.

I had the feeling that when ImageMagick support is compiled in, the other
graphic format
libraries could be removed. But that may not be that simple.
I hoped that someone had a good overview of the various options and comment
on that
feeling.

Fabrice

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