Re: Use Emacs support for image resizing when using org-image-actual-width

[Marco Wahl <marcowahlsoft@gmail.com>]

Hi Terje!

> I am running Emacs version 27 (building from master) and recently
> noticed that my images no longer scales using org-image-actual-width.
>
> I then read that ImageMagick support is no longer enabled by default as
> there is a new "native" resizing method built-in to Emacs.
>
> As seen in the news for on Emacs version 27 (master branch):
>> ** Emacs no longer defaults to using ImageMagick to display images,
>> due to security and stability concerns.  To override the default, use
>> 'configure --with-imagemagick'.
>
> As well as:
>> ** Emacs now supports resizing and rotating images without ImageMagick.
>> All modern systems support this feature.  (On GNU and Unix systems,
>> Cairo drawing or the XRender extension to X11 is required for this to
>> be available; the configure script will test for it and, if found,
>> enable scaling.)
>
>> The new function 'image-transforms-p' can be used to test whether any
>> given frame supports these capabilities.
>
> I then inspected the code of org-mode and noticed there is an expression
> in the cond that figures out how to scale, e.g.:
>> ((not (image-type-available-p 'imagemagick)) nil)
>
> I haven't looked into yet how the scaling is done, but I know some other
> modes such as image-mode had support for using the new method.
>
> I think it would be great to support the native scaling option as well
> when available. Since opting in to imagemagick will be Emacs wide and
> then we loose the benefit of the new functionality.

I committed a fix to the master branch.  I think the way was clear.  But
testing is welcome as always.


Thanks,  Marco