Re: [AUCTeX] Embedded previews in high-DPI?

[YAMAMOTO Mitsuharu]

>>>>> On Wed, 18 May 2016 00:21:47 +0200, Mosè Giordano <address@hidden> said:

>> Recently I posted a Retina display support patch for preview-latex
>> to the emacs-devel list:
>> 
>> http://lists.gnu.org/archive/html/emacs-devel/2016-04/msg00890.html
>> 
>> You need Emacs Mac port, which is also mentioned in the above post.
>> 
>> It makes Ghostscript generate PDF files instead of PNG ones, and
>> let the Mac port render them using the `image-io' image type via
>> PDFKit.  So moving an Emacs frame between Retina and non-Retina
>> displays works gracefully (the Mac port re-renders PDF
>> automatically).  As a bonus, it enables us to use LCD smoothing.
>> So it is actually meaningful also on non-Retina displays.

> This looks very interesting, but for installing the patch into
> AUCTeX I would prefer it to be compatible with vanilla GNU Emacs as
> well.  Is it possible to improve it?

It is compatible with vanilla GNU Emacs in the sense that it does not
add any positive or negative effect.  Vanilla GNU Emacs does not
provide us with any special support for images (as opposed to text) on
a Retina display.  So they are always magnified and look blurry.  This
cannot be solved at the Lisp level.

If you compile vanilla GNU Emacs with ImageMagick support, which can
render PDF if built properly, then you can get the idea how my patch
works with respect to the generation of PDF files by replacing every
occurrence of `image-io' with `imagemagick' in the patch.  It would
work even on other platforms.  But I don't think this is practical for
actual use, because PDF rendering with ImageMagick is much slower.

So, the feature that the patch is trying to add would only be
meaningful for Emacs Mac port, which provides us with special support
for images on a Retina display as well as fast PDF rendering with LCD
smoothing via PDFKit.

                                     YAMAMOTO Mitsuharu
                                address@hidden