SVG displayed image size

SVG displayed image size

[Matt Huszagh]

Hello,

SVG images are displayed smaller than I would expect in Emacs. How is
this controlled? I spent a while looking through image display functions
in elisp, but was not able to figure out how Emacs determines the actual
size of the image display in, e.g., image-mode. I've compiled Emacs with
SVG support, of course.

For instance, I have an SVG image with the width attribute specified as
about 20mm, but it displays as well below 2cm on my screen. I have an
HiDPI display and I expect these things are related.

Thanks for any pointers!
Matt

Re: SVG displayed image size

[Eli Zaretskii]

> From: Matt Huszagh <huszaghmatt@gmail.com>
> Cc: help-gnu-emacs@gnu.org
> Date: Fri, 12 Mar 2021 09:28:22 -0800
> 
> SVG images are displayed smaller than I would expect in Emacs. How is
> this controlled? I spent a while looking through image display functions
> in elisp, but was not able to figure out how Emacs determines the actual
> size of the image display in, e.g., image-mode. I've compiled Emacs with
> SVG support, of course.
> 
> For instance, I have an SVG image with the width attribute specified as
> about 20mm, but it displays as well below 2cm on my screen. I have an
> HiDPI display and I expect these things are related.

If this is a HiDPI display, I guess the next question will be "what
Emacs version is that?"

Re: SVG displayed image size

[Jean Louis]

* Matt Huszagh <huszaghmatt@gmail.com> [2021-03-13 00:16]:
> Hello,
> 
> SVG images are displayed smaller than I would expect in Emacs. How is
> this controlled? I spent a while looking through image display functions
> in elisp, but was not able to figure out how Emacs determines the actual
> size of the image display in, e.g., image-mode. I've compiled Emacs with
> SVG support, of course.
> 
> For instance, I have an SVG image with the width attribute specified as
> about 20mm, but it displays as well below 2cm on my screen. I have an
> HiDPI display and I expect these things are related.

As side notes, what I remember is that X display has its DPI settings,
so the scaling and ratio of display could depend of settings outside
of Emacs.

Please see here various references that could help in tweaking it:
https://wiki.archlinux.org/index.php/HiDPI

Jean

Re: SVG displayed image size

[Matt Huszagh]

Jean Louis <bugs@gnu.support> writes:

> As side notes, what I remember is that X display has its DPI settings,
> so the scaling and ratio of display could depend of settings outside
> of Emacs.
>
> Please see here various references that could help in tweaking it:
> https://wiki.archlinux.org/index.php/HiDPI

Thanks for pointing that out. That changed the size of various parts of
Emacs, but interestingly not the size of the displayed SVGs.

Matt