Appdata screenshot of Emacs might need a refresh

[Joonas Sarajärvi]

Hi,

Sorry for the rambling explanation for a fairly simple thing. If you 
wish me to just get to the point, please skip to the last paragraph. 
Otherwise, here are some details and background.

The etc/emacs.appdata.xml file in the GNU Emacs sources refers to a 
screenshot [1] that seems to be hosted as part of the GNU Emacs web 
site. This image can get displayed by various things that can offer a 
computer user to install GNU Emacs. Of the software I am currently aware 
of, this includes Gnome Software [2] and the Flathub web page [3].

The screenshot in the address at [1] does not currently fully conform to 
the guidelines [4] provided for Appdata screenshots:
- The aspect ratio is close to but not exactly 16:9
- Window borders are not shown
- Content in the window is rather "empty"

Additionally the screenshot is rather small, just barely within spec.

The "teaser" screenshot [5] shown on the GNU Emacs main web page is a 
lot better fit, but also there we have some issues which could be 
improved for Appdata screenshot use:
- Aspect ratio again
- Shadows around the window borders
- Version number 26.0.50 is displayed

I think that addressing these would be a good thing in general, but then 
there is something that might help specifically with an issue that I am 
working on. There is currently an issue with the Flathub web site that 
makes it not display a screenshot at all for Emacs [6]. It is suspected 
that this is because a scaling algorithm crops some content from the 
sides to exactly hit the 16:9 aspect ratio, and then the width of the 
screenshot drops below the 620 pixel minimum. I am not sure if this is 
actually the cause of this issue, but this is just what drew my 
attention to this screenshot.

I think Emacs would benefit from updating that Appdata screenshot, 
regardless of if it addresses that flathub issue that I wish to have 
resolved. If I take a new screenshot of GNU Emacs 26.1 in its default 
settings, and basically make it very similar to the "teaser" picture [5] 
but following the screenshot guidelines [4], could it be installed 
either to the old URL [1] or next to the old one with e.g. a name like 
appdata-26?

Thanks,
- Joonas

[1] https://www.gnu.org/software/emacs/images/appdata.png
[2] https://wiki.gnome.org/Apps/Software
[3] https://flathub.org/apps/details/org.gnu.emacs
[4] https://www.freedesktop.org/software/appstream/docs/chap-Quickstart.html
[5] https://www.gnu.org/software/emacs/images/teaser.png
[6] https://github.com/flathub/org.gnu.emacs/issues/1