Improve support for phone apps

[cahfofpai]

Although Flathub contains more than 250 apps suited for (GNU/)Linux phones (filter for "'mobile fit' 'equals' '5'" and "'distributions' 'contains' 'flathub'" at https://linuxphoneapps.org/find/apps/ to see the number of apps at the bottom of the page), it currently lacks some important functions to better support phone apps.

Therefore I propose to implement these improvements:

• filter search results for control types (e.g. touch support) and supported screen sizes (see https://blog.tenstral.net/2023/10/how-to-indicate-device-compatibility-for-your-app-in-metainfo-data.html)
• global filter: filter not only search results, but also the other pages (e.g. start page, categories)
• filter presets: offer the users some filter presets (e.g. phone), so they do not have to manually select all necessary filter criterias (for only displaying phone apps the criterias "control type = touch", "screen size = 360px" and "arch = aarch64" would be needed)
• device compatibility: show supported hardware at the app pages, similar to GNOME Software (https://gitlab.gnome.org/GNOME/gnome-software/-/wikis/software-metadata#hardware-support-)
• screenshots: show only screenshots matching the device type set in the global filter, e.g. show only phone screenshots
• expand MetaInfo guidelines (https://docs.flathub.org/docs/for-app-authors/metainfo-guidelines/) to include instructions for proper metadata for phone apps

This issue is for discussing the general idea of improving support for phone apps. If necessary, I could split up the proposed improvements into single issues to discuss them in more detail.

I think about applying for NLnet (https://nlnet.nl) funding in the December round in order to implement these improvements.

[bbhtt]

device compatibility: show supported hardware at the app pages, similar to GNOME Software (https://gitlab.gnome.org/GNOME/gnome-software/-/wikis/software-metadata#hardware-support-)

https://github.com/flathub-infra/website/issues/26

expand MetaInfo guidelines (https://docs.flathub.org/docs/for-app-authors/metainfo-guidelines/) to include instructions for proper metadata for phone apps

Open an issue in https://github.com/flathub-infra/documentation

screenshots: show only screenshots matching the device type set in the global filter, e.g. show only phone screenshots

Appstream does not have the metadata fields to tell which screenshots are meant for which devices, so the website cannot filter like that.

Only the search filters seems to be a new feature request here.

[razzeee]

global filter: filter not only search results, but also the other pages (e.g. start page, categories)

https://github.com/flathub-infra/website/issues/1910

[cahfofpai]

Appstream does not have the metadata fields to tell which screenshots are meant for which devices, so the website cannot filter like that.

Thank you for the information, I already know that there is currently no possibility in the Appstream spec to set the form factor for a screenshot. It is more a general idea without the exact implementation / feasibility already known.

Maybe it could be discussed upstream at the Appstream repo whether and how the screenshots could be distinguished.

Currently, a way to guess the form factor of the screenshot is by using its resolution: If the width is bigger than the height it is landscape and therefore probably a desktop screenshot. If the height is bigger than the width it is portrait and maybe a phone screenshot.

[bbhtt]

No guessing like that is unreliable, there are apps/games which have height > width on desktop. You should discuss it in the appstream repo.