Why do some app pages in Discover look good, while others look half-finished at best? Why is it that sometimes in some distros (Like Ubuntu 16.04 and KDE Neon) almost all of the app listings are bad? We’ll dive into that today, and see what the plan is for fixing it.

First thing’s first: Discover does not control an app’s presentation. Instead, we display app metadata (such as screenshots, the description, and links to the app’s website) made available to us by the software’s packagers. It’s all up to them to pass on the metadata. If they don’t give it to us, we can’t display it to you!

Where does this app metadata come from? The app developers themselves, from their AppStream file. If an app doesn’t provide an AppStream file, or its file is very minimal and doesn’t provide much content, then the packagers have to create this information themselves. Some packagers do a better job of this than others, as we’ll see. Ubuntu 16.04 is a particular offender, and while it’s gotten better in later releases, every distro based on Ubuntu 16.04 (like KDE Neon) will unfortunately inherit its deficiencies of metadata-poor packaging. This causes app listings to look bad, and frustrated users blame us or the software developers–almost never the distro, even though they make this their job!

Here’s an example of what good AppStream metadata can do for an app:

It’s got:

• An attractive, high-resolution icon
• A screenshot
• A short and useful description
• A human-readable version number
• A license
• URLs for the homepage and user guide, plus links to pages where you can donate or report a bug.

All apps should look this good! It’s pretty easy to get there if developers put lots of information in their AppStream metadata files, and if distros and other software sources make it available to us. Here’s Hexchat’s AppStream file. This is what a good AppStream file should look like! (there’s only a single problem: the ID is set using a non-recommended form: io.github.Hexchat.desktop. This string shouldn’t have “.desktop” on the end of it).

So what’s the plan? We need to get app developers to improve their AppStream metadata. This is an ongoing effort that I’m heavily involved in, but like everything in the FOSS world, it will go much faster if you help!

How users can help

Let’s say you stumble across an app listing that looks like this:

There’s no screenshot, and the text looks like it was formatted using Markdown, which isn’t formally supported in most software center programs like Discover, so it shows up as an ugly wall of text. The license is “unknown”, and there’s not even a URL for the app’s website! What a mess.

Here’s another:

This app provides a low-resolution icon that isn’t very attractive. Its caption (“Ho22bus’s Dict”) gives no indication what the app is or does. As before, the description appears to use markdown rather than HTML, and provides no license or relevant URLs. The app is a mystifying black box.

Here’s how you can help software developers!

First, find the app’s source code repository. Then, within that, locate the AppStream file. It’ll be named something like[appname].appdata.xml. If it looks fine in the developer’s source repo, and you’re using a distro that ships old software like Ubuntu or Debian, it’s likely that the distro packagers simply haven’t included an up-to-date version of the AppStream file, so file bug on the distro’s packaging itself asking them to.

If the file is subpar… then fix it! On the technical side, check out Hexchat’s AppStream file for a great example of how it should look. Design-wise, here’s a great guide from the ElementaryOS people on how to write a compelling app listing that’s largely applicable to Discover as well.

In some unfortunate cases (e..g. Blender), there may not even be an AppStream file. Well, submit one for them! This stuff is really important!

Make sure to validate the file using an XML Validator, and then once it checks out as being valid XML, run appstreamcli validate on it (you may have to use your distro’s command-line package manager to get appstreamcli). Once it passes both checks, submit it back to the developers, either in a bug report, or even a patch or pull request if you know how to do those things.

How developers can help

Please: provide downstream packagers with AppStream files that you’ve taken the time to craft with love and attention to detail. Distros may do your packaging for you, but they’ll never care about presenting your app nicely as much as you will!

If you don’t supply packagers with high-quality AppStream metadata, you’re making life harder for packagers, and your potential users may well be presented with an ugly, even repellant app listing in software center apps like GNOME Software and KDE Discover. Users may blame you, or they may blame us, but either way, they’ll be looking for someone to blame, because bad or nonexistent AppStream metadata will make your app look bad, guaranteed. Here’s the spec. Follow it, and make your app look beautiful, and users will trip over themselves to install and use your software.

Also, submit your app to Flathub! The Flathub people are easy to work with and are delighted when you include high-quality AppStream metadata. Which leads me to…

Flathub rocks

I want to give a shout-out to the people who run Flathub, the de facto central repository of Flatpaked software. They take their role as packagers seriously, even going so far as to create high-quality metadata for apps that lack it. For example, here’s the version of Blender packaged in KDE Neon, which comes from Ubuntu 16.04:

Doesn’t look too great, right? Blender is amazing, but you wouldn’t know it by looking at this. Sadly, the Blender developers don’t provide an AppStream file, and the Ubuntu packagers didn’t do anything about it. So Blender’s app page looks lousy.

But here’s the Flathub version:

Isn’t that way better!? Lots of screenshots, paragraph breaks, a license and website URL… all that information was added by the Flathub packagers. Now that’s dedication.

Want to help out? Be like the Flathub people and improve the metadata for your favorite apps, but then go even farther: submit your changes back to the developers! Here are some examples of minimal patches I or others have submitted to give you a sense of how easy this can be:

• Endless Sky
• GIMP
• Blender

Get out there and make some apps look good!

A common user complaint about Discover has been that the design could use some improvement. We set out to remedy this in the soon-approaching release of Plasma 5.12, with the aid of KDE’s Visual Design Group. VDG members came up with endless ideas and mockups, and we spent weeks discussing things and iterating on the design. I wanted to share the evolution of a single view in Discover: the application page.

In Plasma 5.11, here’s what we started with:

Not bad! But there were some rough edges we wanted to address. The header was full of technical information that wasn’t always what you wanted to see first. The screenshots needed polishing. And that toolbar on the bottom used a nonstandard UI convention.

First, we turned the bottom bar into a real toolbar like the kind that appears on the top of a window:

That fixed that problem, but it made the app display on top a bit disjointed, and exacerbated the problem with having the app metadata on top. And having the app name and icon only in the toolbar made it easy to mistake the caption for the name!

We resolved that by moving the entire metadata section below the description to reduce its prominence, and returning the app name and icon to the page itself in a simplified form:

This revision got high marks internally, but we wanted to go further and ensure that users of Discover in 5.12 received a really polished experience. So we further tweaked the header, increasing the size of each element to increase its visual prominence, and adding a bit more padding. Then we made the screenshot thumbnails reflect the aspect ratio of their full-sized images and gave them a drop shadow to make them pop:

Next, we decided to improve the whitespace and padding even more. We moved over the app name and caption a bit, increased the margins on the sides of the page, and made the description text left-justified:

That screen looks really good because Krita provides an even number of screenshots that all have the same aspect ratio, and they fit perfectly in the window size that I’ve chosen here. But for apps and window sizes that deviated from this, it didn’t look as good. We also felt that the shadows provided a bit too much depth, and competed with their content. Finally with more than four screenshots, the text was pushed down so far you needed to scroll just to see it. So we decided to reduce the shadow strength and put the screenshots in a horizontal scrollview:

This helped! We decided to implement a fade effect when a thumbnail is cut off, and we made the them bigger and taller because with the design, there will only ever be one row:

Whaddaya think? I’ll tell you what I think: it’s fantastic, and you guys are going to really love this app view. I’d like to thank KDE contributors Andres Betts, Andreas Kainz, and Thomas Pfeiffer for their help with the design work, and Aleix Pol for technical work–and for letting me work on his baby Discover in the first place!

Here are some more screenshots showing how it looks with other apps, and in the smaller Plasma Mobile view:

There’s always room for incremental improvement, and there are a few more tweaks we’ll probably make before Plasma 5.12 is released. But we don’t currently have plans to make any radical changes here. We think you’re all going to love this design in Plasma 5.12!

If you like this kind of work, consider jumping on board and helping to push KDE software to even higher heights! Donating helps, too, and allows KDE to sponsor more work and help students travel to KDE events.

Another important task is to get your favorite software to improve its AppStream metadata! Version numbers, screenshots, better text… the better the data we get from apps, the better we can make the app look in Discover.

I see a lot of people asking about state of AppImage support in Discover.

It’s non-existent, because AppImage does not require centralized software management interfaces like Discover and GNOME Software (or a command-line package manager). AppImage bundles are totally self-contained, and come straight from the developer with zero middlemen, and can be managed on the filesystem using your file manager

This should sound awfully familiar to former Mac users (like myself), because Mac App bundles are totally self-contained, come straight from the developer with zero middlemen, and are managed using the Finder file manager.

It’s the same model. For 20 years, there was no centralized Mac App Store because this distribution model doesn’t require it. Apple did eventually create one, but it’s a shadow of the iOS version, and a lot of popular Mac developers never got on board, continuing to distribute software themselves and update it in the way they choose (often with Sparkle).

When a format’s primary advantage is decentralization and independence, you don’t need a centralized piece of software like Discover do manage it. Of course, it would be nice to be able to have a centralized location to browse AppImage vendors, but a simple website could accomplish that.

AppImage isn’t currently a part of our design because Software Stores aren’t a part of AppImage’s design. We don’t oppose it–nothing of the sort! But the format isn’t relevant to what Discover does. If you want to use AppImage, go ahead! It’s a great format, and you don’t need our help to do it.

I guess I’m becoming a Discover developer, since it’s where I seem to spend most of my time these days. It’s just so darn fun since the lead Developer Aleix Pol is super easy to work with, there’s a lot of low-hanging fruit, and with Kirigami, it’s very simple to make consequential changes even when you’re a novice programmer and not very familiar with the codebase. That said, Aleix is still making about 99% of the code changes, and I’m mostly doing UI tweaks, bug screening, promotion, strategy, and work with apps to get their houses in order.

Anyway, here are the user-facing highlights of what we’ve done in the last week or so. There was a lot of work on Snap and Flatpak in particular.

• Snaps now show their size correctly once installed (KDE bug 389024)
• During installation of Snaps, the Install button changes so you can’t click it multiple times (KDE bug 388916)
• Discover now shows the license for Snaps (KDE bug 388735)
• Discover now shows the size for Snaps that aren’t installed (KDE bug 388734)
  
• Discover no longer shows duplicate information in package changelogs for Debian-based distros (KDE bug 387041)
  
• Discover now shows the version number for Flatpak apps that define information in their AppStream files (KDE Bug 388968)
• Discover’s Home page now communicates that it’s a list of featured apps (KDE Phabricator revision D9868)
• Discover now correctly removes the Tasks entry for an app if you cancel the installation (KDE bug 388915)

Let me share a video that shows a lot of the highlights:

We’ve got Kdenlive available from three sources. Version 17.08.3 is available from a distro, and version 17.12.1 is available straight from the developers via Flatpak. You can also get bleeding-edge development builds if you’d like to follow or participate in the development, or verify that a bug is fixed before the next release. You can install the one that suits you best, and change your selection as your needs and preferences evolve over time. It’s your choice.

You’re looking at the future of software delivery, folks.

Do you want to help make this happen? Instead of my usual spiel about becoming a KDE contributor or donating, consider helping app developers correct and expand their AppStream metadata. The video you just saw isn’t possible without it. Let’s go build the future.

What happens in Discover in when an app is available from multiple sources–say, Flathub as well as your distro’s packages?

As long as both versions of the app provide the same AppStream ID, Discover will show a single entry and let you choose which one you want to install, like this:

But if any of the available versions use a different AppStream ID, they’ll show up separately:

Uuurgh, how awful. Which GIMP is the real GIMP? And why do they all have different names?! Flathub uses org.gimp.GIMP as the AppStream ID, while The GIMP developers provide gimp.desktop for distros to use as the AppStream ID. And the Snap version provides no AppStream ID, sadly.

So we need the GIMP developers to change their AppStream ID to the same one that Flathub uses (which actually follows the AppStream spec). I submitted a patch to fix it that was recently accepted, so this should be resolved with the next GIMP release. That will unify the first two, but the third–which comes from Snap–won’t get rolled up into it until Snap uses AppStream IDs. The Snap folks are on the case, but it’s still a work in progress.

But adopting AppStream only work as long as developers are populating their AppStream files with valid IDs! An AppStream ID is supposed to look like com.myurl.NameOfMyApp, not NameOfMyApp.desktop or com.myurl.NameOfMyApp.desktop. Flathub gets this right, but a lot of app developers themselves get it wrong, and it’s up to us to help them, and make sure the AppStream IDs in their files match those on Flathub.

I’ve started to submit patches for apps that unify their AppStream IDs:

• Blender: Fix AppStream ID and add release information
• Inkscape: Fix AppStream IDand add release information
• GIMP: Fix AppStream ID (done) and add release information
• Endless Sky: Fix AppStream ID and add release information (done)
• Hexchat: Fix AppStream ID (done)
• Telegram add release information and use AppStream Data in Ubuntu packaging
• Transmission: Fix AppStream ID
• Lollypop: Add release information
• VLC: Fix AppStream ID (done)
• Pitivi: Fix AppStream ID and add release information
• FileZilla: Fix AppStream ID (done, but need to redo–see discussion here)
• Shutter: Fix AppStream ID (done, but need to redo for the same reason as FileZilla)
• 0 A.D.: Fix AppStream ID
• Audacity: Fix AppStream ID (done)

What can I do to help?

See all those patches I submitted? You can do the same! If you use any apps that have AppStream IDs in their distro packaging that are incorrect and different from what’s in Flathub, then submit a patch to fix it! Keep in mind the following guidelines:

1. Dashes/hyphens must be replaced with underscores: com.shutter-project.shutter is wrong and should be com.shutter_project.shutter
2. Leading digits in the app name are not allowed: com.wildfiregames.0ad is wrong and should be com.wildfiregames._0ad
3. If the AppStream ID used for Flathub is wrong, don’t replicate that wrongness with your patches; encourage developers to use correct AppStream IDs and file a bug for the app on Flathub, like this one.

For extra credit, you can also submit patches that add information, too. This will make the app’s version string show up in Discover:

And here’s the properly formatted information in HexChat’s AppStream file that provides it: https://github.com/hexchat/hexchat/blob/master/data/misc/io.github.Hexchat.appdata.xml.in#L29

I know this isn’t the most immediately rewarding work, but it’s super important to make Flatpak (and later Snap) work properly in a mixed environment where you also have distro packages available. If you want the world to be Snappier or more Flatpacked, this is probably the easiest way to make it happen if you’re not a programmer or a packager. If you need a hand, you can email flatpak@lists.freedesktop.org or check out the #flatpak IRC channel on freenode.org.

As always, if you find this work useful or valuable, please consider becoming a KDE contributor or donating to KDE! But do consider submitting patches for Apps that have sparse or incorrect AppStream data. You’ll be doing your part to pull Linux software distribution into the future.release

People often ask about the state of Flatpak in Discover, so today I’m going to write about that. Thew good news is that Discover’s Flatpak support is very good and getting better all the time. It’s fully production ready and we encourage you to use it!

To download Flatpak apps in Discover, you need to have the Flatpak backend installed. In many distros, it’s a separate package that doesn’t come installed by default. In Ubuntu-based distros, you can install it by running sudo apt install plasma-discover-flatpak-backend. in Discover 5.12, you’ll even be able to install different backends from within Discover itself, by searching for “Flatpak” or “Snap”. If you want faster Flatpak adoption, please petition your distros to install the Flatpak backend by default!

Once the Flatpak backend is installed, you need to add at least one Flatpak repo. Distros can provision this with default entries, but most don’t. Bug your distro if you want a better experience here! Until then, you can go to Discover’s Settings page and click the “Add Flathub” button to add Flathub as a source. After that, you can access Flatpak apps by browsing or searching through the app lists as normal. You can also go to the settings page and click on the Flatpak entry, which will show you just the Flatpak apps from that repo:

You can add multiple Flatpak repos; to do so, go to the Settings page, click the Hamburger menu button next to the text “Flatpak”, and click “Add Source…” Then enter the URL of the Flatpak repo you want to add. Discover also handles this properly when you click on a repo URL in your web browser.

Multiple Flatpak repos enable users to effortlessly switch between stable and up-to-date versions of apps, each version provided by a different repo. Right now, we’re generally stuck with one or the other, according to our distro’s packaging policy: Arch and other rolling distros say that you always get the latest version; Debian and Ubuntu and other stable release distros say that you always get a specific version that’s frozen in time. Sometimes that’s not right for you, because maybe the latest version has a bad bug, or an old stable version is missing features you want that were implemented in a later version.

Flatpak liberates us from this. You could add Flathub (https://flathub.org/repo/flathub.flatpakrepo) and also KDE’s nightly testing repo (https://distribute.kde.org/kdeapps.flatpakrepo). Then when you go to install a KDE app that’s present in both, you can choose the source! Maybe you want to live on the bleeding edge, but if you run into an issue, you can easily revert your installation to the stable version. It’s pretty awesome.

If any of this seems cool and useful, please don’t hesitate to join our team or make a donation to KDE. My next post shares some specific things you can do to help push Flatpak adoption, even without being a programmer.