Manually set wallpapers

[jiaiz]

Wonderful extension.
One suggestion is to be able to manually set wallpaper inside the plugin instead of fetching it from Plasma.
This would not only prevent the problem with the extension not being able to see the wallpaper but also allow to set different wallpaper per workspace and make it usable with https://github.com/lehklu/Vallpaper

I tried looking through the code but sadly I have no clue about QML and didnt get how to set different Wallpapers on the Repeater item.

[tcorreabr]

I like the idea of having different wallpapers per virtual desktop, so I'll take a look at Vallpaper to better understand how it works.

Regarding the wallpapers not appearing, I'm fixing the problem together with KWin devs. I think that in the next version of KWin and Parachute the problem will be solved.

[alexjp]

this is just an idea for conversation and to check what is your opinion:

instead of "developing support for different wallpapers per virtual desktop", could it be instead support switching activities instead of virtual desktops ?

Activities with just 1 virtual desktop do the same as using virtual desktops, but leaving the wallpaper management to plasma shell.
Also there is dbus/scripting binding to all those activities events, only "hard thing" I mostly see is getting the wallpaper of each activity, but there is the example in the "desktop activity switcher".

The points are:
Pros:

• easy management for those that use activities
• leave implementations of wallpapers to plasma shell
• expose people to activities, even if just use activities for the wallpapers, but no hard done there.

Negatives:

• maybe some recommendation "just use one virtual desktop" ( and use activities as virtual desktops with different wallpapers ) ?

what do you think ?

[tcorreabr]

I also thought that one of the benefits of working with activities instead of virtual desktops would be exactly what you described. Showing several wallpapers in a future activity bar could help to visually identify each one, besides giving a beautiful visual effect. Unfortunately I recently discovered that the desktop window used to show the wallpapers is only one for all activities and plasma is responsible for changing the wallpaper when we change activities. As a practical result of this, only one wallpaper is shown for all activities each time. This could even give the wrong impression that all activities have the same wallpaper.

[alexjp]

Unfortunately I recently discovered that the desktop window used to show the wallpapers is only one for all activities and plasma is responsible for changing the wallpaper when we change activities. As a practical result of this, only one wallpaper is shown for all activities each time.

If you change activities on Parachute, it should update the wallpaper ( maybe needs some kinda of refresh or do like present window and don't actually manage the background ).
For the visual bar on the top, yeah, its a problem because kwin doesn't know the wallpapers and neither plasma shows them. But the solution is on the "desktop activities switcher" code ( i think it tried to find out which wallpapers are set on the activities and actually show them directly).

maybe this would help ( dunno, i am an idiot, so i may be wrong ! ):

property string background : ""

    onBackgroundChanged: if (background[0] !== '#') {
        // We have a proper wallpaper, hurroo!
        backgroundColor.visible = false;

    } else {
        // We have only a color
        backgroundColor.color = background;
        backgroundColor.visible = true;
    }
...
...

Image {
            id: backgroundWallpaper

            anchors.fill: parent

            visible: !backgroundColor.visible
            source: "image://wallpaperthumbnail/" + background
            sourceSize: Qt.size(width, height)
        }

on plasma-desktop/desktoppackage/contents/activitymanager

[tcorreabr]

I also don't know the code responsible for the wallpapers of each activity. Maybe @zzag can help here. Or know who can.

[astatide]

The code here could serve as a good example:

https://github.com/astatide/kwinOverview/blob/master/contents/ui/ActivitiesContainer.qml

I used the activity model, which I just imported from the existing kde/kwin library or whatever. I think this is what they normally use in the activity switcher (which is brought by up ctrl+q in the default KDE config). : )

[astatide]

As an aside, I believe the code there works with Wayland, too. I've run your plugin on Wayland and it works really well, except for the fact that wallpapers don't pop up. I love how your scaling code actually works rather than whatever garbage I cobbled together for kwinOverview.

On that note, you should feel free to liberally take from anything in kwinOverview, as I just don't have the time work on it anymore. Parachute does a lot of things better than kwinOverview ever did, but there might be a few edge cases like the wallpaper issue that I managed to sort out. Check out the v2Rework branch for cleaner, albeit not 100% functional code.

Regarding the wallpaper per desktop issue, my understanding is that goes against the EHWM standard which both Gnome and KDE stick to like glue. The deepin multitasking plugin supports different wallpapers per desktop, but they use their own dbus service to get/receive the appropriate wallpaper. My (VERY ROUGH) understanding is that KWin just normally grabs the wallpaper as specificed by whatever the EHWM standard gives; the grid plugin does this, for instance (if you run kwin as the window manager for deepin 20 and enable the grid plugin, you'll notice that it just displays the wallpaper from the current desktop for each desktop). If you wanted to have 1 wallpaper per desktop, you'd likely have to keep an internal mapping of desktop ID to wallpaper, then signal plasma to change the wallpaper whenever you switch desktops, as plasma is what is responsible for showing the background.

[zzag]

I also don't know the code responsible for the wallpapers of each activity. Maybe @zzag can help here. Or know who can.

Even though I wrote a wallpaper plugin for plasma, I still have pretty limited knowledge of how the wallpaper infrastructure in plasma works under hood. I suggest to ask questions about wallpapers in #plasma on IRC.

[tcorreabr]

Sorry for the delay, tough week here.

@astatide, I know your solution and I imagine the trouble you had to show activities wallpapers. But as you work with image paths we would be loading again images that are already loaded by plasma. Also I'm not sure how your solution would work with plugins like Smart Video Wallpaper. Parachute works by showing live replicas of desktop windows through the PlasmaCore.WindowThumbnail component. I think the ideal solution would be plasma to create a desktop window for each activity, but I don't know if this change would be viable.

EDIT: I haven't had time to get to know Vallpaper better yet.

[astatide]

Great point! I suspect this is how Plasma itself handles it, or close to it, though, as I cribbed pretty liberally from it when writing that component (although it was a few years ago). It would be worth to check out the activity switcher that ships with Plasma and see what they do. It would be interesting to see if they load up the image or if they're able to nab a preloaded element somehow. Activities aren't really well supported in KWin, currently; they don't work in Wayland, and don't seem to be a really high priority. I originally tried to write something like this as an actual plugin (in C++) and while I had some proof of concept stuff working, I ran into problems with activities. I inquired on the mailing list and basically hit a wall of 'we'd have to make changes to the underlying components in KWin and don't really care to at the moment' and I don't think anything has changed there. A lot of the activities stuff is read-only in the scripting interface, for instance. I think KWinFT has changed some of that, but it's also sort of an indictment on the speed of the development process that an active KWin developer had to fork the project to make any progress on things. My suspicion, based on very little, mind you, is that activities are really just a slightly complex way of hiding/starting/closing/showing applications and so they may do things 'on the fly' as much as possible. I don't think a WindowThumbnail component can exist for them because I don't think an activity is something that is 'visible' when it's inactive. I'm wrong about a lot of things though and am definitely not an expert : ) Applications that don't have a KWin decoration exist on the same desktop at the same position in every activity, which suggests something about the underlying way they're managed. It's certainly worth checking in with the KWin/Plasma people on it!

…

On Sat, 30 May 2020 at 14:22, tcorreabr ***@***.***> wrote: Sorry for the delay, tough week here. @astatide <https://github.com/astatide>, I know your solution and I imagine the trouble you had to show activities wallpapers. But as you work with image paths we would be loading again images that are already loaded by plasma. Also I'm not sure how your solution would work with plugins like Smart Video Wallpaper <https://store.kde.org/p/1316299/>. Parachute works by showing live replicas of desktop windows through the PlasmaCore.WindowThumbnail component. I think the ideal solution would be plasma to create a desktop window for each activity, but I don't know if this change would be viable. — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <https://github.com/tcorreabr/Parachute/issues/29#issuecomment-636387098>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ACEYEQ5XJ72SOUYQJJPDBDLRUF2KDANCNFSM4NCTKM7A> .

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[jiaiz]

This is a hard limit on plasmashell, or rather certain outdated X protocols...
The only ugly hack possible I see here is let the user set the Wallpapers for each desktop manually. Yes a very ugly hack but every other way something, whether Parachute, Kwin, Plasmashell, would need a (partial) rewrite.

The Vallpaper thing basically just listens on workspace changed event and then tells plasma to load a new wallpaper through dbus all in a very convoluted way.

[tcorreabr]

@jiaiz, I think allowing Parachute wallpapers in addition to the real wallpapers could lead to a confusing situation.

@astatide, maybe KWin people are more open to changes now. Some changes I proposed were quickly accepted, including changes that allow write access to activities related properties.

But support for different wallpapers per activity the way we discussed here is something that requires more complex changes in Plasma and that is out of my scope at the moment. So until someone decides to venture down this path we won't have the proper view of activities wallpapers in Parachute.

[psifidotos]

https://phabricator.kde.org/T13037 you can read some proposals. For the record the Plasma Activity Manager tracks on its own the plasmashellrc file all the time in order to identify which wallpapers are assigned for each activity. It can understand only files and colors, I think it fails also in multi-screen environments. This is why I propose Solution B in phabricator task, in order to provide a better way to consume wallpaper data.

[criticalsoft]

I'm Using Different Wallpaper For Each Activities, Same Wallpaper For Every Desktop Inside One Activity.
Parachute Is Fetching Wallpaper Well On My Desktop, Even Video Smart Wallpaper.
And KWin Script So Limited, I Think If It's Hard To Do Seamless Wallpaper Loading When Switching Activities (At Least Now), Then I Can Accept Little Flash To Make It Feel Seamless.
I Even Use This Tricky Way Move Window To An Activity By Bind Shortcuts:
xte 'keyup Shift_L' 'keyup Super_L'; xte 'keydown Super_L' 'key j' 'keyup Super_L'; sleep 0.2; xte 'keydown Alt_L' 'key a' 'keyup Alt_L' 'key Return'; xte 'keydown Super_L' 'key j' 'keyup Super_L'; sleep 0.2; xte 'keydown Alt_L' 'key a' 'keyup Alt_L' 'key Down' 'key Down' 'key Down' 'key Down' 'key Return'
(Super + j Is My Window Operations Menu) (If It's Not Work, Increase sleep Time.)