fix windows unable to move between screens #375

benemorius · 2022-06-19T05:54:45Z

Summary

Currently on recent (?) versions of kwin we don't rearrange the tiles correctly when kwin moves windows between monitors instantaneously (versus dragging by mouse) and instead we arrange the moved window back to its original location. This PR fixes that.

I don't think this is the right way to fix it, but since the fix is reported to work and the bug is reported to be severe, I think we should do this for now. I'm currently investigating what changed about the events we receive from kwin. I think there are some other event-related issues too like for example when moving windows between activities or desktops, so I think a wider solution is needed here like maybe finding some missing events.

Test Plan

try moving a window between screens using a kwin keyboard shortcut
without this PR, the previous step fails

Related Issues

Closes #370, closes #374

...instead of forcing it back where it was. KWin changes a window's size before moving it between screens, so we can't react to a geometry change by always changing it back.

benemorius · 2022-06-21T15:21:45Z

Actually the problem is that kwin gives a frameGeometryChanged signal right before the screenChanged signal and we're currently handling the frameGeometryChanged signal by forcing the window back to its tiled geometry.

I don't know what the previous behavior of kwin was before this broke but I've tested as old as kwin 5.21.4 and it still has the bug.

Anyway I've finished going over the signal handling and I pushed an update.

gikari

Not sure how can this PR fix the linked problems, since it does not change the behavior of the program (except may the line you removed, presumably by mistake).

From your description, the problem has to do something with the order of the signals handling, so the PR should do something to run all the necessary handlers in the order we want.

gikari · 2022-06-21T20:21:31Z

src/kwinscript/controller/index.ts

@@ -336,7 +342,11 @@ export class ControllerImpl implements Controller {

  public onWindowGeometryChanged(window: EngineWindow): void {
    this.log.log(["onWindowGeometryChanged", { window }]);
-    this.engine.enforceSize(window);


Not sure if you want to remove this line.

For sure we do. I'm sure it made sense when it was added but we can't do that now. Perhaps kwin used to send this event less often or perhaps it was always a race condition waiting to happen. This line causes us to move a window back to its original location instantaneously after kwin moves it for example to a new screen. It's the direct cause of the linked bugs.

Yes, the change is needed. Otherwise bismuth is not usable by keyboard on multimonitor setups.
Check #374 for how it looks without this change.

This function exists to enforce the window geometry in case an application moves and resizes the window by itself.

The reason why the bug is present, is because this function incorrectly assumes, that window was move and resized by application and not by the user.

One of the ways to make a proper fix without potential breakages is to fix that function. Another option is to remove this function entirely (what this PR is doing de-facto) and let the apps break your tiling layout. I am not actually totally against this, because I think, that when an app moves your window it has a good reason to do so (the person written this function may have a different opinion).

So, this was just to explain why I was hesitant to apply this fix.

We can remove this function now and look for the results from the presence or absence of bug reports about this.

benemorius · 2022-06-22T00:18:22Z

Indeed that one line is the problem. KWin changes a window's
size before moving it between screens, so we can't react to a
geometry change by always changing it back.

krshrimali · 2022-06-24T05:32:56Z

Hi, @benemorius - Thank you for helping fix issues lately. I was just testing this fix, but unfortunately, this doesn't fix on my system. And it's for Google Chrome and Microsoft Edge. Firefox, and other windows are all fine. I have shared more in the linked issue, would you know what's going wrong?

ZackGlenn · 2022-07-03T19:55:30Z

This PR fixes the problem for me. Without it, the only way I can move windows around on kwin 5.25 is to float -> move -> unfloat.

RayJameson · 2022-07-29T18:15:02Z

This one fixed my problem on X11. I'm too lazy to compile, so I just copy-pasted code to usr/share/kwin/scripts/bismuth/contents/code/index.mjs

philgzl · 2022-08-10T17:00:11Z

Solved it for me too. Cloning the current master branch and merging this fix gets me the desired behavior.

git clone https://github.com/Bismuth-Forge/bismuth.git
cd bismuth
git remote add benemorius https://github.com/benemorius/bismuth.git
git fetch benemorius
git checkout -b <new_branch>
git merge benemorius/pr/fix/kwin-move-windows-between-screens
make setup-dev-env
[...]  # rest of build instructions

This really needs to be merged. Not being able to move windows to other screens from the keyboard is a deal breaker.

DashieTM · 2022-08-10T17:43:30Z

Can this please get another look? This bug has been an issue for weeks by now with a fix available but not being merged.

gikari

I presented a bit of reasoning in the code comment. So, could you please remove the definitions of enforceSize function? The fix should be good to go.

gikari · 2022-08-10T22:57:20Z

src/kwinscript/controller/index.ts

@@ -336,7 +342,11 @@ export class ControllerImpl implements Controller {

  public onWindowGeometryChanged(window: EngineWindow): void {
    this.log.log(["onWindowGeometryChanged", { window }]);
-    this.engine.enforceSize(window);


This function exists to enforce the window geometry in case an application moves and resizes the window by itself.

The reason why the bug is present, is because this function incorrectly assumes, that window was move and resized by application and not by the user.

One of the ways to make a proper fix without potential breakages is to fix that function. Another option is to remove this function entirely (what this PR is doing de-facto) and let the apps break your tiling layout. I am not actually totally against this, because I think, that when an app moves your window it has a good reason to do so (the person written this function may have a different opinion).

So, this was just to explain why I was hesitant to apply this fix.

We can remove this function now and look for the results from the presence or absence of bug reports about this.

DriesOlbrechts · 2022-09-01T15:08:45Z

Are there still no plans to merge this pr?

KubiGR · 2022-09-02T07:19:44Z

I have been using this fix for a month and I haven't got any bugs. Without this, I wouldn't use Bismuth because this is happening for most electron apps.

gikari · 2022-09-02T11:30:20Z

Since the OP is not active, I applied the fixes I requested in a separate PR: #419

(In other words: the issue is fixed).

fix(kwinscript): arrange after kwin moves a window between screens

d275b2c

...instead of forcing it back where it was. KWin changes a window's size before moving it between screens, so we can't react to a geometry change by always changing it back.

benemorius force-pushed the pr/fix/kwin-move-windows-between-screens branch from e35a3e0 to d275b2c Compare June 21, 2022 15:17

gikari suggested changes Jun 21, 2022

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gikari suggested changes Aug 10, 2022

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gikari mentioned this pull request Sep 2, 2022

Fix the inability to move windows between screens #419

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gikari closed this Sep 2, 2022

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fix windows unable to move between screens #375

fix windows unable to move between screens #375

benemorius commented Jun 19, 2022 •

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fix windows unable to move between screens #375

fix windows unable to move between screens #375

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benemorius commented Jun 19, 2022 • edited Loading

Summary

Test Plan

Related Issues

benemorius commented Jun 21, 2022

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