Tiled displays tilesets wrongly with qt 6.9

[NetSysFire]

Describe the bug

See title. thorbjorn confirmed on IRC this is apparently related to qt 6.9.
A solution would be using the appimage or flatpak for now apparently.

To Reproduce

1. Use qt 6.9
2. Run tiled.
3. Open any tileset. It is worse with lower zoom levels and with a higher zoom level, the tiles overlap. These tiles are 16x16.
4. See below.

Expected behavior

It would display them as usual.

Specifications:

• OS: Arch Linux
• Tiled Version: 1.11.2-1

[sircodalotkob]

Arch updated Qt6 from 6.8.x to 6.9, but the Tiled in the repo is still built against Qt 6.8.x.
I tried re-building Tiled 1.11.2 from git locally with Qt 6.9 and the issue went away.

[bjorn]

Hmm, that's odd because I could reproduce this issue when compiling Tiled against Qt 6.9 installed through the Qt Online Installer.

[sircodalotkob]

Odd, indeed... To be sure, I checked again.

/usr/bin/tiled (from Manjaro Linux Repo):

/usr/local/bin/tiled (tag v1.11.2 from Github, built using qbs):

[bjorn]

@sircodalotkob Could you confirm whether your Qbs build of Tiled is indeed using Qt 6.9, for example by typing tiled.qtVersion in the Console view?

[sircodalotkob]

@bjorn Good hunch! Aside from Qt6, I still happen to have an old Qt5 installed, and that's what qbs chose for the build. Sorry for the confusion.

I tried to build again, this time against Qt 6.9.0, but it fails and I get this:

[…]/src/libtiled/qtcompat_p.h:31:7: error: conflicting declaration ‘using QStringRef = class QStringView’
[…]
/usr/include/qt6/QtCore/qstringfwd.h:39:7: note: previous declaration as ‘class QStringRef’
   39 | class QStringRef; // defined in qt5compat

[bjorn]

I tried to build again, this time against Qt 6.9.0, but it fails and I get this:

The Tiled 1.11.2 release needs this patch to compile against Qt 6.8.2 and up: 60388da

However I'd recommend to check out the repository instead, using either the master or 1.11 branch.

[sircodalotkob]

I can confirm the tileset view looks as intended when building Tiled against Qt 5.15.18 and Qt 6.8.3.
Built against Qt 6.9.0, the tileset view doesn't re-layout it's cells anymore, leading to the effect the OP described.

[svenstaro]

@bjorn any chance you could look into this? tiled is currently pretty gnarly to use on Arch.

[bjorn]

@svenstaro Yes, I'll have a look into this today. Fedora 42 also updated to Qt 6.9 in the meantime...

[bjorn]

Been debugging with both Qt 6.8.2 and 6.9.0 today but have not been able to figure out the difference yet. Noteworthy I think is that Qt 6.9 appears to behave as if I had not hidden the horizontal and vertical headers (in that, Qt 6.8.2 behaves the same way, if I don't hide those headers).

I also noticed that Qt 6.9 includes some optimization for huge models among its changes, which affects QHeaderView. Maybe it's related to that.

[bjorn]

@svenstaro I've found a workaround which you can use to patch up the 1.11.2 release (#4197). I've reported the issue on the Qt tracker as https://bugreports.qt.io/browse/QTBUG-136453.

[svenstaro]

@svenstaro I've found a workaround which you can use to patch up the 1.11.2 release (#4197). I've reported the issue on the Qt tracker as https://bugreports.qt.io/browse/QTBUG-136453.

https://patch-diff.githubusercontent.com/raw/mapeditor/tiled/pull/4197.patch

Cool stuff. I shall try.