CenterOnScreen Regression

[zquestz]

Checklist

• I have searched the issue tracker for open issues that relate to the same problem, before opening a new one.
• This issue only relates to a single bug. I will open new issues for any other problems.

Describe the bug

I am the author of Fortunate - https://github.com/zquestz/fortunate and recently updated to Fyne 2.6.1.

I noticed that the behavior of CenterOnScreen has changed dramatically between 2.5.2 and 2.6.1. In 2.5.2 it did what I would expect, which is centering the window on the screen, however in 2.6.1 it appears the upper left corner of the window is what was centered. This seems to only happen when SetFixedSize() is used. Oddly, it doesn't matter if true or false is used for SetFixedSize, if it is called at all, the centering is not working as expected. Removing the call to SetFixedSize completely causes the centering to work correctly, but obviously allows the window to be resized.

I did a bit of testing and the regression seems to have been introduced between v2.6.0-alpha1 and v2.6.0-beta1.

How to reproduce

1. Write code that centers a window using CenterOnScreen and SetFixedSize().
2. Notice it is no longer centered as of 2.6.x.

Screenshots

Here is a screenshot of the new behavior.

Example code

appGUI = app.New()
aboutWindow = appGUI.NewWindow("About")
aboutWindow.CenterOnScreen()
aboutWindow.SetFixedSize(true)
aboutWindow.Show()

Fyne version

2.6.1

Go compiler version

1.24.3

Operating system and version

Linux seras 6.14.5-zen1-1-zen #1 ZEN SMP PREEMPT_DYNAMIC Sat, 03 May 2025 13:33:50 +0000 x86_64 GNU/Linux

Additional Information

No response

[zquestz]

Found the bug, not sure why it is happening, but this fixes it.

zquestz@d800767

[andydotxyz]

I think this may also be Linux window manager specific - I cannot replicate it on FyneDesk.

Can you provide more info on your desktop setup?

[zquestz]

I am using Cinnamon with the Muffin WM on X11.

[andydotxyz]

I could not replicate on Cinnamon Mutter - upgrading to see if Muffin is the only one.

[zquestz]

Fortunate 1.1.2 has the bug. Might be easiest to test that release. It affects my main Linux box with Cinnamon running on arch, as well as the latest Linux Mint. I will try it on Xubuntu shortly. On May 11, 2025 2:59 PM, Andy Williams ***@***.***> wrote: andydotxyz left a comment (fyne-io/fyne#5733) I could not replicate on Cinnamon Mutter - upgrading to see if Muffin is the only one. —Reply to this email directly, view it on GitHub, or unsubscribe.You are receiving this because you authored the thread.Message ID: ***@***.***>

[kor-elf]

Just in case, I decided to write down my observations about this problem.

An example of code in which an incomprehensible shift occurs:

appGUI := app.New()
aboutWindow := appGUI.NewWindow("About")
content := container.NewVBox(
    widget.NewLabel("fdgdfg df dg dfg dfg fdgdfg df dg dfg dfg fdgdfg df dg dfg dfg fdgdfg df dg dfg dfg "),
)
aboutWindow.SetContent(content)
aboutWindow.CenterOnScreen()
aboutWindow.SetFixedSize(true)
aboutWindow.ShowAndRun()

Screenshot of the running program

Example code where everything is fine:

appGUI := app.New()
aboutWindow := appGUI.NewWindow("About")
content := container.NewVBox(
    widget.NewLabel("fdgdfg df dg dfg dfg fdgdfg df dg dfg dfg fdgdfg df dg dfg dfg fdgdfg df dg dfg dfg "),
)
aboutWindow.SetContent(content)
aboutWindow.CenterOnScreen()
// aboutWindow.SetFixedSize(true)
aboutWindow.ShowAndRun()

Screenshot of the running program

An example of code where everything is also fine:

appGUI := app.New()
aboutWindow := appGUI.NewWindow("About")
content := container.NewVBox(
    widget.NewLabel("fdgdfg df dg dfg dfg fdgdfg df dg dfg dfg fdgdfg df dg dfg dfg fdgdfg df dg dfg dfg "),
)
aboutWindow.SetContent(content)
aboutWindow.Resize(fyne.NewSize(400, 300))
aboutWindow.CenterOnScreen()
aboutWindow.SetFixedSize(true)
aboutWindow.ShowAndRun()

Screenshot of the running program

Screenshot: Comparison of the running program with aboutWindow.SetFixedSize(true) and without aboutWindow.SetFixedSize(true)

Link to a video where I showed how I open a program with this problem: youtube

I also checked in the OS:
Linux Mint 20.3 mate
Linux Manjaro KDE Plasma
Windows 11

go: 1.23.5
fyne.io/fyne/v2 v2.6.1

[andydotxyz]

Can you please test the linked PR @kor-elf ? that would be super helpful

[kor-elf]

This is a new experience for me. Therefore, I will describe my actions so that you understand whether I did everything correctly.

First I made a fork. Then I executed these commands:

git clone https://github.com/kor-elf/fyne ./
git remote add upstream https://github.com/fyne-io/fyne.git
git fetch upstream pull/5738/head:pr-5738
git checkout pr-5738
git push origin pr-5738

I added this to the go.mod file:

replace fyne.io/fyne/v2 => github.com/kor-elf/fyne/v2 v2.6.1-rc1.0.20250512012700-3056e6978e6a

Now it works well. I tried 3 versions of the code that I wrote above.

I also checked in the OS:
Linux Mint 20.3 mate
Linux Manjaro KDE Plasma
Windows 11

[andydotxyz]

Great thanks!

[andydotxyz]

Resolved on develop and will be in the next release