[DMP 2025]: GTK4 Exploration

[pikurasa]

Ticket Contents

Description

Sugar 0.120 runs on GTK3 and needs to be ported to GT4, we need to
port Sugar and its core activities to support GTK4 before GTK3 gets
to its EOL.

Goals & Mid-Point Milestone

Goals

• Migrate minimal sugar-toolkit-gtk3 components to support Hello World activity, in particular the activity and graphics classes.
• Migrate Hello World activity.
• Document migration strategy based on extending any existing upstream GTK3 to GTK4 porting documentation.
• Migrate remaining toolkit components.
• Extend Hello World to use remaining toolkit components, and rename as a Toolkit Test activity,
• Migrate Sugar.
• Migrate the Fructose activity set, as time permits.

Setup/Installation

No response

Expected Outcome

No response

Acceptance Criteria

No response

Implementation Details

Prerequisites

• Experience with C
• Experience with Python
• Experience with GTK
• Good understanding of Sugar Core architecture

Steps to start

• Plan migration.
• Setup a live build development environment.
• See the GTK4 migrating doc.

Mockups/Wireframes

No response

Product Name

GTK4 Exploration

Organisation Name

Sugar Labs

Domain

⁠Education

Tech Skills Needed

Python, Other

Mentor(s)

Coding Mentors

Ibiam Chihurumnaya

Category

Refactoring

[chimosky]

If you read the opening comment, you'd see there's a "Steps to start" section, the goals section also clearly lays out where the work needs to be done.

[aryan0931]

Hi @chimosky ,

I'm interested in contributing to GTK4 Exploration (#4) and would love some guidance to get started. I’ve gone through the issue, and here's what I understand so far:

The goal is to port Sugar 0.120 from GTK3 to GTK4, starting with sugar-toolkit-gtk3, the Hello World activity, and eventually Sugar core and Fructose activities.
The migration involves both Python and some C components.
Experience with GTK, C, and the Sugar core architecture is important.
Before I dive in, I have a few questions:

For the Hello World activity, are there specific files or modules I should focus on first for GTK4 compatibility?
Would it be okay if I start by replicating the Hello World activity with GTK4 and share my findings in a small write-up for feedback?
Looking forward to your guidance!

Thanks,
Aryan Yadav

[quozl]

It's a big job. All files and modules. sugar-toolkit-gtk3 is a critical dependency of Hello World. Others have begun porting, contributing their work under our LGPL-2.1license, so you can use what they have done. sugarlabs/sugar-toolkit-gtk3#484

[vnmeue]

I'd love to work on this issue

[Himanshuba9hel]

Hi,
This is Himanshu
Email-Id: himanshusinghrohansingh@gamil.com
Discord-ID: 932992702159659029
Title:
✨ First Step in GTK4 Migration: Ported Hello World and Core Toolkit Components

Description:
Hey there! This PR is my first contribution toward the GTK4 migration for Sugar Labs. I’ve started by migrating some basic components from the sugar-toolkit-gtk3 to GTK4 to get a simple "Hello World" activity up and running. The goal is to make sure we’re on the right track before we dive into more complex activity migrations.

Changes:
Migrated activity and graphics classes to GTK4.

Created a minimal "Hello World" activity that works with GTK4.

Updated old GTK3 widgets to their GTK4 equivalents.

Made sure the README reflects these changes and included some migration notes.

Related Issue:
[DMP 2025]: GTK4 Exploration #4

How to Test:
Clone the branch and run the Hello World activity.

Make sure it works smoothly with GTK4 and everything looks good!

Checklist:
Code builds successfully

No more GTK3 code in the updated files

README updated with migration details

CI is passing (if applicable)

Notes:
This is just the first step! More to come as I continue porting the other components. Let me know if you have any feedback or suggestions!

[chimosky]

Hi @Himanshuba9hel your comment seems to have very little effect as to fixing or helping fix the issue, seems like something you copied and pasted from an AI.

Nothing wrong with using AI, but in this context your comment isn't helpful as it contributes nothing, doesn't help fix the issue or point us to what you've done to fix the issue.

[vnmeue]

I believe most changes in # 484 are useless, which is the reason why it is not working. GTK4 in specific requires Box instead of Container, we need to replace that and convert all event handlers to Gtk.EventController. (there's not huge changes but we need to go planned or even being honest) complete rewrite of some subsystems would be more effective than trying to patch the existing GTK3 code, (sugar-cursor-tracker.c) must use Gdk.Seat and Gdk.Device instead of XInput2 hacks.

for context to stack traces:
I am also working on this similar (stack trace issue in WASM implementation on IO based scala), stack traces (either in GTK or WASM) can be obscured by complex signal handling and library abstractions, making it hard to debug issues, much like the stripped-down runtime environment in WASM.
Because we don't have much information about their working.

Manav

[chimosky]

Yes, GtkContainer has been removed in GTK4, but I haven't taken a close look at 484 to verify anything you've said, however I agree that some parts would require a rewrite to be GTK4 centric, that's something that's expected.

You should comment on the PR if you haven't, so the person working on it would see your concerns.