Slow startup due to an import-the-world approach

[apollo13]

Describe the issue
The app is great but it takes a while to start.

To Reproduce
Steps to reproduce the behavior:

1. Start the app
2. Wait a few seconds for it to actually show

Expected behavior
Startup fast and import stuff on demand

Operating system (please complete the following information):

• Distro: Fedora
• Version: 42
• Desktop Environment: Gnome
• Xorg/Wayland: Wayland

Additional context
I profiled the app startup a bit, by delaying some imports like daltonlens (on my machine in power save amount this already requires 200ms) in the colorblind simulator it should be possible to shave off a few seconds startup time.

Importing the WebView from Webkit has similar problems, but there it is used at module definition time

devtoolbox/src/widgets/webview_area.py

Line 19 in e121310

_webview = WebKit.WebView()

making it harder to fix. Begs the question though: Is it even correct to initialize a widget as part of the class and not in __init__. This would mean the instance is shared between all class instantiations (I don't know enough about how the gnome bindings work to say whether this is expected or not).

Would you be open to such fixes?

[aleiepure]

Hi, and thanks a lot for your detailed comment!
The slow startup has always bothered me as well. After the last release, I spent some time trying to improve performance, but unfortunately without any success. Your suggestions sound promising though, especially trying to defer imports.

Right now I’m in the middle of relocating internationally (sorry for taking so long to respond), so it will be a while before I can actively work on the code again. In the meantime, if you would like to experiment with some changes, I would be more than happy to discuss your findings and provide feedback.

[apollo13]

Hi @aleiepure, no worries, take your time relocating. I have put up a PR at #113 -- feel free to take it through a testrun. I am not that happy with the changes in window.py (especially the fact that I have to put ensure_tool_widget at multiple locations) but I am not really a GTK developer so I don't know if it is possible to properly (?) subclass the view stack somehow to make this code nicer. It really cuts down startup times though.