Update file extention when changing image type

[HarmOtten]

As a old PaintShopPro (5.00) user I am used to the tool automatically updating the file extention when saving an image in a different image type via 'Save as...".
Pinta currently does not do that, but that easily results in, for example, saving an jpg-file with an png-extention, which is quite annoying.
I hope this small enhancement could be implemented.

[cameronwhite]

I agree it's rather annoying, but I don't think there's much we can actually do about it in Pinta. This needs to be fixed upstream for the GTK native file chooser (https://gitlab.gnome.org/GNOME/gtk/-/issues/5367)

Commit da6df2a has some details from the last time I looked at it, but the summary was:

• We don't get any notifications about the file filter changing. It's the GTK file dialog which should be handling this, but it doesn't update the extension for you (the macOS native one does, for example).
• After the dialog is accepted, we absolutely cannot change the chosen filename since when running in a sandbox (flatpak or snap, for example) we only have permission to write to that specific file.

[HarmOtten]

I asked in the gitlap gnome project if this issue will be picked up soon. This was their answer:
"Applications that allow selecting a file format when saving should have their own "export" dialog to select the file format".
See also: https://gitlab.gnome.org/GNOME/gtk/-/issues/5367#note_2682135
Any ideas? Maybe implementing a different file chooser dialog?

[cameronwhite]

I definitely don't want to implement a different file chooser dialog since most users want and expect to have their standard platform-native file dialog. Pinta doesn't need the ability to add custom widgets into the dialog, we would just like the native GTK file chooser dialog to have its file filter update the file extension like many other platforms do

Having a separate export dialog or an Export > JPEG menu is an option, but that feels like a more annoying UX than just having the dialog work the way most users would expect :(

[Qronikarz]

we would just like the native GTK file chooser dialog to have its file filter update the file extension like many other platforms do

Well, good luck with that. GNOME is very opinionated. If they are set on something then you need amazing reasoning to convince them otherwise.

https://www.reddit.com/r/linux/comments/104pmod/on_the_gnome_project_and_my_way_or_the_highway/
Recommend both the article and comments for full picture.

At this point I'd just tag this issue as upstream-wontfix and try to at least look at different toolkits as a backup. Not saying to switch right now, but have it in mind.