GTK4 compiling branch

[bhennion]

It doesn't run yet, but we're closing in, I think.

This branch compiles (and links) and starts but the .glade files need to be adapted before testing anything. edit: and works

There are a couple of features I deactivated/commented out to get it to compile, so those need fixing either in gtk4, or before that, in gtk3 (e.g. the sidebar could be pre-ported).

• Optimize cursor creation (cairo->pixbuf->texture->cursor)
• Restore gtk-sourceview (5 is gtk4)
• Zoom
  • Scrollzoom
  • Touch pinch zoom
  • Touchpad pinch zoom
  • Long term: refactor -> new Navigation = ScrollHandler + ZoomControl + unify event handling
• Toolbar Customization
  • Create suitable GtkWidget for toolbars
  • Port ToolbarCustomizeDialog
  • Port drag'n'drop customization
• Colorize svg for toolbar color icons (so they scale)
• Sidebar
  • Port Sidebar
  • Restore page numbers
• Clipboard
• ImageDialog + add PdfPage dialog
• Landscape/portrait icons in FormatDialog
• Fix Gdk-CRITICAL **: 21:20:45.390: gdk_key_event_get_keyval: assertion 'GDK_IS_EVENT_TYPE (event, GDK_KEY_PRESS) || GDK_IS_EVENT_TYPE (event, GDK_KEY_RELEASE)' errors
• Plugins
  • Refactor API for dialogs. Add callbacks
  • Expose new action system. Retire old one.
• Replace GdkPixbuf by GdkTexture?
• @rolandlo's pressure inference thickness issue when running with GDK_BACKEND=x11
• Double and triple click

NB: this branch is built on a merge of various PR's. Not really a pull request...

[bhennion]

It now runs (but doesn't quite work).

Note: the CI fails to build because I put gtk4 >= 4.10.1 in the CMakeFile. Lowering this number should pose no problem, in case you don't have an up-to-date enough setup.

[rolandlo]

Oh, wow, that's awesome! Great job @bhennion ! I'm really excited!

[bhennion]

This is now in a reasonably stable state. Everything works with a couple of exceptions (toolbar customization, touchpad pinch zoom, clipboard, plugins).
I'm not quite sure how to proceed from here on. I can cleanup the commit history a little bit and make a dedicated branch on the repository.

[rolandlo]

Great work @bhennion! It's a giant step forward!
Sure, cleaning up the commit history and making a dedicated branch are good ideas. Probably I'd like to work on some of the remaining issues as well in the coming two weeks (e.g. the plugins), so I can then make a PR to the dedicated branch.

We should also review your previous PR's that went into this PR, so that they can be merged into master.

Moreover I think it's time for some testing of the features that are supposed to work. I will share my observations in this PR.