Draft: GTK4

Let's use this as the tracking place.

General:

• Make sure all new API has docs
• A lot of API has incorrect Since:. I wonder if we should just remove all Sinces, since this is more or less a new library.
• Need to clean up the commits
• Some preparations can be done in GTK3, such as moving icons
• Sync up changes from GTK4, mainly a11y additions as there've been plenty recently
  • GtkStack -> HdyLeaflet, HdySqueezer, partially HdyCarousel/HdyCarouselBox (a11y, transition fixes)
  • GtkStackSwitcher -> HdyViewSwitcher (a11y)
  • GtkDropDown -> HdyComboRow (checkmarks)

HdyActionRow:

• Clicking the row doesn't activate its child, instead it just focuses it. GTK4 has its own implementation for this, we should probably reuse it. gtk!3012 (merged)

HdyAvatar:

• The selector doesn't reset after pressing 🚮️ in the demo.

HdyClamp:

• Split the logic into HdyClampLayout
• Provide a scrollable variant, to be used with GtkListView

HdyCarouselIndicatorDots:

• Dots change shape in a glitchy way unless viewed the scale is really high.
• We have gizmos now, can we replace custom snapshot() with that?

HdyCarouselIndicatorLines:

• Ditto, try to use real widgets

HdyComboRow:

• I removed rounding from first/last rows as we GtkPopover clips corners anyway, but it results in cut-off focus outline (which is much more visible in GTK4), we need to bring it back
• Focus is all over the place
• Switch to GtkListView
• Make API more similar to GtkDropDown
• There's a memory management error somewhere in dispose, test crashes
• No selected item check, same as in GtkDropDown

HdyExpanderRow:

• hdy_expander_row_remove() should be able to remove prefixes/actions.
• Previous sibling is always null in a GtkListView
• Previous sibling approach is simply not viable in a list view anyway

HdyKeypad:

• Buttons aren't square
• Input entry filtering doesn't work

HdyLeaflet/HdyDeck:

• Currently the port merges them back, the mixin was way too unwieldy to work with
• Over and under transitions are noticeably slower on a 4K screen than slide

HdyHeaderBar:

• No back button

HdyHeaderGroup:

• Window flickers when changing decoration layout on header bars. I wonder if we should try a completely different approach instead, like overlaying GtkWindowControls in HdyWindow and having headerbars only change padding. - #372

HdyPreferencesWindow:

• The view switcher can stay at the top if it's small (#341 (closed))

HdySqueezer:

• Small -> large transition is broken.

HdySwipeTracker:

• Cannot start a swipe from GtkScrolledWindow inside a swipeable widget, but can if it's outside. In other words, carousel/deck demo swipes work, but demo->list swipe doesn't. This needs to be fixed upstream, GtkScrolledWindow stopped propagating scroll events for directions without scrollbars. gtk!2953
  • After that's merged, we should unify event handling using capture and bubble phases the same way
• Swipe is broken in HdyPreferencesWindow subpages
• Can we somehow get rid of GtkButton/GtkWindowHandle special cases? - gtk!3001 (merged) should fix it for GtkButton
• Split handle_scroll_event() to begin/update/end and inline it where appropriate, it doesn't make sense anymore
• Since we use event controllers for everything, try to use GTK's velocity calculation instead of our own

HdyViewSwitcher:

• Criticals on size_allocate()

HdyWindow:

• Missing the outline
  • Outline is still there in fullscreen