The renderer does not stick around so we need to disconnect the signal
handler on "dispose". Since the renderer is not a GObject track the
signal id manually instead of using `g_signal_connect_object ()`.
Fixes 1995285 ("eek-renderer: Honor theme changes")
There are some hacks here in the form of an extra field "appears_locked_from", which can be used to hint that the user should see the button as locked. Without it, there's some confusion on user side regarding buttons that change states unprompted.
Geometry is now permanently married to the widget rather the renderer. While geometry is not always defined, C doesn't support sum types, so checks won't be enforced by the compiler. It's OK to pretend there's always some geometry to avoid crashes.
Control and Alt are special in that they aren't expected to switch levels, and so don't need to change what characters are output.
Use in layouts by adding `modifier: Control` or `modifier: Alt` in place of `text: "foo"`.
The latching of the modifier will force the keyboard to emit raw key presses and prevent it from outputting text.
Sizes of widgets can be derived, so storing them was only for C compatibility. Similar with storing position inside of widgets.
Some layout margin and scaling changes could be introduced, meaning a possibility of visual differences.
Moved Cairo context usage to Rust, and rearranged ctx setup (position) to happen in one place.
Removed render calls that were overwritten on each draw call anyway.
Dedicated styling is now possible for themes which have a corresponding style-theme.css file. Adwaita:dark gets one, whereas other themes use the new generic fallback theme.
This fixes some rendering things which would happen with multiple state-sharing buttons. It also removes some interfaces exposing rows, views, layouts, and buttons, bringing the code closer to removing them from the FFI entirely.
The button cache is storing only button outlines (not useful to us), and it only cares about active/inactive states (there are more).
This will have to be rewritten sanely, so for the time being, disabling it is not going to deal a big performance penalty.
