Instead of being a GObject managing two GtkWidgets, make GtkTextHandle
a GtkWidget subclass, representing a single handle.
From the perspective of users (GtkText and GtkTextView), this is not a
big leap since they have to be aware of a great deal of text handles'
state. It actually makes things more direct and simple.
With text handles being widgets, those can be actual children of the
widget, and may have their own GdkSurface that we move around at will.
This is the second major aspect of this refactor.
Similar to previous removals of g_cclosure_marshal_VOID__VOID we can remove
other marshallers for which are a simple G_TYPE_NONE with single parameter.
In those cases, GLib will setup both a c_marshaller and va_marshaller for
us. Before this commit, we would not get a va_marshaller because the
c_marshaller is set.
Related to GNOME/Initiatives#10
GtkTextHandle was neglected by whoever removed the ::draw signal,
leaving it entirely broken. Update to using GtkGizmo so we can
implement snapshot of text handles.
Input has received a revamp too, handling is done through a
GtkGestureDrag and coordinate calculations simplified by storing
the delta to the hotspot on ::begin instead of ::update, as this
value is constant throughout the gesture. Widget state management
on crossing events happens implicitly, so no longer needs to be
done here.
Last but not least, CSS has also been updated so handles are
rendered at the correct size and proportion, and with the padding
that code expects of it.
We now rely on toplevels receiving and forwarding all the events
the windowing should be able to handle. Event masks are no longer a
way to determine whether an event is deliverable ot a widget.
Events will always be delivered in the three captured/target/bubbled
phases, widgets can now just attach GtkEventControllers and let those
handle the events.
Text handles use to connect to the first GtkScrollable up the hierarchy
so they can be repositioned when scrolling. It makes more sense to look
up the first child of a GtkScrolledWindow, it must be an scrollable too,
and will be the scrollable that can actually change the position of the
text handles.
https://bugzilla.gnome.org/show_bug.cgi?id=761676
It is assumed that border.top is the same than pointing_to.height (which
equals the strong cursor position), which is not since some time ago.
The border calculation has been move on top too, it is now used in the
Y position one, and doesn't depend on anything we calculate later.
Text handles are subsurfaces on wayland, so sort of their own toplevel.
This made gtk_widget_translate_coordinates() to bail out there, resulting
in text handles being mispositioned and jumpy. To fix this, translate to
toplevel GtkWindow coordinates manually, and translate coordinates from
there.
Along the way, the coordinates reported in ::handle-dragged have been
fixed so there is no small jumps in either axis (most noticeable in the
X axis when you started dragging, and in the Y axis when moving between
lines of different heights.
This behavior has been made optional on add_popover() time, text handles
will keep being able to overflow the window, in order to allow text
selection on views too close to the window edge.
Regular GtkPopovers are reinstaurated to the previous size positioning
logic though, that is, limited by the visible area of the window.
This will be the widget that the popover relates to (::pointing-to in
GtkPopover, ::parent in GtkTextHandle).
Additional API to check the popover/parent relationship between widgets
has been added, which will be useful wherever this is necessary in a
generic manner.
https://bugzilla.gnome.org/show_bug.cgi?id=750993
When we are close the window edge, we need to shrink the 'invisible
border' around the handle to avoid mispositioning it. A fiddly
calculation, but it works.
