Otherwise a stray scroll controller may prevent others from getting hold
events, even if it always propagates scroll events and does absolutely
nothing.
Handle hold events:
- GDK_TOUCHPAD_GESTURE_PHASE_BEGIN: scroll-begin is emitted.
- GDK_TOUCHPAD_GESTURE_PHASE_END: A hold gesture ends only when all
fingers are lifted from the touchpad without movement, so
scroll-end is emitted right away.
- GDK_TOUCHPAD_GESTURE_PHASE_CANCEL: A hold gesture is cancelled when
some fingers are lifted/put down or movement is detected. In this
case, scroll-end is emitted after a small timeout only if
GDK_SCROLL wasn't detected.
Part-of: <!3454>
We let smooth scroll events that don't trigger a ::scroll signal through.
This is unintended, these are handled, even if just accumulated.
This fixes cases like GtkSpinButton inside GtkScrolledWindow, where both
would handle events, until the GtkSpinButton eventually shifts away from
underneath the pointer.
Brought up at https://gitlab.gnome.org/GNOME/gtk/-/issues/593
Kinetic scrolling (and begin/end tracking) broke with commit cab1dcb696
since the pointing device used on X11 does not get as much GdkInputSource
granularity as the source device used to have in GTK3.
Actually this is kinda pointless, devices incapable of smooth scroll
should send discrete events, without those devices in the picture, we
want kinetic scroll to apply on every other device capable of smooth
scroll, so just do that.
Fixes: https://gitlab.gnome.org/GNOME/gtk/-/issues/3210
Make GdkEvents hold a single GdkDevice. This device is closer to
the logical device conceptually, although it must be sufficient for
device checks (i.e. GdkInputSource), which makes it similar to the
physical devices.
Make the logical devices have a more accurate GdkInputSource where
needed, and conflate the event devices altogether.
Once upon a time, there was a function called gdk_event_get_scroll_deltas().
It returned %TRUE when an event had scroll deltas and that was used as the
condition to decide whether to push scroll deltas to the scroll history,
even when the both deltas are 0 for the stop event at the end of scrolling.
When GtkScrolledWindow kinetic scrolling code was adapted for
GtkEventControllerScroll, it was replaced with a (dx != 0 && dy != 0)
check. This prevented the stop event from getting into the history, and
instead allowed non-smooth scrolling to affect the history as they have
synthetic deltas with one of the values being -1 or 1 and the other on 0.
Instead, check the direction as we already have it as a local variable.
Restructure the getters for event fields to
be more targeted at particular event types.
Update all callers, and replace all direct
event struct access with getters.
As a side-effect, this drops some unused getters.
We want to make events readonly, so stop translating
their coordinates and instead pass the translated
coordinates separately, when propagating events.
While the ::scroll signal always returns whether it handled the event,
the others do not, for example ::decelerate.
Previously, this caused the event to stop at a scroll controller with
CAPTURE phase, never emitting the ::decelerate signal on later
controllers with BUBBLE phase.
Fixes#2151
We don't need to cover every case with a va_marshaller, but there are a
number of them that are useful because they will often only be connected
to by a single signal handler.
Generally speaking, if I opened into a file to add a va_marshaller, I just
set all of them.
If we set c_marshaller manually, then g_signal_newv() will not setup a
va_marshaller for us. However, if we provide c_marshaller as NULL, it will
setup both the c_marshaller (to g_cclosure_marshal_VOID__VOID) and
va_marshaller (to g_cclosure_marshal_VOID__VOIDv) for us.
Currently, gtk_event_controller_scroll_handle_event() always returns
TRUE if it is handled, which stops the propagation of the event. If
there’s a single GtkEventControllerScroll in the widget hierarchy, that
means that no others will run, depending on the propagation phase. In
Nautilus, this can be observed when adding a scroll controller to the
GtkScrolledWindow (ctrl-scrolling controls the zoom level) - either the
scrolling or the zooming breaks.
Fixes https://gitlab.gnome.org/GNOME/gtk/issues/45
The idea is that GTK+ 4 will be an epoch, API-wise.
Everything that was around for 4.0 has been there
since the beginning of the epoch and doesn't need
markers.
Remove all the old 2.x and 3.x version annotations.
GTK+ 4 is a new start, and from the perspective of a
GTK+ 4 developer all these APIs have been around since
the beginning.
There is a gtk_event_controller_scroll_set_flags() call that's meant
to be called after construction (eg. due to scrolledwindow relayouts
hiding/showing scrollbars). The property shouldn't be construct-only
for consistence.
This patch makes that work using 1 of 2 options:
1. Add all missing enums to the switch statement
or
2. Cast the switch argument to a uint to avoid having to do that (mostly
for GdkEventType).
I even found a bug while doing that: clearing a GtkImage with a surface
did not notify thae surface property.
The reason for enabling this flag even though it is tedious at times is
that it is very useful when adding values to an enum, because it makes
GTK immediately warn about all the switch statements where this enum is
relevant.
And I expect changes to enums to be frequent during the GTK4 development
cycle.
This is a GtkEventController implementation to handle mouse
scrolling. It handles both smooth and discrete events and
offers a way for callers to tell their preference too, so
smooth events shall be accumulated and coalesced on request.
On capable devices, it can also emit ::scroll-begin and
::scroll-end enclosing all ::scroll events for a scroll
operation.
It also has builtin kinetic scrolling capabilities, reporting
the initial velocity for both axes after ::scroll-end if
requested.
