The widget window is usually covered by the bin_window,
this is just necessary so the parent scrolled window
picks the right color for drawing the overshoot area.
GDK will only receive touch events when dealing with a multitouch
device, so these must be transformed to pointer events if the
client-side window receiving the event doesn't listen to touch
events, and the touch sequence the event is from does emulate
the pointer.
If a sequence emulates pointer events, it will result in a
button-press, N motions with GDK_BUTTON1_MASK set and a
button-release event, and it will deliver crossing events
as specified by the current device grab.
These are equivalent to an implicit grab (with !owner_events), so
if the touch leaves or enters the grab window, the other window
won't receive the corresponding counter-event.
Touch events don't generate crossing events themselves, so
do not rely on these to determine whether the button release
happened within the event window.
The implicit grab on priv->event_window already warrants that this
widget is the only one getting events while the button is pressed,
so don't spare the GTK+ grab here.
Likewise to pointer events, have touch events during a device
grab with owner_events=TRUE be delivered normally as long as
the widget pertains to the same window group.
If the touch sequence happens on a window with GDK_TOUCH_MASK set,
a GdkTouchGrabInfo is created to back it up. Else a device grab is
only created if the sequence emulates the pointer.
If both a device and a touch grab are present on a window, the later
of them both is obeyed, Any grab on the device happening after a
touch grab generates grab broken on all the windows an implicit
touch grab was going on, and all touches would be automatically
removed from every touch cluster.
If given an event coming from a touch devices,
this functions will read the MT major/minor/orientation
axes and return a cairo_region_t with the touch shape.
In GtkWidget, touch events go through the same handler
than motion events, with the difference that touch_id
will have something meaningful there.
Touch events need to be explicitly selected, so if this
is enabled, the possibility of different motion streams
with different touch IDs must be handled in some way.
These are translated into GDK_TOUCH_PRESS/RELEASE GdkEvents,
which use the GdkEventButton struct, a touch_id parameter
has been added there to cope with touches.
These events' struct is the same than GdkEventMotion, which has been
added a touch_id parameter. The gdk_event_* functions have been modified
to also handle this event type.
This widget is too narrow to make touch interaction tricky enough, so
don't add the penalty of having the slider run farther from the touch
coordinates if it happens to miss the slider.
Instead of just stopping the acceleration source ID, check whether
it's overshooting, and let it snap back if needed after ::grab-notify
and ::button-release-event
Velocity calculation has been refactored out of the captured motion events
handler, and also has more tolerance defore determining that a drag is actually
still.
This is so submenus stay open as the parent menu item is pressed/released,
as the user would typically lift the finger in order to select a submenu
item.
_gtk_widget_set_device_window() is suppose to make accounting of
the topmost widget under the device at each time, so avoid setting
it on virtual crossing events as the device is already in another
window.
gtk_scrolled_window_set_kinetic_scrolling() now takes a set of flags,
GTK_KINETIC_SCROLLING_CAPTURE_BUTTON_PRESS makes the "capture button
press and maybe replay later" vs "let button press go through, but
trust in ::grab-broken to undo things" an opt-in, by default that
flag is set, which is the most conservative approach.
This is so the grab doesn't break the implicit grab on the
child widget's window, which avoids that the button press and
release are possibly sent to different windows, and after the
grab was actually broken.
Anytime a touch device interacts, the crossing events generation
will change to a touch mode where only events with mode
GDK_CROSSING_TOUCH_PRESS/RELEASE are handled, and those are sent
around button press/release. Those are virtual as the master
device may still stay on the window.
Whenever there is a switch of slave device (the user starts
using another non-touch device), a crossing event with mode
GDK_CROSSING_DEVICE_SWITCH may generated if needed, and the normal
crossing event handling is resumed.
This last slave device (stored per master) is used to fill
in the missing slave device in synthesized crossing events
not directly caused by a device event (ie. due to configure
events or grabs)
