EventControllerScroll
Superclasses: EventController
, Object
GtkEventControllerScroll
is an event controller that handles scroll
events.
It is capable of handling both discrete and continuous scroll
events from mice or touchpads, abstracting them both with the
scroll
signal. Deltas in
the discrete case are multiples of 1.
In the case of continuous scroll events, GtkEventControllerScroll
encloses all scroll
emissions
between two scroll_begin
and
scroll_end
signals.
The behavior of the event controller can be modified by the flags
given at creation time, or modified at a later point through
set_flags
(e.g. because the scrolling
conditions of the widget changed).
The controller can be set up to emit motion for either/both vertical
and horizontal scroll events through VERTICAL
,
HORIZONTAL
and BOTH_AXES
.
If any axis is disabled, the respective scroll
delta will be 0. Vertical scroll events will be translated to horizontal
motion for the devices incapable of horizontal scrolling.
The event controller can also be forced to emit discrete events on all
devices through DISCRETE
. This can be used
to implement discrete actions triggered through scroll events (e.g.
switching across combobox options).
The KINETIC
flag toggles the emission of the
decelerate
signal, emitted at the end
of scrolling with two X/Y velocity arguments that are consistent with the
motion that was received.
Constructors
- class EventControllerScroll
- classmethod new(flags: EventControllerScrollFlags) EventController
Creates a new event controller that will handle scroll events.
- Parameters:
flags – flags affecting the controller behavior
Methods
- class EventControllerScroll
- get_flags() EventControllerScrollFlags
Gets the flags conditioning the scroll controller behavior.
- get_unit() ScrollUnit
Gets the scroll unit of the last
scroll
signal received.Always returns
%GDK_SCROLL_UNIT_WHEEL
if theDISCRETE
flag is set.Added in version 4.8.
- set_flags(flags: EventControllerScrollFlags) None
Sets the flags conditioning scroll controller behavior.
- Parameters:
flags – flags affecting the controller behavior
Properties
- class EventControllerScroll
- props.flags: EventControllerScrollFlags
The flags affecting event controller behavior.
Signals
- class EventControllerScroll.signals
- decelerate(vel_x: float, vel_y: float) None
Emitted after scroll is finished if the
KINETIC
flag is set.vel_x
andvel_y
express the initial velocity that was imprinted by the scroll events.vel_x
andvel_y
are expressed in pixels/ms.- Parameters:
vel_x – X velocity
vel_y – Y velocity
- scroll(dx: float, dy: float) bool
Signals that the widget should scroll by the amount specified by
dx
anddy
.For the representation unit of the deltas, see
get_unit
.- Parameters:
dx – X delta
dy – Y delta