mutter/clutter/clutter-pan-action.c
Emmanuele Bassi 8cb326dc54 Explicitly set the trigger edge in GestureAction subclasses
Each GestureAction subclass has its own trigger edge handling, so we
want to be resilient in case of changes in the super-class.

https://bugzilla.gnome.org/show_bug.cgi?id=710227
2013-12-05 15:20:39 +00:00

931 lines
27 KiB
C

/*
* Clutter.
*
* An OpenGL based 'interactive canvas' library.
*
* Copyright (C) 2010 Intel Corporation.
* Copyright (C) 2011 Robert Bosch Car Multimedia GmbH.
* Copyright (C) 2012 Collabora Ltd.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library. If not, see <http://www.gnu.org/licenses/>.
*
* Author:
* Emanuele Aina <emanuele.aina@collabora.com>
*
* Based on ClutterDragAction, ClutterSwipeAction, and MxKineticScrollView,
* written by:
* Emmanuele Bassi <ebassi@linux.intel.com>
* Tomeu Vizoso <tomeu.vizoso@collabora.co.uk>
* Chris Lord <chris@linux.intel.com>
*/
/**
* SECTION:clutter-pan-action
* @Title: ClutterPanAction
* @Short_Description: Action for pan gestures
*
* #ClutterPanAction is a sub-class of #ClutterGestureAction that implements
* the logic for recognizing pan gestures.
*
* The simplest usage of #ClutterPanAction consists in adding it to
* a #ClutterActor with a child and setting it as reactive; for instance,
* the following code:
*
* |[
* clutter_actor_add_action (actor, clutter_pan_action_new ());
* clutter_actor_set_reactive (actor, TRUE);
* ]|
*
* will automatically result in the actor children to be moved
* when dragging.
*
* Since: 1.12
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "clutter-pan-action.h"
#include "clutter-debug.h"
#include "clutter-enum-types.h"
#include "clutter-gesture-action-private.h"
#include "clutter-marshal.h"
#include "clutter-private.h"
#include <math.h>
#define FLOAT_EPSILON (1e-15)
static const gfloat min_velocity = 0.1f; // measured in px/ms
static const gfloat reference_fps = 60.0f; // the fps assumed for the deceleration rate
static const gfloat default_deceleration_rate = 0.95f;
static const gfloat default_acceleration_factor = 1.0f;
typedef enum
{
PAN_STATE_INACTIVE,
PAN_STATE_PANNING,
PAN_STATE_INTERPOLATING
} PanState;
struct _ClutterPanActionPrivate
{
ClutterPanAxis pan_axis;
PanState state;
/* Variables for storing acceleration information */
ClutterTimeline *deceleration_timeline;
gfloat target_x;
gfloat target_y;
gfloat dx;
gfloat dy;
gdouble deceleration_rate;
gdouble acceleration_factor;
/* Inertial motion tracking */
gfloat interpolated_x;
gfloat interpolated_y;
gfloat release_x;
gfloat release_y;
guint should_interpolate : 1;
};
enum
{
PROP_0,
PROP_PAN_AXIS,
PROP_INTERPOLATE,
PROP_DECELERATION,
PROP_ACCELERATION_FACTOR,
PROP_LAST
};
static GParamSpec *pan_props[PROP_LAST] = { NULL, };
enum
{
PAN,
PAN_STOPPED,
LAST_SIGNAL
};
static guint pan_signals[LAST_SIGNAL] = { 0, };
G_DEFINE_TYPE_WITH_PRIVATE (ClutterPanAction, clutter_pan_action, CLUTTER_TYPE_GESTURE_ACTION)
static void
emit_pan (ClutterPanAction *self,
ClutterActor *actor,
gboolean is_interpolated)
{
gboolean retval;
g_signal_emit (self, pan_signals[PAN], 0, actor, is_interpolated, &retval);
}
static void
emit_pan_stopped (ClutterPanAction *self,
ClutterActor *actor)
{
ClutterPanActionPrivate *priv = self->priv;
g_signal_emit (self, pan_signals[PAN_STOPPED], 0, actor);
priv->state = PAN_STATE_INACTIVE;
}
static void
on_deceleration_stopped (ClutterTimeline *timeline,
gboolean is_finished,
ClutterPanAction *self)
{
ClutterPanActionPrivate *priv = self->priv;
ClutterActor *actor;
g_object_unref (timeline);
priv->deceleration_timeline = NULL;
actor = clutter_actor_meta_get_actor (CLUTTER_ACTOR_META (self));
emit_pan_stopped (self, actor);
}
static void
on_deceleration_new_frame (ClutterTimeline *timeline,
gint elapsed_time,
ClutterPanAction *self)
{
ClutterPanActionPrivate *priv = self->priv;
ClutterActor *actor;
gdouble progress;
gfloat interpolated_x, interpolated_y;
progress = clutter_timeline_get_progress (timeline);
interpolated_x = priv->target_x * progress;
interpolated_y = priv->target_y * progress;
priv->dx = interpolated_x - priv->interpolated_x;
priv->dy = interpolated_y - priv->interpolated_y;
priv->interpolated_x = interpolated_x;
priv->interpolated_y = interpolated_y;
actor = clutter_actor_meta_get_actor (CLUTTER_ACTOR_META (self));
emit_pan (self, actor, TRUE);
}
static gboolean
gesture_prepare (ClutterGestureAction *gesture,
ClutterActor *actor)
{
ClutterPanAction *self = CLUTTER_PAN_ACTION (gesture);
ClutterPanActionPrivate *priv = self->priv;
if (priv->state == PAN_STATE_INTERPOLATING && priv->deceleration_timeline)
clutter_timeline_stop (priv->deceleration_timeline);
return TRUE;
}
static gboolean
gesture_begin (ClutterGestureAction *gesture,
ClutterActor *actor)
{
ClutterPanAction *self = CLUTTER_PAN_ACTION (gesture);
ClutterPanActionPrivate *priv = self->priv;
priv->state = PAN_STATE_PANNING;
priv->interpolated_x = priv->interpolated_y = 0.0f;
priv->dx = priv->dy = 0.0f;
return TRUE;
}
static gboolean
gesture_progress (ClutterGestureAction *gesture,
ClutterActor *actor)
{
ClutterPanAction *self = CLUTTER_PAN_ACTION (gesture);
emit_pan (self, actor, FALSE);
return TRUE;
}
static void
gesture_cancel (ClutterGestureAction *gesture,
ClutterActor *actor)
{
ClutterPanAction *self = CLUTTER_PAN_ACTION (gesture);
ClutterPanActionPrivate *priv = self->priv;
priv->state = PAN_STATE_INACTIVE;
}
static void
gesture_end (ClutterGestureAction *gesture,
ClutterActor *actor)
{
ClutterPanAction *self = CLUTTER_PAN_ACTION (gesture);
ClutterPanActionPrivate *priv = self->priv;
gfloat velocity, velocity_x, velocity_y;
gfloat delta_x, delta_y;
gfloat tau;
gint duration;
clutter_gesture_action_get_release_coords (CLUTTER_GESTURE_ACTION (self), 0, &priv->release_x, &priv->release_y);
if (!priv->should_interpolate)
{
priv->state = PAN_STATE_INACTIVE;
return;
}
priv->state = PAN_STATE_INTERPOLATING;
clutter_gesture_action_get_motion_delta (gesture, 0, &delta_x, &delta_y);
velocity = clutter_gesture_action_get_velocity (gesture, 0, &velocity_x, &velocity_y);
/* Exponential timing constant v(t) = v(0) * exp(-t/tau)
* tau = 1000ms / (frame_per_second * - ln(decay_per_frame))
* with frame_per_second = 60 and decay_per_frame = 0.95, tau ~= 325ms
* see http://ariya.ofilabs.com/2011/10/flick-list-with-its-momentum-scrolling-and-deceleration.html */
tau = 1000.0f / (reference_fps * - logf (priv->deceleration_rate));
/* See where the decreasing velocity reaches $min_velocity px/ms
* v(t) = v(0) * exp(-t/tau) = min_velocity
* t = - tau * ln( min_velocity / |v(0)|) */
duration = - tau * logf (min_velocity / (ABS (velocity) * priv->acceleration_factor));
/* Target point: x(t) = v(0) * tau * [1 - exp(-t/tau)] */
priv->target_x = velocity_x * priv->acceleration_factor * tau * (1 - exp ((float)-duration / tau));
priv->target_y = velocity_y * priv->acceleration_factor * tau * (1 - exp ((float)-duration / tau));
if (ABS (velocity) * priv->acceleration_factor > min_velocity && duration > FLOAT_EPSILON)
{
priv->interpolated_x = priv->interpolated_y = 0.0f;
priv->deceleration_timeline = clutter_timeline_new (duration);
clutter_timeline_set_progress_mode (priv->deceleration_timeline, CLUTTER_EASE_OUT_EXPO);
g_signal_connect (priv->deceleration_timeline, "new_frame",
G_CALLBACK (on_deceleration_new_frame), self);
g_signal_connect (priv->deceleration_timeline, "stopped",
G_CALLBACK (on_deceleration_stopped), self);
clutter_timeline_start (priv->deceleration_timeline);
}
else
{
emit_pan_stopped (self, actor);
}
}
static gboolean
clutter_pan_action_real_pan (ClutterPanAction *self,
ClutterActor *actor,
gboolean is_interpolated)
{
ClutterPanActionPrivate *priv = self->priv;
gfloat dx, dy;
ClutterMatrix transform;
clutter_pan_action_get_motion_delta (self, 0, &dx, &dy);
switch (priv->pan_axis)
{
case CLUTTER_PAN_AXIS_NONE:
break;
case CLUTTER_PAN_X_AXIS:
dy = 0.0f;
break;
case CLUTTER_PAN_Y_AXIS:
dx = 0.0f;
break;
}
clutter_actor_get_child_transform (actor, &transform);
cogl_matrix_translate (&transform, dx, dy, 0.0f);
clutter_actor_set_child_transform (actor, &transform);
return TRUE;
}
static void
clutter_pan_action_set_property (GObject *gobject,
guint prop_id,
const GValue *value,
GParamSpec *pspec)
{
ClutterPanAction *self = CLUTTER_PAN_ACTION (gobject);
switch (prop_id)
{
case PROP_PAN_AXIS:
clutter_pan_action_set_pan_axis (self, g_value_get_enum (value));
break;
case PROP_INTERPOLATE :
clutter_pan_action_set_interpolate (self, g_value_get_boolean (value));
break;
case PROP_DECELERATION :
clutter_pan_action_set_deceleration (self, g_value_get_double (value));
break;
case PROP_ACCELERATION_FACTOR :
clutter_pan_action_set_acceleration_factor (self, g_value_get_double (value));
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (gobject, prop_id, pspec);
}
}
static void
clutter_pan_action_get_property (GObject *gobject,
guint prop_id,
GValue *value,
GParamSpec *pspec)
{
ClutterPanAction *self = CLUTTER_PAN_ACTION (gobject);
ClutterPanActionPrivate *priv = self->priv;
switch (prop_id)
{
case PROP_PAN_AXIS:
g_value_set_enum (value, priv->pan_axis);
break;
case PROP_INTERPOLATE :
g_value_set_boolean (value, priv->should_interpolate);
break;
case PROP_DECELERATION :
g_value_set_double (value, priv->deceleration_rate);
break;
case PROP_ACCELERATION_FACTOR :
g_value_set_double (value, priv->acceleration_factor);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (gobject, prop_id, pspec);
}
}
static void
clutter_pan_action_dispose (GObject *gobject)
{
ClutterPanActionPrivate *priv = CLUTTER_PAN_ACTION (gobject)->priv;
g_clear_object (&priv->deceleration_timeline);
G_OBJECT_CLASS (clutter_pan_action_parent_class)->dispose (gobject);
}
static void
clutter_pan_action_set_actor (ClutterActorMeta *meta,
ClutterActor *actor)
{
ClutterPanAction *self = CLUTTER_PAN_ACTION (meta);
ClutterPanActionPrivate *priv = self->priv;
ClutterActor *old_actor;
old_actor = clutter_actor_meta_get_actor (CLUTTER_ACTOR_META (self));
if (old_actor != actor)
{
/* make sure we reset the state */
if (priv->state == PAN_STATE_INTERPOLATING)
g_clear_object (&priv->deceleration_timeline);
}
CLUTTER_ACTOR_META_CLASS (clutter_pan_action_parent_class)->set_actor (meta, actor);
}
static void
clutter_pan_action_class_init (ClutterPanActionClass *klass)
{
GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
ClutterActorMetaClass *meta_class = CLUTTER_ACTOR_META_CLASS (klass);
ClutterGestureActionClass *gesture_class =
CLUTTER_GESTURE_ACTION_CLASS (klass);
klass->pan = clutter_pan_action_real_pan;
gesture_class->gesture_prepare = gesture_prepare;
gesture_class->gesture_begin = gesture_begin;
gesture_class->gesture_progress = gesture_progress;
gesture_class->gesture_cancel = gesture_cancel;
gesture_class->gesture_end = gesture_end;
meta_class->set_actor = clutter_pan_action_set_actor;
/**
* ClutterPanAction:pan-axis:
*
* Constraints the panning action to the specified axis
*
* Since: 1.12
*/
pan_props[PROP_PAN_AXIS] =
g_param_spec_enum ("pan-axis",
P_("Pan Axis"),
P_("Constraints the panning to an axis"),
CLUTTER_TYPE_PAN_AXIS,
CLUTTER_PAN_AXIS_NONE,
CLUTTER_PARAM_READWRITE);
/**
* ClutterPanAction:interpolate:
*
* Whether interpolated events emission is enabled.
*
* Since: 1.12
*/
pan_props[PROP_INTERPOLATE] =
g_param_spec_boolean ("interpolate",
P_("Interpolate"),
P_("Whether interpolated events emission is enabled."),
FALSE,
CLUTTER_PARAM_READWRITE);
/**
* ClutterPanAction:deceleration:
*
* The rate at which the interpolated panning will decelerate in
*
* #ClutterPanAction will emit interpolated ::pan events with decreasing
* scroll deltas, using the rate specified by this property.
*
* Since: 1.12
*/
pan_props[PROP_DECELERATION] =
g_param_spec_double ("deceleration",
P_("Deceleration"),
P_("Rate at which the interpolated panning will decelerate in"),
FLOAT_EPSILON, 1.0, default_deceleration_rate,
CLUTTER_PARAM_READWRITE);
/**
* ClutterPanAction:acceleration-factor:
*
* The initial acceleration factor
*
* The kinetic momentum measured at the time of releasing the pointer will
* be multiplied by the factor specified by this property before being used
* to generate interpolated ::pan events.
*
* Since: 1.12
*/
pan_props[PROP_ACCELERATION_FACTOR] =
g_param_spec_double ("acceleration-factor",
P_("Initial acceleration factor"),
P_("Factor applied to the momentum when starting the interpolated phase"),
1.0, G_MAXDOUBLE, default_acceleration_factor,
CLUTTER_PARAM_READWRITE);
gobject_class->set_property = clutter_pan_action_set_property;
gobject_class->get_property = clutter_pan_action_get_property;
gobject_class->dispose = clutter_pan_action_dispose;
g_object_class_install_properties (gobject_class,
PROP_LAST,
pan_props);
/**
* ClutterPanAction::pan:
* @action: the #ClutterPanAction that emitted the signal
* @actor: the #ClutterActor attached to the @action
* @is_interpolated: if the event is the result of interpolating
* the motion velocity at the end of the drag
*
* The ::pan signal is emitted to keep track of the motion during
* a pan gesture. @is_interpolated is set to %TRUE during the
* interpolation phase of the pan, after the drag has ended and
* the :interpolate property was set to %TRUE.
*
* Return value: %TRUE if the pan should continue, and %FALSE if
* the pan should be cancelled.
*
* Since: 1.12
*/
pan_signals[PAN] =
g_signal_new (I_("pan"),
G_TYPE_FROM_CLASS (klass),
G_SIGNAL_RUN_LAST,
G_STRUCT_OFFSET (ClutterPanActionClass, pan),
_clutter_boolean_continue_accumulator, NULL,
_clutter_marshal_BOOLEAN__OBJECT_BOOLEAN,
G_TYPE_BOOLEAN, 2,
CLUTTER_TYPE_ACTOR,
G_TYPE_BOOLEAN);
/**
* ClutterPanAction::pan-stopped:
* @action: the #ClutterPanAction that emitted the signal
* @actor: the #ClutterActor attached to the @action
*
* The ::pan-stopped signal is emitted at the end of the interpolation
* phase of the pan action, only when :interpolate is set to %TRUE.
*
* Since: 1.12
*/
pan_signals[PAN_STOPPED] =
g_signal_new (I_("pan-stopped"),
G_TYPE_FROM_CLASS (klass),
G_SIGNAL_RUN_LAST,
G_STRUCT_OFFSET (ClutterPanActionClass, pan_stopped),
NULL, NULL,
_clutter_marshal_VOID__OBJECT,
G_TYPE_NONE, 1,
CLUTTER_TYPE_ACTOR);
}
static void
clutter_pan_action_init (ClutterPanAction *self)
{
ClutterGestureAction *gesture;
self->priv = clutter_pan_action_get_instance_private (self);
self->priv->deceleration_rate = default_deceleration_rate;
self->priv->acceleration_factor = default_acceleration_factor;
self->priv->state = PAN_STATE_INACTIVE;
gesture = CLUTTER_GESTURE_ACTION (self);
clutter_gesture_action_set_threshold_trigger_edge (gesture, CLUTTER_GESTURE_TRIGGER_EDGE_AFTER);
}
/**
* clutter_pan_action_new:
*
* Creates a new #ClutterPanAction instance
*
* Return value: the newly created #ClutterPanAction
*
* Since: 1.12
*/
ClutterAction *
clutter_pan_action_new (void)
{
return g_object_new (CLUTTER_TYPE_PAN_ACTION, NULL);
}
/**
* clutter_pan_action_set_pan_axis:
* @self: a #ClutterPanAction
* @axis: the axis to constraint the panning to
*
* Restricts the panning action to a specific axis
*
* Since: 1.12
*/
void
clutter_pan_action_set_pan_axis (ClutterPanAction *self,
ClutterPanAxis axis)
{
ClutterPanActionPrivate *priv;
g_return_if_fail (CLUTTER_IS_PAN_ACTION (self));
g_return_if_fail (axis >= CLUTTER_PAN_AXIS_NONE &&
axis <= CLUTTER_PAN_Y_AXIS);
priv = self->priv;
if (priv->pan_axis == axis)
return;
priv->pan_axis = axis;
g_object_notify_by_pspec (G_OBJECT (self), pan_props[PROP_PAN_AXIS]);
}
/**
* clutter_pan_action_get_pan_axis:
* @self: a #ClutterPanAction
*
* Retrieves the axis constraint set by clutter_pan_action_set_pan_axis()
*
* Return value: the axis constraint
*
* Since: 1.12
*/
ClutterPanAxis
clutter_pan_action_get_pan_axis (ClutterPanAction *self)
{
g_return_val_if_fail (CLUTTER_IS_PAN_ACTION (self),
CLUTTER_PAN_AXIS_NONE);
return self->priv->pan_axis;
}
/**
* clutter_pan_action_set_interpolate:
* @self: a #ClutterPanAction
* @should_interpolate: whether to enable interpolated pan events
*
* Sets whether the action should emit interpolated ::pan events
* after the drag has ended, to emulate the gesture kinetic inertia.
*
* Since: 1.12
*/
void
clutter_pan_action_set_interpolate (ClutterPanAction *self,
gboolean should_interpolate)
{
ClutterPanActionPrivate *priv;
g_return_if_fail (CLUTTER_IS_PAN_ACTION (self));
priv = self->priv;
should_interpolate = !!should_interpolate;
if (priv->should_interpolate == should_interpolate)
return;
priv->should_interpolate = should_interpolate;
g_object_notify_by_pspec (G_OBJECT (self), pan_props[PROP_INTERPOLATE]);
}
/**
* clutter_pan_action_get_interpolate:
* @self: a #ClutterPanAction
*
* Checks if the action should emit ::pan events even after releasing
* the pointer during a panning gesture, to emulate some kind of
* kinetic inertia.
*
* Return value: %TRUE if interpolated events emission is active.
*
* Since: 1.12
*/
gboolean
clutter_pan_action_get_interpolate (ClutterPanAction *self)
{
g_return_val_if_fail (CLUTTER_IS_PAN_ACTION (self),
FALSE);
return self->priv->should_interpolate;
}
/**
* clutter_pan_action_set_deceleration:
* @self: A #ClutterPanAction
* @rate: The deceleration rate
*
* Sets the deceleration rate of the interpolated ::pan events generated
* after a pan gesture. This is approximately the value that the momentum
* at the time of releasing the pointer is divided by every 60th of a second.
*
* Since: 1.12
*/
void
clutter_pan_action_set_deceleration (ClutterPanAction *self,
gdouble rate)
{
g_return_if_fail (CLUTTER_IS_PAN_ACTION (self));
g_return_if_fail (rate <= 1.0);
g_return_if_fail (rate > 0.0);
self->priv->deceleration_rate = rate;
g_object_notify_by_pspec (G_OBJECT (self), pan_props[PROP_DECELERATION]);
}
/**
* clutter_pan_action_get_deceleration:
* @self: A #ClutterPanAction
*
* Retrieves the deceleration rate of interpolated ::pan events.
*
* Return value: The deceleration rate of the interpolated events.
*
* Since: 1.12
*/
gdouble
clutter_pan_action_get_deceleration (ClutterPanAction *self)
{
g_return_val_if_fail (CLUTTER_IS_PAN_ACTION (self), 0.95);
return self->priv->deceleration_rate;
}
/**
* clutter_pan_action_set_acceleration_factor:
* @self: A #ClutterPanAction
* @factor: The acceleration factor
*
* Factor applied to the momentum velocity at the time of releasing the
* pointer when generating interpolated ::pan events.
*
* Since: 1.12
*/
void
clutter_pan_action_set_acceleration_factor (ClutterPanAction *self,
gdouble factor)
{
g_return_if_fail (CLUTTER_IS_PAN_ACTION (self));
g_return_if_fail (factor >= 0.0);
self->priv->acceleration_factor = factor;
g_object_notify_by_pspec (G_OBJECT (self), pan_props[PROP_ACCELERATION_FACTOR]);
}
/**
* clutter_pan_action_get_acceleration_factor:
* @self: A #ClutterPanAction
*
* Retrieves the initial acceleration factor for interpolated ::pan events.
*
* Return value: The initial acceleration factor for interpolated events.
*
* Since: 1.12
*/
gdouble
clutter_pan_action_get_acceleration_factor (ClutterPanAction *self)
{
g_return_val_if_fail (CLUTTER_IS_PAN_ACTION (self), 1.0);
return self->priv->acceleration_factor;
}
/**
* clutter_pan_action_get_interpolated_coords:
* @self: A #ClutterPanAction
* @interpolated_x: (out) (allow-none): return location for the latest
* interpolated event's X coordinate
* @interpolated_y: (out) (allow-none): return location for the latest
* interpolated event's Y coordinate
*
* Retrieves the coordinates, in stage space, of the latest interpolated
* event, analogous to clutter_gesture_action_get_motion_coords().
*
* Since: 1.12
*/
void
clutter_pan_action_get_interpolated_coords (ClutterPanAction *self,
gfloat *interpolated_x,
gfloat *interpolated_y)
{
ClutterPanActionPrivate *priv;
g_return_if_fail (CLUTTER_IS_PAN_ACTION (self));
priv = self->priv;
if (interpolated_x)
*interpolated_x = priv->release_x + priv->interpolated_x;
if (interpolated_y)
*interpolated_y = priv->release_y + priv->interpolated_y;
}
/**
* clutter_pan_action_get_interpolated_delta:
* @self: A #ClutterPanAction
* @delta_x: (out) (allow-none): return location for the X delta since
* the latest interpolated event
* @delta_y: (out) (allow-none): return location for the Y delta since
* the latest interpolated event
*
* Retrieves the delta, in stage space, since the latest interpolated
* event, analogous to clutter_gesture_action_get_motion_delta().
*
* Return value: the distance since the latest interpolated event
*
* Since: 1.12
*/
gfloat
clutter_pan_action_get_interpolated_delta (ClutterPanAction *self,
gfloat *delta_x,
gfloat *delta_y)
{
ClutterPanActionPrivate *priv;
g_return_val_if_fail (CLUTTER_IS_PAN_ACTION (self), 0.0f);
priv = self->priv;
if (delta_x)
*delta_x = priv->dx;
if (delta_y)
*delta_y = priv->dy;
return sqrt ((priv->dx * priv->dx) + (priv->dy * priv->dy));
}
/**
* clutter_pan_action_get_motion_delta:
* @self: A #ClutterPanAction
* @point: the touch point index, with 0 being the first touch
* point received by the action
* @delta_x: (out) (allow-none): return location for the X delta
* @delta_y: (out) (allow-none): return location for the Y delta
*
* Retrieves the delta, in stage space, dependent on the current state
* of the #ClutterPanAction. If it is inactive, both fields will be
* set to 0. If it is panning by user action, the values will be equivalent
* to those returned by clutter_gesture_action_get_motion_delta().
* If it is interpolating with some form of kinetic scrolling, the values
* will be equivalent to those returned by
* clutter_pan_action_get_interpolated_delta(). This is a convenience
* method designed to be used in replacement "pan" signal handlers.
*
* Since: 1.14
*/
gfloat
clutter_pan_action_get_motion_delta (ClutterPanAction *self,
guint point,
gfloat *delta_x,
gfloat *delta_y)
{
ClutterPanActionPrivate *priv;
g_return_val_if_fail (CLUTTER_IS_PAN_ACTION (self), 0.0f);
priv = self->priv;
switch (priv->state)
{
case PAN_STATE_INACTIVE:
if (delta_x)
*delta_x = 0;
if (delta_y)
*delta_y = 0;
return 0;
case PAN_STATE_PANNING:
return clutter_gesture_action_get_motion_delta (CLUTTER_GESTURE_ACTION (self),
point, delta_x, delta_y);
case PAN_STATE_INTERPOLATING:
return clutter_pan_action_get_interpolated_delta (self, delta_x, delta_y);
default:
g_assert_not_reached ();
}
}
/**
* clutter_pan_action_get_motion_coords:
* @self: A #ClutterPanAction
* @point: the touch point index, with 0 being the first touch
* point received by the action
* @motion_x: (out) (allow-none): return location for the X coordinate
* @motion_y: (out) (allow-none): return location for the Y coordinate
*
* Retrieves the coordinates, in stage space, dependent on the current state
* of the #ClutterPanAction. If it is inactive, both fields will be
* set to 0. If it is panning by user action, the values will be equivalent
* to those returned by clutter_gesture_action_get_motion_coords().
* If it is interpolating with some form of kinetic scrolling, the values
* will be equivalent to those returned by
* clutter_pan_action_get_interpolated_coords(). This is a convenience
* method designed to be used in replacement "pan" signal handlers.
*
* Since: 1.14
*/
void
clutter_pan_action_get_motion_coords (ClutterPanAction *self,
guint point,
gfloat *motion_x,
gfloat *motion_y)
{
ClutterPanActionPrivate *priv;
g_return_if_fail (CLUTTER_IS_PAN_ACTION (self));
priv = self->priv;
switch (priv->state)
{
case PAN_STATE_INACTIVE:
if (motion_x)
*motion_x = 0;
if (motion_y)
*motion_y = 0;
break;
case PAN_STATE_PANNING:
clutter_gesture_action_get_motion_coords (CLUTTER_GESTURE_ACTION (self),
point, motion_x, motion_y);
break;
case PAN_STATE_INTERPOLATING:
clutter_pan_action_get_interpolated_coords (self, motion_x, motion_y);
break;
default:
g_assert_not_reached ();
}
}