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gesture-action: add _get_motion_delta()/_get_velocity()

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Add some accessors to simplify common tasks for GestureAction users:

• clutter_gesture_action_get_motion_delta() to get the delta
  on the X and Y axis in stage coordinates since the last motion
  event, and the scalar distance travelled;

• clutter_gesture_action_get_velocity() to get an estimate of the
  speed of the last motion event along the X and Y axis and as a
  scalar value in pixels per millisecond.

https://bugzilla.gnome.org/show_bug.cgi?id=681648
This commit is contained in:
Emanuele Aina 2012-08-25 16:04:24 +02:00 committed by Gustavo Noronha Silva
parent e8e91b62c8
commit 436ebb2716
4 changed files with 131 additions and 4 deletions
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121
clutter/clutter-gesture-action.c
View File

@ -62,7 +62,10 @@
#include "clutter-marshal.h"
#include "clutter-private.h"
#include <math.h>
#define MAX_GESTURE_POINTS (10)
#define FLOAT_EPSILON (1e-15)
typedef struct
{
@ -70,7 +73,10 @@ typedef struct
ClutterEventSequence *sequence;
gfloat press_x, press_y;
gint64 last_motion_time;
gfloat last_motion_x, last_motion_y;
gint64 last_delta_time;
gfloat last_delta_x, last_delta_y;
gfloat release_x, release_y;
} GesturePoint;
@ -118,6 +124,10 @@ gesture_register_point (ClutterGestureAction *action, ClutterEvent *event)
clutter_event_get_coords (event, &point->press_x, &point->press_y);
point->last_motion_x = point->press_x;
point->last_motion_y = point->press_y;
point->last_motion_time = clutter_event_get_time (event);
point->last_delta_x = point->last_delta_y = 0;
point->last_delta_time = 0;
if (clutter_event_type (event) != CLUTTER_BUTTON_PRESS)
point->sequence = clutter_event_get_event_sequence (event);
@ -192,6 +202,8 @@ stage_captured_event_cb (ClutterActor *stage,
gint position;
gboolean return_value;
GesturePoint *point;
gfloat motion_x, motion_y;
gint64 time;
if ((point = gesture_find_point (action, event, &position)) == NULL)
return CLUTTER_EVENT_PROPAGATE;
@ -218,8 +230,8 @@ stage_captured_event_cb (ClutterActor *stage,
case CLUTTER_TOUCH_UPDATE:
clutter_event_get_coords (event,
&point->last_motion_x,
&point->last_motion_y);
&motion_x,
&motion_y);
if (priv->points->len < priv->requested_nb_points)
return CLUTTER_EVENT_PROPAGATE;
@ -233,8 +245,8 @@ stage_captured_event_cb (ClutterActor *stage,
"dnd-drag-threshold", &drag_threshold,
NULL);
if ((ABS (point->press_y - point->last_motion_y) >= drag_threshold) ||
(ABS (point->press_x - point->last_motion_x) >= drag_threshold))
if ((ABS (point->press_y - motion_y) >= drag_threshold) ||
(ABS (point->press_x - motion_x) >= drag_threshold))
{
priv->in_gesture = TRUE;
@ -250,6 +262,15 @@ stage_captured_event_cb (ClutterActor *stage,
return CLUTTER_EVENT_PROPAGATE;
}
point->last_delta_x = motion_x - point->last_motion_x;
point->last_delta_y = motion_y - point->last_motion_y;
point->last_motion_x = motion_x;
point->last_motion_y = motion_y;
time = clutter_event_get_time (event);
point->last_delta_time = time - point->last_motion_time;
point->last_motion_time = time;
g_signal_emit (action, gesture_signals[GESTURE_PROGRESS], 0, actor,
&return_value);
if (!return_value)
@ -267,6 +288,12 @@ stage_captured_event_cb (ClutterActor *stage,
if (priv->in_gesture &&
((priv->points->len - 1) < priv->requested_nb_points))
{
/* Treat the release event as the continuation of the last motion,
* in case the user keeps the pointer still for a while before
* releasing it. */
time = clutter_event_get_time (event);
point->last_delta_time += time - point->last_motion_time;
priv->in_gesture = FALSE;
g_signal_emit (action, gesture_signals[GESTURE_END], 0, actor);
}
@ -572,6 +599,49 @@ clutter_gesture_action_get_motion_coords (ClutterGestureAction *action,
device).last_motion_y;
}
/**
* clutter_gesture_action_get_motion_delta:
* @action: a #ClutterGestureAction
* @device: currently unused, set to 0
* @delta_x: (out) (allow-none): return location for the X axis
* component of the incremental motion delta
* @delta_y: (out) (allow-none): return location for the Y axis
* component of the incremental motion delta
*
* Retrieves the incremental delta since the last motion event
* during the dragging.
*
* Return value: the distance since last motion event
*
* Since: 1.12
*/
gfloat
clutter_gesture_action_get_motion_delta (ClutterGestureAction *action,
guint device,
gfloat *delta_x,
gfloat *delta_y)
{
gfloat d_x, d_y;
g_return_val_if_fail (CLUTTER_IS_GESTURE_ACTION (action), 0);
g_return_val_if_fail (action->priv->points->len > device, 0);
d_x = g_array_index (action->priv->points,
GesturePoint,
device).last_delta_x;
d_y = g_array_index (action->priv->points,
GesturePoint,
device).last_delta_y;
if (delta_x)
*delta_x = d_x;
if (delta_y)
*delta_y = d_y;
return sqrt ((d_x * d_x) + (d_y * d_y));
}
/**
* clutter_gesture_action_get_release_coords:
* @action: a #ClutterGestureAction
@ -606,6 +676,49 @@ clutter_gesture_action_get_release_coords (ClutterGestureAction *action,
device).release_y;
}
/**
* clutter_gesture_action_get_velocity:
* @action: a #ClutterGestureAction
* @device: currently unused, set to 0
* @velocity_x: (out) (allow-none): return location for the latest motion
* event's X velocity
* @velocity_y: (out) (allow-none): return location for the latest motion
* event's Y velocity
*
* Retrieves the velocity, in stage pixels per microseconds, of the
* latest motion event during the dragging
*
* Since: 1.12
*/
gfloat
clutter_gesture_action_get_velocity (ClutterGestureAction *action,
guint device,
gfloat *velocity_x,
gfloat *velocity_y)
{
gfloat d_x, d_y, distance, velocity;
gint64 d_t;
g_return_val_if_fail (CLUTTER_IS_GESTURE_ACTION (action), 0);
g_return_val_if_fail (action->priv->points->len > device, 0);
distance = clutter_gesture_action_get_motion_delta (action, device,
&d_x, &d_y);
d_t = g_array_index (action->priv->points,
GesturePoint,
device).last_delta_time;
if (velocity_x)
*velocity_x = d_t > FLOAT_EPSILON ? d_x / d_t : 0;
if (velocity_y)
*velocity_y = d_t > FLOAT_EPSILON ? d_y / d_t : 0;
velocity = d_t > FLOAT_EPSILON ? distance / d_t : 0;
return velocity;
}
/**
* clutter_gesture_action_get_n_touch_points:
* @action: a #ClutterGestureAction

10
clutter/clutter-gesture-action.h
View File

@ -113,10 +113,20 @@ void clutter_gesture_action_get_motion_coords (ClutterGestureA
guint device,
gfloat *motion_x,
gfloat *motion_y);
CLUTTER_AVAILABLE_IN_1_12
gfloat clutter_gesture_action_get_motion_delta (ClutterGestureAction *action,
guint device,
gfloat *delta_x,
gfloat *delta_y);
void clutter_gesture_action_get_release_coords (ClutterGestureAction *action,
guint device,
gfloat *release_x,
gfloat *release_y);
CLUTTER_AVAILABLE_IN_1_12
gfloat clutter_gesture_action_get_velocity (ClutterGestureAction *action,
guint device,
gfloat *velocity_x,
gfloat *velocity_y);
G_END_DECLS

2
clutter/clutter.symbols
View File

@ -734,10 +734,12 @@ clutter_geometry_get_type
clutter_geometry_intersects
clutter_geometry_union
clutter_gesture_action_get_motion_coords
clutter_gesture_action_get_motion_delta
clutter_gesture_action_get_n_touch_points
clutter_gesture_action_get_press_coords
clutter_gesture_action_get_release_coords
clutter_gesture_action_get_type
clutter_gesture_action_get_velocity
clutter_gesture_action_set_n_touch_points
clutter_gesture_action_new
clutter_get_accessibility_enabled

2
doc/reference/clutter/clutter-sections.txt
View File

@ -2941,7 +2941,9 @@ ClutterGestureActionClass
clutter_gesture_action_new
clutter_gesture_action_get_press_coords
clutter_gesture_action_get_motion_coords
clutter_gesture_action_get_motion_delta
clutter_gesture_action_get_release_coords
clutter_gesture_action_get_velocity
clutter_gesture_action_get_n_touch_points
clutter_gesture_action_set_n_touch_points
<SUBSECTION Standard>