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mutter-performance-source/clutter/clutter-drag-action.c
Emmanuele Bassi f97d16cd2d drag-action: Remove the press event button 
Both ::drag-begin and ::drag-end have a "button" argument - even though
we assume internally, and externally, that dragging can only be the
result of a primary button operation.
2010-06-12 17:45:54 +01:00

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/*
* Clutter.
*
* An OpenGL based 'interactive canvas' library.
*
* Copyright (C) 2010 Intel Corporation.
*
* 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:
* Emmanuele Bassi <ebassi@linux.intel.com>
*/
/**
* SECTION:clutter-drag-action
* @Title: ClutterDragAction
* @Short_Description: Action enabling dragging on actors
*
* #ClutterDragAction is a sub-class of #ClutterAction that implements
* all the necessary logic for dragging actors.
*
* The simplest usage of #ClutterDragAction consists in adding it to
* a #ClutterActor and setting it as reactive; for instance, the following
* code:
*
* |[
* clutter_actor_add_action (actor, clutter_drag_action_new ());
* clutter_actor_set_reactive (actor, TRUE);
* ]|
*
* will automatically result in the actor moving to follow the pointer
* whenever the pointer's button is pressed over the actor and moved
* across the stage.
*
* The #ClutterDragAction will signal the begin and the end of a dragging
* through the #ClutterDragAction::drag-begin and #ClutterDragAction::drag-end
* signals, respectively. Each pointer motion during a drag will also result
* in the #ClutterDragAction::drag-motion signal to be emitted.
*
* It is also possible to set another #ClutterActor as the dragged actor
* by calling clutter_drag_action_set_drag_handle() from within a handle
* of the #ClutterDragAction::drag-begin signal. The drag handle must be
* parented and exist between the emission of #ClutterDragAction::drag-begin
* and #ClutterDragAction::drag-end.
*
* #ClutterDragAction is available since Clutter 1.4
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "clutter-drag-action.h"
#include "clutter-debug.h"
#include "clutter-enum-types.h"
#include "clutter-marshal.h"
#include "clutter-private.h"
struct _ClutterDragActionPrivate
{
ClutterActor *stage;
gfloat drag_threshold;
ClutterActor *drag_handle;
ClutterDragAxis drag_axis;
gulong button_press_id;
gulong capture_id;
gfloat press_x;
gfloat press_y;
ClutterModifierType press_state;
gfloat last_motion_x;
gfloat last_motion_y;
gfloat transformed_press_x;
gfloat transformed_press_y;
guint emit_delayed_press : 1;
guint in_drag : 1;
};
enum
{
PROP_0,
PROP_DRAG_THRESHOLD,
PROP_DRAG_HANDLE,
PROP_DRAG_AXIS
};
enum
{
DRAG_BEGIN,
DRAG_MOTION,
DRAG_END,
LAST_SIGNAL
};
static guint drag_signals[LAST_SIGNAL] = { 0, };
/* forward declaration */
static gboolean on_captured_event (ClutterActor *stage,
ClutterEvent *event,
ClutterDragAction *action);
G_DEFINE_TYPE (ClutterDragAction, clutter_drag_action, CLUTTER_TYPE_ACTION);
static void
emit_drag_begin (ClutterDragAction *action,
ClutterActor *actor,
ClutterEvent *event)
{
ClutterDragActionPrivate *priv = action->priv;
g_signal_emit (action, drag_signals[DRAG_BEGIN], 0,
actor,
priv->press_x, priv->press_y,
priv->press_state);
}
static void
emit_drag_motion (ClutterDragAction *action,
ClutterActor *actor,
ClutterEvent *event)
{
ClutterDragActionPrivate *priv = action->priv;
ClutterActor *drag_handle = NULL;
gfloat delta_x, delta_y;
gfloat motion_x, motion_y;
clutter_event_get_coords (event, &priv->last_motion_x, &priv->last_motion_y);
if (priv->drag_handle != NULL && !priv->emit_delayed_press)
drag_handle = priv->drag_handle;
else
drag_handle = actor;
motion_x = motion_y = 0.0f;
clutter_actor_transform_stage_point (drag_handle,
priv->last_motion_x,
priv->last_motion_y,
&motion_x, &motion_y);
delta_x = delta_y = 0.0f;
switch (priv->drag_axis)
{
case CLUTTER_DRAG_AXIS_NONE:
delta_x = motion_x - priv->transformed_press_x;
delta_y = motion_y - priv->transformed_press_y;
break;
case CLUTTER_DRAG_X_AXIS:
delta_x = motion_x - priv->transformed_press_x;
break;
case CLUTTER_DRAG_Y_AXIS:
delta_y = motion_y - priv->transformed_press_y;
break;
default:
g_assert_not_reached ();
return;
}
if (priv->emit_delayed_press)
{
if (ABS (delta_x) >= priv->drag_threshold ||
ABS (delta_y) >= priv->drag_threshold)
{
priv->emit_delayed_press = FALSE;
emit_drag_begin (action, actor, NULL);
}
else
return;
}
g_signal_emit (action, drag_signals[DRAG_MOTION], 0,
actor,
delta_x, delta_y);
}
static void
emit_drag_end (ClutterDragAction *action,
ClutterActor *actor,
ClutterEvent *event)
{
ClutterDragActionPrivate *priv = action->priv;
clutter_event_get_coords (event, &priv->last_motion_x, &priv->last_motion_y);
/* we might not have emitted ::drag-begin yet */
if (!priv->emit_delayed_press)
g_signal_emit (action, drag_signals[DRAG_END], 0,
actor,
priv->last_motion_x, priv->last_motion_y,
clutter_event_get_state (event));
/* disconnect the capture */
if (priv->capture_id != 0)
{
g_signal_handler_disconnect (priv->stage, priv->capture_id);
priv->capture_id = 0;
}
priv->in_drag = FALSE;
}
static gboolean
on_captured_event (ClutterActor *stage,
ClutterEvent *event,
ClutterDragAction *action)
{
ClutterDragActionPrivate *priv = action->priv;
ClutterActor *actor;
actor = clutter_actor_meta_get_actor (CLUTTER_ACTOR_META (action));
if (!priv->in_drag)
return FALSE;
switch (clutter_event_type (event))
{
case CLUTTER_MOTION:
{
ClutterModifierType mods = clutter_event_get_state (event);
/* we might miss a button-release event in case of grabs,
* so we need to check whether the button is still down
* during a motion event
*/
if (mods & CLUTTER_BUTTON1_MASK)
emit_drag_motion (action, actor, event);
else
emit_drag_end (action, actor, event);
}
break;
case CLUTTER_BUTTON_RELEASE:
if (priv->in_drag)
emit_drag_end (action, actor, event);
break;
default:
break;
}
return FALSE;
}
static gboolean
on_button_press (ClutterActor *actor,
ClutterEvent *event,
ClutterDragAction *action)
{
ClutterDragActionPrivate *priv = action->priv;
if (!clutter_actor_meta_get_enabled (CLUTTER_ACTOR_META (action)))
return FALSE;
if (clutter_event_get_button (event) != 1)
return FALSE;
if (priv->stage == NULL)
priv->stage = clutter_actor_get_stage (actor);
clutter_event_get_coords (event, &priv->press_x, &priv->press_y);
priv->press_state = clutter_event_get_state (event);
priv->last_motion_x = priv->press_x;
priv->last_motion_y = priv->press_y;
priv->transformed_press_x = priv->press_x;
priv->transformed_press_y = priv->press_y;
clutter_actor_transform_stage_point (actor, priv->press_x, priv->press_y,
&priv->transformed_press_x,
&priv->transformed_press_y);
if (priv->drag_threshold == 0)
emit_drag_begin (action, actor, event);
else
priv->emit_delayed_press = TRUE;
priv->in_drag = TRUE;
priv->capture_id = g_signal_connect_after (priv->stage, "captured-event",
G_CALLBACK (on_captured_event),
action);
return FALSE;
}
static void
clutter_drag_action_set_actor (ClutterActorMeta *meta,
ClutterActor *actor)
{
ClutterDragActionPrivate *priv = CLUTTER_DRAG_ACTION (meta)->priv;
if (priv->button_press_id != 0)
{
ClutterActor *old_actor;
old_actor = clutter_actor_meta_get_actor (meta);
g_signal_handler_disconnect (old_actor, priv->button_press_id);
if (priv->capture_id != 0)
g_signal_handler_disconnect (old_actor, priv->capture_id);
priv->button_press_id = 0;
priv->capture_id = 0;
priv->stage = NULL;
}
if (actor != NULL)
priv->button_press_id = g_signal_connect (actor, "button-press-event",
G_CALLBACK (on_button_press),
meta);
CLUTTER_ACTOR_META_CLASS (clutter_drag_action_parent_class)->set_actor (meta, actor);
}
static void
clutter_drag_action_real_drag_motion (ClutterDragAction *action,
ClutterActor *actor,
gfloat delta_x,
gfloat delta_y)
{
ClutterActor *drag_handle;
if (action->priv->drag_handle != NULL)
drag_handle = action->priv->drag_handle;
else
drag_handle = actor;
clutter_actor_move_by (drag_handle, delta_x, delta_y);
}
static void
clutter_drag_action_set_property (GObject *gobject,
guint prop_id,
const GValue *value,
GParamSpec *pspec)
{
ClutterDragAction *action = CLUTTER_DRAG_ACTION (gobject);
switch (prop_id)
{
case PROP_DRAG_THRESHOLD:
clutter_drag_action_set_drag_threshold (action, g_value_get_uint (value));
break;
case PROP_DRAG_HANDLE:
clutter_drag_action_set_drag_handle (action, g_value_get_object (value));
break;
case PROP_DRAG_AXIS:
clutter_drag_action_set_drag_axis (action, g_value_get_enum (value));
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (gobject, prop_id, pspec);
}
}
static void
clutter_drag_action_get_property (GObject *gobject,
guint prop_id,
GValue *value,
GParamSpec *pspec)
{
ClutterDragActionPrivate *priv = CLUTTER_DRAG_ACTION (gobject)->priv;
switch (prop_id)
{
case PROP_DRAG_THRESHOLD:
g_value_set_uint (value, priv->drag_threshold);
break;
case PROP_DRAG_HANDLE:
g_value_set_object (value, priv->drag_handle);
break;
case PROP_DRAG_AXIS:
g_value_set_enum (value, priv->drag_axis);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (gobject, prop_id, pspec);
}
}
static void
clutter_drag_action_dispose (GObject *gobject)
{
ClutterDragActionPrivate *priv = CLUTTER_DRAG_ACTION (gobject)->priv;
if (priv->capture_id != 0)
{
if (priv->stage != NULL)
g_signal_handler_disconnect (priv->stage, priv->capture_id);
priv->capture_id = 0;
priv->stage = NULL;
}
if (priv->button_press_id != 0)
{
ClutterActor *actor;
actor = clutter_actor_meta_get_actor (CLUTTER_ACTOR_META (gobject));
g_signal_handler_disconnect (actor, priv->button_press_id);
priv->button_press_id = 0;
}
G_OBJECT_CLASS (clutter_drag_action_parent_class)->dispose (gobject);
}
static void
clutter_drag_action_class_init (ClutterDragActionClass *klass)
{
ClutterActorMetaClass *meta_class = CLUTTER_ACTOR_META_CLASS (klass);
GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
GParamSpec *pspec;
g_type_class_add_private (klass, sizeof (ClutterDragActionPrivate));
gobject_class->set_property = clutter_drag_action_set_property;
gobject_class->get_property = clutter_drag_action_get_property;
gobject_class->dispose = clutter_drag_action_dispose;
meta_class->set_actor = clutter_drag_action_set_actor;
klass->drag_motion = clutter_drag_action_real_drag_motion;
/**
* ClutterDragAction:drag-threshold:
*
* The threshold, in pixels, that begins a drag action
*
* When set to a non-zero value, #ClutterDragAction will only emit
* #ClutterDragAction::drag-begin if the pointer has moved at least
* of the given amount of pixels since the button press event
*
* Since: 1.4
*/
pspec = g_param_spec_uint ("drag-threshold",
"Drag Threshold",
"The amount of pixels required to start "
"dragging",
0, G_MAXUINT,
0,
CLUTTER_PARAM_READWRITE);
g_object_class_install_property (gobject_class, PROP_DRAG_THRESHOLD, pspec);
/**
* ClutterDragAction:drag-handle:
*
* The #ClutterActor that is effectively being dragged
*
* A #ClutterDragActor will, be default, use the #ClutterActor that
* has been attached to the action; it is possible to create a
* separate #ClutterActor and use it instead.
*
* Setting this property has no effect on the #ClutterActor argument
* passed to the #ClutterDragAction signals
*
* Since: 1.4
*/
pspec = g_param_spec_object ("drag-handle",
"Drag Handle",
"The actor that is being dragged",
CLUTTER_TYPE_ACTOR,
CLUTTER_PARAM_READWRITE);
g_object_class_install_property (gobject_class, PROP_DRAG_HANDLE, pspec);
/**
* ClutterDragAction:drag-axis:
*
* Constraints the dragging action to the specified axis
*
* Since: 1.4
*/
pspec = g_param_spec_enum ("drag-axis",
"Drag Axis",
"Constraints the dragging to an axis",
CLUTTER_TYPE_DRAG_AXIS,
CLUTTER_DRAG_AXIS_NONE,
CLUTTER_PARAM_READWRITE);
g_object_class_install_property (gobject_class, PROP_DRAG_AXIS, pspec);
/**
* ClutterDragAction::drag-begin:
* @action: the #ClutterDragAction that emitted the signal
* @actor: the #ClutterActor attached to the action
* @event_x: the X coordinate (in stage space) of the press event
* @event_y: the Y coordinate (in stage space) of the press event
* @modifiers: the modifiers of the press event
*
* The ::drag-begin signal is emitted when the #ClutterDragAction
* starts the dragging
*
* The emission of this signal can be delayed by using the
* #ClutterDragAction:drag-threshold property
*
* Since: 1.4
*/
drag_signals[DRAG_BEGIN] =
g_signal_new (I_("drag-begin"),
CLUTTER_TYPE_DRAG_ACTION,
G_SIGNAL_RUN_LAST,
G_STRUCT_OFFSET (ClutterDragActionClass, drag_begin),
NULL, NULL,
_clutter_marshal_VOID__OBJECT_FLOAT_FLOAT_FLAGS,
G_TYPE_NONE, 4,
CLUTTER_TYPE_ACTOR,
G_TYPE_FLOAT,
G_TYPE_FLOAT,
CLUTTER_TYPE_MODIFIER_TYPE);
/**
* ClutterDragAction::drag-motion
* @action: the #ClutterDragAction that emitted the signal
* @actor: the #ClutterActor attached to the action
* @delta_x: the X component of the distance between the press event
* that began the dragging and the current position of the pointer,
* as of the latest motion event
* @delta_y: the Y component of the distance between the press event
* that began the dragging and the current position of the pointer,
* as of the latest motion event
*
* The ::drag-motion signal is emitted for each motion event after
* the #ClutterDragAction::drag-begin signal has been emitted.
*
* The components of the distance between the press event and the
* latest motion event are computed in the actor's coordinate space,
* to take into account eventual transformations. If you want the
* stage coordinates of the latest motion event you can use
* clutter_drag_action_get_motion_coords().
*
* The default handler of the signal will call clutter_actor_move_by()
* either on @actor or, if set, of #ClutterDragAction:drag-handle using
* the @delta_x and @delta_y components of the dragging motion. If you
* want to override the default behaviour, you can connect to this
* signal and call g_signal_stop_emission_by_name() from within your
* callback.
*
* Since: 1.4
*/
drag_signals[DRAG_MOTION] =
g_signal_new (I_("drag-motion"),
CLUTTER_TYPE_DRAG_ACTION,
G_SIGNAL_RUN_LAST,
G_STRUCT_OFFSET (ClutterDragActionClass, drag_motion),
NULL, NULL,
_clutter_marshal_VOID__OBJECT_FLOAT_FLOAT,
G_TYPE_NONE, 3,
CLUTTER_TYPE_ACTOR,
G_TYPE_FLOAT,
G_TYPE_FLOAT);
/**
* ClutterDragAction::drag-end:
* @action: the #ClutterDragAction that emitted the signal
* @actor: the #ClutterActor attached to the action
* @event_x: the X coordinate (in stage space) of the release event
* @event_y: the Y coordinate (in stage space) of the release event
* @modifiers: the modifiers of the release event
*
* The ::drag-end signal is emitted at the end of the dragging,
* when the pointer button's is released
*
* This signal is emitted if and only if the #ClutterDragAction::drag-begin
* signal has been emitted first
*
* Since: 1.4
*/
drag_signals[DRAG_END] =
g_signal_new (I_("drag-end"),
CLUTTER_TYPE_DRAG_ACTION,
G_SIGNAL_RUN_LAST,
G_STRUCT_OFFSET (ClutterDragActionClass, drag_end),
NULL, NULL,
_clutter_marshal_VOID__OBJECT_FLOAT_FLOAT_FLAGS,
G_TYPE_NONE, 4,
CLUTTER_TYPE_ACTOR,
G_TYPE_FLOAT,
G_TYPE_FLOAT,
CLUTTER_TYPE_MODIFIER_TYPE);
}
static void
clutter_drag_action_init (ClutterDragAction *self)
{
self->priv = G_TYPE_INSTANCE_GET_PRIVATE (self, CLUTTER_TYPE_DRAG_ACTION,
ClutterDragActionPrivate);
}
/**
* clutter_drag_action_new:
*
* Creates a new #ClutterDragAction instance
*
* Return value: the newly created #ClutterDragAction
*
* Since: 1.4
*/
ClutterAction *
clutter_drag_action_new (void)
{
return g_object_new (CLUTTER_TYPE_DRAG_ACTION, NULL);
}
/**
* clutter_drag_action_set_drag_threshold:
* @action: a #ClutterDragAction
* @threshold: a distance, in pixels
*
* Sets the drag threshold that must be cleared by the pointer
* before @action can begin the dragging
*
* Since: 1.4
*/
void
clutter_drag_action_set_drag_threshold (ClutterDragAction *action,
guint threshold)
{
ClutterDragActionPrivate *priv;
g_return_if_fail (CLUTTER_IS_DRAG_ACTION (action));
priv = action->priv;
if (priv->drag_threshold == threshold)
return;
priv->drag_threshold = threshold;
g_object_notify (G_OBJECT (action), "drag-threshold");
}
/**
* clutter_drag_action_get_drag_threshold:
* @action: a #ClutterDragAction
*
* Retrieves the value set by clutter_drag_action_set_drag_threshold()
*
* Return value: the drag threshold value, in pixels
*
* Since: 1.4
*/
guint
clutter_drag_action_get_drag_threshold (ClutterDragAction *action)
{
g_return_val_if_fail (CLUTTER_IS_DRAG_ACTION (action), 0);
return action->priv->drag_threshold;
}
/**
* clutter_drag_action_set_drag_handle:
* @action: a #ClutterDragHandle
* @handle: a #ClutterActor
*
* Sets the actor to be used as the drag handle
*
* Since: 1.4
*/
void
clutter_drag_action_set_drag_handle (ClutterDragAction *action,
ClutterActor *handle)
{
ClutterDragActionPrivate *priv;
g_return_if_fail (CLUTTER_IS_DRAG_ACTION (action));
g_return_if_fail (CLUTTER_IS_ACTOR (handle));
priv = action->priv;
if (priv->drag_handle == handle)
return;
priv->drag_handle = handle;
g_object_notify (G_OBJECT (action), "drag-handle");
}
/**
* clutter_drag_action_get_drag_handle:
* @action: a #ClutterDragAction
*
* Retrieves the drag handle set by clutter_drag_action_set_drag_handle()
*
* Return value: (transfer none): a #ClutterActor, used as the drag
* handle, or %NULL if none was set
*
* Since: 1.4
*/
ClutterActor *
clutter_drag_action_get_drag_handle (ClutterDragAction *action)
{
g_return_val_if_fail (CLUTTER_IS_DRAG_ACTION (action), NULL);
return action->priv->drag_handle;
}
/**
* clutter_drag_action_set_drag_axis:
* @action: a #ClutterDragAction
* @axis: the axis to constraint the dragging to
*
* Restricts the dragging action to a specific axis
*
* Since: 1.4
*/
void
clutter_drag_action_set_drag_axis (ClutterDragAction *action,
ClutterDragAxis axis)
{
ClutterDragActionPrivate *priv;
g_return_if_fail (CLUTTER_IS_DRAG_ACTION (action));
g_return_if_fail (axis >= CLUTTER_DRAG_AXIS_NONE &&
axis <= CLUTTER_DRAG_Y_AXIS);
priv = action->priv;
if (priv->drag_axis == axis)
return;
priv->drag_axis = axis;
g_object_notify (G_OBJECT (action), "drag-axis");
}
/**
* clutter_drag_action_get_drag_axis:
* @action: a #ClutterDragAction
*
* Retrieves the axis constraint set by clutter_drag_action_set_drag_axis()
*
* Return value: the axis constraint
*
* Since: 1.4
*/
ClutterDragAxis
clutter_drag_action_get_drag_axis (ClutterDragAction *action)
{
g_return_val_if_fail (CLUTTER_IS_DRAG_ACTION (action),
CLUTTER_DRAG_AXIS_NONE);
return action->priv->drag_axis;
}
/**
* clutter_drag_action_get_press_coords:
* @action: a #ClutterDragAction
* @press_x: (out): return location for the press event's X coordinate
* @press_y: (out): return location for the press event's Y coordinate
*
* Retrieves the coordinates, in stage space, of the press event
* that started the dragging
*
* Since: 1.4
*/
void
clutter_drag_action_get_press_coords (ClutterDragAction *action,
gfloat *press_x,
gfloat *press_y)
{
g_return_if_fail (CLUTTER_IS_DRAG_ACTION (action));
if (press_x)
*press_x = action->priv->press_x;
if (press_y)
*press_y = action->priv->press_y;
}
/**
* clutter_drag_action_get_motion_coords:
* @action: a #ClutterDragAction
* @motion_x: (out): return location for the latest motion
* event's X coordinate
* @motion_y: (out): return location for the latest motion
* event's Y coordinate
*
* Retrieves the coordinates, in stage space, of the latest motion
* event during the dragging
*
* Since: 1.4
*/
void
clutter_drag_action_get_motion_coords (ClutterDragAction *action,
gfloat *motion_x,
gfloat *motion_y)
{
g_return_if_fail (CLUTTER_IS_DRAG_ACTION (action));
if (motion_x)
*motion_x = action->priv->last_motion_x;
if (motion_y)
*motion_y = action->priv->last_motion_y;
}
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