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Functions
Properties
| ClutterRect * | drag-area | Read / Write |
| gboolean | drag-area-set | Read |
| ClutterDragAxis | drag-axis | Read / Write |
| ClutterActor * | drag-handle | Read / Write |
| gint | x-drag-threshold | Read / Write |
| gint | y-drag-threshold | Read / Write |
Signals
| void | drag-begin | Run Last |
| void | drag-end | Run Last |
| void | drag-motion | Run Last |
| gboolean | drag-progress | Run Last |
Object Hierarchy
GObject
╰── GInitiallyUnowned
╰── ClutterActorMeta
╰── ClutterAction
╰── ClutterDragAction
Description
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:
1 2 |
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 “drag-begin” and “drag-end” signals, respectively. Each pointer motion during a drag will also result in the “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 “drag-begin” signal. The drag handle must be
parented and exist between the emission of “drag-begin”
and “drag-end”.
The drag-action example
allows dragging the rectangle around the stage using a ClutterDragAction.
When pressing the Shift key the actor that is being dragged will be a
separate rectangle, and when the drag ends, the original rectangle will be
animated to the final drop coordinates.
ClutterDragAction is available since Clutter 1.4
Functions
clutter_drag_action_new ()
ClutterAction *
clutter_drag_action_new (void);
Creates a new ClutterDragAction instance
Since: 1.4
clutter_drag_action_set_drag_threshold ()
void clutter_drag_action_set_drag_threshold (ClutterDragAction *action,gint x_threshold,gint y_threshold);
Sets the horizontal and vertical drag thresholds that must be
cleared by the pointer before action
can begin the dragging.
If x_threshold
or y_threshold
are set to -1 then the default
drag threshold stored in the “dnd-drag-threshold”
property of ClutterSettings will be used.
Parameters
action |
||
x_threshold |
a distance on the horizontal axis, in pixels, or -1 to use the default drag threshold from ClutterSettings |
|
y_threshold |
a distance on the vertical axis, in pixels, or -1 to use the default drag threshold from ClutterSettings |
Since: 1.4
clutter_drag_action_get_drag_threshold ()
void clutter_drag_action_get_drag_threshold (ClutterDragAction *action,guint *x_threshold,guint *y_threshold);
Retrieves the values set by clutter_drag_action_set_drag_threshold().
If the “x-drag-threshold” property or the “y-drag-threshold” property have been set to -1 then this function will return the default drag threshold value as stored by the “dnd-drag-threshold” property of ClutterSettings.
Parameters
action |
||
x_threshold |
return location for the horizontal drag threshold value, in pixels. |
[out] |
y_threshold |
return location for the vertical drag threshold value, in pixels. |
[out] |
Since: 1.4
clutter_drag_action_set_drag_handle ()
void clutter_drag_action_set_drag_handle (ClutterDragAction *action,ClutterActor *handle);
Sets the actor to be used as the drag handle.
Since: 1.4
clutter_drag_action_get_drag_handle ()
ClutterActor *
clutter_drag_action_get_drag_handle (ClutterDragAction *action);
Retrieves the drag handle set by clutter_drag_action_set_drag_handle()
Since: 1.4
clutter_drag_action_set_drag_axis ()
void clutter_drag_action_set_drag_axis (ClutterDragAction *action,ClutterDragAxis axis);
Restricts the dragging action to a specific axis
Since: 1.4
clutter_drag_action_get_drag_axis ()
ClutterDragAxis
clutter_drag_action_get_drag_axis (ClutterDragAction *action);
Retrieves the axis constraint set by clutter_drag_action_set_drag_axis()
Since: 1.4
clutter_drag_action_set_drag_area ()
void clutter_drag_action_set_drag_area (ClutterDragAction *action,const ClutterRect *drag_area);
Sets drag_area
to constrain the dragging of the actor associated
with action
, so that it position is always within drag_area
, expressed
in parent's coordinates.
If drag_area
is NULL, the actor is not constrained.
clutter_drag_action_get_drag_area ()
gboolean clutter_drag_action_get_drag_area (ClutterDragAction *action,ClutterRect *drag_area);
Retrieves the "drag area" associated with action
, that
is a ClutterRect that constrains the actor movements,
in parents coordinates.
clutter_drag_action_get_press_coords ()
void clutter_drag_action_get_press_coords (ClutterDragAction *action,gfloat *press_x,gfloat *press_y);
Retrieves the coordinates, in stage space, of the press event that started the dragging
Parameters
action |
||
press_x |
return location for the press event's X coordinate. |
[out] |
press_y |
return location for the press event's Y coordinate. |
[out] |
Since: 1.4
clutter_drag_action_get_motion_coords ()
void clutter_drag_action_get_motion_coords (ClutterDragAction *action,gfloat *motion_x,gfloat *motion_y);
Retrieves the coordinates, in stage space, of the latest motion event during the dragging
Parameters
action |
||
motion_x |
return location for the latest motion event's X coordinate. |
[out] |
motion_y |
return location for the latest motion event's Y coordinate. |
[out] |
Since: 1.4
Types and Values
struct ClutterDragAction
struct ClutterDragAction;
The ClutterDragAction structure contains only private data and should be accessed using the provided API
Since: 1.4
struct ClutterDragActionClass
struct ClutterDragActionClass {
void (* drag_begin) (ClutterDragAction *action,
ClutterActor *actor,
gfloat event_x,
gfloat event_y,
ClutterModifierType modifiers);
void (* drag_motion) (ClutterDragAction *action,
ClutterActor *actor,
gfloat delta_x,
gfloat delta_y);
void (* drag_end) (ClutterDragAction *action,
ClutterActor *actor,
gfloat event_x,
gfloat event_y,
ClutterModifierType modifiers);
gboolean (* drag_progress) (ClutterDragAction *action,
ClutterActor *actor,
gfloat delta_x,
gfloat delta_y);
};
The ClutterDragActionClass structure contains only private data
Members
class handler of the “drag-begin” signal |
||
class handler of the “drag-motion” signal |
||
class handler of the “drag-end” signal |
||
class handler of the “drag-progress” signal |
Since: 1.4
enum ClutterDragAxis
The axis of the constraint that should be applied on the dragging action
Since: 1.4
Property Details
The “drag-area” property
“drag-area” ClutterRect *
Constains the dragging action (or in particular, the resulting actor position) to the specified ClutterRect, in parent's coordinates.
Flags: Read / Write
Since: 1.12
The “drag-area-set” property
“drag-area-set” gboolean
Whether the “drag-area” property has been set.
Flags: Read
Default value: FALSE
Since: 1.12
The “drag-axis” property
“drag-axis” ClutterDragAxis
Constraints the dragging action to the specified axis
Flags: Read / Write
Default value: CLUTTER_DRAG_AXIS_NONE
Since: 1.4
The “drag-handle” property
“drag-handle” ClutterActor *
The ClutterActor that is effectively being dragged
A ClutterDragAction 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
Flags: Read / Write
Since: 1.4
The “x-drag-threshold” property
“x-drag-threshold” gint
The horizontal threshold, in pixels, that the cursor must travel in order to begin a drag action.
When set to a positive value, ClutterDragAction will only emit “drag-begin” if the pointer has moved horizontally at least of the given amount of pixels since the button press event.
When set to -1, ClutterDragAction will use the default threshold stored in the “dnd-drag-threshold” property of ClutterSettings.
When read, this property will always return a valid drag threshold, either as set or the default one.
Flags: Read / Write
Allowed values: >= -1
Default value: 0
Since: 1.4
The “y-drag-threshold” property
“y-drag-threshold” gint
The vertical threshold, in pixels, that the cursor must travel in order to begin a drag action.
When set to a positive value, ClutterDragAction will only emit “drag-begin” if the pointer has moved vertically at least of the given amount of pixels since the button press event.
When set to -1, ClutterDragAction will use the value stored in the “dnd-drag-threshold” property of ClutterSettings.
When read, this property will always return a valid drag threshold, either as set or the default one.
Flags: Read / Write
Allowed values: >= -1
Default value: 0
Since: 1.4
Signal Details
The “drag-begin” signal
void user_function (ClutterDragAction *action, ClutterActor *actor, gfloat event_x, gfloat event_y, ClutterModifierType modifiers, gpointer user_data)
The ::drag-begin signal is emitted when the ClutterDragAction starts the dragging
The emission of this signal can be delayed by using the “x-drag-threshold” and “y-drag-threshold” properties
Parameters
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 |
|
user_data |
user data set when the signal handler was connected. |
Flags: Run Last
Since: 1.4
The “drag-end” signal
void user_function (ClutterDragAction *action, ClutterActor *actor, gfloat event_x, gfloat event_y, ClutterModifierType modifiers, gpointer user_data)
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 “drag-begin” signal has been emitted first
Parameters
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 |
|
user_data |
user data set when the signal handler was connected. |
Flags: Run Last
Since: 1.4
The “drag-motion” signal
void user_function (ClutterDragAction *action, ClutterActor *actor, gfloat delta_x, gfloat delta_y, gpointer user_data)
The ::drag-motion signal is emitted for each motion event after the “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 “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 the
“drag-progress” signal and return FALSE from the
handler.
Parameters
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 |
|
user_data |
user data set when the signal handler was connected. |
Flags: Run Last
Since: 1.4
The “drag-progress” signal
gboolean user_function (ClutterDragAction *action, ClutterActor *actor, gfloat delta_x, gfloat delta_y, gpointer user_data)
The ::drag-progress signal is emitted for each motion event after the “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 will emit “drag-motion”,
if “drag-progress” emission returns TRUE.
Parameters
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 |
|
user_data |
user data set when the signal handler was connected. |
Flags: Run Last
Since: 1.12