gnome-shell/js/ui/dnd.js

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// -*- mode: js; js-indent-level: 4; indent-tabs-mode: nil -*-
const Clutter = imports.gi.Clutter;
const Gtk = imports.gi.Gtk;
const St = imports.gi.St;
const Lang = imports.lang;
const Shell = imports.gi.Shell;
const Signals = imports.signals;
const Tweener = imports.ui.tweener;
const Main = imports.ui.main;
const Params = imports.misc.params;
// Time to scale down to maxDragActorSize
const SCALE_ANIMATION_TIME = 0.25;
// Time to animate to original position on cancel
const SNAP_BACK_ANIMATION_TIME = 0.25;
// Time to animate to original position on success
const REVERT_ANIMATION_TIME = 0.75;
const DragMotionResult = {
NO_DROP: 0,
COPY_DROP: 1,
MOVE_DROP: 2,
CONTINUE: 3
};
const DRAG_CURSOR_MAP = {
0: Shell.Cursor.DND_UNSUPPORTED_TARGET,
1: Shell.Cursor.DND_COPY,
2: Shell.Cursor.DND_MOVE
};
const DragDropResult = {
FAILURE: 0,
SUCCESS: 1,
CONTINUE: 2
};
let eventHandlerActor = null;
let currentDraggable = null;
let dragMonitors = [];
function _getEventHandlerActor() {
if (!eventHandlerActor) {
eventHandlerActor = new Clutter.Rectangle();
eventHandlerActor.width = 0;
eventHandlerActor.height = 0;
Main.uiGroup.add_actor(eventHandlerActor);
// We connect to 'event' rather than 'captured-event' because the capturing phase doesn't happen
// when you've grabbed the pointer.
eventHandlerActor.connect('event',
function(actor, event) {
return currentDraggable._onEvent(actor, event);
});
}
return eventHandlerActor;
}
function addDragMonitor(monitor) {
dragMonitors.push(monitor);
}
function removeDragMonitor(monitor) {
for (let i = 0; i < dragMonitors.length; i++)
if (dragMonitors[i] == monitor) {
dragMonitors.splice(i, 1);
return;
}
}
const _Draggable = new Lang.Class({
Name: 'Draggable',
_init : function(actor, params) {
params = Params.parse(params, { manualMode: false,
restoreOnSuccess: false,
dragActorMaxSize: undefined,
dragActorOpacity: undefined });
this.actor = actor;
if (!params.manualMode)
this.actor.connect('button-press-event',
Lang.bind(this, this._onButtonPress));
this.actor.connect('destroy', Lang.bind(this, function() {
this._actorDestroyed = true;
// If the drag actor is destroyed and we were going to fix
// up its hover state, fix up the parent hover state instead
if (this.actor == this._firstLeaveActor)
this._firstLeaveActor = this._dragOrigParent;
if (this._dragInProgress && this._dragCancellable)
this._cancelDrag(global.get_current_time());
this.disconnectAll();
}));
this._onEventId = null;
this._restoreOnSuccess = params.restoreOnSuccess;
this._dragActorMaxSize = params.dragActorMaxSize;
this._dragActorOpacity = params.dragActorOpacity;
this._buttonDown = false; // The mouse button has been pressed and has not yet been released.
this._dragInProgress = false; // The drag has been started, and has not been dropped or cancelled yet.
this._animationInProgress = false; // The drag is over and the item is in the process of animating to its original position (snapping back or reverting).
this._dragCancellable = true;
// During the drag, we eat enter/leave events so that actors don't prelight.
// But we remember the actors that we first left/last entered so we can
// fix up the hover state after the drag ends.
this._firstLeaveActor = null;
this._lastEnterActor = null;
this._eventsGrabbed = false;
},
_onButtonPress : function (actor, event) {
if (event.get_button() != 1)
return false;
if (Tweener.getTweenCount(actor))
return false;
this._buttonDown = true;
this._grabActor();
let [stageX, stageY] = event.get_coords();
this._dragStartX = stageX;
this._dragStartY = stageY;
return false;
},
_grabActor: function() {
Clutter.grab_pointer(this.actor);
this._onEventId = this.actor.connect('event',
Lang.bind(this, this._onEvent));
},
_ungrabActor: function() {
if (!this._onEventId)
return;
Clutter.ungrab_pointer();
this.actor.disconnect(this._onEventId);
this._onEventId = null;
},
_grabEvents: function() {
if (!this._eventsGrabbed) {
Clutter.grab_pointer(_getEventHandlerActor());
Clutter.grab_keyboard(_getEventHandlerActor());
this._eventsGrabbed = true;
}
},
_ungrabEvents: function() {
if (this._eventsGrabbed) {
Clutter.ungrab_pointer();
Clutter.ungrab_keyboard();
this._eventsGrabbed = false;
}
},
_onEvent: function(actor, event) {
// We intercept BUTTON_RELEASE event to know that the button was released in case we
// didn't start the drag, to drop the draggable in case the drag was in progress, and
// to complete the drag and ensure that whatever happens to be under the pointer does
// not get triggered if the drag was cancelled with Esc.
if (event.type() == Clutter.EventType.BUTTON_RELEASE) {
this._buttonDown = false;
if (this._dragInProgress) {
return this._dragActorDropped(event);
} else if (this._dragActor != null && !this._animationInProgress) {
// Drag must have been cancelled with Esc.
this._dragComplete();
return true;
} else {
// Drag has never started.
this._ungrabActor();
return false;
}
// We intercept MOTION event to figure out if the drag has started and to draw
// this._dragActor under the pointer when dragging is in progress
} else if (event.type() == Clutter.EventType.MOTION) {
if (this._dragInProgress) {
return this._updateDragPosition(event);
} else if (this._dragActor == null) {
return this._maybeStartDrag(event);
}
// We intercept KEY_PRESS event so that we can process Esc key press to cancel
// dragging and ignore all other key presses.
} else if (event.type() == Clutter.EventType.KEY_PRESS && this._dragInProgress) {
let symbol = event.get_key_symbol();
if (symbol == Clutter.Escape) {
this._cancelDrag(event.get_time());
return true;
}
} else if (event.type() == Clutter.EventType.LEAVE) {
if (this._firstLeaveActor == null)
this._firstLeaveActor = event.get_source();
} else if (event.type() == Clutter.EventType.ENTER) {
this._lastEnterActor = event.get_source();
}
return false;
},
/**
* fakeRelease:
*
* Fake a release event.
* Must be called if you want to intercept release events on draggable
* actors for other purposes (for example if you're using
* PopupMenu.ignoreRelease())
*/
fakeRelease: function() {
this._buttonDown = false;
this._ungrabActor();
},
/**
* startDrag:
* @stageX: X coordinate of event
* @stageY: Y coordinate of event
* @time: Event timestamp
*
* Directly initiate a drag and drop operation from the given actor.
* This function is useful to call if you've specified manualMode
* for the draggable.
*/
startDrag: function (stageX, stageY, time) {
currentDraggable = this;
this._dragInProgress = true;
// Special-case St.Button: the pointer grab messes with the internal
// state, so force a reset to a reasonable state here
if (this.actor instanceof St.Button) {
this.actor.fake_release();
this.actor.hover = false;
}
this.emit('drag-begin', time);
if (this._onEventId)
this._ungrabActor();
this._grabEvents();
global.set_cursor(Shell.Cursor.DND_IN_DRAG);
this._dragX = this._dragStartX = stageX;
this._dragY = this._dragStartY = stageY;
if (this.actor._delegate && this.actor._delegate.getDragActor) {
this._dragActor = this.actor._delegate.getDragActor();
this._dragActor.reparent(Main.uiGroup);
this._dragActor.raise_top();
Shell.util_set_hidden_from_pick(this._dragActor, true);
// Drag actor does not always have to be the same as actor. For example drag actor
// can be an image that's part of the actor. So to perform "snap back" correctly we need
// to know what was the drag actor source.
if (this.actor._delegate.getDragActorSource) {
this._dragActorSource = this.actor._delegate.getDragActorSource();
// If the user dragged from the source, then position
// the dragActor over it. Otherwise, center it
// around the pointer
let [sourceX, sourceY] = this._dragActorSource.get_transformed_position();
let x, y;
if (stageX > sourceX && stageX <= sourceX + this._dragActor.width &&
stageY > sourceY && stageY <= sourceY + this._dragActor.height) {
x = sourceX;
y = sourceY;
} else {
x = stageX - this._dragActor.width / 2;
y = stageY - this._dragActor.height / 2;
}
this._dragActor.set_position(x, y);
} else {
this._dragActorSource = this.actor;
}
this._dragOrigParent = undefined;
this._dragOffsetX = this._dragActor.x - this._dragStartX;
this._dragOffsetY = this._dragActor.y - this._dragStartY;
} else {
this._dragActor = this.actor;
this._dragActorSource = undefined;
this._dragOrigParent = this.actor.get_parent();
this._dragOrigX = this._dragActor.x;
this._dragOrigY = this._dragActor.y;
this._dragOrigScale = this._dragActor.scale_x;
this._dragActor.reparent(Main.uiGroup);
this._dragActor.raise_top();
Shell.util_set_hidden_from_pick(this._dragActor, true);
let [actorStageX, actorStageY] = this.actor.get_transformed_position();
this._dragOffsetX = actorStageX - this._dragStartX;
this._dragOffsetY = actorStageY - this._dragStartY;
// Set the actor's scale such that it will keep the same
// transformed size when it's reparented to the uiGroup
let [scaledWidth, scaledHeight] = this.actor.get_transformed_size();
this.actor.set_scale(scaledWidth / this.actor.width,
scaledHeight / this.actor.height);
}
this._dragOrigOpacity = this._dragActor.opacity;
if (this._dragActorOpacity != undefined)
this._dragActor.opacity = this._dragActorOpacity;
this._snapBackX = this._dragStartX + this._dragOffsetX;
this._snapBackY = this._dragStartY + this._dragOffsetY;
this._snapBackScale = this._dragActor.scale_x;
if (this._dragActorMaxSize != undefined) {
let [scaledWidth, scaledHeight] = this._dragActor.get_transformed_size();
let currentSize = Math.max(scaledWidth, scaledHeight);
if (currentSize > this._dragActorMaxSize) {
let scale = this._dragActorMaxSize / currentSize;
let origScale = this._dragActor.scale_x;
let origDragOffsetX = this._dragOffsetX;
let origDragOffsetY = this._dragOffsetY;
// The position of the actor changes as we scale
// around the drag position, but we can't just tween
// to the final position because that tween would
// fight with updates as the user continues dragging
// the mouse; instead we do the position computations in
// an onUpdate() function.
Tweener.addTween(this._dragActor,
{ scale_x: scale * origScale,
scale_y: scale * origScale,
time: SCALE_ANIMATION_TIME,
transition: 'easeOutQuad',
onUpdate: function() {
let currentScale = this._dragActor.scale_x / origScale;
this._dragOffsetX = currentScale * origDragOffsetX;
this._dragOffsetY = currentScale * origDragOffsetY;
this._dragActor.set_position(this._dragX + this._dragOffsetX,
this._dragY + this._dragOffsetY);
},
onUpdateScope: this });
}
}
},
_maybeStartDrag: function(event) {
let [stageX, stageY] = event.get_coords();
// See if the user has moved the mouse enough to trigger a drag
let threshold = Gtk.Settings.get_default().gtk_dnd_drag_threshold;
if ((Math.abs(stageX - this._dragStartX) > threshold ||
Math.abs(stageY - this._dragStartY) > threshold)) {
this.startDrag(stageX, stageY, event.get_time());
this._updateDragPosition(event);
}
return true;
},
_updateDragPosition : function (event) {
let [stageX, stageY] = event.get_coords();
this._dragX = stageX;
this._dragY = stageY;
// If we are dragging, update the position
if (this._dragActor) {
this._dragActor.set_position(stageX + this._dragOffsetX,
stageY + this._dragOffsetY);
let target = this._dragActor.get_stage().get_actor_at_pos(Clutter.PickMode.ALL,
stageX, stageY);
// We call observers only once per motion with the innermost
// target actor. If necessary, the observer can walk the
// parent itself.
let dragEvent = {
x: stageX,
y: stageY,
dragActor: this._dragActor,
source: this.actor._delegate,
targetActor: target
};
for (let i = 0; i < dragMonitors.length; i++) {
let motionFunc = dragMonitors[i].dragMotion;
if (motionFunc) {
let result = motionFunc(dragEvent);
if (result != DragMotionResult.CONTINUE) {
global.set_cursor(DRAG_CURSOR_MAP[result]);
return true;
}
}
}
while (target) {
if (target._delegate && target._delegate.handleDragOver) {
let [r, targX, targY] = target.transform_stage_point(stageX, stageY);
// We currently loop through all parents on drag-over even if one of the children has handled it.
// We can check the return value of the function and break the loop if it's true if we don't want
// to continue checking the parents.
let result = target._delegate.handleDragOver(this.actor._delegate,
this._dragActor,
targX,
targY,
event.get_time());
if (result != DragMotionResult.CONTINUE) {
global.set_cursor(DRAG_CURSOR_MAP[result]);
return true;
}
}
target = target.get_parent();
}
global.set_cursor(Shell.Cursor.DND_IN_DRAG);
}
return true;
},
_dragActorDropped: function(event) {
let [dropX, dropY] = event.get_coords();
let target = this._dragActor.get_stage().get_actor_at_pos(Clutter.PickMode.ALL,
dropX, dropY);
// We call observers only once per motion with the innermost
// target actor. If necessary, the observer can walk the
// parent itself.
let dropEvent = {
dropActor: this._dragActor,
targetActor: target,
clutterEvent: event
};
for (let i = 0; i < dragMonitors.length; i++) {
let dropFunc = dragMonitors[i].dragDrop;
if (dropFunc)
switch (dropFunc(dropEvent)) {
case DragDropResult.FAILURE:
case DragDropResult.SUCCESS:
return true;
case DragDropResult.CONTINUE:
continue;
}
}
// At this point it is too late to cancel a drag by destroying
// the actor, the fate of which is decided by acceptDrop and its
// side-effects
this._dragCancellable = false;
while (target) {
if (target._delegate && target._delegate.acceptDrop) {
let [r, targX, targY] = target.transform_stage_point(dropX, dropY);
if (target._delegate.acceptDrop(this.actor._delegate,
this._dragActor,
targX,
targY,
event.get_time())) {
// If it accepted the drop without taking the actor,
// handle it ourselves.
if (this._dragActor.get_parent() == Main.uiGroup) {
if (this._restoreOnSuccess) {
this._restoreDragActor(event.get_time());
return true;
} else
this._dragActor.destroy();
}
this._dragInProgress = false;
global.unset_cursor();
this.emit('drag-end', event.get_time(), true);
this._dragComplete();
return true;
}
}
target = target.get_parent();
}
this._cancelDrag(event.get_time());
return true;
},
_getRestoreLocation: function() {
let x, y, scale;
if (this._dragActorSource && this._dragActorSource.visible) {
// Snap the clone back to its source
[x, y] = this._dragActorSource.get_transformed_position();
let [sourceScaledWidth, sourceScaledHeight] = this._dragActorSource.get_transformed_size();
scale = this._dragActor.width / sourceScaledWidth;
} else if (this._dragOrigParent) {
// Snap the actor back to its original position within
// its parent, adjusting for the fact that the parent
// may have been moved or scaled
let [parentX, parentY] = this._dragOrigParent.get_transformed_position();
let [parentWidth, parentHeight] = this._dragOrigParent.get_size();
let [parentScaledWidth, parentScaledHeight] = this._dragOrigParent.get_transformed_size();
let parentScale = 1.0;
if (parentWidth != 0)
parentScale = parentScaledWidth / parentWidth;
x = parentX + parentScale * this._dragOrigX;
y = parentY + parentScale * this._dragOrigY;
scale = this._dragOrigScale * parentScale;
} else {
// Snap back actor to its original stage position
x = this._snapBackX;
y = this._snapBackY;
scale = this._snapBackScale;
}
return [x, y, scale];
},
_cancelDrag: function(eventTime) {
this.emit('drag-cancelled', eventTime);
this._dragInProgress = false;
let [snapBackX, snapBackY, snapBackScale] = this._getRestoreLocation();
if (this._actorDestroyed) {
global.unset_cursor();
if (!this._buttonDown)
this._dragComplete();
this.emit('drag-end', eventTime, false);
if (!this._dragOrigParent)
this._dragActor.destroy();
return;
}
this._animationInProgress = true;
// No target, so snap back
Tweener.addTween(this._dragActor,
{ x: snapBackX,
y: snapBackY,
scale_x: snapBackScale,
scale_y: snapBackScale,
opacity: this._dragOrigOpacity,
time: SNAP_BACK_ANIMATION_TIME,
transition: 'easeOutQuad',
onComplete: this._onAnimationComplete,
onCompleteScope: this,
onCompleteParams: [this._dragActor, eventTime]
});
},
_restoreDragActor: function(eventTime) {
this._dragInProgress = false;
[restoreX, restoreY, restoreScale] = this._getRestoreLocation();
// fade the actor back in at its original location
this._dragActor.set_position(restoreX, restoreY);
this._dragActor.set_scale(restoreScale, restoreScale);
this._dragActor.opacity = 0;
this._animationInProgress = true;
Tweener.addTween(this._dragActor,
{ opacity: this._dragOrigOpacity,
time: REVERT_ANIMATION_TIME,
transition: 'easeOutQuad',
onComplete: this._onAnimationComplete,
onCompleteScope: this,
onCompleteParams: [this._dragActor, eventTime]
});
},
_onAnimationComplete : function (dragActor, eventTime) {
if (this._dragOrigParent) {
dragActor.reparent(this._dragOrigParent);
dragActor.set_scale(this._dragOrigScale, this._dragOrigScale);
dragActor.set_position(this._dragOrigX, this._dragOrigY);
} else {
dragActor.destroy();
}
global.unset_cursor();
this.emit('drag-end', eventTime, false);
this._animationInProgress = false;
if (!this._buttonDown)
this._dragComplete();
},
// Actor is an actor we have entered or left during the drag; call
// st_widget_sync_hover on all StWidget ancestors
_syncHover: function(actor) {
while (actor) {
let parent = actor.get_parent();
if (actor instanceof St.Widget)
actor.sync_hover();
actor = parent;
}
},
_dragComplete: function() {
if (!this._actorDestroyed)
Shell.util_set_hidden_from_pick(this._dragActor, false);
this._ungrabEvents();
if (this._firstLeaveActor) {
this._syncHover(this._firstLeaveActor);
this._firstLeaveActor = null;
}
if (this._lastEnterActor) {
this._syncHover(this._lastEnterActor);
this._lastEnterActor = null;
}
this._dragActor = undefined;
currentDraggable = null;
}
});
Signals.addSignalMethods(_Draggable.prototype);
/**
* makeDraggable:
* @actor: Source actor
* @params: (optional) Additional parameters
*
* Create an object which controls drag and drop for the given actor.
*
* If %manualMode is %true in @params, do not automatically start
* drag and drop on click
*
* If %dragActorMaxSize is present in @params, the drag actor will
* be scaled down to be no larger than that size in pixels.
*
* If %dragActorOpacity is present in @params, the drag actor will
* will be set to have that opacity during the drag.
*
* Note that when the drag actor is the source actor and the drop
* succeeds, the actor scale and opacity aren't reset; if the drop
* target wants to reuse the actor, it's up to the drop target to
* reset these values.
*/
function makeDraggable(actor, params) {
return new _Draggable(actor, params);
}