gnome-shell/js/ui/dnd.js
Colin Walters 3c87d76741 dnd: Fix used of undefined variables
The variables this._yOffset and this._xOffset are included in the
drop coordinates, but as far as I can tell never defined.  Looking
back on the commit that introduced this code, they weren't removed
from anywhere else either.

The drop coordinates seem correct without them, so just delete them.
2009-08-08 10:09:30 -04:00

220 lines
9.0 KiB
JavaScript

/* -*- mode: js2; js2-basic-offset: 4; tab-width: 4; indent-tabs-mode: nil -*- */
const Clutter = imports.gi.Clutter;
const Gtk = imports.gi.Gtk;
const Lang = imports.lang;
const Signals = imports.signals;
const Tweener = imports.ui.tweener;
const SNAP_BACK_ANIMATION_TIME = 0.25;
function _Draggable(actor) {
this._init(actor);
}
_Draggable.prototype = {
_init : function(actor) {
this.actor = actor;
this.actor.connect('button-press-event',
Lang.bind(this, this._onButtonPress));
},
_onButtonPress : function (actor, event) {
// FIXME: we should make sure it's button 1, but we can't currently
// check that from JavaScript
if (Tweener.getTweenCount(actor))
return false;
this._grabActor(actor);
let [stageX, stageY] = event.get_coords();
this._dragStartX = stageX;
this._dragStartY = stageY;
return false;
},
_grabActor : function (actor) {
Clutter.grab_pointer(actor);
// We intercept motion and button-release events so that when
// you release after dragging, the app doesn't see that and
// think you just clicked. We connect to 'event' rather than
// 'captured-event' because the capturing phase doesn't happen
// when you've grabbed the pointer.
this._onEventId = actor.connect('event',
Lang.bind(this, this._onEvent));
},
_ungrabActor : function (actor) {
Clutter.ungrab_pointer();
actor.disconnect(this._onEventId);
},
_onEvent : function (actor, event) {
if (this._dragActor) {
if (actor != this._dragActor )
return false;
} else if (actor != this.actor)
return false;
if (event.type() == Clutter.EventType.BUTTON_RELEASE)
return this._onButtonRelease(actor, event);
else if (event.type() == Clutter.EventType.MOTION)
return this._onMotion(actor, event);
else
return false;
},
_onMotion : function (actor, event) {
let [stageX, stageY] = event.get_coords();
// If we haven't begun a drag, see if the user has moved the
// mouse enough to trigger a drag
let threshold = Gtk.Settings.get_default().gtk_dnd_drag_threshold;
if (!this._dragActor &&
(Math.abs(stageX - this._dragStartX) > threshold ||
Math.abs(stageY - this._dragStartY) > threshold)) {
this.emit('drag-begin', event.get_time());
if (this.actor._delegate && this.actor._delegate.getDragActor) {
this._dragActor = this.actor._delegate.getDragActor(this._dragStartX, this._dragStartY);
// 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();
else
this._dragActorSource = this.actor;
this._dragOrigParent = undefined;
this._ungrabActor(actor);
this._grabActor(this._dragActor);
this._dragOffsetX = this._dragActor.x - this._dragStartX;
this._dragOffsetY = this._dragActor.y - this._dragStartY;
} else {
this._dragActor = actor;
this._dragActorSource = undefined;
this._dragOrigParent = actor.get_parent();
this._dragOrigX = this._dragActor.x;
this._dragOrigY = this._dragActor.y;
this._dragOrigScale = this._dragActor.scale_x;
let [actorStageX, actorStageY] = 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 stage
let [scaledWidth, scaledHeight] = actor.get_transformed_size();
actor.set_scale(scaledWidth / actor.width,
scaledHeight / actor.height);
}
this._dragActor.reparent(actor.get_stage());
this._dragActor.raise_top();
}
// If we are dragging, update the position
if (this._dragActor) {
this._dragActor.set_position(stageX + this._dragOffsetX,
stageY + this._dragOffsetY);
// Because we want to find out what other actor is located at the current position of this._dragActor,
// we have to temporarily hide this._dragActor.
this._dragActor.hide();
let target = actor.get_stage().get_actor_at_pos(Clutter.PickMode.ALL,
stageX + this._dragOffsetX,
stageY + this._dragOffsetY);
this._dragActor.show();
while (target) {
if (target._delegate && target._delegate.handleDragOver) {
let [targX, targY] = target.get_transformed_position();
// 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.
target._delegate.handleDragOver(this.actor._delegate, actor,
(stageX + this._dragOffsetX - targX) / target.scale_x,
(stageY + this._dragOffsetY - targY) / target.scale_y,
event.get_time());
}
target = target.get_parent();
}
}
return true;
},
_onButtonRelease : function (actor, event) {
this._ungrabActor(actor);
let dragging = (actor == this._dragActor);
this._dragActor = undefined;
if (!dragging)
return false;
// Find a drop target
actor.hide();
let [dropX, dropY] = event.get_coords();
let target = actor.get_stage().get_actor_at_pos(Clutter.PickMode.ALL,
dropX, dropY);
actor.show();
while (target) {
if (target._delegate && target._delegate.acceptDrop) {
let [targX, targY] = target.get_transformed_position();
if (target._delegate.acceptDrop(this.actor._delegate, actor,
(dropX - targX) / target.scale_x,
(dropY - targY) / target.scale_y,
event.get_time())) {
// If it accepted the drop without taking the actor,
// destroy it.
if (actor.get_parent() == actor.get_stage())
actor.destroy();
this.emit('drag-end', event.get_time(), true);
return true;
}
}
target = target.get_parent();
}
// Snap back to the actor source if the source is still around, snap back
// to the original location if the actor itself was being dragged or the
// source is no longer around.
let snapBackX = this._dragStartX + this._dragOffsetX;
let snapBackY = this._dragStartY + this._dragOffsetY;
if (this._dragActorSource && this._dragActorSource.visible) {
[snapBackX, snapBackY] = this._dragActorSource.get_transformed_position();
}
// No target, so snap back
Tweener.addTween(actor,
{ x: snapBackX,
y: snapBackY,
time: SNAP_BACK_ANIMATION_TIME,
transition: "easeOutQuad",
onComplete: this._onSnapBackComplete,
onCompleteScope: this,
onCompleteParams: [actor, event.get_time()]
});
return true;
},
_onSnapBackComplete : 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();
}
this.emit('drag-end', eventTime, false);
}
};
Signals.addSignalMethods(_Draggable.prototype);
function makeDraggable(actor) {
return new _Draggable(actor);
}