7d8c3f1ecd
Previously we were looking at the source size, which is not necessarily the same as the drag actor size. https://bugzilla.gnome.org/show_bug.cgi?id=607821
334 lines
13 KiB
JavaScript
334 lines
13 KiB
JavaScript
/* -*- mode: js2; js2-basic-offset: 4; tab-width: 4; indent-tabs-mode: nil -*- */
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const Clutter = imports.gi.Clutter;
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const Gtk = imports.gi.Gtk;
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const Lang = imports.lang;
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const Signals = imports.signals;
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const Tweener = imports.ui.tweener;
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const SNAP_BACK_ANIMATION_TIME = 0.25;
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let eventHandlerActor = null;
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let currentDraggable = null;
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function _getEventHandlerActor() {
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if (!eventHandlerActor) {
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eventHandlerActor = new Clutter.Rectangle();
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eventHandlerActor.width = 0;
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eventHandlerActor.height = 0;
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global.stage.add_actor(eventHandlerActor);
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// We connect to 'event' rather than 'captured-event' because the capturing phase doesn't happen
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// when you've grabbed the pointer.
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eventHandlerActor.connect('event',
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function(actor, event) {
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return currentDraggable._onEvent(actor, event);
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});
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}
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return eventHandlerActor;
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}
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function _Draggable(actor, manualMode) {
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this._init(actor, manualMode);
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}
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_Draggable.prototype = {
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_init : function(actor, manualMode) {
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this.actor = actor;
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if (!manualMode)
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this.actor.connect('button-press-event',
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Lang.bind(this, this._onButtonPress));
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this._onEventId = null;
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this._buttonDown = false; // The mouse button has been pressed and has not yet been released.
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this._dragInProgress = false; // The drag has been started, and has not been dropped or cancelled yet.
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this._snapBackInProgress = false; // The drag has been cancelled and the item is in the process of snapping back.
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},
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_onButtonPress : function (actor, event) {
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// FIXME: we should make sure it's button 1, but we can't currently
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// check that from JavaScript
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if (Tweener.getTweenCount(actor))
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return false;
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this._buttonDown = true;
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this._grabActor();
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let [stageX, stageY] = event.get_coords();
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this._dragStartX = stageX;
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this._dragStartY = stageY;
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return false;
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},
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_grabActor: function() {
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Clutter.grab_pointer(this.actor);
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this._onEventId = this.actor.connect('event',
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Lang.bind(this, this._onEvent));
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},
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_ungrabActor: function() {
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Clutter.ungrab_pointer();
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this.actor.disconnect(this._onEventId);
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this._onEventId = null;
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},
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_grabEvents: function() {
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Clutter.grab_pointer(_getEventHandlerActor());
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Clutter.grab_keyboard(_getEventHandlerActor());
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},
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_ungrabEvents: function() {
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Clutter.ungrab_pointer();
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Clutter.ungrab_keyboard();
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},
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_onEvent: function(actor, event) {
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// We intercept BUTTON_RELEASE event to know that the button was released in case we
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// didn't start the drag, to drop the draggable in case the drag was in progress, and
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// to complete the drag and ensure that whatever happens to be under the pointer does
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// not get triggered if the drag was cancelled with Esc.
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if (event.type() == Clutter.EventType.BUTTON_RELEASE) {
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this._buttonDown = false;
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if (this._dragInProgress) {
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return this._dragActorDropped(event);
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} else if (this._dragActor != null && !this._snapBackInProgress) {
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// Drag must have been cancelled with Esc.
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this._dragComplete();
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return true;
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} else {
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// Drag has never started.
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this._ungrabActor();
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return false;
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}
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// We intercept MOTION event to figure out if the drag has started and to draw
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// this._dragActor under the pointer when dragging is in progress
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} else if (event.type() == Clutter.EventType.MOTION) {
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if (this._dragInProgress) {
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return this._updateDragPosition(event);
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} else if (this._dragActor == null) {
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return this._maybeStartDrag(event);
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}
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// We intercept KEY_PRESS event so that we can process Esc key press to cancel
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// dragging and ignore all other key presses.
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} else if (event.type() == Clutter.EventType.KEY_PRESS && this._dragInProgress) {
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let symbol = event.get_key_symbol();
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if (symbol == Clutter.Escape) {
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this._cancelDrag(event.get_time());
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return true;
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}
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}
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return false;
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},
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/**
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* startDrag:
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* @stageX: X coordinate of event
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* @stageY: Y coordinate of event
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* @time: Event timestamp
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*
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* Directly initiate a drag and drop operation from the given actor.
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* This function is useful to call if you've specified manualMode
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* for the draggable.
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*/
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startDrag: function (stageX, stageY, time) {
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currentDraggable = this;
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this._dragInProgress = true;
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this.emit('drag-begin', time);
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if (this._onEventId)
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this._ungrabActor();
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this._grabEvents();
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this._dragStartX = stageX;
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this._dragStartY = stageY;
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if (this.actor._delegate && this.actor._delegate.getDragActor) {
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this._dragActor = this.actor._delegate.getDragActor(this._dragStartX, this._dragStartY);
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// Drag actor does not always have to be the same as actor. For example drag actor
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// can be an image that's part of the actor. So to perform "snap back" correctly we need
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// to know what was the drag actor source.
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if (this.actor._delegate.getDragActorSource) {
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this._dragActorSource = this.actor._delegate.getDragActorSource();
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// If the user dragged from the source, then position
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// the dragActor over it. Otherwise, center it
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// around the pointer
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let [sourceX, sourceY] = this._dragActorSource.get_transformed_position();
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let x, y;
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if (stageX > sourceX && stageX <= sourceX + this._dragActor.width &&
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stageY > sourceY && stageY <= sourceY + this._dragActor.height) {
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x = sourceX;
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y = sourceY;
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} else {
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x = stageX - this._dragActor.width / 2;
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y = stageY - this._dragActor.height / 2;
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}
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this._dragActor.set_position(x, y);
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} else {
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this._dragActorSource = this.actor;
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}
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this._dragOrigParent = undefined;
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this._dragOffsetX = this._dragActor.x - this._dragStartX;
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this._dragOffsetY = this._dragActor.y - this._dragStartY;
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} else {
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this._dragActor = this.actor;
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this._dragActorSource = undefined;
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this._dragOrigParent = this.actor.get_parent();
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this._dragOrigX = this._dragActor.x;
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this._dragOrigY = this._dragActor.y;
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this._dragOrigScale = this._dragActor.scale_x;
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let [actorStageX, actorStageY] = this.actor.get_transformed_position();
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this._dragOffsetX = actorStageX - this._dragStartX;
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this._dragOffsetY = actorStageY - this._dragStartY;
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// Set the actor's scale such that it will keep the same
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// transformed size when it's reparented to the stage
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let [scaledWidth, scaledHeight] = this.actor.get_transformed_size();
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this.actor.set_scale(scaledWidth / this.actor.width,
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scaledHeight / this.actor.height);
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}
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this._dragActor.reparent(this.actor.get_stage());
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this._dragActor.raise_top();
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},
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_maybeStartDrag: function(event) {
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let [stageX, stageY] = event.get_coords();
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// See if the user has moved the mouse enough to trigger a drag
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let threshold = Gtk.Settings.get_default().gtk_dnd_drag_threshold;
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if ((Math.abs(stageX - this._dragStartX) > threshold ||
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Math.abs(stageY - this._dragStartY) > threshold)) {
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this.startDrag(stageX, stageY, event.get_time());
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this._updateDragPosition(event);
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}
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return true;
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},
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_updateDragPosition : function (event) {
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let [stageX, stageY] = event.get_coords();
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// If we are dragging, update the position
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if (this._dragActor) {
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this._dragActor.set_position(stageX + this._dragOffsetX,
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stageY + this._dragOffsetY);
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// Because we want to find out what other actor is located at the current position of this._dragActor,
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// we have to temporarily hide this._dragActor.
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this._dragActor.hide();
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let target = this._dragActor.get_stage().get_actor_at_pos(Clutter.PickMode.ALL,
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stageX, stageY);
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this._dragActor.show();
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while (target) {
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if (target._delegate && target._delegate.handleDragOver) {
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let [targX, targY] = target.get_transformed_position();
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// We currently loop through all parents on drag-over even if one of the children has handled it.
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// We can check the return value of the function and break the loop if it's true if we don't want
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// to continue checking the parents.
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target._delegate.handleDragOver(this.actor._delegate, this._dragActor,
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(stageX - targX) / target.scale_x,
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(stageY - targY) / target.scale_y,
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event.get_time());
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}
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target = target.get_parent();
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}
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}
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return true;
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},
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_dragActorDropped: function(event) {
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// Find a drop target. Because we want to find out what other actor is located at
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// the current position of this._dragActor, we have to temporarily hide this._dragActor.
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this._dragActor.hide();
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let [dropX, dropY] = event.get_coords();
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let target = this._dragActor.get_stage().get_actor_at_pos(Clutter.PickMode.ALL,
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dropX, dropY);
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this._dragActor.show();
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while (target) {
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if (target._delegate && target._delegate.acceptDrop) {
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let [targX, targY] = target.get_transformed_position();
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if (target._delegate.acceptDrop(this.actor._delegate, this._dragActor,
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(dropX - targX) / target.scale_x,
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(dropY - targY) / target.scale_y,
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event.get_time())) {
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// If it accepted the drop without taking the actor,
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// destroy it.
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if (this._dragActor.get_parent() == this._dragActor.get_stage())
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this._dragActor.destroy();
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this._dragInProgress = false;
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this.emit('drag-end', event.get_time(), true);
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this._dragComplete();
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return true;
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}
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}
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target = target.get_parent();
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}
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this._cancelDrag(event.get_time());
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return true;
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},
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_cancelDrag: function(eventTime) {
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this._dragInProgress = false;
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// Snap back to the actor source if the source is still around, snap back
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// to the original location if the actor itself was being dragged or the
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// source is no longer around.
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let snapBackX = this._dragStartX + this._dragOffsetX;
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let snapBackY = this._dragStartY + this._dragOffsetY;
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if (this._dragActorSource && this._dragActorSource.visible) {
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[snapBackX, snapBackY] = this._dragActorSource.get_transformed_position();
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}
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this._snapBackInProgress = true;
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// No target, so snap back
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Tweener.addTween(this._dragActor,
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{ x: snapBackX,
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y: snapBackY,
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time: SNAP_BACK_ANIMATION_TIME,
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transition: "easeOutQuad",
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onComplete: this._onSnapBackComplete,
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onCompleteScope: this,
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onCompleteParams: [this._dragActor, eventTime]
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});
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},
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_onSnapBackComplete : function (dragActor, eventTime) {
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if (this._dragOrigParent) {
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dragActor.reparent(this._dragOrigParent);
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dragActor.set_scale(this._dragOrigScale, this._dragOrigScale);
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dragActor.set_position(this._dragOrigX, this._dragOrigY);
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} else {
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dragActor.destroy();
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}
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this.emit('drag-end', eventTime, false);
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this._snapBackInProgress = false;
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if (!this._buttonDown)
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this._dragComplete();
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},
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_dragComplete: function() {
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this._dragActor = undefined;
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currentDraggable = null;
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this._ungrabEvents();
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}
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};
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Signals.addSignalMethods(_Draggable.prototype);
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/**
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* makeDraggable:
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* @actor: Source actor
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* @manualMode: If given, do not automatically start drag and drop on click
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*
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* Create an object which controls drag and drop for the given actor.
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*/
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function makeDraggable(actor, manualMode) {
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return new _Draggable(actor, manualMode);
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}
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