scratch-blocks/core/dragged_connection_manager.js
2020-05-17 20:06:13 -04:00

260 lines
8.3 KiB
JavaScript

/**
* @license
* Visual Blocks Editor
*
* Copyright 2017 Google Inc.
* https://developers.google.com/blockly/
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/**
* @fileoverview Class that controls updates to connections during drags.
* @author fenichel@google.com (Rachel Fenichel)
*/
'use strict';
goog.provide('Blockly.DraggedConnectionManager');
goog.require('Blockly.BlockAnimations');
goog.require('Blockly.RenderedConnection');
goog.require('goog.math.Coordinate');
/**
* Class that controls updates to connections during drags. It is primarily
* responsible for finding the closest eligible connection and highlighting or
* unhiglighting it as needed during a drag.
* @param {!Blockly.BlockSvg} block The top block in the stack being dragged.
* @constructor
*/
Blockly.DraggedConnectionManager = function(block) {
Blockly.selected = block;
/**
* The top block in the stack being dragged.
* Does not change during a drag.
* @type {!Blockly.Block}
* @private
*/
this.topBlock_ = block;
/**
* The workspace on which these connections are being dragged.
* Does not change during a drag.
* @type {!Blockly.WorkspaceSvg}
* @private
*/
this.workspace_ = block.workspace;
/**
* The connections on the dragging blocks that are available to connect to
* other blocks. This includes all open connections on the top block, as well
* as the last connection on the block stack.
* Does not change during a drag.
* @type {!Array.<!Blockly.RenderedConnection>}
* @private
*/
this.availableConnections_ = this.initAvailableConnections_();
/**
* The connection that this block would connect to if released immediately.
* Updated on every mouse move.
* @type {Blockly.RenderedConnection}
* @private
*/
this.closestConnection_ = null;
/**
* The connection that would connect to this.closestConnection_ if this block
* were released immediately.
* Updated on every mouse move.
* @type {Blockly.RenderedConnection}
* @private
*/
this.localConnection_ = null;
/**
* The distance between this.closestConnection_ and this.localConnection_,
* in workspace units.
* Updated on every mouse move.
* @type {number}
* @private
*/
this.radiusConnection_ = 0;
/**
* Whether the block would be deleted if it were dropped immediately.
* Updated on every mouse move.
* @type {boolean}
* @private
*/
this.wouldDeleteBlock_ = false;
};
/**
* Sever all links from this object.
* @package
*/
Blockly.DraggedConnectionManager.prototype.dispose = function() {
this.topBlock_ = null;
this.workspace_ = null;
this.availableConnections_.length = 0;
this.closestConnection_ = null;
this.localConnection_ = null;
};
/**
* Return whether the block would be deleted if dropped immediately, based on
* information from the most recent move event.
* @return {boolean} true if the block would be deleted if dropped immediately.
* @package
*/
Blockly.DraggedConnectionManager.prototype.wouldDeleteBlock = function() {
return this.wouldDeleteBlock_;
};
/**
* Return whether the block would be connected if dropped immediately, based on
* information from the most recent move event.
* @return {boolean} true if the block would be connected if dropped immediately.
* @package
*/
Blockly.DraggedConnectionManager.prototype.wouldConnectBlock = function() {
return !!this.closestConnection_;
};
/**
* Connect to the closest connection and render the results.
* This should be called at the end of a drag.
* @package
*/
Blockly.DraggedConnectionManager.prototype.applyConnections = function() {
if (this.closestConnection_) {
// Connect two blocks together.
this.localConnection_.connect(this.closestConnection_);
if (this.topBlock_.rendered) {
// Trigger a connection animation.
// Determine which connection is inferior (lower in the source stack).
var inferiorConnection = this.localConnection_.isSuperior() ?
this.closestConnection_ : this.localConnection_;
Blockly.BlockAnimations.connectionUiEffect(
inferiorConnection.getSourceBlock());
// Bring the just-edited stack to the front.
var rootBlock = this.topBlock_.getRootBlock();
rootBlock.bringToFront();
}
this.removeHighlighting_();
}
};
/**
* Update highlighted connections based on the most recent move location.
* @param {!goog.math.Coordinate} dxy Position relative to drag start,
* in workspace units.
* @param {?number} deleteArea One of {@link Blockly.DELETE_AREA_TRASH},
* {@link Blockly.DELETE_AREA_TOOLBOX}, or {@link Blockly.DELETE_AREA_NONE}.
* @param {?boolean} isOutside True if the drag is going outside the blocks workspace
* @package
*/
Blockly.DraggedConnectionManager.prototype.update = function(dxy, deleteArea, isOutside) {
var oldClosestConnection;
var closestConnectionChanged;
// If dragged outside, don't connect, since the connections aren't visible.
if (!isOutside) {
oldClosestConnection = this.closestConnection_;
closestConnectionChanged = this.updateClosest_(dxy);
if (closestConnectionChanged && oldClosestConnection) {
oldClosestConnection.unhighlight();
}
} else if (this.closestConnection_) {
this.closestConnection_.unhighlight();
this.closestConnection_ = null;
}
// Prefer connecting over dropping into the trash can, but prefer dragging to
// the toolbox over connecting to other blocks.
var wouldConnect = !!this.closestConnection_ &&
deleteArea != Blockly.DELETE_AREA_TOOLBOX;
var wouldDelete = !!deleteArea && !this.topBlock_.getParent() &&
this.topBlock_.isDeletable();
this.wouldDeleteBlock_ = wouldDelete && !wouldConnect;
if (!this.wouldDeleteBlock_ && closestConnectionChanged &&
this.closestConnection_) {
this.addHighlighting_();
}
};
/**
* Remove highlighting from the currently highlighted connection, if it exists.
* @private
*/
Blockly.DraggedConnectionManager.prototype.removeHighlighting_ = function() {
if (this.closestConnection_) {
this.closestConnection_.unhighlight();
}
};
/**
* Add highlighting to the closest connection, if it exists.
* @private
*/
Blockly.DraggedConnectionManager.prototype.addHighlighting_ = function() {
if (this.closestConnection_) {
this.closestConnection_.highlight();
}
};
/**
* Populate the list of available connections on this block stack. This should
* only be called once, at the beginning of a drag.
* @return {!Array.<!Blockly.RenderedConnection>} a list of available
* connections.
* @private
*/
Blockly.DraggedConnectionManager.prototype.initAvailableConnections_ = function() {
var available = this.topBlock_.getConnections_(false);
// Also check the last connection on this stack
var lastOnStack = this.topBlock_.lastConnectionInStack();
if (lastOnStack && lastOnStack != this.topBlock_.nextConnection) {
available.push(lastOnStack);
}
return available;
};
/**
* Find the new closest connection, and update internal state in response.
* @param {!goog.math.Coordinate} dxy Position relative to the drag start,
* in workspace units.
* @return {boolean} Whether the closest connection has changed.
* @private
*/
Blockly.DraggedConnectionManager.prototype.updateClosest_ = function(dxy) {
var oldClosestConnection = this.closestConnection_;
this.closestConnection_ = null;
this.localConnection_ = null;
this.radiusConnection_ = Blockly.SNAP_RADIUS;
for (var i = 0; i < this.availableConnections_.length; i++) {
var myConnection = this.availableConnections_[i];
var neighbour = myConnection.closest(this.radiusConnection_, dxy);
if (neighbour.connection) {
this.closestConnection_ = neighbour.connection;
this.localConnection_ = myConnection;
this.radiusConnection_ = neighbour.radius;
}
}
return oldClosestConnection != this.closestConnection_;
};