let Hammer = require('../../module/hammer');
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let hammerUtil = require('../../hammerUtil');
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let util = require('../../util');
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/**
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* Create the main frame for the Network.
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* This function is executed once when a Network object is created. The frame
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* contains a canvas, and this canvas contains all objects like the axis and
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* nodes.
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*/
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class Canvas {
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/**
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* @param {Object} body
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*/
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constructor(body) {
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this.body = body;
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this.pixelRatio = 1;
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this.resizeTimer = undefined;
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this.resizeFunction = this._onResize.bind(this);
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this.cameraState = {};
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this.initialized = false;
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this.canvasViewCenter = {};
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this.options = {};
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this.defaultOptions = {
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autoResize: true,
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height: '100%',
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width: '100%'
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};
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util.extend(this.options, this.defaultOptions);
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this.bindEventListeners();
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}
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/**
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* Binds event listeners
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*/
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bindEventListeners() {
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// bind the events
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this.body.emitter.once("resize", (obj) => {
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if (obj.width !== 0) {
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this.body.view.translation.x = obj.width * 0.5;
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}
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if (obj.height !== 0) {
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this.body.view.translation.y = obj.height * 0.5;
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}
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});
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this.body.emitter.on("setSize", this.setSize.bind(this));
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this.body.emitter.on("destroy", () => {
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this.hammerFrame.destroy();
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this.hammer.destroy();
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this._cleanUp();
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});
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}
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/**
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* @param {Object} options
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*/
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setOptions(options) {
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if (options !== undefined) {
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let fields = ['width','height','autoResize'];
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util.selectiveDeepExtend(fields,this.options, options);
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}
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if (this.options.autoResize === true) {
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// automatically adapt to a changing size of the browser.
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this._cleanUp();
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this.resizeTimer = setInterval(() => {
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let changed = this.setSize();
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if (changed === true) {
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this.body.emitter.emit("_requestRedraw");
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}
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}, 1000);
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this.resizeFunction = this._onResize.bind(this);
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util.addEventListener(window,'resize',this.resizeFunction);
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}
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}
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/**
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* @private
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*/
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_cleanUp() {
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// automatically adapt to a changing size of the browser.
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if (this.resizeTimer !== undefined) {
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clearInterval(this.resizeTimer);
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}
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util.removeEventListener(window,'resize',this.resizeFunction);
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this.resizeFunction = undefined;
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}
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/**
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* @private
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*/
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_onResize() {
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this.setSize();
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this.body.emitter.emit("_redraw");
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}
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/**
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* Get and store the cameraState
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*
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* @param {number} [pixelRatio=this.pixelRatio]
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* @private
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*/
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_getCameraState(pixelRatio = this.pixelRatio) {
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if (this.initialized === true) {
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this.cameraState.previousWidth = this.frame.canvas.width / pixelRatio;
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this.cameraState.previousHeight = this.frame.canvas.height / pixelRatio;
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this.cameraState.scale = this.body.view.scale;
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this.cameraState.position = this.DOMtoCanvas({
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x: 0.5 * this.frame.canvas.width / pixelRatio,
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y: 0.5 * this.frame.canvas.height / pixelRatio
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});
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}
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}
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/**
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* Set the cameraState
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* @private
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*/
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_setCameraState() {
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if (this.cameraState.scale !== undefined &&
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this.frame.canvas.clientWidth !== 0 &&
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this.frame.canvas.clientHeight !== 0 &&
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this.pixelRatio !== 0 &&
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this.cameraState.previousWidth > 0) {
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let widthRatio = (this.frame.canvas.width / this.pixelRatio) / this.cameraState.previousWidth;
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let heightRatio = (this.frame.canvas.height / this.pixelRatio) / this.cameraState.previousHeight;
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let newScale = this.cameraState.scale;
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if (widthRatio != 1 && heightRatio != 1) {
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newScale = this.cameraState.scale * 0.5 * (widthRatio + heightRatio);
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}
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else if (widthRatio != 1) {
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newScale = this.cameraState.scale * widthRatio;
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}
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else if (heightRatio != 1) {
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newScale = this.cameraState.scale * heightRatio;
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}
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this.body.view.scale = newScale;
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// this comes from the view module.
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var currentViewCenter = this.DOMtoCanvas({
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x: 0.5 * this.frame.canvas.clientWidth,
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y: 0.5 * this.frame.canvas.clientHeight
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});
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var distanceFromCenter = { // offset from view, distance view has to change by these x and y to center the node
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x: currentViewCenter.x - this.cameraState.position.x,
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y: currentViewCenter.y - this.cameraState.position.y
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};
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this.body.view.translation.x += distanceFromCenter.x * this.body.view.scale;
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this.body.view.translation.y += distanceFromCenter.y * this.body.view.scale;
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}
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}
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/**
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*
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* @param {number|string} value
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* @returns {string}
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* @private
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*/
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_prepareValue(value) {
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if (typeof value === 'number') {
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return value + 'px';
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}
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else if (typeof value === 'string') {
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if (value.indexOf('%') !== -1 || value.indexOf('px') !== -1) {
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return value;
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}
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else if (value.indexOf('%') === -1) {
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return value + 'px';
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}
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}
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throw new Error('Could not use the value supplied for width or height:' + value);
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}
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/**
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* Create the HTML
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*/
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_create() {
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// remove all elements from the container element.
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while (this.body.container.hasChildNodes()) {
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this.body.container.removeChild(this.body.container.firstChild);
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}
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this.frame = document.createElement('div');
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this.frame.className = 'vis-network';
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this.frame.style.position = 'relative';
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this.frame.style.overflow = 'hidden';
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this.frame.tabIndex = 900; // tab index is required for keycharm to bind keystrokes to the div instead of the window
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//////////////////////////////////////////////////////////////////
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this.frame.canvas = document.createElement("canvas");
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this.frame.canvas.style.position = 'relative';
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this.frame.appendChild(this.frame.canvas);
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if (!this.frame.canvas.getContext) {
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let noCanvas = document.createElement( 'DIV' );
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noCanvas.style.color = 'red';
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noCanvas.style.fontWeight = 'bold' ;
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noCanvas.style.padding = '10px';
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noCanvas.innerHTML = 'Error: your browser does not support HTML canvas';
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this.frame.canvas.appendChild(noCanvas);
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}
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else {
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this._setPixelRatio();
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this.setTransform();
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}
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// add the frame to the container element
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this.body.container.appendChild(this.frame);
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this.body.view.scale = 1;
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this.body.view.translation = {x: 0.5 * this.frame.canvas.clientWidth,y: 0.5 * this.frame.canvas.clientHeight};
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this._bindHammer();
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}
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/**
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* This function binds hammer, it can be repeated over and over due to the uniqueness check.
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* @private
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*/
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_bindHammer() {
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if (this.hammer !== undefined) {
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this.hammer.destroy();
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}
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this.drag = {};
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this.pinch = {};
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// init hammer
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this.hammer = new Hammer(this.frame.canvas);
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this.hammer.get('pinch').set({enable: true});
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// enable to get better response, todo: test on mobile.
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this.hammer.get('pan').set({threshold:5, direction: Hammer.DIRECTION_ALL});
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hammerUtil.onTouch(this.hammer, (event) => {this.body.eventListeners.onTouch(event)});
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this.hammer.on('tap', (event) => {this.body.eventListeners.onTap(event)});
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this.hammer.on('doubletap', (event) => {this.body.eventListeners.onDoubleTap(event)});
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this.hammer.on('press', (event) => {this.body.eventListeners.onHold(event)});
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this.hammer.on('panstart', (event) => {this.body.eventListeners.onDragStart(event)});
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this.hammer.on('panmove', (event) => {this.body.eventListeners.onDrag(event)});
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this.hammer.on('panend', (event) => {this.body.eventListeners.onDragEnd(event)});
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this.hammer.on('pinch', (event) => {this.body.eventListeners.onPinch(event)});
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// TODO: neatly cleanup these handlers when re-creating the Canvas, IF these are done with hammer, event.stopPropagation will not work?
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this.frame.canvas.addEventListener('mousewheel', (event) => {this.body.eventListeners.onMouseWheel(event)});
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this.frame.canvas.addEventListener('DOMMouseScroll', (event) => {this.body.eventListeners.onMouseWheel(event)});
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this.frame.canvas.addEventListener('mousemove', (event) => {this.body.eventListeners.onMouseMove(event)});
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this.frame.canvas.addEventListener('contextmenu', (event) => {this.body.eventListeners.onContext(event)});
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this.hammerFrame = new Hammer(this.frame);
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hammerUtil.onRelease(this.hammerFrame, (event) => {this.body.eventListeners.onRelease(event)});
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}
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/**
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* Set a new size for the network
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* @param {string} width Width in pixels or percentage (for example '800px'
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* or '50%')
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* @param {string} height Height in pixels or percentage (for example '400px'
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* or '30%')
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* @returns {boolean}
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*/
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setSize(width = this.options.width, height = this.options.height) {
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width = this._prepareValue(width);
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height= this._prepareValue(height);
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let emitEvent = false;
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let oldWidth = this.frame.canvas.width;
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let oldHeight = this.frame.canvas.height;
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// update the pixel ratio
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//
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// NOTE: Comment in following is rather inconsistent; this is the ONLY place in the code
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// where it is assumed that the pixel ratio could change at runtime.
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// The only way I can think of this happening is a rotating screen or tablet; but then
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// there should be a mechanism for reloading the data (TODO: check if this is present).
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//
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// If the assumption is true (i.e. pixel ratio can change at runtime), then *all* usage
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// of pixel ratio must be overhauled for this.
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//
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// For the time being, I will humor the assumption here, and in the rest of the code assume it is
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// constant.
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let previousRatio = this.pixelRatio; // we cache this because the camera state storage needs the old value
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this._setPixelRatio();
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if (width != this.options.width || height != this.options.height || this.frame.style.width != width || this.frame.style.height != height) {
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this._getCameraState(previousRatio);
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this.frame.style.width = width;
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this.frame.style.height = height;
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this.frame.canvas.style.width = '100%';
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this.frame.canvas.style.height = '100%';
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this.frame.canvas.width = Math.round(this.frame.canvas.clientWidth * this.pixelRatio);
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this.frame.canvas.height = Math.round(this.frame.canvas.clientHeight * this.pixelRatio);
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this.options.width = width;
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this.options.height = height;
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this.canvasViewCenter = {
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x: 0.5 * this.frame.clientWidth,
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y: 0.5 * this.frame.clientHeight
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};
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emitEvent = true;
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}
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else {
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// this would adapt the width of the canvas to the width from 100% if and only if
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// there is a change.
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let newWidth = Math.round(this.frame.canvas.clientWidth * this.pixelRatio);
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let newHeight = Math.round(this.frame.canvas.clientHeight * this.pixelRatio);
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// store the camera if there is a change in size.
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if (this.frame.canvas.width !== newWidth || this.frame.canvas.height !== newHeight) {
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this._getCameraState(previousRatio);
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}
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if (this.frame.canvas.width !== newWidth) {
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this.frame.canvas.width = newWidth;
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emitEvent = true;
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}
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if (this.frame.canvas.height !== newHeight) {
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this.frame.canvas.height = newHeight;
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emitEvent = true;
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}
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}
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if (emitEvent === true) {
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this.body.emitter.emit('resize', {
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width : Math.round(this.frame.canvas.width / this.pixelRatio),
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height : Math.round(this.frame.canvas.height / this.pixelRatio),
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oldWidth : Math.round(oldWidth / this.pixelRatio),
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oldHeight: Math.round(oldHeight / this.pixelRatio)
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});
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// restore the camera on change.
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this._setCameraState();
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}
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// set initialized so the get and set camera will work from now on.
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this.initialized = true;
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return emitEvent;
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}
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/**
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*
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* @returns {CanvasRenderingContext2D}
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*/
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getContext() {
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return this.frame.canvas.getContext("2d");
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}
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/**
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* Determine the pixel ratio for various browsers.
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*
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* @returns {number}
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* @private
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*/
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_determinePixelRatio() {
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let ctx = this.getContext();
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if (ctx === undefined) {
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throw new Error("Could not get canvax context");
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}
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var numerator = 1;
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if(typeof window !== 'undefined') { // (window !== undefined) doesn't work here!
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// Protection during unit tests, where 'window' can be missing
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numerator = (window.devicePixelRatio || 1);
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}
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var denominator = (ctx.webkitBackingStorePixelRatio ||
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ctx.mozBackingStorePixelRatio ||
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ctx.msBackingStorePixelRatio ||
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ctx.oBackingStorePixelRatio ||
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ctx.backingStorePixelRatio || 1);
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return numerator / denominator;
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}
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/**
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* Lazy determination of pixel ratio.
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*
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* @private
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*/
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_setPixelRatio() {
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this.pixelRatio = this._determinePixelRatio();
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}
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/**
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* Set the transform in the contained context, based on its pixelRatio
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*/
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setTransform() {
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let ctx = this.getContext();
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if (ctx === undefined) {
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throw new Error("Could not get canvax context");
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}
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ctx.setTransform(this.pixelRatio, 0, 0, this.pixelRatio, 0, 0);
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}
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/**
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* Convert the X coordinate in DOM-space (coordinate point in browser relative to the container div) to
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* the X coordinate in canvas-space (the simulation sandbox, which the camera looks upon)
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* @param {number} x
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* @returns {number}
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* @private
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*/
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_XconvertDOMtoCanvas(x) {
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return (x - this.body.view.translation.x) / this.body.view.scale;
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}
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/**
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* Convert the X coordinate in canvas-space (the simulation sandbox, which the camera looks upon) to
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* the X coordinate in DOM-space (coordinate point in browser relative to the container div)
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* @param {number} x
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* @returns {number}
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* @private
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*/
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_XconvertCanvasToDOM(x) {
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return x * this.body.view.scale + this.body.view.translation.x;
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}
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/**
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* Convert the Y coordinate in DOM-space (coordinate point in browser relative to the container div) to
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* the Y coordinate in canvas-space (the simulation sandbox, which the camera looks upon)
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* @param {number} y
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* @returns {number}
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* @private
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*/
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_YconvertDOMtoCanvas(y) {
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return (y - this.body.view.translation.y) / this.body.view.scale;
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}
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/**
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* Convert the Y coordinate in canvas-space (the simulation sandbox, which the camera looks upon) to
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* the Y coordinate in DOM-space (coordinate point in browser relative to the container div)
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* @param {number} y
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* @returns {number}
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* @private
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*/
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_YconvertCanvasToDOM(y) {
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return y * this.body.view.scale + this.body.view.translation.y;
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}
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/**
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* @param {point} pos
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* @returns {point}
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*/
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canvasToDOM (pos) {
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return {x: this._XconvertCanvasToDOM(pos.x), y: this._YconvertCanvasToDOM(pos.y)};
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}
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/**
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*
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* @param {point} pos
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* @returns {point}
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*/
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DOMtoCanvas (pos) {
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return {x: this._XconvertDOMtoCanvas(pos.x), y: this._YconvertDOMtoCanvas(pos.y)};
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}
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}
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export default Canvas;
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