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