lib/network/modules/CanvasRenderer.js
/**
* Initializes window.requestAnimationFrame() to a usable form.
*
* Specifically, set up this method for the case of running on node.js with jsdom enabled.
*
* NOTES:
*
* * On node.js, when calling this directly outside of this class, `window` is not defined.
* This happens even if jsdom is used.
* * For node.js + jsdom, `window` is available at the moment the constructor is called.
* For this reason, the called is placed within the constructor.
* * Even then, `window.requestAnimationFrame()` is not defined, so it still needs to be added.
* * During unit testing, it happens that the window object is reset during execution, causing
* a runtime error due to missing `requestAnimationFrame()`. This needs to be compensated for,
* see `_requestNextFrame()`.
* * Since this is a global object, it may affect other modules besides `Network`. With normal
* usage, this does not cause any problems. During unit testing, errors may occur. These have
* been compensated for, see comment block in _requestNextFrame().
*
* @private
*/
function _initRequestAnimationFrame() {
var func;
if (window !== undefined) {
func = window.requestAnimationFrame
|| window.mozRequestAnimationFrame
|| window.webkitRequestAnimationFrame
|| window.msRequestAnimationFrame;
}
if (func === undefined) {
// window or method not present, setting mock requestAnimationFrame
window.requestAnimationFrame =
function(callback) {
//console.log("Called mock requestAnimationFrame");
callback();
}
} else {
window.requestAnimationFrame = func;
}
}
let util = require('../../util');
/**
* The canvas renderer
*/
class CanvasRenderer {
/**
* @param {Object} body
* @param {Canvas} canvas
*/
constructor(body, canvas) {
_initRequestAnimationFrame();
this.body = body;
this.canvas = canvas;
this.redrawRequested = false;
this.renderTimer = undefined;
this.requiresTimeout = true;
this.renderingActive = false;
this.renderRequests = 0;
this.allowRedraw = true;
this.dragging = false;
this.options = {};
this.defaultOptions = {
hideEdgesOnDrag: false,
hideNodesOnDrag: false
};
util.extend(this.options, this.defaultOptions);
this._determineBrowserMethod();
this.bindEventListeners();
}
/**
* Binds event listeners
*/
bindEventListeners() {
this.body.emitter.on("dragStart", () => { this.dragging = true; });
this.body.emitter.on("dragEnd", () => { this.dragging = false; });
this.body.emitter.on("_resizeNodes", () => { this._resizeNodes(); });
this.body.emitter.on("_redraw", () => {
if (this.renderingActive === false) {
this._redraw();
}
});
this.body.emitter.on("_blockRedraw", () => {this.allowRedraw = false;});
this.body.emitter.on("_allowRedraw", () => {this.allowRedraw = true; this.redrawRequested = false;});
this.body.emitter.on("_requestRedraw", this._requestRedraw.bind(this));
this.body.emitter.on("_startRendering", () => {
this.renderRequests += 1;
this.renderingActive = true;
this._startRendering();
});
this.body.emitter.on("_stopRendering", () => {
this.renderRequests -= 1;
this.renderingActive = this.renderRequests > 0;
this.renderTimer = undefined;
});
this.body.emitter.on('destroy', () => {
this.renderRequests = 0;
this.allowRedraw = false;
this.renderingActive = false;
if (this.requiresTimeout === true) {
clearTimeout(this.renderTimer);
}
else {
window.cancelAnimationFrame(this.renderTimer);
}
this.body.emitter.off();
});
}
/**
*
* @param {Object} options
*/
setOptions(options) {
if (options !== undefined) {
let fields = ['hideEdgesOnDrag','hideNodesOnDrag'];
util.selectiveDeepExtend(fields,this.options, options);
}
}
/**
* Prepare the drawing of the next frame.
*
* Calls the callback when the next frame can or will be drawn.
*
* @param {function} callback
* @param {number} delay - timeout case only, wait this number of milliseconds
* @returns {function|undefined}
* @private
*/
_requestNextFrame(callback, delay) {
// During unit testing, it happens that the mock window object is reset while
// the next frame is still pending. Then, either 'window' is not present, or
// 'requestAnimationFrame()' is not present because it is not defined on the
// mock window object.
//
// As a consequence, unrelated unit tests may appear to fail, even if the problem
// described happens in the current unit test.
//
// This is not something that will happen in normal operation, but we still need
// to take it into account.
//
if (typeof window === 'undefined') return; // Doing `if (window === undefined)` does not work here!
let timer;
var myWindow = window; // Grab a reference to reduce the possibility that 'window' is reset
// while running this method.
if (this.requiresTimeout === true) {
// wait given number of milliseconds and perform the animation step function
timer = myWindow.setTimeout(callback, delay);
} else {
if (myWindow.requestAnimationFrame) {
timer = myWindow.requestAnimationFrame(callback);
}
}
return timer;
}
/**
*
* @private
*/
_startRendering() {
if (this.renderingActive === true) {
if (this.renderTimer === undefined) {
this.renderTimer = this._requestNextFrame(this._renderStep.bind(this), this.simulationInterval);
}
}
}
/**
*
* @private
*/
_renderStep() {
if (this.renderingActive === true) {
// reset the renderTimer so a new scheduled animation step can be set
this.renderTimer = undefined;
if (this.requiresTimeout === true) {
// this schedules a new simulation step
this._startRendering();
}
this._redraw();
if (this.requiresTimeout === false) {
// this schedules a new simulation step
this._startRendering();
}
}
}
/**
* Redraw the network with the current data
* chart will be resized too.
*/
redraw() {
this.body.emitter.emit('setSize');
this._redraw();
}
/**
* Redraw the network with the current data
* @private
*/
_requestRedraw() {
if (this.redrawRequested !== true && this.renderingActive === false && this.allowRedraw === true) {
this.redrawRequested = true;
this._requestNextFrame(() => {this._redraw(false);}, 0);
}
}
/**
* Redraw the network with the current data
* @param {boolean} [hidden=false] | Used to get the first estimate of the node sizes.
* Only the nodes are drawn after which they are quickly drawn over.
* @private
*/
_redraw(hidden = false) {
if (this.allowRedraw === true) {
this.body.emitter.emit("initRedraw");
this.redrawRequested = false;
// when the container div was hidden, this fixes it back up!
if (this.canvas.frame.canvas.width === 0 || this.canvas.frame.canvas.height === 0) {
this.canvas.setSize();
}
this.canvas.setTransform();
let ctx = this.canvas.getContext();
// clear the canvas
let w = this.canvas.frame.canvas.clientWidth;
let h = this.canvas.frame.canvas.clientHeight;
ctx.clearRect(0, 0, w, h);
// if the div is hidden, we stop the redraw here for performance.
if (this.canvas.frame.clientWidth === 0) {
return;
}
// set scaling and translation
ctx.save();
ctx.translate(this.body.view.translation.x, this.body.view.translation.y);
ctx.scale(this.body.view.scale, this.body.view.scale);
ctx.beginPath();
this.body.emitter.emit("beforeDrawing", ctx);
ctx.closePath();
if (hidden === false) {
if (this.dragging === false || (this.dragging === true && this.options.hideEdgesOnDrag === false)) {
this._drawEdges(ctx);
}
}
if (this.dragging === false || (this.dragging === true && this.options.hideNodesOnDrag === false)) {
this._drawNodes(ctx, hidden);
}
ctx.beginPath();
this.body.emitter.emit("afterDrawing", ctx);
ctx.closePath();
// restore original scaling and translation
ctx.restore();
if (hidden === true) {
ctx.clearRect(0, 0, w, h);
}
}
}
/**
* Redraw all nodes
*
* @param {CanvasRenderingContext2D} ctx
* @param {boolean} [alwaysShow]
* @private
*/
_resizeNodes() {
this.canvas.setTransform();
let ctx = this.canvas.getContext();
ctx.save();
ctx.translate(this.body.view.translation.x, this.body.view.translation.y);
ctx.scale(this.body.view.scale, this.body.view.scale);
let nodes = this.body.nodes;
let node;
// resize all nodes
for (let nodeId in nodes) {
if (nodes.hasOwnProperty(nodeId)) {
node = nodes[nodeId];
node.resize(ctx);
node.updateBoundingBox(ctx, node.selected);
}
}
// restore original scaling and translation
ctx.restore();
}
/**
* Redraw all nodes
*
* @param {CanvasRenderingContext2D} ctx 2D context of a HTML canvas
* @param {boolean} [alwaysShow]
* @private
*/
_drawNodes(ctx, alwaysShow = false) {
let nodes = this.body.nodes;
let nodeIndices = this.body.nodeIndices;
let node;
let selected = [];
let margin = 20;
let topLeft = this.canvas.DOMtoCanvas({x:-margin,y:-margin});
let bottomRight = this.canvas.DOMtoCanvas({
x: this.canvas.frame.canvas.clientWidth+margin,
y: this.canvas.frame.canvas.clientHeight+margin
});
let viewableArea = {top:topLeft.y,left:topLeft.x,bottom:bottomRight.y,right:bottomRight.x};
// draw unselected nodes;
for (let i = 0; i < nodeIndices.length; i++) {
node = nodes[nodeIndices[i]];
// set selected nodes aside
if (node.isSelected()) {
selected.push(nodeIndices[i]);
}
else {
if (alwaysShow === true) {
node.draw(ctx);
}
else if (node.isBoundingBoxOverlappingWith(viewableArea) === true) {
node.draw(ctx);
}
else {
node.updateBoundingBox(ctx, node.selected);
}
}
}
// draw the selected nodes on top
for (let i = 0; i < selected.length; i++) {
node = nodes[selected[i]];
node.draw(ctx);
}
}
/**
* Redraw all edges
* @param {CanvasRenderingContext2D} ctx 2D context of a HTML canvas
* @private
*/
_drawEdges(ctx) {
let edges = this.body.edges;
let edgeIndices = this.body.edgeIndices;
let edge;
for (let i = 0; i < edgeIndices.length; i++) {
edge = edges[edgeIndices[i]];
if (edge.connected === true) {
edge.draw(ctx);
}
}
}
/**
* Determine if the browser requires a setTimeout or a requestAnimationFrame. This was required because
* some implementations (safari and IE9) did not support requestAnimationFrame
* @private
*/
_determineBrowserMethod() {
if (typeof window !== 'undefined') {
let browserType = navigator.userAgent.toLowerCase();
this.requiresTimeout = false;
if (browserType.indexOf('msie 9.0') != -1) { // IE 9
this.requiresTimeout = true;
}
else if (browserType.indexOf('safari') != -1) { // safari
if (browserType.indexOf('chrome') <= -1) {
this.requiresTimeout = true;
}
}
}
else {
this.requiresTimeout = true;
}
}
}
export default CanvasRenderer;