497 lines
18 KiB
JavaScript
497 lines
18 KiB
JavaScript
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/*!
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* Signature Pad v3.0.0-beta.4 | https://github.com/szimek/signature_pad
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* (c) 2020 Szymon Nowak | Released under the MIT license
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*/
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class Point {
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constructor(x, y, time) {
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this.x = x;
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this.y = y;
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this.time = time || Date.now();
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}
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distanceTo(start) {
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return Math.sqrt(Math.pow(this.x - start.x, 2) + Math.pow(this.y - start.y, 2));
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}
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equals(other) {
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return this.x === other.x && this.y === other.y && this.time === other.time;
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}
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velocityFrom(start) {
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return this.time !== start.time
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? this.distanceTo(start) / (this.time - start.time)
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: 0;
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}
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}
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class Bezier {
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constructor(startPoint, control2, control1, endPoint, startWidth, endWidth) {
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this.startPoint = startPoint;
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this.control2 = control2;
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this.control1 = control1;
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this.endPoint = endPoint;
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this.startWidth = startWidth;
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this.endWidth = endWidth;
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}
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static fromPoints(points, widths) {
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const c2 = this.calculateControlPoints(points[0], points[1], points[2]).c2;
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const c3 = this.calculateControlPoints(points[1], points[2], points[3]).c1;
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return new Bezier(points[1], c2, c3, points[2], widths.start, widths.end);
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}
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static calculateControlPoints(s1, s2, s3) {
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const dx1 = s1.x - s2.x;
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const dy1 = s1.y - s2.y;
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const dx2 = s2.x - s3.x;
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const dy2 = s2.y - s3.y;
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const m1 = { x: (s1.x + s2.x) / 2.0, y: (s1.y + s2.y) / 2.0 };
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const m2 = { x: (s2.x + s3.x) / 2.0, y: (s2.y + s3.y) / 2.0 };
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const l1 = Math.sqrt(dx1 * dx1 + dy1 * dy1);
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const l2 = Math.sqrt(dx2 * dx2 + dy2 * dy2);
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const dxm = m1.x - m2.x;
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const dym = m1.y - m2.y;
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const k = l2 / (l1 + l2);
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const cm = { x: m2.x + dxm * k, y: m2.y + dym * k };
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const tx = s2.x - cm.x;
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const ty = s2.y - cm.y;
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return {
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c1: new Point(m1.x + tx, m1.y + ty),
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c2: new Point(m2.x + tx, m2.y + ty),
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};
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}
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length() {
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const steps = 10;
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let length = 0;
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let px;
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let py;
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for (let i = 0; i <= steps; i += 1) {
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const t = i / steps;
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const cx = this.point(t, this.startPoint.x, this.control1.x, this.control2.x, this.endPoint.x);
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const cy = this.point(t, this.startPoint.y, this.control1.y, this.control2.y, this.endPoint.y);
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if (i > 0) {
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const xdiff = cx - px;
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const ydiff = cy - py;
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length += Math.sqrt(xdiff * xdiff + ydiff * ydiff);
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}
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px = cx;
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py = cy;
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}
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return length;
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}
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point(t, start, c1, c2, end) {
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return (start * (1.0 - t) * (1.0 - t) * (1.0 - t))
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+ (3.0 * c1 * (1.0 - t) * (1.0 - t) * t)
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+ (3.0 * c2 * (1.0 - t) * t * t)
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+ (end * t * t * t);
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}
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}
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function throttle(fn, wait = 250) {
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let previous = 0;
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let timeout = null;
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let result;
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let storedContext;
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let storedArgs;
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const later = () => {
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previous = Date.now();
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timeout = null;
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result = fn.apply(storedContext, storedArgs);
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if (!timeout) {
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storedContext = null;
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storedArgs = [];
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}
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};
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return function wrapper(...args) {
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const now = Date.now();
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const remaining = wait - (now - previous);
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storedContext = this;
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storedArgs = args;
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if (remaining <= 0 || remaining > wait) {
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if (timeout) {
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clearTimeout(timeout);
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timeout = null;
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}
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previous = now;
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result = fn.apply(storedContext, storedArgs);
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if (!timeout) {
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storedContext = null;
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storedArgs = [];
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}
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}
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else if (!timeout) {
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timeout = window.setTimeout(later, remaining);
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}
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return result;
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};
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}
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class SignaturePad {
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constructor(canvas, options = {}) {
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this.canvas = canvas;
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this.options = options;
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this._handleMouseDown = (event) => {
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if (event.which === 1) {
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this._mouseButtonDown = true;
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this._strokeBegin(event);
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}
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};
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this._handleMouseMove = (event) => {
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if (this._mouseButtonDown) {
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this._strokeMoveUpdate(event);
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}
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};
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this._handleMouseUp = (event) => {
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if (event.which === 1 && this._mouseButtonDown) {
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this._mouseButtonDown = false;
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this._strokeEnd(event);
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}
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};
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this._handleTouchStart = (event) => {
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event.preventDefault();
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if (event.targetTouches.length === 1) {
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const touch = event.changedTouches[0];
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this._strokeBegin(touch);
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}
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};
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this._handleTouchMove = (event) => {
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event.preventDefault();
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const touch = event.targetTouches[0];
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this._strokeMoveUpdate(touch);
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};
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this._handleTouchEnd = (event) => {
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const wasCanvasTouched = event.target === this.canvas;
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if (wasCanvasTouched) {
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event.preventDefault();
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const touch = event.changedTouches[0];
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this._strokeEnd(touch);
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}
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};
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this.velocityFilterWeight = options.velocityFilterWeight || 0.7;
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this.minWidth = options.minWidth || 0.5;
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this.maxWidth = options.maxWidth || 2.5;
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this.throttle = ('throttle' in options ? options.throttle : 16);
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this.minDistance = ('minDistance' in options
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? options.minDistance
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: 5);
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this.dotSize =
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options.dotSize ||
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function dotSize() {
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return (this.minWidth + this.maxWidth) / 2;
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};
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this.penColor = options.penColor || 'black';
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this.backgroundColor = options.backgroundColor || 'rgba(0,0,0,0)';
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this.onBegin = options.onBegin;
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this.onEnd = options.onEnd;
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this._strokeMoveUpdate = this.throttle
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? throttle(SignaturePad.prototype._strokeUpdate, this.throttle)
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: SignaturePad.prototype._strokeUpdate;
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this._ctx = canvas.getContext('2d');
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this.clear();
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this.on();
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}
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clear() {
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const { _ctx: ctx, canvas } = this;
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ctx.fillStyle = this.backgroundColor;
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ctx.clearRect(0, 0, canvas.width, canvas.height);
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ctx.fillRect(0, 0, canvas.width, canvas.height);
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this._data = [];
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this._reset();
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this._isEmpty = true;
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}
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fromDataURL(dataUrl, options = {}, callback) {
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const image = new Image();
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const ratio = options.ratio || window.devicePixelRatio || 1;
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const width = options.width || this.canvas.width / ratio;
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const height = options.height || this.canvas.height / ratio;
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this._reset();
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image.onload = () => {
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this._ctx.drawImage(image, 0, 0, width, height);
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if (callback) {
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callback();
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}
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};
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image.onerror = (error) => {
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if (callback) {
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callback(error);
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}
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};
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image.src = dataUrl;
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this._isEmpty = false;
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}
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toDataURL(type = 'image/png', encoderOptions) {
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switch (type) {
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case 'image/svg+xml':
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return this._toSVG();
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default:
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return this.canvas.toDataURL(type, encoderOptions);
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}
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}
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on() {
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this.canvas.style.touchAction = 'none';
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this.canvas.style.msTouchAction = 'none';
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if (window.PointerEvent) {
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this._handlePointerEvents();
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}
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else {
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this._handleMouseEvents();
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if ('ontouchstart' in window) {
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this._handleTouchEvents();
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}
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}
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}
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off() {
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this.canvas.style.touchAction = 'auto';
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this.canvas.style.msTouchAction = 'auto';
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this.canvas.removeEventListener('pointerdown', this._handleMouseDown);
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this.canvas.removeEventListener('pointermove', this._handleMouseMove);
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document.removeEventListener('pointerup', this._handleMouseUp);
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this.canvas.removeEventListener('mousedown', this._handleMouseDown);
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this.canvas.removeEventListener('mousemove', this._handleMouseMove);
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document.removeEventListener('mouseup', this._handleMouseUp);
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this.canvas.removeEventListener('touchstart', this._handleTouchStart);
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this.canvas.removeEventListener('touchmove', this._handleTouchMove);
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this.canvas.removeEventListener('touchend', this._handleTouchEnd);
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}
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isEmpty() {
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return this._isEmpty;
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}
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fromData(pointGroups) {
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this.clear();
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this._fromData(pointGroups, ({ color, curve }) => this._drawCurve({ color, curve }), ({ color, point }) => this._drawDot({ color, point }));
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this._data = pointGroups;
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}
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toData() {
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return this._data;
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}
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_strokeBegin(event) {
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const newPointGroup = {
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color: this.penColor,
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points: [],
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};
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if (typeof this.onBegin === 'function') {
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this.onBegin(event);
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}
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this._data.push(newPointGroup);
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this._reset();
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this._strokeUpdate(event);
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}
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_strokeUpdate(event) {
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if (this._data.length === 0) {
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this._strokeBegin(event);
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return;
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}
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const x = event.clientX;
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const y = event.clientY;
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const point = this._createPoint(x, y);
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const lastPointGroup = this._data[this._data.length - 1];
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const lastPoints = lastPointGroup.points;
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const lastPoint = lastPoints.length > 0 && lastPoints[lastPoints.length - 1];
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const isLastPointTooClose = lastPoint
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? point.distanceTo(lastPoint) <= this.minDistance
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: false;
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const color = lastPointGroup.color;
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if (!lastPoint || !(lastPoint && isLastPointTooClose)) {
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const curve = this._addPoint(point);
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if (!lastPoint) {
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this._drawDot({ color, point });
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}
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else if (curve) {
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this._drawCurve({ color, curve });
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}
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lastPoints.push({
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time: point.time,
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x: point.x,
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y: point.y,
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});
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}
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}
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_strokeEnd(event) {
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this._strokeUpdate(event);
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if (typeof this.onEnd === 'function') {
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this.onEnd(event);
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}
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}
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_handlePointerEvents() {
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this._mouseButtonDown = false;
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this.canvas.addEventListener('pointerdown', this._handleMouseDown);
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this.canvas.addEventListener('pointermove', this._handleMouseMove);
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document.addEventListener('pointerup', this._handleMouseUp);
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}
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_handleMouseEvents() {
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this._mouseButtonDown = false;
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this.canvas.addEventListener('mousedown', this._handleMouseDown);
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this.canvas.addEventListener('mousemove', this._handleMouseMove);
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document.addEventListener('mouseup', this._handleMouseUp);
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}
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_handleTouchEvents() {
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this.canvas.addEventListener('touchstart', this._handleTouchStart);
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this.canvas.addEventListener('touchmove', this._handleTouchMove);
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this.canvas.addEventListener('touchend', this._handleTouchEnd);
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}
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_reset() {
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this._lastPoints = [];
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this._lastVelocity = 0;
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this._lastWidth = (this.minWidth + this.maxWidth) / 2;
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this._ctx.fillStyle = this.penColor;
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}
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_createPoint(x, y) {
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const rect = this.canvas.getBoundingClientRect();
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return new Point(x - rect.left, y - rect.top, new Date().getTime());
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}
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_addPoint(point) {
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const { _lastPoints } = this;
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_lastPoints.push(point);
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if (_lastPoints.length > 2) {
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if (_lastPoints.length === 3) {
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_lastPoints.unshift(_lastPoints[0]);
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}
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const widths = this._calculateCurveWidths(_lastPoints[1], _lastPoints[2]);
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const curve = Bezier.fromPoints(_lastPoints, widths);
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_lastPoints.shift();
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return curve;
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}
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return null;
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}
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_calculateCurveWidths(startPoint, endPoint) {
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const velocity = this.velocityFilterWeight * endPoint.velocityFrom(startPoint) +
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(1 - this.velocityFilterWeight) * this._lastVelocity;
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const newWidth = this._strokeWidth(velocity);
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const widths = {
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end: newWidth,
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start: this._lastWidth,
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};
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this._lastVelocity = velocity;
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this._lastWidth = newWidth;
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return widths;
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}
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_strokeWidth(velocity) {
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return Math.max(this.maxWidth / (velocity + 1), this.minWidth);
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}
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_drawCurveSegment(x, y, width) {
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const ctx = this._ctx;
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ctx.moveTo(x, y);
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ctx.arc(x, y, width, 0, 2 * Math.PI, false);
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this._isEmpty = false;
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}
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_drawCurve({ color, curve }) {
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const ctx = this._ctx;
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const widthDelta = curve.endWidth - curve.startWidth;
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const drawSteps = Math.floor(curve.length()) * 2;
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ctx.beginPath();
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ctx.fillStyle = color;
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for (let i = 0; i < drawSteps; i += 1) {
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const t = i / drawSteps;
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const tt = t * t;
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const ttt = tt * t;
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const u = 1 - t;
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const uu = u * u;
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const uuu = uu * u;
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let x = uuu * curve.startPoint.x;
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x += 3 * uu * t * curve.control1.x;
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x += 3 * u * tt * curve.control2.x;
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x += ttt * curve.endPoint.x;
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let y = uuu * curve.startPoint.y;
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y += 3 * uu * t * curve.control1.y;
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y += 3 * u * tt * curve.control2.y;
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y += ttt * curve.endPoint.y;
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const width = Math.min(curve.startWidth + ttt * widthDelta, this.maxWidth);
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this._drawCurveSegment(x, y, width);
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}
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ctx.closePath();
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ctx.fill();
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}
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_drawDot({ color, point, }) {
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const ctx = this._ctx;
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const width = typeof this.dotSize === 'function' ? this.dotSize() : this.dotSize;
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ctx.beginPath();
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this._drawCurveSegment(point.x, point.y, width);
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ctx.closePath();
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ctx.fillStyle = color;
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ctx.fill();
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}
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_fromData(pointGroups, drawCurve, drawDot) {
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for (const group of pointGroups) {
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const { color, points } = group;
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if (points.length > 1) {
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for (let j = 0; j < points.length; j += 1) {
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const basicPoint = points[j];
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const point = new Point(basicPoint.x, basicPoint.y, basicPoint.time);
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this.penColor = color;
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|
if (j === 0) {
|
||
|
this._reset();
|
||
|
}
|
||
|
const curve = this._addPoint(point);
|
||
|
if (curve) {
|
||
|
drawCurve({ color, curve });
|
||
|
}
|
||
|
}
|
||
|
}
|
||
|
else {
|
||
|
this._reset();
|
||
|
drawDot({
|
||
|
color,
|
||
|
point: points[0],
|
||
|
});
|
||
|
}
|
||
|
}
|
||
|
}
|
||
|
_toSVG() {
|
||
|
const pointGroups = this._data;
|
||
|
const ratio = Math.max(window.devicePixelRatio || 1, 1);
|
||
|
const minX = 0;
|
||
|
const minY = 0;
|
||
|
const maxX = this.canvas.width / ratio;
|
||
|
const maxY = this.canvas.height / ratio;
|
||
|
const svg = document.createElementNS('http://www.w3.org/2000/svg', 'svg');
|
||
|
svg.setAttribute('width', this.canvas.width.toString());
|
||
|
svg.setAttribute('height', this.canvas.height.toString());
|
||
|
this._fromData(pointGroups, ({ color, curve }) => {
|
||
|
const path = document.createElement('path');
|
||
|
if (!isNaN(curve.control1.x) &&
|
||
|
!isNaN(curve.control1.y) &&
|
||
|
!isNaN(curve.control2.x) &&
|
||
|
!isNaN(curve.control2.y)) {
|
||
|
const attr = `M ${curve.startPoint.x.toFixed(3)},${curve.startPoint.y.toFixed(3)} ` +
|
||
|
`C ${curve.control1.x.toFixed(3)},${curve.control1.y.toFixed(3)} ` +
|
||
|
`${curve.control2.x.toFixed(3)},${curve.control2.y.toFixed(3)} ` +
|
||
|
`${curve.endPoint.x.toFixed(3)},${curve.endPoint.y.toFixed(3)}`;
|
||
|
path.setAttribute('d', attr);
|
||
|
path.setAttribute('stroke-width', (curve.endWidth * 2.25).toFixed(3));
|
||
|
path.setAttribute('stroke', color);
|
||
|
path.setAttribute('fill', 'none');
|
||
|
path.setAttribute('stroke-linecap', 'round');
|
||
|
svg.appendChild(path);
|
||
|
}
|
||
|
}, ({ color, point }) => {
|
||
|
const circle = document.createElement('circle');
|
||
|
const dotSize = typeof this.dotSize === 'function' ? this.dotSize() : this.dotSize;
|
||
|
circle.setAttribute('r', dotSize.toString());
|
||
|
circle.setAttribute('cx', point.x.toString());
|
||
|
circle.setAttribute('cy', point.y.toString());
|
||
|
circle.setAttribute('fill', color);
|
||
|
svg.appendChild(circle);
|
||
|
});
|
||
|
const prefix = 'data:image/svg+xml;base64,';
|
||
|
const header = '<svg' +
|
||
|
' xmlns="http://www.w3.org/2000/svg"' +
|
||
|
' xmlns:xlink="http://www.w3.org/1999/xlink"' +
|
||
|
` viewBox="${minX} ${minY} ${maxX} ${maxY}"` +
|
||
|
` width="${maxX}"` +
|
||
|
` height="${maxY}"` +
|
||
|
'>';
|
||
|
let body = svg.innerHTML;
|
||
|
if (body === undefined) {
|
||
|
const dummy = document.createElement('dummy');
|
||
|
const nodes = svg.childNodes;
|
||
|
dummy.innerHTML = '';
|
||
|
for (let i = 0; i < nodes.length; i += 1) {
|
||
|
dummy.appendChild(nodes[i].cloneNode(true));
|
||
|
}
|
||
|
body = dummy.innerHTML;
|
||
|
}
|
||
|
const footer = '</svg>';
|
||
|
const data = header + body + footer;
|
||
|
return prefix + btoa(data);
|
||
|
}
|
||
|
}
|
||
|
|
||
|
export default SignaturePad;
|
||
|
//# sourceMappingURL=signature_pad.js.map
|