mirror of
https://github.com/snipe/snipe-it.git
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390 lines
12 KiB
JavaScript
Executable file
390 lines
12 KiB
JavaScript
Executable file
(function (root, factory) {
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if (typeof define === 'function' && define.amd) {
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// AMD. Register as an anonymous module unless amdModuleId is set
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define([], function () {
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return (root['SignaturePad'] = factory());
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});
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} else if (typeof exports === 'object') {
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// Node. Does not work with strict CommonJS, but
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// only CommonJS-like environments that support module.exports,
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// like Node.
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module.exports = factory();
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} else {
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root['SignaturePad'] = factory();
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}
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}(this, function () {
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/*!
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* Signature Pad v1.5.3
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* https://github.com/szimek/signature_pad
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*
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* Copyright 2016 Szymon Nowak
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* Released under the MIT license
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*
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* The main idea and some parts of the code (e.g. drawing variable width Bézier curve) are taken from:
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* http://corner.squareup.com/2012/07/smoother-signatures.html
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*
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* Implementation of interpolation using cubic Bézier curves is taken from:
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* http://benknowscode.wordpress.com/2012/09/14/path-interpolation-using-cubic-bezier-and-control-point-estimation-in-javascript
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*
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* Algorithm for approximated length of a Bézier curve is taken from:
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* http://www.lemoda.net/maths/bezier-length/index.html
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*
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*/
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var SignaturePad = (function (document) {
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"use strict";
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var SignaturePad = function (canvas, options) {
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var self = this,
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opts = options || {};
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this.velocityFilterWeight = opts.velocityFilterWeight || 0.7;
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this.minWidth = opts.minWidth || 0.5;
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this.maxWidth = opts.maxWidth || 2.5;
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this.dotSize = opts.dotSize || function () {
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return (this.minWidth + this.maxWidth) / 2;
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};
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this.penColor = opts.penColor || "black";
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this.backgroundColor = opts.backgroundColor || "rgba(0,0,0,0)";
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this.onEnd = opts.onEnd;
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this.onBegin = opts.onBegin;
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this._canvas = canvas;
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this._ctx = canvas.getContext("2d");
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this.clear();
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// we need add these inline so they are available to unbind while still having
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// access to 'self' we could use _.bind but it's not worth adding a dependency
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this._handleMouseDown = function (event) {
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if (event.which === 1) {
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self._mouseButtonDown = true;
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self._strokeBegin(event);
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}
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};
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this._handleMouseMove = function (event) {
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if (self._mouseButtonDown) {
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self._strokeUpdate(event);
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}
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};
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this._handleMouseUp = function (event) {
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if (event.which === 1 && self._mouseButtonDown) {
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self._mouseButtonDown = false;
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self._strokeEnd(event);
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}
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};
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this._handleTouchStart = function (event) {
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if (event.targetTouches.length == 1) {
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var touch = event.changedTouches[0];
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self._strokeBegin(touch);
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}
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};
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this._handleTouchMove = function (event) {
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// Prevent scrolling.
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event.preventDefault();
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var touch = event.targetTouches[0];
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self._strokeUpdate(touch);
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};
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this._handleTouchEnd = function (event) {
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var wasCanvasTouched = event.target === self._canvas;
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if (wasCanvasTouched) {
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event.preventDefault();
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self._strokeEnd(event);
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}
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};
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this._handleMouseEvents();
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this._handleTouchEvents();
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};
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SignaturePad.prototype.clear = function () {
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var ctx = this._ctx,
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canvas = this._canvas;
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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._reset();
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};
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SignaturePad.prototype.toDataURL = function (imageType, quality) {
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var canvas = this._canvas;
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return canvas.toDataURL.apply(canvas, arguments);
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};
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SignaturePad.prototype.fromDataURL = function (dataUrl) {
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var self = this,
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image = new Image(),
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ratio = window.devicePixelRatio || 1,
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width = this._canvas.width / ratio,
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height = this._canvas.height / ratio;
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this._reset();
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image.src = dataUrl;
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image.onload = function () {
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self._ctx.drawImage(image, 0, 0, width, height);
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};
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this._isEmpty = false;
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};
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SignaturePad.prototype._strokeUpdate = function (event) {
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var point = this._createPoint(event);
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this._addPoint(point);
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};
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SignaturePad.prototype._strokeBegin = function (event) {
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this._reset();
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this._strokeUpdate(event);
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if (typeof this.onBegin === 'function') {
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this.onBegin(event);
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}
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};
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SignaturePad.prototype._strokeDraw = function (point) {
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var ctx = this._ctx,
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dotSize = typeof(this.dotSize) === 'function' ? this.dotSize() : this.dotSize;
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ctx.beginPath();
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this._drawPoint(point.x, point.y, dotSize);
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ctx.closePath();
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ctx.fill();
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};
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SignaturePad.prototype._strokeEnd = function (event) {
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var canDrawCurve = this.points.length > 2,
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point = this.points[0];
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if (!canDrawCurve && point) {
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this._strokeDraw(point);
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}
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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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SignaturePad.prototype._handleMouseEvents = function () {
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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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SignaturePad.prototype._handleTouchEvents = function () {
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// Pass touch events to canvas element on mobile IE11 and Edge.
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this._canvas.style.msTouchAction = 'none';
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this._canvas.style.touchAction = 'none';
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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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SignaturePad.prototype.on = function () {
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this._handleMouseEvents();
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this._handleTouchEvents();
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};
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SignaturePad.prototype.off = function () {
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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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SignaturePad.prototype.isEmpty = function () {
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return this._isEmpty;
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};
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SignaturePad.prototype._reset = function () {
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this.points = [];
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this._lastVelocity = 0;
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this._lastWidth = (this.minWidth + this.maxWidth) / 2;
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this._isEmpty = true;
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this._ctx.fillStyle = this.penColor;
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};
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SignaturePad.prototype._createPoint = function (event) {
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var rect = this._canvas.getBoundingClientRect();
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return new Point(
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event.clientX - rect.left,
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event.clientY - rect.top
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);
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};
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SignaturePad.prototype._addPoint = function (point) {
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var points = this.points,
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c2, c3,
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curve, tmp;
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points.push(point);
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if (points.length > 2) {
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// To reduce the initial lag make it work with 3 points
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// by copying the first point to the beginning.
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if (points.length === 3) points.unshift(points[0]);
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tmp = this._calculateCurveControlPoints(points[0], points[1], points[2]);
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c2 = tmp.c2;
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tmp = this._calculateCurveControlPoints(points[1], points[2], points[3]);
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c3 = tmp.c1;
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curve = new Bezier(points[1], c2, c3, points[2]);
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this._addCurve(curve);
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// Remove the first element from the list,
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// so that we always have no more than 4 points in points array.
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points.shift();
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}
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};
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SignaturePad.prototype._calculateCurveControlPoints = function (s1, s2, s3) {
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var dx1 = s1.x - s2.x, dy1 = s1.y - s2.y,
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dx2 = s2.x - s3.x, dy2 = s2.y - s3.y,
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m1 = {x: (s1.x + s2.x) / 2.0, y: (s1.y + s2.y) / 2.0},
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m2 = {x: (s2.x + s3.x) / 2.0, y: (s2.y + s3.y) / 2.0},
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l1 = Math.sqrt(dx1*dx1 + dy1*dy1),
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l2 = Math.sqrt(dx2*dx2 + dy2*dy2),
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dxm = (m1.x - m2.x),
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dym = (m1.y - m2.y),
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k = l2 / (l1 + l2),
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cm = {x: m2.x + dxm*k, y: m2.y + dym*k},
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tx = s2.x - cm.x,
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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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SignaturePad.prototype._addCurve = function (curve) {
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var startPoint = curve.startPoint,
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endPoint = curve.endPoint,
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velocity, newWidth;
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velocity = endPoint.velocityFrom(startPoint);
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velocity = this.velocityFilterWeight * velocity
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+ (1 - this.velocityFilterWeight) * this._lastVelocity;
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newWidth = this._strokeWidth(velocity);
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this._drawCurve(curve, this._lastWidth, newWidth);
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this._lastVelocity = velocity;
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this._lastWidth = newWidth;
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};
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SignaturePad.prototype._drawPoint = function (x, y, size) {
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var ctx = this._ctx;
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ctx.moveTo(x, y);
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ctx.arc(x, y, size, 0, 2 * Math.PI, false);
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this._isEmpty = false;
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};
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SignaturePad.prototype._drawCurve = function (curve, startWidth, endWidth) {
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var ctx = this._ctx,
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widthDelta = endWidth - startWidth,
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drawSteps, width, i, t, tt, ttt, u, uu, uuu, x, y;
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drawSteps = Math.floor(curve.length());
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ctx.beginPath();
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for (i = 0; i < drawSteps; i++) {
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// Calculate the Bezier (x, y) coordinate for this step.
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t = i / drawSteps;
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tt = t * t;
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ttt = tt * t;
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u = 1 - t;
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uu = u * u;
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uuu = uu * u;
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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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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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width = startWidth + ttt * widthDelta;
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this._drawPoint(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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SignaturePad.prototype._strokeWidth = function (velocity) {
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return Math.max(this.maxWidth / (velocity + 1), this.minWidth);
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};
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var Point = function (x, y, time) {
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this.x = x;
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this.y = y;
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this.time = time || new Date().getTime();
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};
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Point.prototype.velocityFrom = function (start) {
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return (this.time !== start.time) ? this.distanceTo(start) / (this.time - start.time) : 1;
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};
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Point.prototype.distanceTo = function (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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var Bezier = function (startPoint, control1, control2, endPoint) {
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this.startPoint = startPoint;
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this.control1 = control1;
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this.control2 = control2;
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this.endPoint = endPoint;
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};
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// Returns approximated length.
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Bezier.prototype.length = function () {
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var steps = 10,
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length = 0,
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i, t, cx, cy, px, py, xdiff, ydiff;
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for (i = 0; i <= steps; i++) {
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t = i / steps;
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cx = this._point(t, this.startPoint.x, this.control1.x, this.control2.x, this.endPoint.x);
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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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xdiff = cx - px;
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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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Bezier.prototype._point = function (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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return SignaturePad;
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})(document);
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return SignaturePad;
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}));
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