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Extra Components of GWT Material Framework
/*!
* Signature Pad v2.3.0
* https://github.com/szimek/signature_pad
*
* Copyright 2017 Szymon Nowak
* Released under the MIT license
*
* The main idea and some parts of the code (e.g. drawing variable width Bézier curve) are taken from:
* http://corner.squareup.com/2012/07/smoother-signatures.html
*
* Implementation of interpolation using cubic Bézier curves is taken from:
* http://benknowscode.wordpress.com/2012/09/14/path-interpolation-using-cubic-bezier-and-control-point-estimation-in-javascript
*
* Algorithm for approximated length of a Bézier curve is taken from:
* http://www.lemoda.net/maths/bezier-length/index.html
*
*/
(function (global, factory) {
typeof exports === 'object' && typeof module !== 'undefined' ? module.exports = factory() :
typeof define === 'function' && define.amd ? define(factory) :
(global.SignaturePad = factory());
}(this, (function () { 'use strict';
function Point(x, y, time) {
this.x = x;
this.y = y;
this.time = time || new Date().getTime();
}
Point.prototype.velocityFrom = function (start) {
return this.time !== start.time ? this.distanceTo(start) / (this.time - start.time) : 1;
};
Point.prototype.distanceTo = function (start) {
return Math.sqrt(Math.pow(this.x - start.x, 2) + Math.pow(this.y - start.y, 2));
};
Point.prototype.equals = function (other) {
return this.x === other.x && this.y === other.y && this.time === other.time;
};
function Bezier(startPoint, control1, control2, endPoint) {
this.startPoint = startPoint;
this.control1 = control1;
this.control2 = control2;
this.endPoint = endPoint;
}
// Returns approximated length.
Bezier.prototype.length = function () {
var steps = 10;
var length = 0;
var px = void 0;
var py = void 0;
for (var i = 0; i <= steps; i += 1) {
var t = i / steps;
var cx = this._point(t, this.startPoint.x, this.control1.x, this.control2.x, this.endPoint.x);
var cy = this._point(t, this.startPoint.y, this.control1.y, this.control2.y, this.endPoint.y);
if (i > 0) {
var xdiff = cx - px;
var ydiff = cy - py;
length += Math.sqrt(xdiff * xdiff + ydiff * ydiff);
}
px = cx;
py = cy;
}
return length;
};
/* eslint-disable no-multi-spaces, space-in-parens */
Bezier.prototype._point = function (t, start, c1, c2, end) {
return start * (1.0 - t) * (1.0 - t) * (1.0 - t) + 3.0 * c1 * (1.0 - t) * (1.0 - t) * t + 3.0 * c2 * (1.0 - t) * t * t + end * t * t * t;
};
/* eslint-disable */
// http://stackoverflow.com/a/27078401/815507
function throttle(func, wait, options) {
var context, args, result;
var timeout = null;
var previous = 0;
if (!options) options = {};
var later = function later() {
previous = options.leading === false ? 0 : Date.now();
timeout = null;
result = func.apply(context, args);
if (!timeout) context = args = null;
};
return function () {
var now = Date.now();
if (!previous && options.leading === false) previous = now;
var remaining = wait - (now - previous);
context = this;
args = arguments;
if (remaining <= 0 || remaining > wait) {
if (timeout) {
clearTimeout(timeout);
timeout = null;
}
previous = now;
result = func.apply(context, args);
if (!timeout) context = args = null;
} else if (!timeout && options.trailing !== false) {
timeout = setTimeout(later, remaining);
}
return result;
};
}
function SignaturePad(canvas, options) {
var self = this;
var opts = options || {};
this.velocityFilterWeight = opts.velocityFilterWeight || 0.7;
this.minWidth = opts.minWidth || 0.5;
this.maxWidth = opts.maxWidth || 2.5;
this.throttle = 'throttle' in opts ? opts.throttle : 16; // in miliseconds
this.minDistance = opts.minDistance || 5;
if (this.throttle) {
this._strokeMoveUpdate = throttle(SignaturePad.prototype._strokeUpdate, this.throttle);
} else {
this._strokeMoveUpdate = SignaturePad.prototype._strokeUpdate;
}
this.dotSize = opts.dotSize || function () {
return (this.minWidth + this.maxWidth) / 2;
};
this.penColor = opts.penColor || 'black';
this.backgroundColor = opts.backgroundColor || 'rgba(0,0,0,0)';
this.onBegin = opts.onBegin;
this.onEnd = opts.onEnd;
this._canvas = canvas;
this._ctx = canvas.getContext('2d');
this.clear();
// We need add these inline so they are available to unbind while still having
// access to 'self' we could use _.bind but it's not worth adding a dependency.
this._handleMouseDown = function (event) {
if (event.which === 1) {
self._mouseButtonDown = true;
self._strokeBegin(event);
}
};
this._handleMouseMove = function (event) {
if (self._mouseButtonDown) {
self._strokeMoveUpdate(event);
}
};
this._handleMouseUp = function (event) {
if (event.which === 1 && self._mouseButtonDown) {
self._mouseButtonDown = false;
self._strokeEnd(event);
}
};
this._handleTouchStart = function (event) {
if (event.targetTouches.length === 1) {
var touch = event.changedTouches[0];
self._strokeBegin(touch);
}
};
this._handleTouchMove = function (event) {
// Prevent scrolling.
event.preventDefault();
var touch = event.targetTouches[0];
self._strokeMoveUpdate(touch);
};
this._handleTouchEnd = function (event) {
var wasCanvasTouched = event.target === self._canvas;
if (wasCanvasTouched) {
event.preventDefault();
self._strokeEnd(event);
}
};
// Enable mouse and touch event handlers
this.on();
}
// Public methods
SignaturePad.prototype.clear = function () {
var ctx = this._ctx;
var canvas = this._canvas;
ctx.fillStyle = this.backgroundColor;
ctx.clearRect(0, 0, canvas.width, canvas.height);
ctx.fillRect(0, 0, canvas.width, canvas.height);
this._data = [];
this._reset();
this._isEmpty = true;
};
SignaturePad.prototype.fromDataURL = function (dataUrl) {
var _this = this;
var options = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : {};
var image = new Image();
var ratio = options.ratio || window.devicePixelRatio || 1;
var width = options.width || this._canvas.width / ratio;
var height = options.height || this._canvas.height / ratio;
this._reset();
image.src = dataUrl;
image.onload = function () {
_this._ctx.drawImage(image, 0, 0, width, height);
};
this._isEmpty = false;
};
SignaturePad.prototype.toDataURL = function (type) {
var _canvas;
switch (type) {
case 'image/svg+xml':
return this._toSVG();
default:
for (var _len = arguments.length, options = Array(_len > 1 ? _len - 1 : 0), _key = 1; _key < _len; _key++) {
options[_key - 1] = arguments[_key];
}
return (_canvas = this._canvas).toDataURL.apply(_canvas, [type].concat(options));
}
};
SignaturePad.prototype.on = function () {
this._handleMouseEvents();
this._handleTouchEvents();
};
SignaturePad.prototype.off = function () {
this._canvas.removeEventListener('mousedown', this._handleMouseDown);
this._canvas.removeEventListener('mousemove', this._handleMouseMove);
document.removeEventListener('mouseup', this._handleMouseUp);
this._canvas.removeEventListener('touchstart', this._handleTouchStart);
this._canvas.removeEventListener('touchmove', this._handleTouchMove);
this._canvas.removeEventListener('touchend', this._handleTouchEnd);
};
SignaturePad.prototype.isEmpty = function () {
return this._isEmpty;
};
// Private methods
SignaturePad.prototype._strokeBegin = function (event) {
this._data.push([]);
this._reset();
this._strokeUpdate(event);
if (typeof this.onBegin === 'function') {
this.onBegin(event);
}
};
SignaturePad.prototype._strokeUpdate = function (event) {
var x = event.clientX;
var y = event.clientY;
var point = this._createPoint(x, y);
var lastPointGroup = this._data[this._data.length - 1];
var lastPoint = lastPointGroup && lastPointGroup[lastPointGroup.length - 1];
var isLastPointTooClose = lastPoint && point.distanceTo(lastPoint) < this.minDistance;
// Skip this point if it's too close to the previous one
if (!(lastPoint && isLastPointTooClose)) {
var _addPoint = this._addPoint(point),
curve = _addPoint.curve,
widths = _addPoint.widths;
if (curve && widths) {
this._drawCurve(curve, widths.start, widths.end);
}
this._data[this._data.length - 1].push({
x: point.x,
y: point.y,
time: point.time,
color: this.penColor
});
}
};
SignaturePad.prototype._strokeEnd = function (event) {
var canDrawCurve = this.points.length > 2;
var point = this.points[0]; // Point instance
if (!canDrawCurve && point) {
this._drawDot(point);
}
if (point) {
var lastPointGroup = this._data[this._data.length - 1];
var lastPoint = lastPointGroup[lastPointGroup.length - 1]; // plain object
// When drawing a dot, there's only one point in a group, so without this check
// such group would end up with exactly the same 2 points.
if (!point.equals(lastPoint)) {
lastPointGroup.push({
x: point.x,
y: point.y,
time: point.time,
color: this.penColor
});
}
}
if (typeof this.onEnd === 'function') {
this.onEnd(event);
}
};
SignaturePad.prototype._handleMouseEvents = function () {
this._mouseButtonDown = false;
this._canvas.addEventListener('mousedown', this._handleMouseDown);
this._canvas.addEventListener('mousemove', this._handleMouseMove);
document.addEventListener('mouseup', this._handleMouseUp);
};
SignaturePad.prototype._handleTouchEvents = function () {
// Pass touch events to canvas element on mobile IE11 and Edge.
this._canvas.style.msTouchAction = 'none';
this._canvas.style.touchAction = 'none';
this._canvas.addEventListener('touchstart', this._handleTouchStart);
this._canvas.addEventListener('touchmove', this._handleTouchMove);
this._canvas.addEventListener('touchend', this._handleTouchEnd);
};
SignaturePad.prototype._reset = function () {
this.points = [];
this._lastVelocity = 0;
this._lastWidth = (this.minWidth + this.maxWidth) / 2;
this._ctx.fillStyle = this.penColor;
};
SignaturePad.prototype._createPoint = function (x, y, time) {
var rect = this._canvas.getBoundingClientRect();
return new Point(x - rect.left, y - rect.top, time || new Date().getTime());
};
SignaturePad.prototype._addPoint = function (point) {
var points = this.points;
var tmp = void 0;
points.push(point);
if (points.length > 2) {
// To reduce the initial lag make it work with 3 points
// by copying the first point to the beginning.
if (points.length === 3) points.unshift(points[0]);
tmp = this._calculateCurveControlPoints(points[0], points[1], points[2]);
var c2 = tmp.c2;
tmp = this._calculateCurveControlPoints(points[1], points[2], points[3]);
var c3 = tmp.c1;
var curve = new Bezier(points[1], c2, c3, points[2]);
var widths = this._calculateCurveWidths(curve);
// Remove the first element from the list,
// so that we always have no more than 4 points in points array.
points.shift();
return { curve: curve, widths: widths };
}
return {};
};
SignaturePad.prototype._calculateCurveControlPoints = function (s1, s2, s3) {
var dx1 = s1.x - s2.x;
var dy1 = s1.y - s2.y;
var dx2 = s2.x - s3.x;
var dy2 = s2.y - s3.y;
var m1 = { x: (s1.x + s2.x) / 2.0, y: (s1.y + s2.y) / 2.0 };
var m2 = { x: (s2.x + s3.x) / 2.0, y: (s2.y + s3.y) / 2.0 };
var l1 = Math.sqrt(dx1 * dx1 + dy1 * dy1);
var l2 = Math.sqrt(dx2 * dx2 + dy2 * dy2);
var dxm = m1.x - m2.x;
var dym = m1.y - m2.y;
var k = l2 / (l1 + l2);
var cm = { x: m2.x + dxm * k, y: m2.y + dym * k };
var tx = s2.x - cm.x;
var ty = s2.y - cm.y;
return {
c1: new Point(m1.x + tx, m1.y + ty),
c2: new Point(m2.x + tx, m2.y + ty)
};
};
SignaturePad.prototype._calculateCurveWidths = function (curve) {
var startPoint = curve.startPoint;
var endPoint = curve.endPoint;
var widths = { start: null, end: null };
var velocity = this.velocityFilterWeight * endPoint.velocityFrom(startPoint) + (1 - this.velocityFilterWeight) * this._lastVelocity;
var newWidth = this._strokeWidth(velocity);
widths.start = this._lastWidth;
widths.end = newWidth;
this._lastVelocity = velocity;
this._lastWidth = newWidth;
return widths;
};
SignaturePad.prototype._strokeWidth = function (velocity) {
return Math.max(this.maxWidth / (velocity + 1), this.minWidth);
};
SignaturePad.prototype._drawPoint = function (x, y, size) {
var ctx = this._ctx;
ctx.moveTo(x, y);
ctx.arc(x, y, size, 0, 2 * Math.PI, false);
this._isEmpty = false;
};
SignaturePad.prototype._drawCurve = function (curve, startWidth, endWidth) {
var ctx = this._ctx;
var widthDelta = endWidth - startWidth;
var drawSteps = Math.floor(curve.length());
ctx.beginPath();
for (var i = 0; i < drawSteps; i += 1) {
// Calculate the Bezier (x, y) coordinate for this step.
var t = i / drawSteps;
var tt = t * t;
var ttt = tt * t;
var u = 1 - t;
var uu = u * u;
var uuu = uu * u;
var x = uuu * curve.startPoint.x;
x += 3 * uu * t * curve.control1.x;
x += 3 * u * tt * curve.control2.x;
x += ttt * curve.endPoint.x;
var y = uuu * curve.startPoint.y;
y += 3 * uu * t * curve.control1.y;
y += 3 * u * tt * curve.control2.y;
y += ttt * curve.endPoint.y;
var width = startWidth + ttt * widthDelta;
this._drawPoint(x, y, width);
}
ctx.closePath();
ctx.fill();
};
SignaturePad.prototype._drawDot = function (point) {
var ctx = this._ctx;
var width = typeof this.dotSize === 'function' ? this.dotSize() : this.dotSize;
ctx.beginPath();
this._drawPoint(point.x, point.y, width);
ctx.closePath();
ctx.fill();
};
SignaturePad.prototype._fromData = function (pointGroups, drawCurve, drawDot) {
for (var i = 0; i < pointGroups.length; i += 1) {
var group = pointGroups[i];
if (group.length > 1) {
for (var j = 0; j < group.length; j += 1) {
var rawPoint = group[j];
var point = new Point(rawPoint.x, rawPoint.y, rawPoint.time);
var color = rawPoint.color;
if (j === 0) {
// First point in a group. Nothing to draw yet.
this._reset();
this._addPoint(point);
} else if (j !== group.length - 1) {
// Middle point in a group.
var _addPoint2 = this._addPoint(point),
curve = _addPoint2.curve,
widths = _addPoint2.widths;
if (curve && widths) {
drawCurve(curve, widths, color);
}
} else {
// Last point in a group. Do nothing.
}
}
} else {
this._reset();
var _rawPoint = group[0];
drawDot(_rawPoint);
}
}
};
SignaturePad.prototype._toSVG = function () {
var _this2 = this;
var pointGroups = this._data;
var canvas = this._canvas;
var ratio = Math.max(window.devicePixelRatio || 1, 1);
var minX = 0;
var minY = 0;
var maxX = canvas.width / ratio;
var maxY = canvas.height / ratio;
var svg = document.createElementNS('http://www.w3.org/2000/svg', 'svg');
svg.setAttributeNS(null, 'width', canvas.width);
svg.setAttributeNS(null, 'height', canvas.height);
this._fromData(pointGroups, function (curve, widths, color) {
var path = document.createElement('path');
// Need to check curve for NaN values, these pop up when drawing
// lines on the canvas that are not continuous. E.g. Sharp corners
// or stopping mid-stroke and than continuing without lifting mouse.
if (!isNaN(curve.control1.x) && !isNaN(curve.control1.y) && !isNaN(curve.control2.x) && !isNaN(curve.control2.y)) {
var 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', (widths.end * 2.25).toFixed(3));
path.setAttribute('stroke', color);
path.setAttribute('fill', 'none');
path.setAttribute('stroke-linecap', 'round');
svg.appendChild(path);
}
}, function (rawPoint) {
var circle = document.createElement('circle');
var dotSize = typeof _this2.dotSize === 'function' ? _this2.dotSize() : _this2.dotSize;
circle.setAttribute('r', dotSize);
circle.setAttribute('cx', rawPoint.x);
circle.setAttribute('cy', rawPoint.y);
circle.setAttribute('fill', rawPoint.color);
svg.appendChild(circle);
});
var prefix = 'data:image/svg+xml;base64,';
var header = '';
var body = svg.innerHTML;
// IE hack for missing innerHTML property on SVGElement
if (body === undefined) {
var dummy = document.createElement('dummy');
var nodes = svg.childNodes;
dummy.innerHTML = '';
for (var i = 0; i < nodes.length; i += 1) {
dummy.appendChild(nodes[i].cloneNode(true));
}
body = dummy.innerHTML;
}
var footer = '';
var data = header + body + footer;
return prefix + btoa(data);
};
SignaturePad.prototype.fromData = function (pointGroups) {
var _this3 = this;
this.clear();
this._fromData(pointGroups, function (curve, widths) {
return _this3._drawCurve(curve, widths.start, widths.end);
}, function (rawPoint) {
return _this3._drawDot(rawPoint);
});
this._data = pointGroups;
};
SignaturePad.prototype.toData = function () {
return this._data;
};
return SignaturePad;
})));