@kwiz/fluentui
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KWIZ common controls for FluentUI
504 lines • 20.9 kB
JavaScript
import { GetDefaultProp, isNotEmptyArray, isNullOrEmptyString, throttle } from "@kwiz/common";
import { CustomEventTargetBase } from './CustomEventTargetBase';
import { Bezier } from './bezier';
import { Point } from './point';
//inspired by https://www.npmjs.com/package/signature_pad
export default class DrawPadManager extends CustomEventTargetBase {
constructor(canvas, options = {}) {
super();
this.canvas = canvas;
// Public stuff
this.dotSize = GetDefaultProp(0);
this.minWidth = GetDefaultProp(0.5);
this.maxWidth = GetDefaultProp(2.5);
this.penColor = GetDefaultProp("black");
this.minDistance = GetDefaultProp(5);
this.velocityFilterWeight = GetDefaultProp(0.7);
this.backgroundColor = GetDefaultProp(null);
this.throttle = GetDefaultProp(16);
// Event handlers
this._handleMouseDown = (event) => {
if (event.buttons === 1) {
this._drawningStroke = true;
this._strokeBegin(event);
}
};
this._handleMouseMove = (event) => {
if (this._drawningStroke) {
this._strokeMoveUpdate(event);
}
};
this._handleMouseUp = (event) => {
if (event.buttons === 1 && this._drawningStroke) {
this._drawningStroke = false;
this._strokeEnd(event);
}
};
this._handleTouchStart = (event) => {
// Prevent scrolling.
event.preventDefault();
if (event.targetTouches.length === 1) {
const touch = event.changedTouches[0];
this._strokeBegin(touch);
}
};
this._handleTouchMove = (event) => {
// Prevent scrolling.
event.preventDefault();
const touch = event.targetTouches[0];
this._strokeMoveUpdate(touch);
};
this._handleTouchEnd = (event) => {
const wasCanvasTouched = event.target === this.canvas;
if (wasCanvasTouched) {
event.preventDefault();
const touch = event.changedTouches[0];
this._strokeEnd(touch);
}
};
this._handlePointerStart = (event) => {
this._drawningStroke = true;
event.preventDefault();
this._strokeBegin(event);
};
this._handlePointerMove = (event) => {
if (this._drawningStroke) {
event.preventDefault();
this._strokeMoveUpdate(event);
}
};
this._handlePointerEnd = (event) => {
this._drawningStroke = false;
const wasCanvasTouched = event.target === this.canvas;
if (wasCanvasTouched) {
event.preventDefault();
this._strokeEnd(event);
}
};
this.velocityFilterWeight.value = options.velocityFilterWeight;
this.minWidth.value = options.minWidth;
this.maxWidth.value = options.maxWidth;
this.throttle.value = options.throttle; // in milisecondss
this.minDistance.value = options.minDistance; // in pixels
this.dotSize.value = options.dotSize;
this.penColor.value = options.penColor;
this.backgroundColor.value = options.backgroundColor;
this._strokeMoveUpdate = this.throttle.value
? throttle(this._strokeUpdate, this.throttle.value, this)
: this._strokeUpdate;
this._ctx = canvas.getContext('2d');
this.clear();
// Enable mouse and touch event handlers
this.on();
}
clear() {
const { _ctx: ctx, canvas } = this;
// Clear canvas using background color
ctx.fillStyle = this.backgroundColor.value;
ctx.clearRect(0, 0, canvas.width, canvas.height);
if (!isNullOrEmptyString(this.backgroundColor.value)) //otherwise, leave it transparent
ctx.fillRect(0, 0, canvas.width, canvas.height);
this._data = [];
this._reset();
this._isEmpty = true;
this.resizeCanvas();
}
fromDataURL(dataUrl,
/** default: clear, shrink and stretch all true */
options = {
clear: true,
shrinkToFit: true,
stretchToFit: true
}) {
return new Promise((resolve, reject) => {
const img = new Image();
this._reset();
img.onload = () => {
if (options.clear) {
this.clear();
}
/**
* smallest factor
* 1 - image is smaller than canvas. keep as is.
* less than 1 - width, height or both are too big - this is the smaller factor that contains both
*/
//use clientHeight/clientWidth to supprot phones properly and compensate for window.devicePixelRatio
let factor = Math.min(this.canvas.clientWidth / img.width, this.canvas.clientHeight / img.height);
if (options.shrinkToFit !== true && factor < 1)
factor = 1;
if (options.stretchToFit !== true && factor > 1)
factor = 1;
//make sure its contained
let width = img.width * factor;
let height = img.height * factor;
//center it
var centerShift_x = this.canvas.clientWidth > width ? (this.canvas.clientWidth / 2) - (width / 2) : 0;
var centerShift_y = this.canvas.clientHeight > height ? (this.canvas.clientHeight / 2) - (height / 2) : 0;
this._ctx.drawImage(img, centerShift_x, centerShift_y, width, height);
resolve();
};
img.onerror = (error) => {
reject(error);
};
img.crossOrigin = 'anonymous';
img.src = dataUrl;
this._isEmpty = false;
});
}
toPng() {
let value = "";
if (!this.isEmpty()) {
value = this.toDataURL("image/png");
}
return value;
}
toDataURL(type = 'image/png', encoderOptions) {
switch (type) {
case 'image/svg+xml':
return this._toSVG();
default:
return this.canvas.toDataURL(type, encoderOptions);
}
}
on() {
// Disable panning/zooming when touching canvas element
this.canvas.style.touchAction = 'none';
this.canvas.style.msTouchAction = 'none';
this.canvas.style.userSelect = 'none';
const isIOS = /Macintosh/.test(navigator.userAgent) && 'ontouchstart' in document;
// The "Scribble" feature of iOS intercepts point events. So that we can lose some of them when tapping rapidly.
// Use touch events for iOS platforms to prevent it. See https://developer.apple.com/forums/thread/664108 for more information.
if (window.PointerEvent && !isIOS) {
this._handlePointerEvents();
}
else {
this._handleMouseEvents();
if ('ontouchstart' in window) {
this._handleTouchEvents();
}
}
}
off() {
// Enable panning/zooming when touching canvas element
this.canvas.style.touchAction = 'auto';
this.canvas.style.msTouchAction = 'auto';
this.canvas.style.userSelect = 'auto';
this.canvas.removeEventListener('pointerdown', this._handlePointerStart);
this.canvas.removeEventListener('pointermove', this._handlePointerMove);
document.removeEventListener('pointerup', this._handlePointerEnd);
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);
}
isEmpty() {
return this._isEmpty;
}
canUndo() {
var data = this.toData();
return isNotEmptyArray(data);
}
undoLast() {
if (this.canUndo()) {
var data = this.toData();
data.pop(); // remove the last dot or line
this.fromData(data);
}
}
resizeCanvas() {
var ratio = Math.max(window.devicePixelRatio || 1, 1);
this.canvas.width = this.canvas.offsetWidth * ratio;
this.canvas.height = this.canvas.offsetHeight * ratio;
this.canvas.getContext("2d").scale(ratio, ratio);
}
fromData(pointGroups, { clear = true } = {}) {
if (clear) {
this.clear();
}
this._fromData(pointGroups, this._drawCurve.bind(this), this._drawDot.bind(this));
this._data = clear ? pointGroups : this._data.concat(pointGroups);
}
toData() {
return this._data;
}
// Private methods
_strokeBegin(event) {
this.dispatchEvent(new CustomEvent('beginStroke', { detail: event }));
const newPointGroup = {
dotSize: this.dotSize.value,
minWidth: this.minWidth.value,
maxWidth: this.maxWidth.value,
penColor: this.penColor.value,
points: [],
};
this._data.push(newPointGroup);
this._reset();
this._strokeUpdate(event);
}
_strokeUpdate(event) {
if (this._data.length === 0) {
// This can happen if clear() was called while a drawing is still in progress,
// or if there is a race condition between start/update events.
this._strokeBegin(event);
return;
}
this.dispatchEvent(new CustomEvent('beforeUpdateStroke', { detail: event }));
const x = event.clientX;
const y = event.clientY;
const pressure = event.pressure !== undefined
? event.pressure
: event.force !== undefined
? event.force
: 0;
const point = this._createPoint(x, y, pressure);
const lastPointGroup = this._data[this._data.length - 1];
const lastPoints = lastPointGroup.points;
const lastPoint = lastPoints.length > 0 && lastPoints[lastPoints.length - 1];
const isLastPointTooClose = lastPoint
? point.distanceTo(lastPoint) <= this.minDistance.value
: false;
const { penColor, dotSize, minWidth, maxWidth } = lastPointGroup;
// Skip this point if it's too close to the previous one
if (!lastPoint || !(lastPoint && isLastPointTooClose)) {
const curve = this._addPoint(point);
if (!lastPoint) {
this._drawDot(point, {
penColor,
dotSize,
minWidth,
maxWidth,
});
}
else if (curve) {
this._drawCurve(curve, {
penColor,
dotSize,
minWidth,
maxWidth,
});
}
lastPoints.push({
time: point.time,
x: point.x,
y: point.y,
pressure: point.pressure,
});
}
this.dispatchEvent(new CustomEvent('afterUpdateStroke', { detail: event }));
}
_strokeEnd(event) {
this._strokeUpdate(event);
this.dispatchEvent(new CustomEvent('endStroke', { detail: event }));
}
_handlePointerEvents() {
this._drawningStroke = false;
this.canvas.addEventListener('pointerdown', this._handlePointerStart);
this.canvas.addEventListener('pointermove', this._handlePointerMove);
document.addEventListener('pointerup', this._handlePointerEnd);
}
_handleMouseEvents() {
this._drawningStroke = false;
this.canvas.addEventListener('mousedown', this._handleMouseDown);
this.canvas.addEventListener('mousemove', this._handleMouseMove);
document.addEventListener('mouseup', this._handleMouseUp);
}
_handleTouchEvents() {
this.canvas.addEventListener('touchstart', this._handleTouchStart);
this.canvas.addEventListener('touchmove', this._handleTouchMove);
this.canvas.addEventListener('touchend', this._handleTouchEnd);
}
// Called when a new line is started
_reset() {
this._lastPoints = [];
this._lastVelocity = 0;
this._lastWidth = (this.minWidth.value + this.maxWidth.value) / 2;
this._ctx.fillStyle = this.penColor.value;
}
_createPoint(x, y, pressure) {
const rect = this.canvas.getBoundingClientRect();
return new Point(x - rect.left, y - rect.top, pressure, new Date().getTime());
}
// Add point to _lastPoints array and generate a new curve if there are enough points (i.e. 3)
_addPoint(point) {
const { _lastPoints } = this;
_lastPoints.push(point);
if (_lastPoints.length > 2) {
// To reduce the initial lag make it work with 3 points
// by copying the first point to the beginning.
if (_lastPoints.length === 3) {
_lastPoints.unshift(_lastPoints[0]);
}
// _points array will always have 4 points here.
const widths = this._calculateCurveWidths(_lastPoints[1], _lastPoints[2]);
const curve = Bezier.fromPoints(_lastPoints, widths);
// Remove the first element from the list, so that there are no more than 4 points at any time.
_lastPoints.shift();
return curve;
}
return null;
}
_calculateCurveWidths(startPoint, endPoint) {
const velocity = this.velocityFilterWeight.value * endPoint.velocityFrom(startPoint) +
(1 - this.velocityFilterWeight.value) * this._lastVelocity;
const newWidth = this._strokeWidth(velocity);
const widths = {
end: newWidth,
start: this._lastWidth,
};
this._lastVelocity = velocity;
this._lastWidth = newWidth;
return widths;
}
_strokeWidth(velocity) {
return Math.max(this.maxWidth.value / (velocity + 1), this.minWidth.value);
}
_drawCurveSegment(x, y, width) {
const ctx = this._ctx;
ctx.moveTo(x, y);
ctx.arc(x, y, width, 0, 2 * Math.PI, false);
this._isEmpty = false;
}
_drawCurve(curve, options) {
const ctx = this._ctx;
const widthDelta = curve.endWidth - curve.startWidth;
// '2' is just an arbitrary number here. If only lenght is used, then
// there are gaps between curve segments :/
const drawSteps = Math.ceil(curve.length()) * 2;
ctx.beginPath();
ctx.fillStyle = options.penColor;
for (let i = 0; i < drawSteps; i += 1) {
// Calculate the Bezier (x, y) coordinate for this step.
const t = i / drawSteps;
const tt = t * t;
const ttt = tt * t;
const u = 1 - t;
const uu = u * u;
const uuu = uu * u;
let x = uuu * curve.startPoint.x;
x += 3 * uu * t * curve.control1.x;
x += 3 * u * tt * curve.control2.x;
x += ttt * curve.endPoint.x;
let y = uuu * curve.startPoint.y;
y += 3 * uu * t * curve.control1.y;
y += 3 * u * tt * curve.control2.y;
y += ttt * curve.endPoint.y;
const width = Math.min(curve.startWidth + ttt * widthDelta, options.maxWidth);
this._drawCurveSegment(x, y, width);
}
ctx.closePath();
ctx.fill();
}
_drawDot(point, options) {
const ctx = this._ctx;
const width = options.dotSize > 0
? options.dotSize
: (options.minWidth + options.maxWidth) / 2;
ctx.beginPath();
this._drawCurveSegment(point.x, point.y, width);
ctx.closePath();
ctx.fillStyle = options.penColor;
ctx.fill();
}
_fromData(pointGroups, drawCurve, drawDot) {
for (const group of pointGroups) {
const { penColor, dotSize, minWidth, maxWidth, points } = group;
if (points.length > 1) {
for (let j = 0; j < points.length; j += 1) {
const basicPoint = points[j];
const point = new Point(basicPoint.x, basicPoint.y, basicPoint.pressure, basicPoint.time);
// All points in the group have the same color, so it's enough to set
// penColor just at the beginning.
this.penColor.value = penColor;
if (j === 0) {
this._reset();
}
const curve = this._addPoint(point);
if (curve) {
drawCurve(curve, {
penColor,
dotSize,
minWidth,
maxWidth,
});
}
}
}
else {
this._reset();
drawDot(points[0], {
penColor,
dotSize,
minWidth,
maxWidth,
});
}
}
}
_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, (curve, { penColor }) => {
const 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.
/* eslint-disable no-restricted-globals */
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', penColor);
path.setAttribute('fill', 'none');
path.setAttribute('stroke-linecap', 'round');
svg.appendChild(path);
}
/* eslint-enable no-restricted-globals */
}, (point, { penColor, dotSize, minWidth, maxWidth }) => {
const circle = document.createElement('circle');
const size = dotSize > 0 ? dotSize : (minWidth + maxWidth) / 2;
circle.setAttribute('r', size.toString());
circle.setAttribute('cx', point.x.toString());
circle.setAttribute('cy', point.y.toString());
circle.setAttribute('fill', penColor);
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} ${this.canvas.width} ${this.canvas.height}"` +
` width="${maxX}"` +
` height="${maxY}"` +
'>';
let body = svg.innerHTML;
// IE hack for missing innerHTML property on SVGElement
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);
}
}
//# sourceMappingURL=DrawPadManager.js.map