142 lines
3.7 KiB
JavaScript
142 lines
3.7 KiB
JavaScript
// vim: set ts=2 sw=2 et tw=80:
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class App {
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static get BRUSHES() {
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return {
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"PenBrush": new PenBrush(),
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"DiscBrush": new DiscBrush(),
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"StarBrush": new StarBrush(),
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};
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}
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constructor(conf) {
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if (!(typeof conf === 'object' && conf)) {
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throw new Error('Argument conf different from specification');
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}
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this.canvas = document.getElementById(conf.canvas);
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if (!this.canvas || this.canvas.tagName !== 'CANVAS') {
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throw new Error(`canvas is not a canvas`);
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}
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this.ctx = this.canvas.getContext('2d');
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this.favourites = document.querySelector('div#favourites');
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if (typeof conf.buttons === 'object' && conf.buttons) {
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this.buttons = {}
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for (const b of ['clear', 'undo', 'camera'])
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this.buttons[b] = document.getElementById(conf.buttons[b]);
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if (this.buttons.clear)
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this.buttons.clear.addEventListener('click', () => {
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this.erase();
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history.clear();
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});
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if (this.buttons.undo)
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this.buttons.undo.addEventListener('click', () => history.pop(this));
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if (this.buttons.camera)
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this.buttons.camera.addEventListener('click', () => {
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const base64 = this.canvas.toDataURL();
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const img = document.createElement('img');
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img.src = base64;
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const span = document.createElement('span');
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span.contentEditable = true;
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this.favourites.appendChild(img);
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this.favourites.appendChild(span);
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});
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}
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this.ctx.lineWidth = 1;
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this.strokeStyle = this.constructor.defaultStrokeStyle;
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this.brush = "PenBrush";
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const brushToolbar = document.querySelector('#brush-toolbar');
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for (const name in App.BRUSHES) {
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const b = document.createElement('button');
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b.innerText = name;
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b.addEventListener('click', () => this.brush = name);
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brushToolbar.appendChild(b);
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}
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this.canvas.addEventListener('mousedown', this.startPath.bind(this));
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this.canvas.addEventListener('mousemove', this.draw.bind(this));
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this.canvas.addEventListener('mouseup', this.endPath.bind(this));
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this.canvas.addEventListener('mouseout', this.endPath.bind(this));
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}
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static get defaultStrokeStyle() {
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return 'black';
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}
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get strokeStyle() {
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return this.ctx.strokeStyle;
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}
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set strokeStyle(style) {
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if (typeof style !== 'string') {
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throw new Error('style is not a string');
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}
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this.ctx.strokeStyle = style;
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}
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get brush() {
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return this._brush.name;
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}
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set brush(brushName) {
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this._brush = App.BRUSHES[brushName];
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}
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erase() {
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this.ctx.clearRect(0, 0, this.canvas.width, this.canvas.height);
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}
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startPath(e, record = true) {
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this.ctx.beginPath();
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this.ctx.moveTo(e.offsetX, e.offsetY);
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if (record) {
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history.initializeNewPath();
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history.push(new Stroke(this.brush, e.offsetX, e.offsetY));
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}
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this.mousedown = true;
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}
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draw(e, beginNew = true, record = true) {
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if (this.mousedown) {
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this._brush.draw(this.ctx, this.strokeStyle, e.offsetX, e.offsetY);
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if (record) {
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history.push(new Stroke(this.brush, e.offsetX, e.offsetY));
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}
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if (beginNew) {
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this.ctx.beginPath();
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this.ctx.moveTo(e.offsetX, e.offsetY);
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} else {
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this.mousedown = false;
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}
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}
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}
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endPath(e, record = true) {
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this.draw(e, false, record);
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}
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drawPath(path) {
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const last = path.length - 1;
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const lastBrush = this.brush;
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for (let i = 0; i <= last; i++) {
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this.brush = path[i].brushName;
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switch(i) {
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case 0: this.startPath(path[i], false); break;
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case last: this.endPath(path[i], false); break;
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default: this.draw(path[i], true, false);
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}
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}
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this.brush = lastBrush;
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}
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}
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