projectile
This commit is contained in:
Ladd Hoffman
parent
e53d88c991
commit
4c093c1fad
245
draw.js
245
draw.js
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@ -1,19 +1,18 @@
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class Drawing {
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constructor() {
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const div = document.createElement('div');
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const buttonsDiv = document.createElement('div');
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this.startButton = document.createElement('button');
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this.startButton.onclick = () => this.start();
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this.startButton.innerHTML = "Start";
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this.stopButton = document.createElement('button');
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this.stopButton.onclick = () => this.stop();
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this.stopButton.innerHTML = "Stop";
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constructor(divId) {
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this.div = document.getElementById(divId);
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this.div.classList.add('drawing');
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this.div.classList.add('container');
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this.buttonsDiv = document.createElement('div');
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this.titleDiv = document.createElement('div');
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this.titleDiv.classList.add('title');
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this.captionDiv = document.createElement('div');
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this.captionDiv.classList.add('caption');
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this.canvas = document.createElement('canvas');
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buttonsDiv.appendChild(this.startButton);
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buttonsDiv.appendChild(this.stopButton);
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div.appendChild(buttonsDiv);
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div.appendChild(this.canvas);
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document.body.appendChild(div);
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this.div.appendChild(this.titleDiv);
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this.div.appendChild(this.buttonsDiv);
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this.div.appendChild(this.canvas);
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this.div.appendChild(this.captionDiv);
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this.ctx = this.canvas.getContext('2d');
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this.sequence = [];
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this.t = 0;
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@ -21,34 +20,128 @@ class Drawing {
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this.dt = 0;
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this.points = {};
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this.stopped = true;
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this.frame = [[-50, -50], [150, 150]];
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this.frame = [[-10, -10], [110, 110]];
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this.frameMargin = 10;
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this.scale = 1.0;
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this.canvas.width = (this.frame[1][0] - this.frame[0][0]) * this.scale;
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this.canvas.height = (this.frame[1][1] - this.frame[0][1]) * this.scale;
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this.speed = 1.0;
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this.rendered = false;
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this.updateCanvasSize();
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}
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addButtons() {
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if (!this.buttonsAdded) {
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this.startButton = document.createElement('button');
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this.startButton.onclick = () => this.start();
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this.startButton.innerHTML = "Start";
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this.stopButton = document.createElement('button');
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this.stopButton.onclick = () => this.stop();
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this.stopButton.innerHTML = "Stop";
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this.buttonsDiv.appendChild(this.startButton);
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this.buttonsDiv.appendChild(this.stopButton);
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this.buttonsAdded = true;
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this.updateButtonStates();
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}
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}
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updateButtonStates() {
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if (this.stopped) {
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this.stopButton.disabled = true;
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this.startButton.disabled = false;
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} else {
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this.stopButton.disabled = false;
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this.startButton.disabled = true;
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}
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}
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setTitle(title) {
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this.titleDiv.innerHTML = title;
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}
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setCaption(caption) {
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this.captionDiv.innerHTML = caption;
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}
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start() {
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if (this.stopped) {
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this.elideInterval = true;
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this.stopped = false;
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}
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if (this.onStartFn) {
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this.onStartFn();
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}
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this.addButtons();
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this.updateButtonStates();
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this.animate();
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}
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stop() {
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this.stopped = true;
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this.updateButtonStates();
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}
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render() {
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for (let action of this.sequence) {
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action();
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}
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this.rendered = true;
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}
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animate() {
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this.ctx.reset();
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this.render();
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if (!this.stopped) {
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requestAnimationFrame((prevt) => {
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const rt = document.timeline.currentTime;
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const elapsed = rt - prevt;
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if (this.elideInterval) {
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this.dt = 0;
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this.elideInterval = false;
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} else {
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this.dt = (rt - this.rt + elapsed) * this.speed;
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}
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this.t += this.dt;
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this.rt = rt;
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this.animate();
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});
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}
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}
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pixel([x, y]) {
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return [
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(x - this.frame[0][0]) * this.scale,
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this.canvas.height - (y - this.frame[0][1]) * this.scale
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(x - this.frame[0][0]) * this.scale + this.frameMargin,
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this.canvas.height - (y - this.frame[0][1]) * this.scale - this.frameMargin
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];
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}
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onStart(fn) {
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this.onStartFn = fn;
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}
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setSpeed(speed) {
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this.speed = speed;
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}
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updateCanvasSize() {
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this.canvas.width = (this.frame[1][0] - this.frame[0][0]) * this.scale + 2 * this.frameMargin;
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this.canvas.height = (this.frame[1][1] - this.frame[0][1]) * this.scale + 2 * this.frameMargin;
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if (this.rendered) {
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this.render();
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}
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}
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setFrame([x1, y1], [x2, y2]) {
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this.frame = [[x1, y1], [x2, y2]];
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this.canvas.width = (this.frame[1][0] - this.frame[0][0]) * this.scale;
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this.canvas.height = (this.frame[1][1] - this.frame[0][1]) * this.scale;
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this.updateCanvasSize();
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}
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setFrameMargin(frameMargin) {
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this.frameMargin = frameMargin;
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this.updateCanvasSize();
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}
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setScale(zoom) {
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this.scale = zoom;
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this.canvas.width = (this.frame[1][0] - this.frame[0][0]) * this.scale;
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this.canvas.height = (this.frame[1][1] - this.frame[0][1]) * this.scale;
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this.updateCanvasSize();
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}
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setStroke(style, width) {
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@ -64,6 +157,24 @@ class Drawing {
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});
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}
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definePoint(name, fn) {
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this.points[name] = fn;
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}
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getPoint(p) {
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if (typeof p === 'string') {
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const fn = this.points[p];
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if (!fn) {
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const e = new Error;
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e.message = `Point '${p}' is not defined`;
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throw e;
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}
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return fn();
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} else {
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return p;
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}
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}
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line(p1, p2) {
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this.sequence.push(() => {
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this.ctx.beginPath();
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@ -73,6 +184,15 @@ class Drawing {
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});
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}
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arrow(p1, p2) {
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this.sequence.push(() => {
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this.ctx.beginPath();
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this.ctx.moveTo(...this.pixel(this.getPoint(p1)));
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this.ctx.lineTo(...this.pixel(this.getPoint(p2)));
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this.ctx.stroke();
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});
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}
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polyline(...points) {
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this.sequence.push(() => {
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this.ctx.beginPath();
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@ -115,7 +235,7 @@ class Drawing {
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if (oldest >= 0) {
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history = history.slice(oldest);
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}
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this.ctx.strokeStyle = 'black';
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this.ctx.strokeStyle = 'gray';
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this.ctx.lineWidth = 1;
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this.ctx.beginPath();
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this.ctx.moveTo(...this.pixel(history[0].p));
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@ -128,78 +248,43 @@ class Drawing {
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}
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this.ctx.stroke();
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fn(x, y);
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})
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});
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return {
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reset: () => {
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history = [];
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distance = 0;
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}
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};
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}
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square(p, opts) {
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const size = opts?.size ?? 10;
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this.object(p, opts, (x, y) => {
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return this.object(p, opts, (x, y) => {
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this.ctx.fillRect(...this.pixel([x - size / 2, y + size / 2]), size * this.scale, size * this.scale);
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});
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}
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circle(p, opts) {
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const radius = opts?.radius ?? 5;
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this.object(p, opts, (x, y) => {
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return this.object(p, opts, (x, y) => {
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this.ctx.beginPath();
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this.ctx.ellipse(...this.pixel([x, y]), radius * this.scale, radius * this.scale, 0, 0, 2*Math.PI);
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this.ctx.fill();
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});
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}
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definePoint(name, fn) {
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this.points[name] = fn;
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func(opts, fn) {
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const origin = opts?.origin ?? [0, 0];
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const domain = opts?.domain ?? [this.frame[0][0], this.frame[1][0]];
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const step = opts?.step ?? 1;
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this.sequence.push(() => {
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this.ctx.beginPath();
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this.ctx.moveTo(...this.pixel([domain[0], fn(domain[0])]));
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for (let x = domain[0] + step; x <= domain[1]; x += step) {
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this.ctx.lineTo(...this.pixel([x, fn(x)]));
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}
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getPoint(p) {
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if (typeof p === 'string') {
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const fn = this.points[p];
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if (!fn) {
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const e = new Error;
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e.message = `Point '${p}' is not defined`;
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throw e;
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}
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return fn();
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} else {
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return p;
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}
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}
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render() {
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for (let action of this.sequence) {
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action();
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}
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}
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animate() {
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this.ctx.reset();
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this.render();
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if (!this.stopped) {
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requestAnimationFrame((prevt) => {
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const rt = document.timeline.currentTime;
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const elapsed = rt - prevt;
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if (this.elideInterval) {
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this.dt = 0;
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this.elideInterval = false;
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} else {
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this.dt = (rt - this.rt + elapsed) * this.speed;
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}
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this.t += this.dt;
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this.rt = rt;
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this.animate();
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});
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}
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}
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stop() {
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this.stopped = true;
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}
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start() {
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if (this.stopped) {
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this.elideInterval = true;
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this.stopped = false;
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}
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this.animate();
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this.ctx.lineTo(...this.pixel([domain[1], fn(domain[1])]));
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this.ctx.stroke();
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})
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}
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}
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25
main.css
25
main.css
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@ -1,6 +1,27 @@
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body {
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margin: 50px;
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margin: 1em;
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}
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canvas {
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border: 1px red dashed;
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/* border: 1px red dashed; */
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margin: 0.5em;
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}
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button {
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margin: 0.25em;
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}
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.drawing.container {
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/* border: 1px black solid; */
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display: inline-block;
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margin: 1em;
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}
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.drawing > .title {
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font-size: large;
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}
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.drawing > .caption {
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font-size: small;
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text-align: center;
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}
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98
test.html
98
test.html
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@ -8,8 +8,22 @@
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</head>
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<body>
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<div id="d1"></div>
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<p>
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Some body text
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</p>
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<div id="d2"></div>
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<div id="d3"></div>
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<div id="d4"></div>
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<div id="d5"></div>
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<script>
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const d = new Drawing();
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let d1, d2, d3, d4;
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{
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const d = new Drawing('d1');
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d1 = d;
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d.setTitle('Example Animation');
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d.setCaption('Lissajou figure (skewed)');
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d.addButtons();
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d.setStroke('black', 4);
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d.polyline([0, 100], [0, 0], [100, 0]);
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d.definePoint('p1', () => d.oscillatingPoint([25, 50], [100, 100], 5000));
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@ -24,7 +38,89 @@
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d.setFill('cyan');
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d.circle('p1');
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d.start();
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}
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{
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const d = new Drawing('d2');
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d2 = d;
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d.setTitle('Sine Wave');
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d.setCaption('y = sin(x)');
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d.setStroke('black', 4);
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d.line([0, 0], [2*Math.PI, 0]);
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d.line([0, -1], [0, 1]);
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d.setStroke('red', 2);
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d.setFrame([0, -1], [2*Math.PI, 1]);
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d.setScale(100 / Math.PI);
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d.func({step: 0.1}, (x) => Math.sin(x));
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d.render();
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}
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{
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const d = new Drawing('d3');
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d3 = d;
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d.setTitle('Oscillating Sine Wave');
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d.setCaption('y = sin(x) * sin(t)');
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d.setStroke('black', 4);
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d.line([0, 0], [2*Math.PI, 0]);
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d.line([0, -1], [0, 1]);
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d.setStroke('red', 2);
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d.setFrame([0, -1], [2*Math.PI, 1]);
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d.setScale(100 / Math.PI);
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d.func({step: 0.1}, (x) => Math.sin(x) * d.oscillatingValue(-1, 1, 500));
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d.start();
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}
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{
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const d = new Drawing('d4');
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d4 = d;
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d.setTitle('Travelling Sine Wave');
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d.setCaption('y = sin(x + t)');
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d.setStroke('black', 4);
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d.line([0, 0], [2*Math.PI, 0]);
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d.line([0, -1], [0, 1]);
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d.setStroke('red', 2);
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d.setFrame([0, -1], [2*Math.PI, 1]);
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d.setScale(100 / Math.PI);
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d.func({step: 0.1}, (x) => Math.sin(x + 2*Math.PI*d.t / 1000));
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d.start();
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}
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{
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const d = new Drawing('d5');
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d5 = d;
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d.setTitle('Projectile');
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d.setCaption('y = v0y * t - g * t^2<br>x = v0x * t');
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d.setFrame([0, 0], [300, 100]);
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d.setStroke('black', 4);
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d.polyline([0, 100], [0, 0], [300, 0]);
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const v0 = 80;
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const angle = Math.PI / 4;
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const v0x = v0 * Math.cos(angle);
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const v0y = v0 * Math.sin(angle);
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d.definePoint('p1', () => {
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const t = d.t / 1000;
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const x = v0x * t;
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const y = v0y * t - 9.81 * t**2;
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if (t > 0 && (y <= 0 || x >= d.frame[1][0])) {
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d.stop();
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d.t = 0;
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}
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return [x, y];
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})
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d.setStroke('green', 1);
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d.line([0, 0], [v0x, v0y]);
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d.setFill('blue');
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const projectile = d.circle('p1', {trace: {age: -1}})
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d.onStart(() => {
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if (d.t == 0) {
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projectile.reset();
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}
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})
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d.start();
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}
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</script>
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</body>
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</html>
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