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CLICK THE CIRCLE
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| <canvas id="canvas" width="600px" height="400px"></canvas> | |
| <script src="./index.js"></script> |
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| let x = 200; | |
| let y = 200; | |
| let r = 100; | |
| let color = 'black'; | |
| let canvas = document.getElementById('canvas'); | |
| let ctx = canvas.getContext('2d'); | |
| let colors = []; | |
| // so the trick is to go the center, rotate, translate by r | |
| let acc = 0.001; | |
| let vx = 0; | |
| let offset = 0; | |
| let rad = Math.PI / 180; | |
| let colorIndex = {}, colorsRGB = []; | |
| let clicked = []; | |
| let hovered; | |
| function draw() { | |
| ctx.clearRect(0, 0, 800, 400); | |
| for (let i = 0, j = 0; j < 360; i++, j = i * 20) { | |
| if (!colors[i]) { | |
| let r = Math.floor(Math.random() * 255); | |
| let g = Math.floor(Math.random() * 255); | |
| let b = Math.floor(Math.random() * 255); | |
| colors[i] = `rgba(${r}, ${g}, ${b}, 1)`; | |
| colorsRGB[i] = [r, g, b]; | |
| colorIndex[`${r}${g}${b}`] = i; | |
| } | |
| ctx.save(); | |
| ctx.translate(x, y); | |
| ctx.rotate(rad * j + offset); | |
| ctx.translate(5, -100); | |
| let stroke = false; | |
| if (clicked[i]) { | |
| clicked[i].scale += 1; | |
| clicked[i].opacity -= 0.02; | |
| ctx.translate( clicked[i].scale * 2, clicked[i].scale * 2); | |
| [r, g, b] = colorsRGB[i]; | |
| let opacity = clicked[i].opacity; | |
| colors[i] = `rgba(${r}, ${g}, ${b}, ${opacity})`; | |
| ctx.scale(clicked[i].scale, clicked[i].scale); | |
| } else { | |
| stroke = hovered === i; | |
| } | |
| drawCircle(0, 0, 10, colors[i], stroke); | |
| ctx.restore(); | |
| } | |
| vx += acc; | |
| if (vx < -0.03) { | |
| acc = 0.0001; | |
| } | |
| if (vx > 0.03) { | |
| acc = -0.0001; | |
| } | |
| offset += vx; | |
| window.requestAnimationFrame(draw); | |
| } | |
| draw(); | |
| document.getElementById('canvas').addEventListener('click', e => { | |
| let x = e.offsetX; | |
| let y = e.offsetY; | |
| let p = ctx.getImageData(x, y, 1, 1).data; | |
| let r = p[0], g = p[1], b = p[2]; | |
| let key = `${r}${g}${b}` | |
| let i = (colorIndex[key]); | |
| if (i || i === 0) { | |
| clicked[i] = { | |
| scale: 1, | |
| opacity: 1 | |
| } | |
| } | |
| }); | |
| document.getElementById('canvas').addEventListener('mousemove', e => { | |
| let x = e.offsetX; | |
| let y = e.offsetY; | |
| let p = ctx.getImageData(x, y, 1, 1).data; | |
| let r = p[0], g = p[1], b = p[2]; | |
| let key = `${r}${g}${b}`; | |
| hovered = (colorIndex[key]); | |
| }); | |
| function drawCircle(x, y, radius, color, stroke) { | |
| ctx.fillStyle = color; | |
| ctx.beginPath(); | |
| ctx.arc(x, y, radius, 0, 2*Math.PI); | |
| ctx.fill(); | |
| if (stroke) { | |
| ctx.lineWidth = 3; | |
| ctx.stroke(); | |
| } | |
| } |
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