javascript canvas rectangle rounded corners

1function draw() {
2  var canvas = document.getElementById('canvas');
3  if (canvas.getContext) {
4    var ctx = canvas.getContext('2d');
5
6    roundedRect(ctx, 12, 12, 150, 150, 15);
7    roundedRect(ctx, 19, 19, 150, 150, 9);
8    roundedRect(ctx, 53, 53, 49, 33, 10);
9    roundedRect(ctx, 53, 119, 49, 16, 6);
10    roundedRect(ctx, 135, 53, 49, 33, 10);
11    roundedRect(ctx, 135, 119, 25, 49, 10);
12
13    ctx.beginPath();
14    ctx.arc(37, 37, 13, Math.PI / 7, -Math.PI / 7, false);
15    ctx.lineTo(31, 37);
16    ctx.fill();
17
18    for (var i = 0; i < 8; i++) {
19      ctx.fillRect(51 + i * 16, 35, 4, 4);
20    }
21
22    for (i = 0; i < 6; i++) {
23      ctx.fillRect(115, 51 + i * 16, 4, 4);
24    }
25
26    for (i = 0; i < 8; i++) {
27      ctx.fillRect(51 + i * 16, 99, 4, 4);
28    }
29
30    ctx.beginPath();
31    ctx.moveTo(83, 116);
32    ctx.lineTo(83, 102);
33    ctx.bezierCurveTo(83, 94, 89, 88, 97, 88);
34    ctx.bezierCurveTo(105, 88, 111, 94, 111, 102);
35    ctx.lineTo(111, 116);
36    ctx.lineTo(106.333, 111.333);
37    ctx.lineTo(101.666, 116);
38    ctx.lineTo(97, 111.333);
39    ctx.lineTo(92.333, 116);
40    ctx.lineTo(87.666, 111.333);
41    ctx.lineTo(83, 116);
42    ctx.fill();
43
44    ctx.fillStyle = 'white';
45    ctx.beginPath();
46    ctx.moveTo(91, 96);
47    ctx.bezierCurveTo(88, 96, 87, 99, 87, 101);
48    ctx.bezierCurveTo(87, 103, 88, 106, 91, 106);
49    ctx.bezierCurveTo(94, 106, 95, 103, 95, 101);
50    ctx.bezierCurveTo(95, 99, 94, 96, 91, 96);
51    ctx.moveTo(103, 96);
52    ctx.bezierCurveTo(100, 96, 99, 99, 99, 101);
53    ctx.bezierCurveTo(99, 103, 100, 106, 103, 106);
54    ctx.bezierCurveTo(106, 106, 107, 103, 107, 101);
55    ctx.bezierCurveTo(107, 99, 106, 96, 103, 96);
56    ctx.fill();
57
58    ctx.fillStyle = 'black';
59    ctx.beginPath();
60    ctx.arc(101, 102, 2, 0, Math.PI * 2, true);
61    ctx.fill();
62
63    ctx.beginPath();
64    ctx.arc(89, 102, 2, 0, Math.PI * 2, true);
65    ctx.fill();
66  }
67}
68
69// A utility function to draw a rectangle with rounded corners.
70
71function roundedRect(ctx, x, y, width, height, radius) {
72  ctx.beginPath();
73  ctx.moveTo(x, y + radius);
74  ctx.lineTo(x, y + height - radius);
75  ctx.arcTo(x, y + height, x + radius, y + height, radius);
76  ctx.lineTo(x + width - radius, y + height);
77  ctx.arcTo(x + width, y + height, x + width, y + height-radius, radius);
78  ctx.lineTo(x + width, y + radius);
79  ctx.arcTo(x + width, y, x + width - radius, y, radius);
80  ctx.lineTo(x + radius, y);
81  ctx.arcTo(x, y, x, y + radius, radius);
82  ctx.stroke();
83}
84

1let canvas = document.getElementById('example');
2let ctx = canvas.getContext('2d');  
3ctx.beginPath();
4ctx.roundedRectangle(0, 0, 100, 100, 20);
5ctx.stroke();
6
7ctx.beginPath();  
8ctx.roundedRectangle(5, 5, 90, 90, 15);
9ctx.stroke();
10
11CanvasRenderingContext2D.prototype.roundedRectangle = function(x, y, width, height, rounded) {
12  const radiansInCircle = 2 * Math.PI;
13  const halfRadians = (2 * Math.PI)/2;
14  const quarterRadians = (2 * Math.PI)/4;  
15  
16  // top left arc
17  this.arc(rounded + x, rounded + y, rounded, -quarterRadians, halfRadians, true);
18  
19  // line from top left to bottom left
20  this.lineTo(x, y + height - rounded);
21
22  // bottom left arc  
23  this.arc(rounded + x, height - rounded + y, rounded, halfRadians, quarterRadians, true); 
24  
25  // line from bottom left to bottom right
26  this.lineTo(x + width - rounded, y + height);
27
28  // bottom right arc
29  this.arc(x + width - rounded, y + height - rounded, rounded, quarterRadians, 0, true);  
30  
31  // line from bottom right to top right
32  this.lineTo(x + width, y + rounded);
33
34  // top right arc
35  this.arc(x + width - rounded, y + rounded, rounded, 0, -quarterRadians, true); 
36  
37  // line from top right to top left
38  this.lineTo(x + rounded, y);
39}
40

1ctx.save();
2ctx.beginPath();
3ctx.closePath();
4ctx.clip();
5ctx.drawImage(Image)
6ctx.restore();