function drawPoint()

in Hands-on lab/lab-files/starter-project/NorthwindMVC/wwwroot/lib/Chart.js/chart.js [1241:1342]


function drawPoint(ctx, options, x, y) {
  let type, xOffset, yOffset, size, cornerRadius;
  const style = options.pointStyle;
  const rotation = options.rotation;
  const radius = options.radius;
  let rad = (rotation || 0) * RAD_PER_DEG;
  if (style && typeof style === 'object') {
    type = style.toString();
    if (type === '[object HTMLImageElement]' || type === '[object HTMLCanvasElement]') {
      ctx.save();
      ctx.translate(x, y);
      ctx.rotate(rad);
      ctx.drawImage(style, -style.width / 2, -style.height / 2, style.width, style.height);
      ctx.restore();
      return;
    }
  }
  if (isNaN(radius) || radius <= 0) {
    return;
  }
  ctx.beginPath();
  switch (style) {
  default:
    ctx.arc(x, y, radius, 0, TAU);
    ctx.closePath();
    break;
  case 'triangle':
    ctx.moveTo(x + Math.sin(rad) * radius, y - Math.cos(rad) * radius);
    rad += TWO_THIRDS_PI;
    ctx.lineTo(x + Math.sin(rad) * radius, y - Math.cos(rad) * radius);
    rad += TWO_THIRDS_PI;
    ctx.lineTo(x + Math.sin(rad) * radius, y - Math.cos(rad) * radius);
    ctx.closePath();
    break;
  case 'rectRounded':
    cornerRadius = radius * 0.516;
    size = radius - cornerRadius;
    xOffset = Math.cos(rad + QUARTER_PI) * size;
    yOffset = Math.sin(rad + QUARTER_PI) * size;
    ctx.arc(x - xOffset, y - yOffset, cornerRadius, rad - PI, rad - HALF_PI);
    ctx.arc(x + yOffset, y - xOffset, cornerRadius, rad - HALF_PI, rad);
    ctx.arc(x + xOffset, y + yOffset, cornerRadius, rad, rad + HALF_PI);
    ctx.arc(x - yOffset, y + xOffset, cornerRadius, rad + HALF_PI, rad + PI);
    ctx.closePath();
    break;
  case 'rect':
    if (!rotation) {
      size = Math.SQRT1_2 * radius;
      ctx.rect(x - size, y - size, 2 * size, 2 * size);
      break;
    }
    rad += QUARTER_PI;
  case 'rectRot':
    xOffset = Math.cos(rad) * radius;
    yOffset = Math.sin(rad) * radius;
    ctx.moveTo(x - xOffset, y - yOffset);
    ctx.lineTo(x + yOffset, y - xOffset);
    ctx.lineTo(x + xOffset, y + yOffset);
    ctx.lineTo(x - yOffset, y + xOffset);
    ctx.closePath();
    break;
  case 'crossRot':
    rad += QUARTER_PI;
  case 'cross':
    xOffset = Math.cos(rad) * radius;
    yOffset = Math.sin(rad) * radius;
    ctx.moveTo(x - xOffset, y - yOffset);
    ctx.lineTo(x + xOffset, y + yOffset);
    ctx.moveTo(x + yOffset, y - xOffset);
    ctx.lineTo(x - yOffset, y + xOffset);
    break;
  case 'star':
    xOffset = Math.cos(rad) * radius;
    yOffset = Math.sin(rad) * radius;
    ctx.moveTo(x - xOffset, y - yOffset);
    ctx.lineTo(x + xOffset, y + yOffset);
    ctx.moveTo(x + yOffset, y - xOffset);
    ctx.lineTo(x - yOffset, y + xOffset);
    rad += QUARTER_PI;
    xOffset = Math.cos(rad) * radius;
    yOffset = Math.sin(rad) * radius;
    ctx.moveTo(x - xOffset, y - yOffset);
    ctx.lineTo(x + xOffset, y + yOffset);
    ctx.moveTo(x + yOffset, y - xOffset);
    ctx.lineTo(x - yOffset, y + xOffset);
    break;
  case 'line':
    xOffset = Math.cos(rad) * radius;
    yOffset = Math.sin(rad) * radius;
    ctx.moveTo(x - xOffset, y - yOffset);
    ctx.lineTo(x + xOffset, y + yOffset);
    break;
  case 'dash':
    ctx.moveTo(x, y);
    ctx.lineTo(x + Math.cos(rad) * radius, y + Math.sin(rad) * radius);
    break;
  }
  ctx.fill();
  if (options.borderWidth > 0) {
    ctx.stroke();
  }
}