freesewing/markdown/dev/reference/api/utils/pointonline/en.md

***

## title: pointOnLine()

```js
bool utils.pointOnLine(
  Point from, 
  Point to, 
  Point check, 
  float precision = 1e6
)
```

Returns `true` if the point `check` lies on a line segment from point `from` to point `to`.

The fourth parameter controls the precision. See [pointOnBeam](#utilspointonbeam).

<Example part="utils_pointonline" caption="A Utils.pointOnLine() example" />

```js
let {
  Point,
  points,
  Path,
  paths,
  Snippet,
  snippets,
  utils
} = part.shorthand();

points.from1 = new Point(10, 10);
points.to1 = new Point(90, 60);
points.from2 = new Point(10, 30);
points.to2 = new Point(90, 80);
points.b1 = new Point(170, 110);
points.b2 = new Point(170, 130);

let scatter = [];
for (let i = 1; i < 36; i++) {
  for (let j = 1; j < 27; j++) {
    scatter.push(new Point(i * 10, j * 10));
  }
}
let snippet;
for (let point of scatter) {
  if (utils.pointOnLine(points.from1, points.to1, point)) snippet = "notch";
  else snippet = "bnotch";
  snippets[part.getId()] = new Snippet(snippet, point);
  if (utils.pointOnLine(points.from2, points.to2, point, 0.01)) {
    snippet = "notch";
  } else snippet = "bnotch";
  snippets[part.getId()] = new Snippet(snippet, point);
}
paths.line1 = new Path()
  .move(points.from1)
  .line(points.to1)
  .attr("class", "fabric stroke-lg");
paths.lne1 = new Path()
  .move(points.to1)
  .line(points.b1)
  .attr("class", "fabric dashed");
paths.line2 = new Path()
  .move(points.from2)
  .line(points.to2)
  .attr("class", "fabric stroke-lg");
paths.lne2 = new Path()
  .move(points.to2)
  .line(points.b2)
  .attr("class", "fabric dashed");
```