freesewing/sites/dev/docs/reference/api/utils/curveintersectsx/readme.mdx

---
title: utils.curveIntersectsX()
---

The `utils.curveIntersectsX()` function finds the point(s) where a curve
intersects a given X-value.

## Signature

```js
array | Point | false utils.curveIntersectsX(
  Point start,
  Point cp1,
  Point cp2,
  Point end,
  float x)
```

This returns `false` if no intersections are found,
a [Point](/reference/api/point) object if
a single intersection is found, and an array
of [Point](/reference/api/point) objects if
multiple intersections are found.

## Example

<Example caption="A Utils.curveIntersectX() example">
```js
({ Point, points, Path, paths, Snippet, snippets, utils, part }) => {

points.start = new Point(10, 15)
points.cp1 = new Point(80, 10)
points.cp2 = new Point(-50, 80)
points.end = new Point(110, 70)

paths.curve = new Path()
.move(points.start)
.curve(points.cp1, points.cp2, points.end)

for (let x of [30, 40]) {
points["from" + x] = new Point(x, 10)
points["to" + x] = new Point(x, 80)
paths["line" + x] = new Path()
.move(points["from" + x])
.line(points["to" + x])
.addClass("lining dashed")
}

snippets.i40 = new Snippet(
"notch",
utils.curveIntersectsX(points.start, points.cp1, points.cp2, points.end, 40)
)

for (let p of utils.curveIntersectsX(
points.start,
points.cp1,
points.cp2,
points.end,
30
))
snippets[p.y] = new Snippet("notch", p)

return part
}

```
</Example>


## Notes

This is a low-level (and faster) variant
of [`Path.intersectsX()`](/reference/api/path/intersectsx).
Instead of a path, you describe a single curve by passing the four
points that describes it.
```