freesewing/markdown/dev/reference/api/path/trim/en.md

title
trim()

Path path.trim()

Returns a new Path that is this path with overlapping parts removed.

This method is typically used when Path.offset() caused some overlap.

Use sparsely or performance will suffer

This method is recursive and complex, and the performance penalty for using it on a long/complex path will be significant.

To limit the impact of path.trim(), follow this approach:

• construct a minimal path that contains the overlap
• trim it
• now join it to the rest of your path

You can see an example of this in the front part of the Bruce pattern.

Example of the Path.trim() method

let { Point, points, Path, paths } = part.shorthand();

points.center = new Point(0, 0);
points.base = new Point(0, 10);
points.tip = new Point(0, 50);
points.tipCpRight = new Point(30, 50);
points.tipCpLeft = new Point(-30, 50);
paths.example = new Path().move(points.base);
for (let i = 0; i < 4; i++) {
  points["base" + i] = points.base.rotate(60 * i, points.center);
  points["tip" + i] = points.tip.rotate(60 * i, points.center);
  points["tipCpRight" + i] = points.tipCpRight.rotate(60 * i, points.center);
  points["tipCpLeft" + i] = points.tipCpLeft.rotate(60 * i, points.center);
  if (i < 2) {
    paths.example
      .line(points["base" + i])
      .curve(points["base" + i], points["tipCpLeft" + i], points["tip" + i])
      .curve(
        points["tipCpRight" + i],
        points["base" + i],
        points["base" + i]
      );
  } else {
    paths.example
      .line(points["base" + i])
      .line(points["tip" + i])
      .line(points["tipCpRight" + i])
      .line(points["base" + i]);
  }
}

paths.offset = paths.example
  .offset(10)
  .attr("class", "lining dotted stroke-sm");

paths.trimmed = paths.offset
  .trim()
  .attr("class", "various stroke-xl")
  .attr("style", "stroke-opacity: 0.5;");