trimPath function

Path trimPath(Path source, double percentage, { bool firstOnly = true, PathTrimOrigin origin = PathTrimOrigin.begin, })

Trims percentage of the source Path away and returns a new path.

The percentage parameter will be clamped between 0..1 and must not be null.

Use the firstOnly parameter to specify whether this should apply only to the first segment of the path (and thus return only the first trimmed segment) or all segments of the path. Multi-segment paths (i.e. paths with a move verb) will all be trimmed if this is false; otherwise, a trimmed version of only the first path segment will be returned. It must not be null.

The origin parameter allows the user to control which end of the path will be trimmed. It must not be null.

If source is empty, an empty path will be returned.

Implementation

Path trimPath(
    Path source,
    double percentage, {
      bool firstOnly = true,
      PathTrimOrigin origin = PathTrimOrigin.begin,
    }) {
  assert(percentage != null); // ignore: unnecessary_null_comparison
  assert(firstOnly != null); // ignore: unnecessary_null_comparison
  assert(origin != null); // ignore: unnecessary_null_comparison

  percentage = percentage.clamp(0.0, 1.0);
  if (percentage == 1.0) {
    return Path();
  }
  if (percentage == 0.0) {
    return Path.from(source);
  }
  if (origin == PathTrimOrigin.end) {
    percentage = 1.0 - percentage;
  }

  final Path dest = Path();
  for (final PathMetric metric in source.computeMetrics()) {
    switch (origin) {
      case PathTrimOrigin.end:
        dest.addPath(
          metric.extractPath(0.0, metric.length * percentage),
          Offset.zero,
        );
        break;
      case PathTrimOrigin.begin:
        dest.addPath(
          metric.extractPath(metric.length * percentage, metric.length),
          Offset.zero,
        );
        break;
    }
    if (firstOnly) {
      break;
    }
  }

  return dest;
}