computePieDataBounds function

Rect computePieDataBounds(List<DataPoint> pies, double offset)

Data-space bounds of pie centerlines and offsets.

Visual thickness, borders, corner radii, and markers are intentionally not included, matching the bounds behavior of line and bar charts.

Implementation

Rect computePieDataBounds(List<DataPoint> pies, double offset) {
  Rect? bounds;

  for (final pie in pies) {
    if (pie.x <= 0.0001 || pie.dy <= 0.0001) continue;

    final center = toCartesian(pie.pieOffset?.pieOffset ?? offset, pie);
    final start = pie.y;
    final end = pie.fy;
    final angles = <double>[start, end];

    if (end - start >= 2 * pi) {
      angles.addAll(const [0.0, pi / 2, pi, 3 * pi / 2]);
    } else {
      final firstQuarter = (start / (pi / 2)).ceil();
      final lastQuarter = (end / (pi / 2)).floor();
      for (var quarter = firstQuarter; quarter <= lastQuarter; quarter++) {
        angles.add(quarter * pi / 2);
      }
    }

    for (final angle in angles) {
      final point = center + Offset(pie.x * cos(angle), pie.x * sin(angle));
      final pointBounds = Rect.fromLTWH(point.dx, point.dy, 0, 0);
      bounds =
          bounds == null ? pointBounds : bounds.expandToInclude(pointBounds);
    }
  }

  return bounds ?? const Rect.fromLTRB(0, 0, 1, 1);
}