Update arc.rs with improved documentation

added units and improved description to field comments of Arc and Ellipse structs.

graphics/src/geometry/path/arc.rs

@@ -8,9 +8,9 @@ pub struct Arc {
  pub center: Point,
  /// The radius of the arc.
  pub radius: f32,
- /// The start of the segment's angle, clockwise rotation.
+ /// The start of the segment's angle in radians, clockwise rotation from positive x-axis.
  pub start_angle: f32,
- /// The end of the segment's angle, clockwise rotation.
+ /// The end of the segment's angle in radians, clockwise rotation from positive x-axis.
  pub end_angle: f32,
 }
 
@@ -19,13 +19,13 @@ pub struct Arc {
 pub struct Elliptical {
  /// The center of the arc.
  pub center: Point,
- /// The radii of the arc's ellipse, defining its axes.
+ /// The radii of the arc's ellipse. The horizontal and vertical half-dimensions of the ellipse will match the x and y values of the radii vector.
  pub radii: Vector,
- /// The rotation of the arc's ellipse.
+ /// The clockwise rotation of the arc's ellipse.
  pub rotation: f32,
- /// The start of the segment's angle, clockwise rotation.
+ /// The start of the segment's angle in radians, clockwise rotation from positive x-axis.
  pub start_angle: f32,
- /// The end of the segment's angle, clockwise rotation.
+ /// The end of the segment's angle in radians, clockwise rotation from positive x-axis.
  pub end_angle: f32,
 }