MSFCelestialArc

Objective-C


@interface MSFCelestialArc : MSFCelestialObject

Swift

class MSFCelestialArc : MSFCelestialObject

A curve drawn on the sky.

Two ways to define one, and the first is what a daily path is:

  • as a CIRCLE about an axis: every direction at a fixed angle from the axis. The daily path of a distant body is exactly this - the axis is the rotation axis and the angle is the complement of the declination - so an application draws it with an axis and one angle rather than by sampling positions through the day.
  • as an explicit list of directions, for a path that is not a circle: a satellite track, a flight plan, a sampled trajectory.

The curve is generated once and drawn as a line strip; its width is in pixels, so it stays legible at any field of view.

  • Undocumented

    Declaration

    Objective-C

    -(id)init;

    Swift

    init!()

  • Defines the arc as a circle about an axis.

    Declaration

    Objective-C

    - (void)setCircle:(float)axisAzimuth
     axisAltitude:(float)axisAltitude
           radius:(float)radius;

    Swift

    func setCircle(_ axisAzimuth: Float, axisAltitude: Float, radius: Float)

    Parameters

    axisAzimuth

    The azimuth of the axis in degrees, clockwise from north.
    axisAltitude

    The altitude of the axis in degrees above the horizon.
    radius

    The angular radius in degrees: the angle between the axis and the curve.

  • Defines the arc as an explicit list of directions, each an (azimuth, altitude) pair in degrees. The curve runs through them in order and is not closed.

    Declaration

    Objective-C

    - (void)setDirections:(MSFDoubleVector *)directions;

    Swift

    func setDirections(_ directions: MSFDoubleVector!)

    Parameters

    directions

    The directions, as alternating azimuth and altitude values in degrees.

  • Defines the arc as a list of SEPARATE segments: every pair of directions is one line and consecutive pairs are not joined. A figure drawn between fixed directions is exactly this - a set of lines that is not a single path - and it stays ONE object, so it is one draw call and one clickable thing.

    Declaration

    Objective-C

    - (void)setSegments:(MSFDoubleVector *)directions;

    Swift

    func setSegments(_ directions: MSFDoubleVector!)

    Parameters

    directions

    The directions, as alternating azimuth and altitude values in degrees.

  • Returns true if the directions are read as separate segments rather than as a path.

    Declaration

    Objective-C

    - (BOOL)isSegmented;

    Swift

    func isSegmented() -> Bool

    Return Value

    True if the arc is a segment list.

  • Returns the directions of an explicitly defined arc.

    Declaration

    Objective-C

    - (MSFDoubleVector *)getDirections;

    Swift

    func getDirections() -> MSFDoubleVector!

    Return Value

    The directions, as alternating azimuth and altitude values in degrees.

  • Returns the angular radius of a circular arc.

    Declaration

    Objective-C

    - (float)getRadius;

    Swift

    func getRadius() -> Float

    Return Value

    The angular radius in degrees.

  • Returns the line width.

    Declaration

    Objective-C

    - (float)getWidth;

    Swift

    func getWidth() -> Float

    Return Value

    The width in pixels.

  • Sets the line width.

    Declaration

    Objective-C

    - (void)setWidth:(float)pixels;

    Swift

    func setWidth(_ pixels: Float)

    Parameters

    pixels

    The width in pixels.

  • Returns whether the part of the curve below the horizon is drawn.

    Declaration

    Objective-C

    - (BOOL)isBelowHorizonVisible;

    Swift

    func isBelowHorizonVisible() -> Bool

    Return Value

    True if the curve is drawn below the horizon.

  • Sets whether the part of the curve below the horizon is drawn. A daily path looks right with this off - the arc then rises and sets like the body on it does.

    Declaration

    Objective-C

    - (void)setBelowHorizonVisible:(BOOL)visible;

    Swift

    func setBelowHorizonVisible(_ visible: Bool)

    Parameters

    visible

    True to draw the curve below the horizon.

  • Returns the click radius of the curve.

    Declaration

    Objective-C

    - (float)getClickRadius;

    Swift

    func getClickRadius() -> Float

    Return Value

    The click radius in degrees.

  • Sets the click radius of the curve: how far, in degrees, a touch ray may miss the curve and still hit it. A curve is a line a pixel or two wide, so without this nothing could ever be aimed at. 0 makes the curve unclickable. The default is 2 degrees.

    Declaration

    Objective-C

    - (void)setClickRadius:(float)degrees;

    Swift

    func setClickRadius(_ degrees: Float)

    Parameters

    degrees

    The click radius in degrees.

  • Undocumented

    Declaration

    Objective-C

    -(void)dealloc;

    Swift

    func dealloc()