Package com.macrofocus.high_d.parallelcoordinates.geometry.curve

Class Curve

  • Direct Known Subclasses:
    BezierCurve, BSpline, CardinalSpline, CatmullRomSpline, CubicBSpline, LagrangeCurve, NaturalCubicSpline
    public abstract class Curve
extends java.lang.Object

    A Curve is an object that defines itself using mathematical equations and points of a control-path in a given dimension. Classes that extend Curve must define the appendTo method.

    A Curve object can be appended to a MultiPath object which creates a series of points that represent the curve. Most curves in the com.graphbuilder.curve package extend the ParametricCurve class, with one exception being the Polyline class. The ParametricCurve class allows curves to use the BinaryCurveApproximationAlgorithm class to generate the points. The number of points created depends on the curve properties, the control points, the sample limit and the flatness. The flatness is the only parameter that is controlled by the multi-path. How the flatness and sample limit affect the number of points created is described in the BinaryCurveApproximationAlgorithm class.

    The data representation of a point is a double array. The double array was chosen because it offers a high degree of precision. An array based representation supports n-dimensional curves, with index locations acting as dimensions.

    The ControlPath stores com.graphbuilder.curve.Point objects. The reason the ControlPath stores Point objects and not double arrays is to provide one level of indirection. For example, suppose two different objects had a reference to the same double array. To change the dimension of the array, a new array has to be created. This would require updating the references in each of the objects to the new array. However, if a Point object stores the array, and the objects refer to the Point object, then only the reference to the array in the Point object needs to be updated. However, multi-paths do not store Point objects, but instead references to double arrays. There is no need for MultiPaths to reference Point objects because the points inside a multi-path are generated.

    In many of the implementations, curve instances share static memory blocks which are used to store the results of computations. The reason this is done is to avoid using excessive memory. However, none of the methods in the curve package are synchronized. Thus, multiple threads should not be appending curves to multi-paths, otherwise the results of computations will be overwritten.

    See Also:
    MultiPath, ControlPath, GroupIterator, BinaryCurveApproximationAlgorithm, ParametricCurve, Point, appendTo(MultiPath)

    • Method Summary

      All Methods Instance Methods Abstract Methods Concrete Methods 
      Modifier and Type Method Description
      abstract void appendTo​(com.macrofocus.high_d.parallelcoordinates.geometry.curve.MultiPath mp)
      Appends a sequence of points defined by this curve to the multi-path.
      boolean getConnect()
      Connect is used in the appendTo method to determine if the first point appended should be of type MOVE_TO or LINE_TO.
      ControlPath getControlPath()
      Returns the control-path this curve uses to define itself.
      GroupIterator getGroupIterator()
      Returns the group-iterator associated with this curve.
      void resetMemory()
      Resets the shared memory to the initial state.
      void setConnect​(boolean b)
      Sets the value of the boolean connect flag.

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

    • Method Detail

      • getGroupIterator

        public GroupIterator getGroupIterator()
        Returns the group-iterator associated with this curve. The group-iterator determines which points from the control-path, and the order of the points this curve uses to define itself.
        See Also:
        setGroupIterator(GroupIterator), getControlPath()

      • getConnect

        public boolean getConnect()
        Connect is used in the appendTo method to determine if the first point appended should be of type MOVE_TO or LINE_TO. If connect is true then LINE_TO is used. If connect is false then MOVE_TO is used.
        See Also:
        setConnect(boolean), appendTo(MultiPath), MultiPath.MOVE_TO, MultiPath.LINE_TO

      • setConnect

        public void setConnect​(boolean b)
        Sets the value of the boolean connect flag.
        See Also:
        getConnect()

      • appendTo

        public abstract void appendTo​(com.macrofocus.high_d.parallelcoordinates.geometry.curve.MultiPath mp)
        Appends a sequence of points defined by this curve to the multi-path. If the internal state of the curve is such that it cannot be evaluated, then the specification is for this method to return quietly.
        See Also:
        MultiPath, BinaryCurveApproximationAlgorithm

      • resetMemory

        public void resetMemory()
        Resets the shared memory to the initial state.