edu.mit.sketch.ddg
Class Util

java.lang.Object
  edu.mit.sketch.ddg.Util

public class Util
extends java.lang.Object

This class implements several static methods useful for the package.

Util.java Created: Tue Apr 5 19:47:00 2002

Author:

Olya Veselova

Field Summary

static boolean	DEBUG_MODE Determines whether the system is in debug mode
static double	MAX_ANGULAR_OFFSET The maximum angle that can be considered negligible
static double	MAX_OFFSET The maximum offset after which the distance between two points cannot be considered negligible
static double	OBSTRUCTION_SENSITIVITY Determines how sensitive constraints are to obstruction
static double	SIZE_TO_OFFSET_RATIO How much larger the object should be than the distance from this object to some other point so that that the confidence distance is just considered negligible

Constructor Summary

Util()

Method Summary

static boolean	aboveLine(Point p, Line l) Returns true if the given point is in the upper hyperplane as defined by the line
static double	angleNegligible(double angle) The confidence that the given angle (in radians) can be considered negligible.
static boolean	belowLine(Point p, Line l) Returns true if the given point is in the lower hyperplane as defined by the line
static Polygon	closedContour(DrawnObject object, ConnectsConstraint connectsConstraint, IntersectsConstraint intersectsConstraint) If the given object is a closed contour return a polygon that is the boundary.
static Point	closestPoint(Ellipse e, Point p) Returns the closest point on the ellipse to the given point
static Point	closestPoint(Line line, Point p) Returns the closest point on the line to a given point
static int	closestPointType(Ellipse e, Point p) Returns the closest qualitative point type on the ellipse to the given point
static void	debug(java.lang.String txt) Prints out debugging information if in debugging mode
static double	distanceNegligible(double distance, double objectSize) The confidence that the given distance can be considered negligible.
static Line[]	eightLineEllipseApproximation(Ellipse e) Approximate the ellipse with 8 lines and return the list
static GeometricObjectList	ellipseApproximation(Ellipse e) Approximate the ellipse with a list of lines and return the list
static boolean	isHorizontal(Line line)
static boolean	isVertical(Line line)
static boolean	leftOfLine(Point p, Line l) Returns true if the given point is in the left hyperplane as defined by the line
static double	minDistance(GeometricObject o1, GeometricObject o2) Calculte the minimum distance between two primitives.
static double	minLineDistance(Line l1, Line l2) Calculate the minimun distance between two line segments
static boolean	onSameAxis(Line l1, Line l2)
static double	parallelity(Line l1, Line l2) Returns the degree of parallelity from 0 to 1;
static Line	parallelSegment(Line l, Ellipse e) Find the closest of the two ellipse segments that are most parallel to the given line
static boolean	rightOfLine(Point p, Line l) Returns true if the given point is in the right hyperplane as defined by the line
static double	roundToPrecision(double value, int precision) Round a double to a given number of decimal places
static boolean	sameSide(Line line, Point p1, Point p2) Takes in a line, that defines a hyperplane, and returns true is the second point is in the same hyperplane as the first point.
static double	sigmoid(double a, double x, double b) Returns the value of the function 1 / (1 + exp{-a*(x - b)})
static double	size(GeometricObject object) Calculate the size of the geometric object
static double	twoSlopeRoofFunction(double value, double smallWidth, double largeWidth, double maxX, double medY) Two-slope-roof-like function returning value in the interval [0;1].

Methods inherited from class java.lang.Object

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

Field Detail

SIZE_TO_OFFSET_RATIO

public static double SIZE_TO_OFFSET_RATIO

How much larger the object should be than the distance from this object to some other point so that that the confidence distance is just considered negligible

MAX_OFFSET

public static double MAX_OFFSET

The maximum offset after which the distance between two points cannot be considered negligible

MAX_ANGULAR_OFFSET

public static double MAX_ANGULAR_OFFSET

The maximum angle that can be considered negligible

OBSTRUCTION_SENSITIVITY

public static double OBSTRUCTION_SENSITIVITY

Determines how sensitive constraints are to obstruction

DEBUG_MODE

public static boolean DEBUG_MODE

Determines whether the system is in debug mode

Constructor Detail

Util

public Util()

Method Detail

angleNegligible

public static double angleNegligible(double angle)

The confidence that the given angle (in radians) can be considered negligible. Returns a value in the interval [0;1]. The angle that is larger than MAX_ANGULAR_OFFSET cannont be negligible

distanceNegligible

public static double distanceNegligible(double distance,
                                        double objectSize)

The confidence that the given distance can be considered negligible. Returns a value in the interval [0;1]. The distance and object size should be passed in pixels devided by the line width on the screen. That is the distance is measured in the perceived pixels.
Ideally the confidence depends on two factors:
- object size - the larger, the more the confidence, given the same distance
- distance - the smaller, the more the confidence, given the same size
Here we approximate this function by size factor if distance is below MAX_OFFSET, and by distance factor if size-to-distance ratio is more than SIZE_TO_OFFSET_RATIO

closedContour

public static Polygon closedContour(DrawnObject object,
                                    ConnectsConstraint connectsConstraint,
                                    IntersectsConstraint intersectsConstraint)

If the given object is a closed contour return a polygon that is the boundary. Otherwise return null. A closed contour is a contour where each line connects to exactly two other lines on both sides and no lines intersect each other. Currently only handles closed contours consisting of lines.

twoSlopeRoofFunction

public static double twoSlopeRoofFunction(double value,
                                          double smallWidth,
                                          double largeWidth,
                                          double maxX,
                                          double medY)
                                   throws InvalidParameterException

Two-slope-roof-like function returning value in the interval [0;1]. The function reaches the maximum of 1 at maxX, falls off on both sides to a medY value that is at maxX +- smallWidth, and then falls off to 0 on both sides at maxX +- largeWidth. medY should be in [0;1] interval. If not throws an exception.

Throws:

InvalidParameterException

debug

public static void debug(java.lang.String txt)

Prints out debugging information if in debugging mode

roundToPrecision

public static double roundToPrecision(double value,
                                      int precision)

Round a double to a given number of decimal places

parallelity

public static double parallelity(Line l1,
                                 Line l2)

Returns the degree of parallelity from 0 to 1;

parallelSegment

public static Line parallelSegment(Line l,
                                   Ellipse e)

Find the closest of the two ellipse segments that are most parallel to the given line

eightLineEllipseApproximation

public static Line[] eightLineEllipseApproximation(Ellipse e)

Approximate the ellipse with 8 lines and return the list

ellipseApproximation

public static GeometricObjectList ellipseApproximation(Ellipse e)

Approximate the ellipse with a list of lines and return the list

minDistance

public static double minDistance(GeometricObject o1,
                                 GeometricObject o2)

Calculte the minimum distance between two primitives. Note: the distance between ellipses determined by the distance between their axes.

size

public static double size(GeometricObject object)

Calculate the size of the geometric object

minLineDistance

public static double minLineDistance(Line l1,
                                     Line l2)

Calculate the minimun distance between two line segments

aboveLine

public static boolean aboveLine(Point p,
                                Line l)

Returns true if the given point is in the upper hyperplane as defined by the line

belowLine

public static boolean belowLine(Point p,
                                Line l)

Returns true if the given point is in the lower hyperplane as defined by the line

rightOfLine

public static boolean rightOfLine(Point p,
                                  Line l)

Returns true if the given point is in the right hyperplane as defined by the line

leftOfLine

public static boolean leftOfLine(Point p,
                                 Line l)

Returns true if the given point is in the left hyperplane as defined by the line

sameSide

public static boolean sameSide(Line line,
                               Point p1,
                               Point p2)

Takes in a line, that defines a hyperplane, and returns true is the second point is in the same hyperplane as the first point. Assumes that both points are not on the infinite line defined by the line.

sigmoid

public static double sigmoid(double a,
                             double x,
                             double b)

Returns the value of the function 1 / (1 + exp{-a*(x - b)})

closestPoint

public static Point closestPoint(Ellipse e,
                                 Point p)

Returns the closest point on the ellipse to the given point

closestPointType

public static int closestPointType(Ellipse e,
                                   Point p)

Returns the closest qualitative point type on the ellipse to the given point

closestPoint

public static Point closestPoint(Line line,
                                 Point p)

Returns the closest point on the line to a given point

isVertical

public static boolean isVertical(Line line)

isHorizontal

public static boolean isHorizontal(Line line)

onSameAxis

public static boolean onSameAxis(Line l1,
                                 Line l2)