org.eclipse.graphiti.ui.internal.util.draw2d

Class LineSeg

java.lang.Object

org.eclipse.graphiti.ui.internal.util.draw2d.LineSeg

All Implemented Interfaces:

java.io.Serializable, org.eclipse.draw2d.geometry.Translatable

public class LineSeg
extends java.lang.Object
implements java.io.Serializable, org.eclipse.draw2d.geometry.Translatable

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	LineSeg.KeyPoint Enumeration class for defining the keypoint along a line segment.
static class	LineSeg.Sign Enumeration class for defining the orientations of a point relative to the line segment.
static class	LineSeg.TrigValues Structure to hold onto trig values that represent an angle

Constructor Summary

Constructors

Constructor and Description
LineSeg(LineSeg.KeyPoint start, int fromX, int fromY, float slope, long len, int xdir) Creates a segment using (fromX, fromY) as either the first point of the segment (start == Origin) or the midpoint of the segment (start == Midpoint), and using slope as its new slope and len as the new length.
LineSeg(org.eclipse.draw2d.geometry.Point ptStart, org.eclipse.draw2d.geometry.Point ptEnd) Constructor

Method Summary

Modifier and Type	Method and Description
boolean	containsPoint(org.eclipse.draw2d.geometry.Point aPoint, int tolerance) Checks if this line segment contains the given point within a tolerance value.
float	distanceAlong(org.eclipse.draw2d.geometry.Point coord) Finds the percentage distance along this line segement where the given point resides.
long	distanceToPoint(int xCoord, int yCoord) Finds the perpendicular distance from a point coordinates to this line segment.
boolean	equals(java.lang.Object seg)
double[]	getEquation() Returns array with 3 numbers in it, which are the coefficients of the generalized line equation of the line corresponding to this line segment a*x+b*y=c is the equation => result[0]=a, result[1]=b, result[2]=c
org.eclipse.draw2d.geometry.Point	getInfimum() Get a Point representing the lowest point value for this line segment.
static double[]	getLineEquation(double x1, double y1, double x2, double y2) Returns the coefficients of the generalized equation of the line passing through points (x1,y1) and (x2,y2) Generalized line equation: ax+by=c => a==result[0], b==result[1], c==result[2]
org.eclipse.draw2d.geometry.PointList	getLineIntersectionsWithEllipse(org.eclipse.draw2d.geometry.Rectangle ellipseBounds) Calculates intersection points of the line of the line segment and ellipse
org.eclipse.draw2d.geometry.PointList	getLineIntersectionsWithLineSegs(org.eclipse.draw2d.geometry.PointList points) Calculates intersection points of the line that contains this line segment with a list of other line segments.
org.eclipse.draw2d.geometry.PointList	getLinesIntersections(LineSeg line) Returns intersection points of two lines that contain this line segment and the argumet line segment.
org.eclipse.draw2d.geometry.Point	getOrigin() Accesssor to retrieve the origin point of the line segement.
LineSeg	getParallelLineSegThroughPoint(org.eclipse.draw2d.geometry.Point ptLoc) Returns a new LineSeg that is parallel to this by the given distance.
org.eclipse.draw2d.geometry.Point	getSupremum() Get points representing the highest point value for this line segment.
org.eclipse.draw2d.geometry.Point	getTerminus() Accesssor to retrieve the terminal point of the line segement.
LineSeg.TrigValues	getTrigValues(org.eclipse.draw2d.geometry.Vector ptToVector) Gets the trig values associated with the angle from this line segment to the given vector.
int	hashCode()
org.eclipse.draw2d.geometry.Point	intersect(LineSeg line, int nTolerance) Determines the intersect point between this line and the line passed in as a parameter.
boolean	isHorizontal() Determines if this a horizontal segment
boolean	isVertical() Determines if this a vertical segment
double	length() Calculate the length of the line segment.
org.eclipse.draw2d.geometry.Point	locatePoint(double pctDist, long theHeight, LineSeg.Sign asOriented) Locates a point at a given height and distance along the line segment.
void	performScale(double factor)
void	performTranslate(int dx, int dy)
org.eclipse.draw2d.geometry.Point	perpIntersect(int startX, int startY) Calculates the perpendicular intersection point on the line segment from the given point.
float	perpSlope() Calculates the perpendicular slope of this line segment.
boolean	pointOn(long theDistance, LineSeg.KeyPoint fromKeyPoint, org.eclipse.draw2d.geometry.Point ptResult) Gets the point on the line segment at the given distance away from the key point.
LineSeg.Sign	positionRelativeTo(org.eclipse.draw2d.geometry.Point rel) Returns out a positive or negative value (Positive / Negative) depending on the orientation of the given point to the line.
double	projection(int xCoord, int yCoord) Calculates the projection of the given point onto the line segment.
void	setOrigin(org.eclipse.draw2d.geometry.Point origin) Sets the origin point of the line segment
void	setTerminus(org.eclipse.draw2d.geometry.Point terminus) Sets the terminating point of the line segment.
float	slope() Calculates the slope of this line segment (y=mx+b)

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

LineSeg

public LineSeg(LineSeg.KeyPoint start,
               int fromX,
               int fromY,
               float slope,
               long len,
               int xdir)

Creates a segment using (fromX, fromY) as either the first point of the segment (start == Origin) or the midpoint of the segment (start == Midpoint), and using slope as its new slope and len as the new length. xdir indicates which direction the segment should go in the x-axis.

Parameters:

start - KeyPoint from which the other parameters are relative to

fromX - int x value of start KeyPoint

fromY - int y value of start KeyPoint

slope - float slope of the line

len - long length of the line

xdir - direction

LineSeg

public LineSeg(org.eclipse.draw2d.geometry.Point ptStart,
               org.eclipse.draw2d.geometry.Point ptEnd)

Constructor

Parameters:

ptStart - Point indicating the start of the line segment

ptEnd - Point indicating the end of the line segment

Method Detail

getLineEquation

public static double[] getLineEquation(double x1,
                                       double y1,
                                       double x2,
                                       double y2)

Returns the coefficients of the generalized equation of the line passing through points (x1,y1) and (x2,y2) Generalized line equation: ax+by=c => a==result[0], b==result[1], c==result[2]

Parameters:

x1 - - x coordinate of the 1st point

y1 - - y coordinate of the 1st point

x2 - - x coordinate of the 2nd point

y2 - - y coordinate of the 2nd point

Returns:

the coefficients of the generalized equation of the line passing through points (x1,y1) and (x2,y2)

containsPoint

public final boolean containsPoint(org.eclipse.draw2d.geometry.Point aPoint,
                                   int tolerance)

Checks if this line segment contains the given point within a tolerance value.

Parameters:

aPoint - Point to test if contained in this line.

tolerance - int tolerance value for detecting the intersection.

Returns:

boolean true if the given point lies on this segment, false otherwise.

distanceAlong

public final float distanceAlong(org.eclipse.draw2d.geometry.Point coord)

Finds the percentage distance along this line segement where the given point resides.

Parameters:

coord - Point to determine how far along the line segment it resides.

Returns:

float the distance along the line segment where the ptCoord is in a percentage from.

distanceToPoint

public final long distanceToPoint(int xCoord,
                                  int yCoord)

Finds the perpendicular distance from a point coordinates to this line segment. If point is "inside" line segment, then use distance from point to the line, otherwise use distance to nearest endpoint of segment

Parameters:

xCoord - the x coordinate of the point.

yCoord - the y coordinate of the point.

Returns:

long the distance from the line segment to the given point.

equals

public boolean equals(java.lang.Object seg)

Overrides:

equals in class java.lang.Object

getEquation

public double[] getEquation()

Returns array with 3 numbers in it, which are the coefficients of the generalized line equation of the line corresponding to this line segment a*x+b*y=c is the equation => result[0]=a, result[1]=b, result[2]=c

Returns:

an array with 3 numbers in it, which are the coefficients of the generalized line equation

getInfimum

public final org.eclipse.draw2d.geometry.Point getInfimum()

Get a Point representing the lowest point value for this line segment.

Returns:

Point Representing the lowest point value.

getLineIntersectionsWithEllipse

public org.eclipse.draw2d.geometry.PointList getLineIntersectionsWithEllipse(org.eclipse.draw2d.geometry.Rectangle ellipseBounds)

Calculates intersection points of the line of the line segment and ellipse

Parameters:

ellipseBounds - - width and height of the ellipse

Returns:

- PointList containing all intersection points

getLineIntersectionsWithLineSegs

public org.eclipse.draw2d.geometry.PointList getLineIntersectionsWithLineSegs(org.eclipse.draw2d.geometry.PointList points)

Calculates intersection points of the line that contains this line segment with a list of other line segments. If the list of points (line segments) form a closed PolyLine, i.e form a closed polygon figure, then the method will claculate intersections of a line and a figure

Parameters:

points - - list of points that form linesegments, i.e the PolyLine

Returns:

the intersection points of the line that contains this line segment with a list of other line segments.

getLinesIntersections

public org.eclipse.draw2d.geometry.PointList getLinesIntersections(LineSeg line)

Returns intersection points of two lines that contain this line segment and the argumet line segment. The list of intersection points may contain at most two points and will contain 2 points if and only if the lines are equal. The 2 points will be the end points of the parameter line segment

Parameters:

line - - the line segment

Returns:

intersection points of two lines that contain this line segment and the argumet line segment.

getOrigin

public org.eclipse.draw2d.geometry.Point getOrigin()

Accesssor to retrieve the origin point of the line segement.

Returns:

Point the origin of the line segment.

getParallelLineSegThroughPoint

public final LineSeg getParallelLineSegThroughPoint(org.eclipse.draw2d.geometry.Point ptLoc)

Returns a new LineSeg that is parallel to this by the given distance. Orientation is relative to the start and end. Negative implies to the left and Position implies to the right.

Parameters:

ptLoc - Point value to constrain the line to.

Returns:

LineSeg line that was calculated going through the given point

getSupremum

public final org.eclipse.draw2d.geometry.Point getSupremum()

Get points representing the highest point value for this line segment.

Returns:

Point Representing the highest point value.

getTerminus

public org.eclipse.draw2d.geometry.Point getTerminus()

Accesssor to retrieve the terminal point of the line segement.

Returns:

Point the terminating point of the line segment

getTrigValues

public LineSeg.TrigValues getTrigValues(org.eclipse.draw2d.geometry.Vector ptToVector)

Gets the trig values associated with the angle from this line segment to the given vector.

Parameters:

ptToVector - Ray value to calculate trig values of.

Returns:

TrigValues object representing the trigonometry values for the angle of the passed in Ray relative to this or null if calculation is not possible,

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object

intersect

public org.eclipse.draw2d.geometry.Point intersect(LineSeg line,
                                                   int nTolerance)

Determines the intersect point between this line and the line passed in as a parameter. If they intersect, then true is returned and the point reference passed in will be set to the intersect point. If they don't intersect, then the method returns false.

Parameters:

line - LineSeg to test the intersection against.

nTolerance - int tolerance value for detecting the intersection.

Returns:

Point that represents the intersection with this line, or null if the calculation is not possible.

isHorizontal

public final boolean isHorizontal()

Determines if this a horizontal segment

Returns:

boolean true if horizontal, false otherwise.

isVertical

public final boolean isVertical()

Determines if this a vertical segment

Returns:

boolean true if vertical, false otherwise.

length

public final double length()

Calculate the length of the line segment.

Returns:

the double length of the line segment.

locatePoint

public final org.eclipse.draw2d.geometry.Point locatePoint(double pctDist,
                                                           long theHeight,
                                                           LineSeg.Sign asOriented)

Locates a point at a given height and distance along the line segment. B (the point we are looking for) + | dist |h this segment P1-----------+-------------------> A get point A (on picture above)

Parameters:

pctDist - double distance along the line

theHeight - long height above the line

asOriented - Sign indicating relative position of the point to be located

Returns:

Point value that was located on the line.

performScale

public void performScale(double factor)

Specified by:

performScale in interface org.eclipse.draw2d.geometry.Translatable

performTranslate

public void performTranslate(int dx,
                             int dy)

Specified by:

performTranslate in interface org.eclipse.draw2d.geometry.Translatable

perpIntersect

public final org.eclipse.draw2d.geometry.Point perpIntersect(int startX,
                                                             int startY)

Calculates the perpendicular intersection point on the line segment from the given point.

Parameters:

startX - the x coordinate of the point

startY - the y coordinate of the point

Returns:

Point value containment the perpendicular intersection point.

perpSlope

public final float perpSlope()

Calculates the perpendicular slope of this line segment. This calculates the slope and then inverts it. Again, to avoid divide by zero errors, the constant BIGSLOPE is returned if the calculated slope before inverting it was zero.

Returns:

float the perpendicular slope value of the line segment.

pointOn

public final boolean pointOn(long theDistance,
                             LineSeg.KeyPoint fromKeyPoint,
                             org.eclipse.draw2d.geometry.Point ptResult)

Gets the point on the line segment at the given distance away from the key point.

Parameters:

theDistance - long distance along the line

fromKeyPoint - KeyPoint to calculate the distance from

ptResult - Point where the resulting calculating value is stored.

Returns:

boolean true if point can be calculated, false otherwise.

positionRelativeTo

public final LineSeg.Sign positionRelativeTo(org.eclipse.draw2d.geometry.Point rel)

Returns out a positive or negative value (Positive / Negative) depending on the orientation of the given point to the line. Point on this side: Positive. P1------------------------------> this segment Point on this side: Negative.

Parameters:

rel - Point to test the relative position against this line.

Returns:

Sign value indicating the relative position of the given point.

projection

public final double projection(int xCoord,
                               int yCoord)

Calculates the projection of the given point onto the line segment.

Parameters:

xCoord - the x coordinate of the point.

yCoord - the y coordinate of the point.

Returns:

double value of the calculated projection.

setOrigin

public void setOrigin(org.eclipse.draw2d.geometry.Point origin)

Sets the origin point of the line segment

Parameters:

origin - Point to set as origin

setTerminus

public void setTerminus(org.eclipse.draw2d.geometry.Point terminus)

Sets the terminating point of the line segment.

Parameters:

terminus - Point to set as terminus

slope

public final float slope()

Calculates the slope of this line segment (y=mx+b)

Returns:

float the slope of this segment. If the slope is not defined such as when the line segment is vertical, then the constant BIGSLOPE is returned to avoid divide by zero errors.