y.geom
Class BorderLine

java.lang.Object
  y.geom.BorderLine

public class BorderLine
extends java.lang.Object

This class can be used to easily model an orthogonal border line or sky-line. It provides methods for measuring the distance between different BorderLine instances, merging multiple instances, modifying and efficiently moving them around.

Nested Class Summary

static class

BorderLine.Segment The handle of a segment of a borderline.

Constructor Summary

BorderLine(double value)
Creates a new BorderLine with the given value from -Double.MAX_VALUE to +Double.MAX_VALUE.

BorderLine(double min, double max, double value)
Creates a new BorderLine from a single segment.

BorderLine(double min, double max, double valueAtMin, double valueAtMax)
Creates a new BorderLine from a single segment.

Method Summary

void	addOffset(double delta) Adds the given offset to the segments' positions.
void	addValueOffset(double delta) Adds the given offset to the current values of the whole borderline.
void	adoptValues(BorderLine other) Convenience method that copies the actual data from the given argument to this instance.
BorderLine	createCopy(boolean negateValues, boolean negateOffsets) Creates a copy of this borderline.
BorderLine	createMax(BorderLine other) Merges this borderline with the given borderline using the "maximum" policy.
BorderLine	createMin(BorderLine other) Merges this borderline with the given borderline using the "minimum" policy.
BorderLine.Segment	firstSegment() Returns the first segment or null if there is no such segment.
double	getDistanceTo(BorderLine greater) Calculates the minimal distance between this borderline and the other one.
double	getMax() Returns the greatest position of this borderline
double	getMax(BorderLine.Segment s) Returns the maximum position of the given segment.
double	getMaxValue() Returns the maximum value that is set on this borderline
double	getMaxValue(double from, double to) Calculates the maximum value in the interval from->to.
double	getMin() Returns the smallest position of this borderline
double	getMin(BorderLine.Segment s) Returns the minimum position of the given segment.
double	getMinValue() Returns the minimum value that is set on this borderline
double	getMinValue(double from, double to) Calculates the minimum value in the interval from->to.
BorderLine.Segment	getSegmentAt(double pos) Returns the segment at the given position.
double	getSlope(BorderLine.Segment s) Returns the slope of the given segment.
double	getValue(BorderLine.Segment s) Returns the value of the minimum of the given segment.
double	getValueAt(BorderLine.Segment segment, double pos) Returns the value that is set on this borderline at the specified position.
double	getValueAt(double pos) Returns the value that is set on this borderline at the specified position.
double	getValueAt(ListCell cell, double pos) Returns the value that is set on this borderline at the specified position.
void	grow(double toMin, double toMax, boolean positive) Grows this borderline horizontally, so that the values of the borderline stay the same however their start and end points are moved in the direction of toMin and toMax.
BorderLine.Segment	lastSegment() Returns the last segment or null if there is no such segment.
void	mergeWithMax(BorderLine other) Merges this borderline with the given borderline using the "maximum" policy.
void	mergeWithMin(BorderLine other) Merges this borderline with the given borderline using the "minimum" policy.
BorderLine.Segment	next(BorderLine.Segment s) Returns the next segment or null if there is no such segment.
BorderLine.Segment	prev(BorderLine.Segment s) Returns the previous segment or null if there is no such segment.
void	setMaxValue(double min, double max, double value) Assures that all values in the given interval are greater or equal than the given value.
void	setMinValue(double min, double max, double value) Assures that all values in the given interval are less or equal than the given value.
void	setSloped(double min, double max, double value, double slope) Sets a specific interval to a slope starting at a given value.
void	setValue(double min, double max, double value) Sets a specific interval described by min and max to a given value.
java.lang.String	toString() Returns a lengthy String representation of this borderline.

Methods inherited from class java.lang.Object

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

Constructor Detail

BorderLine

public BorderLine(double value)

Creates a new BorderLine with the given value from -Double.MAX_VALUE to +Double.MAX_VALUE.

Parameters:

value - the value of the segment

BorderLine

public BorderLine(double min,
                  double max,
                  double value)

Creates a new BorderLine from a single segment.

Parameters:

min - the beginning of this borderline

max - the ending of this borderline

value - the value of the segment

BorderLine

public BorderLine(double min,
                  double max,
                  double valueAtMin,
                  double valueAtMax)

Creates a new BorderLine from a single segment.

Parameters:

min - the beginning of this borderline

max - the ending of this borderline

valueAtMin - the value of the segment at the beginning of this borderline

valueAtMax - the value of the segment at the ending of this borderline

Method Detail

createCopy

public BorderLine createCopy(boolean negateValues,
                             boolean negateOffsets)

Creates a copy of this borderline. Optionally negates the values or offsets.

Parameters:

negateValues - whether the values are negated

negateOffsets - whether the offsets are negated

Returns:

the copy of the borderline

setMinValue

public void setMinValue(double min,
                        double max,
                        double value)

Assures that all values in the given interval are less or equal than the given value.

Parameters:

min - the lower end of the interval

max - the upper end of the interval

value - the greatest possible value for the interval

setMaxValue

public void setMaxValue(double min,
                        double max,
                        double value)

Assures that all values in the given interval are greater or equal than the given value.

Parameters:

min - the lower end of the interval

max - the upper end of the interval

value - the smallest possible value for the interval

adoptValues

public void adoptValues(BorderLine other)

Convenience method that copies the actual data from the given argument to this instance.

Parameters:

other - the argument to retrieve the values from

setValue

public void setValue(double min,
                     double max,
                     double value)

Sets a specific interval described by min and max to a given value.

Parameters:

min - the left side of the interval.

max - the right side of the interval.

value - the value for the whole interval.

setSloped

public void setSloped(double min,
                      double max,
                      double value,
                      double slope)

Sets a specific interval to a slope starting at a given value.

Parameters:

min - the left side of the interval.

max - the right side of the interval.

value - the value at min where the slope starts.

slope - the slope of the segment in the given interval.

Throws:

java.lang.IllegalArgumentException - if min is greater than max.

addValueOffset

public void addValueOffset(double delta)

Adds the given offset to the current values of the whole borderline. This method has complexity O(1).

Parameters:

delta - the delta to add to the values

addOffset

public void addOffset(double delta)

Adds the given offset to the segments' positions. This method has complexity O(1).

Parameters:

delta - the delta to add to the positions

getMin

public double getMin()

Returns the smallest position of this borderline

getMax

public double getMax()

Returns the greatest position of this borderline

getMinValue

public double getMinValue()

Returns the minimum value that is set on this borderline

Returns:

the value

getMaxValue

public double getMaxValue()

Returns the maximum value that is set on this borderline

Returns:

the value

getValueAt

public double getValueAt(double pos)

Returns the value that is set on this borderline at the specified position.

Parameters:

pos - the position

Returns:

the value

Throws:

java.lang.IndexOutOfBoundsException - if the position is outside of the borderline.

getValueAt

public double getValueAt(ListCell cell,
                         double pos)

Returns the value that is set on this borderline at the specified position. The position must lie within the range of the segment that is stored in cell.

Parameters:

cell - The list cell containing the segment whose value shall be returned.

pos - the position

Returns:

the value

Throws:

java.lang.IllegalArgumentException - if pos is outside the segment's range that is stored in cell.

getValueAt

public double getValueAt(BorderLine.Segment segment,
                         double pos)

Returns the value that is set on this borderline at the specified position. The position must lie within the range of the segment.

Parameters:

segment - The segment whose value shall be returned.

pos - the position where the value will be retrieved.

Returns:

the value

Throws:

java.lang.IllegalArgumentException - if pos is outside the segment's range.

createMax

public BorderLine createMax(BorderLine other)

Merges this borderline with the given borderline using the "maximum" policy. That means the resulting borderline will have greater value of both borderline on each position. If you imagine each borderline as a the upper border of a plane, the resulting borderline will be the upper border of the merged planes.

Parameters:

other - the other borderline

Returns:

a new borderline that is the result of the merge

createMin

public BorderLine createMin(BorderLine other)

Merges this borderline with the given borderline using the "minimum" policy. That means the resulting borderline will have smaller value of both borderline on each position. If you imagine each borderline as a the lower border of a plane, the resulting borderline will be the lower border of the merged planes.

Parameters:

other - the other borderline

Returns:

a new borderline that is the result of the merge

mergeWithMax

public void mergeWithMax(BorderLine other)

Merges this borderline with the given borderline using the "maximum" policy.

Parameters:

other - the other borderline

mergeWithMin

public void mergeWithMin(BorderLine other)

Merges this borderline with the given borderline using the "minimum" policy.

Parameters:

other - the other borderline

getValue

public double getValue(BorderLine.Segment s)

Returns the value of the minimum of the given segment. If the segment's slope is 0, it's the value of the whole segment. In case the slope differs from 0, it's the value of the start of the slope.

Parameters:

s - the segment

getMin

public double getMin(BorderLine.Segment s)

Returns the minimum position of the given segment.

Parameters:

s - the segment

getSlope

public double getSlope(BorderLine.Segment s)

Returns the slope of the given segment.

Parameters:

s - the segment

getSegmentAt

public BorderLine.Segment getSegmentAt(double pos)

Returns the segment at the given position.

Parameters:

pos - the position

getMax

public double getMax(BorderLine.Segment s)

Returns the maximum position of the given segment.

Parameters:

s - the segment

firstSegment

public BorderLine.Segment firstSegment()

Returns the first segment or null if there is no such segment.

lastSegment

public BorderLine.Segment lastSegment()

Returns the last segment or null if there is no such segment.

prev

public BorderLine.Segment prev(BorderLine.Segment s)

Returns the previous segment or null if there is no such segment.

next

public BorderLine.Segment next(BorderLine.Segment s)

Returns the next segment or null if there is no such segment.

getMaxValue

public double getMaxValue(double from,
                          double to)

Calculates the maximum value in the interval from->to.

If the from value is larger or equal to the to value, the algorithm always returns -Double.MAX_VALUE.

getMinValue

public double getMinValue(double from,
                          double to)

Calculates the minimum value in the interval from->to.

If the from value is larger or equal to the to value, the algorithm always returns Double.MAX_VALUE.

getDistanceTo

public double getDistanceTo(BorderLine greater)

Calculates the minimal distance between this borderline and the other one. The other one is treated as if the values were all greater.

toString

public java.lang.String toString()

Returns a lengthy String representation of this borderline.

Overrides:

toString in class java.lang.Object

grow

public void grow(double toMin,
                 double toMax,
                 boolean positive)

Grows this borderline horizontally, so that the values of the borderline stay the same however their start and end points are moved in the direction of toMin and toMax. This is useful for scenarios where a borderline is needed that consists of an enlarged border.

Note that this method normalizes the segments, i.e., it transforms each segment with slope != 0 to a segment with slope == 0.

Parameters:

toMin - the delta by which the border should be extended towards -Infinity

toMax - the delta by which the border should be extended towards +Infinity

positive - whether the borderline should be interpreted to point in positive direction. This influences the direction into which a segment's border is extended.