Line (Apache SIS utilities 0.6 API)

Object
- Line

All Implemented Interfaces:

Serializable, Cloneable
```
public class Line
extends Object
implements Cloneable, Serializable
```
Equation of a line in a two dimensional space (x,y). A line can be expressed by the y = slope⋅x + y₀ equation where y₀ is the value of y at x = 0.
The equation parameters for a Line object can be set at construction time or using one of the setLine(…) methods. The y value can be computed for a given x value using the y(double) method. Method x(double) computes the converse and should work even if the line is vertical.

Comparison with Java2D geometries: At the difference of Line2D which is bounded by (x₁,y₁) and (x₂,y₂) points, Line objects extend toward infinity.

Since:

0.5

See Also:
Plane, org.apache.sis.referencing.operation.builder.LinearTransformBuilder, Serialized Form

Defined in the sis-utility module

Constructor Summary

Constructors
Constructor and Description

Line()
Constructs an uninitialized line.

Line(double slope, double y0)
Constructs a line with the specified slope and offset.

Constructors
Constructor and Description
`Line()` Constructs an uninitialized line.
`Line(double slope, double y0)` Constructs a line with the specified slope and offset.

Method Summary

Methods
Modifier and Type	Method and Description
`Line`	`clone()` Returns a clone of this line.
`boolean`	`equals(Object object)` Compares this line with the specified object for equality.
`double`	`fit(double[] x, double[] y)` Given a set of data points `x`[0 … `n`-1], `y`[0 … `n`-1], fits them to a straight line `y` = `slope`⋅`x` + `y`₀ in a least-squares senses.
`double`	`fit(Iterable<? extends DirectPosition> points)` Given a sequence of points, fits them to a straight line `y` = `slope`⋅`x` + `y`₀ in a least-squares senses.
`int`	`hashCode()` Returns a hash code value for this line.
`void`	`setEquation(double slope, double y0)` Sets this line to the specified slope and offset.
`void`	`setFromPoints(double x1, double y1, double x2, double y2)` Sets a line through the specified points.
`double`	`slope()` Returns the slope.
`String`	`toString()` Returns a string representation of this line.
`void`	`translate(double dx, double dy)` Translates the line.
`double`	`x(double y)` Computes `x` = `f`⁻¹(`y`).
`double`	`x0()` Returns the `x` value for `y` = 0.
`double`	`y(double x)` Computes `y` = `f`(`x`).
`double`	`y0()` Returns the `y` value for `x` = 0.

Methods inherited from class Object
finalize, getClass, notify, notifyAll, wait, wait, wait

- Constructor Detail
  - Line
```
public Line()
```
    Constructs an uninitialized line. All methods will return Double.NaN.
  - Line
```
public Line(double slope,
    double y0)
```
    Constructs a line with the specified slope and offset. The linear equation will be y = slope⋅x + y₀.
    
    Parameters:
    slope - The slope.
    y0 - The y value at x = 0.
    See Also:
    setEquation(double, double)
- Method Detail
  - slope
```
public final double slope()
```
    Returns the slope.
    
    Returns:
    The slope.
    See Also:
    x0(), y0()
  - x0
```
public final double x0()
```
    Returns the x value for y = 0. Coordinate (x₀, 0) is the intersection point with the x axis.
    
    Returns:
    The x value for y = 0.
    See Also:
    y0(), slope()
  - x
```
public final double x(double y)
```
    Computes x = f⁻¹(y). If the line is horizontal, then this method returns an infinite value.
    
    Parameters:
    y - The y value where to evaluate the inverse function.
    
    Returns:
    The x value for the given y value.
    See Also:
    y(double)
  - y0
```
public final double y0()
```
    Returns the y value for x = 0. Coordinate (0, y₀) is the intersection point with the y axis.
    
    Returns:
    The y value for x = 0.
    See Also:
    x0(), slope()
  - y
```
public final double y(double x)
```
    Computes y = f(x). If the line is vertical, then this method returns an infinite value.
    
    Parameters:
    x - The x value where to evaluate the inverse function.
    
    Returns:
    The y value for the given x value.
    See Also:
    x(double)
  - translate
```
public void translate(double dx,
             double dy)
```
    Translates the line. The slope stay unchanged.
    
    Parameters:
    dx - The horizontal translation.
    dy - The vertical translation.
  - setEquation
```
public void setEquation(double slope,
               double y0)
```
    Sets this line to the specified slope and offset. The linear equation will be y = slope⋅x + y₀.
    
    Parameters:
    slope - The slope.
    y0 - The y value at x = 0.
    See Also:
    setFromPoints(double, double, double, double), fit(double[], double[])
  - setFromPoints
```
public void setFromPoints(double x1,
                 double y1,
                 double x2,
                 double y2)
```
    Sets a line through the specified points. The line will continue toward infinity after the points.
    
    Parameters:
    x1 - Ordinate x of the first point.
    y1 - Ordinate y of the first point.
    x2 - Ordinate x of the second point.
    y2 - Ordinate y of the second point.
  - fit
```
public double fit(double[] x,
         double[] y)
```
    Given a set of data points x[0 … n-1], y[0 … n-1], fits them to a straight line y = slope⋅x + y₀ in a least-squares senses. This method assume that the x values are precise and all uncertainty is in y.
    
    Parameters:
    x - Vector of x values (independent variable).
    y - Vector of y values (dependent variable).
    
    Returns:
    Estimation of the correlation coefficient. The closer this coefficient is to +1 or -1, the better the fit.
    
    Throws:
    
    IllegalArgumentException - if x and y do not have the same length.
  - fit
```
public double fit(Iterable<? extends DirectPosition> points)
```
    Given a sequence of points, fits them to a straight line y = slope⋅x + y₀ in a least-squares senses. This method assume that the x values are precise and all uncertainty is in y.
    Points shall be two dimensional with ordinate values in the (x,y) order. Double.NaN ordinate values are ignored.
    
    Parameters:
    points - The two-dimensional points.
    
    Returns:
    Estimation of the correlation coefficient. The closer this coefficient is to +1 or -1, the better the fit.
    
    Throws:
    
    MismatchedDimensionException - if a point is not two-dimensional.
  - clone
```
public Line clone()
```
    Returns a clone of this line.
    
    Overrides:
    
    clone in class Object
    
    Returns:
    A clone of this line.
  - equals
```
public boolean equals(Object object)
```
    Compares this line with the specified object for equality.
    
    Overrides:
    
    equals in class Object
    
    Parameters:
    object - The object to compare with this line for equality.
    
    Returns:
    true if both objects are equal.
  - hashCode
```
public int hashCode()
```
    Returns a hash code value for this line.
    
    Overrides:
    
    hashCode in class Object
  - toString
```
public String toString()
```
    Returns a string representation of this line. This method returns the linear equation in the form y = slope⋅x + y₀.
    
    Overrides:
    
    toString in class Object
    
    Returns:
    A string representation of this line.

Class Line

Constructor Summary

Method Summary

Methods inherited from class Object

Constructor Detail

Line

Line

Method Detail

slope

x0

x

y0

y

translate

setEquation

setFromPoints

fit

fit

clone

equals

hashCode

toString