Package codedraw

Class Matrix2D

java.lang.Object

codedraw.Matrix2D

public class Matrix2D
extends Object

This class is used to transform the input coordinates. You can pass matrices with different transformations to Image.setTransformation(Matrix2D) and Image.setTransformation(Matrix2D). All methods except for the multiply(Matrix2D) method apply their operations left-to-right. multiply(Matrix2D) applies its operation right-to-left like in normal matrix multiplication.

Field Summary

Fields

Modifier and Type	Field	Description
static final Matrix2D	IDENTITY	The identity matrix.
static final Matrix2D	ZERO	The zero matrix where all values are 0.

Method Summary

Modifier and Type	Method	Description
boolean	equals(Matrix2D other, double error)	Compares this matrix to the matrix given as a parameter.
boolean	equals(Object o)
static Matrix2D	fromColumnMajor(double[][] matrix)	Creates a new matrix from a 3x3 column major matrix.
static Matrix2D	fromColumnMajor(double r0c0, double r1c0, double r2c0, double r0c1, double r1c1, double r2c1, double r0c2, double r1c2, double r2c2)	Creates a new matrix from a 3x3 column major matrix.
static Matrix2D	fromRowMajor(double[][] matrix)	Creates a new matrix from a 3x3 row major matrix.
static Matrix2D	fromRowMajor(double r0c0, double r0c1, double r0c2, double r1c0, double r1c1, double r1c2, double r2c0, double r2c1, double r2c2)	Creates a new matrix from a 3x3 row major matrix.
double	get(int row, int column)	Gets a value from this matrix.
int	hashCode()
Matrix2D	inverse()	Calculates the inverse of this matrix.
Matrix2D	mirror(double angleRadians)	Mirrors the coordinate system at the (0, 0) coordinate.
Matrix2D	mirrorAt(double x, double y, double angleRadians)	Mirrors the coordinate system at the specified coordinate.
Point2D	multiply(double x, double y)	Transforms the point given as a coordinate according to this matrix.
Matrix2D	multiply(Matrix2D other)	Multiplies two matrices with each other.
Point2D	multiply(Point2D point)	Transforms the point given as a coordinate according to this matrix.
Matrix2D	rotate(double angleRadians)	Rotates the coordinate system at the (0, 0) coordinate.
Matrix2D	rotateAt(double x, double y, double radians)	Rotates the coordinate system at the specified coordinate.
Matrix2D	scale(double xScale, double yScale)	Scales the coordinate system at the (0, 0) coordinate.
Matrix2D	scaleAt(double x, double y, double scaleX, double scaleY)	Scales the coordinate system from the specified coordinates.
Matrix2D	set(int row, int column, double value)	Creates a new matrix and changes the value in the matrix at the specified location.
Matrix2D	shear(double shearX, double shearY)	Shears the coordinate system from the (0, 0) coordinate.
Matrix2D	shearAt(double x, double y, double shearX, double shearY)	Shears the coordinate system at the specified coordinate.
String	toString()
Matrix2D	translate(double tx, double ty)	Moves the coordinate system in the x and y direction.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Details

ZERO

public static final Matrix2D ZERO

The zero matrix where all values are 0.

IDENTITY

public static final Matrix2D IDENTITY

The identity matrix. This matrix would not modify a coordinate system.

Method Details

fromRowMajor

public static Matrix2D fromRowMajor(double[][] matrix)

Creates a new matrix from a 3x3 row major matrix. If in doubt you probably want to use row-major as it visually aligns with most examples.

Parameters:

matrix - 3x3 matrix

Returns:

the matrix.

fromColumnMajor

public static Matrix2D fromColumnMajor(double[][] matrix)

Creates a new matrix from a 3x3 column major matrix. If in doubt you probably want to use row-major as it visually aligns with most examples.

Parameters:

matrix - 3x3 matrix

Returns:

the matrix.

fromRowMajor

public static Matrix2D fromRowMajor(double r0c0,
 double r0c1,
 double r0c2,
 double r1c0,
 double r1c1,
 double r1c2,
 double r2c0,
 double r2c1,
 double r2c2)

Creates a new matrix from a 3x3 row major matrix. If in doubt you probably want to use row-major as it visually aligns with most examples.

Returns:

the matrix.

fromColumnMajor

public static Matrix2D fromColumnMajor(double r0c0,
 double r1c0,
 double r2c0,
 double r0c1,
 double r1c1,
 double r2c1,
 double r0c2,
 double r1c2,
 double r2c2)

Creates a new matrix from a 3x3 column major matrix. If in doubt you probably want to use row-major as it visually aligns with most examples.

Returns:

the matrix.

get

public double get(int row,
 int column)

Gets a value from this matrix.

Parameters:

row - Can be either 0, 1 or 2.

column - Can be either 0, 1 or 2.

Returns:

The value.

set

public Matrix2D set(int row,
 int column,
 double value)

Creates a new matrix and changes the value in the matrix at the specified location.

Parameters:

row - Can be either 0, 1 or 2.

column - Can be either 0, 1 or 2.

value - The value to be set at the specified location.

Returns:

The new matrix with the changed value.

inverse

public Matrix2D inverse()

Calculates the inverse of this matrix. A matrix M times its inverse is the IDENTITY matrix.

Returns:

The inverse of this matrix.

translate

public Matrix2D translate(double tx,
 double ty)

Moves the coordinate system in the x and y direction.

Parameters:

tx - The change in the x direction.

ty - The change in the y direction.

Returns:

A new matrix with the translated coordinate system.

rotate

public Matrix2D rotate(double angleRadians)

Rotates the coordinate system at the (0, 0) coordinate.

Parameters:

angleRadians - Angle in radians. The angle rotates objects clockwise.

Returns:

The rotated matrix.

rotateAt

public Matrix2D rotateAt(double x,
 double y,
 double radians)

Rotates the coordinate system at the specified coordinate.

Parameters:

x - Coordinate to rotate around.

y - Coordinate to rotate around.

radians - Angle in radians. The angle rotates objects clockwise.

Returns:

The rotated matrix.

scale

public Matrix2D scale(double xScale,
 double yScale)

Scales the coordinate system at the (0, 0) coordinate.

Parameters:

xScale - The scale in the x direction.

yScale - The scale in the y direction.

Returns:

A new matrix with the scaled coordinate system.

scaleAt

public Matrix2D scaleAt(double x,
 double y,
 double scaleX,
 double scaleY)

Scales the coordinate system from the specified coordinates.

Parameters:

x - The coordinate to scale from.

y - The coordinate to scale from.

scaleX - The scale in the x direction.

scaleY - The scale in the y direction.

Returns:

A new matrix with the scaled coordinate system.

shear

public Matrix2D shear(double shearX,
 double shearY)

Shears the coordinate system from the (0, 0) coordinate.

Parameters:

shearX - The shear in the x direction.

shearY - The shear in the y direction.

Returns:

A new matrix with the sheared coordinate system.

shearAt

public Matrix2D shearAt(double x,
 double y,
 double shearX,
 double shearY)

Shears the coordinate system at the specified coordinate.

Parameters:

x - The coordinate to shear from.

y - The coordinate to shear from.

shearX - The shear in the x direction.

shearY - The shear in the y direction.

Returns:

A new matrix with the sheared coordinate system.

mirror

public Matrix2D mirror(double angleRadians)

Mirrors the coordinate system at the (0, 0) coordinate. An angle with the value 0 would mirror the coordinate system along the x-axis. An angle with the value Math.PI / 2 would mirror the coordinate system along the y-axis.

Parameters:

angleRadians - The angle which represents an infinite line that passes through the (0, 0) coordinate. The mirror line

Returns:

A new matrix with the mirrored coordinate system.

mirrorAt

public Matrix2D mirrorAt(double x,
 double y,
 double angleRadians)

Mirrors the coordinate system at the specified coordinate. An angle with the value 0 would mirror the coordinate system along the x-axis. An angle with the value Math.PI / 2 would mirror the coordinate system along the y-axis.

Parameters:

x - The x coordinate where the mirror line goes through.

y - The y coordinate where the mirror line goes through.

angleRadians - The angle which represents an infinite line that passes through the specified coordinate.

Returns:

A new matrix with the mirrored coordinate system.

multiply

public Matrix2D multiply(Matrix2D other)

Multiplies two matrices with each other. This multiply method works the same as normal matrix multiplication. This means that the operational order would be right-to-left.

Parameters:

other - The other matrix to multiply this matrix with.

Returns:

The multiplied matrix as the result.

multiply

public Point2D multiply(Point2D point)

Transforms the point given as a coordinate according to this matrix.

Parameters:

point - A point.

Returns:

The transformed point.

multiply

public Point2D multiply(double x,
 double y)

Transforms the point given as a coordinate according to this matrix.

Parameters:

x - the x coordinate of the point

y - the y coordinate of the point

Returns:

The transformed point.

equals

public boolean equals(Object o)

Overrides:

equals in class Object

equals

public boolean equals(Matrix2D other,
 double error)

Compares this matrix to the matrix given as a parameter. The error allows for some difference between their values. For example if the first value of this matrix is 1 and the first values of the other matrix is 0.999998 and an error of 0.0001 is given then this function will return true. equals(Object) would return false. However, if a value of this matrix is 1 and the same value is 2 in the other matrix and the error is 0.0001 this function and equals(Object) would both return false.

Parameters:

other - The matrix to compare with.

error - The maximum difference allowed by the values in the matrix.

Returns:

Whether these two matrices are the same within some error.

hashCode

public int hashCode()

Overrides:

hashCode in class Object

toString

public String toString()

Overrides:

toString in class Object