Class Matrix

java.lang.Object

com.itextpdf.kernel.geom.Matrix

public class Matrix
extends Object

Keeps all the values of a 3 by 3 matrix and allows you to do some math with matrices.

Field Summary

Fields

Modifier and Type	Field	Description
static final int	I11	the row=1, col=1 position ('a') in the matrix.
static final int	I12	the row=1, col=2 position ('b') in the matrix.
static final int	I13	the row=1, col=3 position (always 0 for 2-D) in the matrix.
static final int	I21	the row=2, col=1 position ('c') in the matrix.
static final int	I22	the row=2, col=2 position ('d') in the matrix.
static final int	I23	the row=2, col=3 position (always 0 for 2-D) in the matrix.
static final int	I31	the row=3, col=1 ('e', or X translation) position in the matrix.
static final int	I32	the row=3, col=2 ('f', or Y translation) position in the matrix.
static final int	I33	the row=3, col=3 position (always 1 for 2-D) in the matrix.
private final float[]	vals	The values inside the matrix (the identity matrix by default).

Constructor Summary

Constructors

Constructor	Description
Matrix()	constructs a new Matrix with identity.
Matrix(float tx, float ty)	Constructs a matrix that represents translation.
Matrix(float a, float b, float c, float d, float e, float f)	Creates a Matrix with 6 specified entries.
Matrix(float e11, float e12, float e13, float e21, float e22, float e23, float e31, float e32, float e33)	Creates a Matrix with 9 specified entries.

Method Summary

Modifier and Type	Method	Description
Matrix	add(Matrix arg)	Adds a matrix from this matrix and returns the results.
boolean	equals(Object obj)	Checks equality of matrices.
float	get(int index)	Gets a specific value inside the matrix.
float	getDeterminant()	Computes the determinant of the matrix.
int	hashCode()	Generates a hash code for this object.
Matrix	multiply(Matrix by)	multiplies this matrix by 'b' and returns the result.
Matrix	subtract(Matrix arg)	Subtracts a matrix from this matrix and returns the results.
String	toString()	Generates a String representation of the matrix.

Methods inherited from class Object

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

Field Details

I11

public static final int I11

the row=1, col=1 position ('a') in the matrix.

See Also:

• Constant Field Values

I12

public static final int I12

the row=1, col=2 position ('b') in the matrix.

See Also:

• Constant Field Values

I13

public static final int I13

the row=1, col=3 position (always 0 for 2-D) in the matrix.

See Also:

• Constant Field Values

I21

public static final int I21

the row=2, col=1 position ('c') in the matrix.

See Also:

• Constant Field Values

I22

public static final int I22

the row=2, col=2 position ('d') in the matrix.

See Also:

• Constant Field Values

I23

public static final int I23

the row=2, col=3 position (always 0 for 2-D) in the matrix.

See Also:

• Constant Field Values

I31

public static final int I31

the row=3, col=1 ('e', or X translation) position in the matrix.

See Also:

• Constant Field Values

I32

public static final int I32

the row=3, col=2 ('f', or Y translation) position in the matrix.

See Also:

• Constant Field Values

I33

public static final int I33

the row=3, col=3 position (always 1 for 2-D) in the matrix.

See Also:

• Constant Field Values

vals

private final float[] vals

The values inside the matrix (the identity matrix by default).

For reference, the indeces are as follows:
I11 I12 I13
I21 I22 I23
I31 I32 I33

Constructor Details

Matrix

public Matrix()

constructs a new Matrix with identity.

Matrix

public Matrix(float tx,
 float ty)

Constructs a matrix that represents translation.

Parameters:

tx - x-axis translation

ty - y-axis translation

Matrix

public Matrix(float e11,
 float e12,
 float e13,
 float e21,
 float e22,
 float e23,
 float e31,
 float e32,
 float e33)

Creates a Matrix with 9 specified entries.

Parameters:

e11 - element at position (1,1)

e12 - element at position (1,2)

e13 - element at position (1,3)

e21 - element at position (2,1)

e22 - element at position (2,2)

e23 - element at position (2,3)

e31 - element at position (3,1)

e32 - element at position (3,2)

e33 - element at position (3,3)

Matrix

public Matrix(float a,
 float b,
 float c,
 float d,
 float e,
 float f)

Creates a Matrix with 6 specified entries. The third column will always be [0 0 1] (row, column)

Parameters:

a - element at (1,1)

b - element at (1,2)

c - element at (2,1)

d - element at (2,2)

e - element at (3,1)

f - element at (3,2)

Method Details

get

public float get(int index)

Gets a specific value inside the matrix.

For reference, the indeces are as follows:
I11 I12 I13
I21 I22 I23
I31 I32 I33

Parameters:

index - an array index corresponding with a value inside the matrix

Returns:

the value at that specific position.

multiply

public Matrix multiply(Matrix by)

multiplies this matrix by 'b' and returns the result. See http://en.wikipedia.org/wiki/Matrix_multiplication

Parameters:

by - The matrix to multiply by

Returns:

the resulting matrix

add

public Matrix add(Matrix arg)

Adds a matrix from this matrix and returns the results.

Parameters:

arg - the matrix to subtract from this matrix

Returns:

a Matrix object

subtract

public Matrix subtract(Matrix arg)

Subtracts a matrix from this matrix and returns the results.

Parameters:

arg - the matrix to subtract from this matrix

Returns:

a Matrix object

getDeterminant

public float getDeterminant()

Computes the determinant of the matrix.

Returns:

the determinant of the matrix

equals

public boolean equals(Object obj)

Checks equality of matrices.

Overrides:

equals in class Object

Parameters:

obj - the other Matrix that needs to be compared with this matrix.

Returns:

true if both matrices are equal

See Also:

• Object.equals(java.lang.Object)

hashCode

public int hashCode()

Generates a hash code for this object.

Overrides:

hashCode in class Object

Returns:

the hash code of this object

See Also:

• Object.hashCode()

toString

public String toString()

Generates a String representation of the matrix.

Overrides:

toString in class Object

Returns:

the values, delimited with tabs and newlines.

See Also:

• Object.toString()