Package com.pdftools.toolbox.geometry.real

Class AffineTransform

java.lang.Object

com.pdftools.toolbox.internal.NativeBase

com.pdftools.toolbox.geometry.real.AffineTransform

public class AffineTransform
extends NativeBase

Field Summary

Fields

Modifier and Type	Field	Description
double	a	The 'a' matrix element.
double	b	The 'b' matrix element.
double	c	The 'c' matrix element.
double	d	The 'd' matrix element.
double	e	The 'e' matrix element.
double	f	The 'f' matrix element.

Constructor Summary

Constructors

Constructor	Description
AffineTransform()	Constructor.
AffineTransform(double a, double b, double c, double d, double e, double f)

Method Summary

Modifier and Type	Method	Description
void	concatenate(AffineTransform other)	Concatenate transform with other transform.
boolean	equals(java.lang.Object obj)
double	getA()	Gets a
double	getB()	Gets b
double	getC()	Gets c
double	getD()	Gets d
double	getE()	Gets e
double	getF()	Gets f
static AffineTransform	getIdentity()	The identity transform (Getter)
int	hashCode()
void	invert()	Invert the transform
void	rotate(double angle, Point center)	Rotate.
void	scale(double sx, double sy)	Scale.
void	setA(double a)	Sets a
void	setB(double b)	Sets b
void	setC(double c)	Sets c
void	setD(double d)	Sets d
void	setE(double e)	Sets e
void	setF(double f)	Sets f
void	skew(double alpha, double beta)	Skew.
Point	transformPoint(Point original)	Transforms the given point.
Quadrilateral	transformQuadrilateral(Quadrilateral original)	Transform a given quadrilateral
Quadrilateral	transformRectangle(Rectangle original)	Transform the given rectangle
void	translate(double tx, double ty)	Translate.

Methods inherited from class java.lang.Object

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

Field Detail

a

public double a

The 'a' matrix element.

This is the 'a' element in the affine transformation matrix [a b 0; c d 0; e f 1]

b

public double b

The 'b' matrix element.

This is the 'b' element in the affine transformation matrix [a b 0; c d 0; e f 1]

c

public double c

The 'c' matrix element.

This is the 'c' element in the affine transformation matrix [a b 0; c d 0; e f 1]

d

public double d

The 'd' matrix element.

This is the 'd' element in the affine transformation matrix [a b 0; c d 0; e f 1]

e

public double e

The 'e' matrix element.

This is the 'e' element in the affine transformation matrix [a b 0; c d 0; e f 1]

f

public double f

The 'f' matrix element.

This is the 'f' element in the affine transformation matrix [a b 0; c d 0; e f 1]

Constructor Detail

AffineTransform

public AffineTransform()

Constructor.

AffineTransform

public AffineTransform(double a,
                       double b,
                       double c,
                       double d,
                       double e,
                       double f)

Method Detail

getA

public double getA()

Gets a

setA

public void setA(double a)

Sets a

getB

public double getB()

Gets b

setB

public void setB(double b)

Sets b

getC

public double getC()

Gets c

setC

public void setC(double c)

Sets c

getD

public double getD()

Gets d

setD

public void setD(double d)

Sets d

getE

public double getE()

Gets e

setE

public void setE(double e)

Sets e

getF

public double getF()

Gets f

setF

public void setF(double f)

Sets f

equals

public boolean equals(java.lang.Object obj)

Overrides:

equals in class java.lang.Object

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object

translate

public void translate(double tx,
                      double ty)

Translate.

Translations are specified as [1 0 0 1 tx ty], where tx and ty are the distances to translate the origin of the coordinate system in the horizontal and vertical dimensions, respectively.

Parameters:

tx - horizontal translation

ty - vertical translation

Throws:

java.lang.IllegalStateException - If the affine transform is singular, e.g. default initialized. (Use getIdentity() as an initial value.)

scale

public void scale(double sx,
                  double sy)

Scale.

Scaling is obtained by [sx 0 0 sy 0 0]. This scales the coordinates so that 1 unit in the horizontal and vertical dimensions of the new coordinate system is the same size as sx and sy units, respectively, in the previous coordinate system.

Parameters:

sx - horizontal scale factor

sy - vertical scale factor

Throws:

java.lang.IllegalStateException - If the affine transform is singular, e.g. default initialized. (Use getIdentity() as an initial value.)

rotate

public void rotate(double angle,
                   Point center)

Rotate.

Rotations are produced by [cos(a) sin(a) -sin(a) cos(a) 0 0], which has the effect of rotating the coordinate system axes by an angle "a" in counterclockwise direction around the origin.

If the given center is not null, then the rotation is performed around the given center point, which is equivalent to the following sequence:

• translate(double, double) to center.
• rotate(double, com.pdftools.toolbox.geometry.real.Point) by angle around the origin.
• translate(double, double) "back" to the original origin.

Parameters:

angle - The angle of the rotation in degrees.

center - The center of the rotation. If null then the origin (0/0) is taken as center.

Throws:

java.lang.IllegalStateException - If the affine transform is singular, e.g. default initialized. (Use getIdentity() as an initial value.)

skew

public void skew(double alpha,
                 double beta)

Skew.

Skew is specified by [1 tan a tan b 1 0 0], which skews the x axis by an angle a and the y axis by an angle b.

Parameters:

alpha - angle a in degrees

beta - angle b in degrees

Throws:

java.lang.IllegalStateException - If the affine transform is singular, e.g. default initialized. (Use getIdentity() as an initial value.)

java.lang.IllegalArgumentException - if any of the given angles is too close to 90 + k*180 degrees for k = ..., -2, -1, 0, 1, 2, ...

concatenate

public void concatenate(AffineTransform other)

Concatenate transform with other transform.

Concatenating a transform with an other transform is equivalent to left-multiplying the transform's matrix with with the other transform's matrix.

Parameters:

other - the transform to be concatenated to this transform

Throws:

java.lang.IllegalStateException - If the affine transform is singular, e.g. default initialized. (Use getIdentity() as an initial value.)

java.lang.IllegalArgumentException - If the other affine transform is singular, e.g. default initialized. (Use getIdentity() as an initial value.)

java.lang.IllegalArgumentException - if other is null

invert

public void invert()

Invert the transform

A transform usually maps from the transformed coordinate system to the untransformed coordinate system. Use this method to create the reverse transform.

Throws:

java.lang.IllegalStateException - If the affine transform is singular, e.g. default initialized. (Use getIdentity() as an initial value.)

transformPoint

public Point transformPoint(Point original)

Transforms the given point.

Parameters:

original - the point to be transformed

Returns:

the transformed point

Throws:

java.lang.IllegalStateException - If the affine transform is singular, e.g. default initialized. (Use getIdentity() as an initial value.)

java.lang.IllegalArgumentException - if original is null

transformRectangle

public Quadrilateral transformRectangle(Rectangle original)

Transform the given rectangle

For a general affine transformation, the returned Quadrilateral is a parallelogram.

Parameters:

original - the rectangle to be transformed

Returns:

the transformed rectangle. For a general affine transform this is a parallelogram.

Throws:

java.lang.IllegalStateException - if the affine transform is singular, e.g. default initialized. (Use getIdentity() as an initial value.)

java.lang.IllegalArgumentException - if original is null

transformQuadrilateral

public Quadrilateral transformQuadrilateral(Quadrilateral original)

Transform a given quadrilateral

If the input quadrilateral is a parallelogram, then the output is also a parallelogram.

Parameters:

original - the quadrilateral to be transformed

Returns:

the transformed quadrilateral. If the input is a parallelogram then the output is also a parallelogram.

Throws:

java.lang.IllegalStateException - if the affine transform is singular, e.g. default initialized. (Use getIdentity() as an initial value.)

java.lang.IllegalArgumentException - if original is null

getIdentity

public static AffineTransform getIdentity()

The identity transform (Getter)