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Class java.awt.geom.AffineTransform

java.lang.Object
  |
  +--java.awt.geom.AffineTransform

public class AffineTransform

extends Object

implements Cloneable, Serializable

This class represents a 2D affine transform which performs a linear mapping from 2D coordinates to other 2D coordinates in a manner which preserves the "straightness" and "parallelness" of lines. Affine transformations can be constructed using sequences of translations, scales, flips, rotations, and shears.

Such a coordinate transformation can be represented by a 3 row by 3 column matrix with an implied last row of [ 0 0 1 ] which transforms source coordinates (x, y) into destination coordinates (x', y') by considering them to be a column vector and multiplying the coordinate vector by the matrix according to the following process.

	[ x']   [  m00  m01  m02  ] [ x ]   [ m00x + m01y + m02 ]
	[ y'] = [  m10  m11  m12  ] [ y ] = [ m10x + m11y + m12 ]
	[ 1 ]   [   0    0    1   ] [ 1 ]   [         1         ]
 

See Also:

Serialized Form

Field Summary

static int	TYPE_FLIP This flag bit indicates that the transform defined by this object performs a mirror image flip about some axis which changes the normally right handed coordinate system into a left handed system in addition to the conversions indicated by other flag bits.
static int	TYPE_GENERAL_ROTATION This flag bit indicates that the transform defined by this object performs a rotation by an arbitrary angle in addition to the conversions indicated by other flag bits.
static int	TYPE_GENERAL_SCALE This flag bit indicates that the transform defined by this object performs a general scale in addition to the conversions indicated by other flag bits.
static int	TYPE_GENERAL_TRANSFORM This constant indicates that the transform defined by this object performs an arbitrary conversion of the input coordinates.
static int	TYPE_IDENTITY This constant indicates that the transform defined by this object is an identity transform.
static int	TYPE_MASK_ROTATION This constant is a bit mask for any of the rotation flag bits.
static int	TYPE_MASK_SCALE This constant is a bit mask for any of the scale flag bits.
static int	TYPE_QUADRANT_ROTATION This flag bit indicates that the transform defined by this object performs a quadrant rotation by some multiple of 90 degrees in addition to the conversions indicated by other flag bits.
static int	TYPE_TRANSLATION This flag bit indicates that the transform defined by this object performs a translation in addition to the conversions indicated by other flag bits.
static int	TYPE_UNIFORM_SCALE This flag bit indicates that the transform defined by this object performs a uniform scale in addition to the conversions indicated by other flag bits.

Constructor Summary

AffineTransform()
Constructs a new AffineTransform representing the Identity transformation.

AffineTransform(AffineTransform Tx)
Constructs a new AffineTransform representing a copy of another AffineTransform object.

AffineTransform(double m00, double m10, double m01, double m11, double m02, double m12)
Constructs a new AffineTransform from 6 double precision values representing the 6 specifiable entries of the 3x3 transformation matrix.

AffineTransform(double[] flatmatrix)
Constructs a new AffineTransform from an array of double precision values representing either the 4 non-translation or the 6 specifiable entries of the 3x3 transformation matrix.

AffineTransform(float m00, float m10, float m01, float m11, float m02, float m12)
Constructs a new AffineTransform from 6 floating point values representing the 6 specifiable entries of the 3x3 transformation matrix.

AffineTransform(float[] flatmatrix)
Constructs a new AffineTransform from an array of floating point values representing either the 4 non-translation or the 6 specifiable entries of the 3x3 transformation matrix.

Method Summary

Object	clone() Returns a copy of this AffineTransform object.
void	concatenate(AffineTransform Tx) Concatenates an AffineTransform Tx to this AffineTransform Cx in the most commonly useful way to provide a new user space which is mapped to the former user space by Tx.
AffineTransform	createInverse() Returns an AffineTransform object representing the inverse transformation.
Shape	createTransformedShape(Shape pSrc) Returns a new Shape object defined by the geometry of the specified Shape argument transformed by this transform.
void	deltaTransform(double[] srcPts, int srcOff, double[] dstPts, int dstOff, int numPts) Transforms an array of relative distance vectors by this transform.
Point2D	deltaTransform(Point2D ptSrc, Point2D ptDst) Transforms the relative distance vector specified by ptSrc and stores the result in ptDst.
boolean	equals(Object obj) Returns true if this AffineTransform represents the same affine coordinate transform as the given argument.
double	getDeterminant() Returns the determinant of the matrix representation of the transform.
void	getMatrix(double[] flatmatrix) Retrieves the 6 specifiable values in the 3x3 affine transformation matrix into an array of double precisions values.
static AffineTransform	getRotateInstance(double theta, double x, double y) Returns a transform that rotates coordinates around an anchor point.
static AffineTransform	getRotateInstance(double theta) Returns a transform representing a rotation transformation.
static AffineTransform	getScaleInstance(double sx, double sy) Returns a transform representing a scaling transformation.
double	getScaleX() Returns the X coordinate scaling element (m00) of the 3x3 affine transformation matrix.
double	getScaleY() Returns the Y coordinate scaling element (m11) of the 3x3 affine transformation matrix.
static AffineTransform	getShearInstance(double shx, double shy) Returns a transform representing a shearing transformation.
double	getShearX() Returns the X coordinate shearing element (m01) of the 3x3 affine transformation matrix.
double	getShearY() Returns the Y coordinate shearing element (m10) of the 3x3 affine transformation matrix.
static AffineTransform	getTranslateInstance(double tx, double ty) Returns a transform representing a translation transformation.
double	getTranslateX() Returns the X coordinate translation element (m02) of the 3x3 affine transformation matrix.
double	getTranslateY() Returns the Y coordinate translation element (m12) of the 3x3 affine transformation matrix.
int	getType() Retrieves the flag bits describing the conversion properties of this transform.
void	inverseTransform(double[] srcPts, int srcOff, double[] dstPts, int dstOff, int numPts) Inverse transforms an array of double precision coordinates by this transform.
Point2D	inverseTransform(Point2D ptSrc, Point2D ptDst) Inverse transforms the specified ptSrc and stores the result in ptDst.
boolean	isIdentity() Returns true if this AffineTransform is an identity transform.
void	preConcatenate(AffineTransform Tx) Concatenates an AffineTransform Tx to this AffineTransform Cx in a less commonly used way such that Tx modifies the coordinate transformation relative to the absolute pixel space rather than relative to the existing user space.
void	rotate(double theta, double x, double y) Concatenates this transform with a transform that rotates coordinates around an anchor point.
void	rotate(double theta) Concatenates this transform with a rotation transformation.
void	scale(double sx, double sy) Concatenates this transform with a scaling transformation.
void	setToIdentity() Resets this transform to the Identity transform.
void	setToRotation(double theta, double x, double y) Sets this transform to a translated rotation transformation.
void	setToRotation(double theta) Sets this transform to a rotation transformation.
void	setToScale(double sx, double sy) Sets this transform to a scaling transformation.
void	setToShear(double shx, double shy) Sets this transform to a shearing transformation.
void	setToTranslation(double tx, double ty) Sets this transform to a translation transformation.
void	setTransform(AffineTransform Tx) Sets this transform to a copy of the transform in the indicated AffineTransform object.
void	setTransform(double m00, double m10, double m01, double m11, double m02, double m12) Sets this transform to the matrix specified by the 6 double precision values.
void	shear(double shx, double shy) Concatenates this transform with a shearing transformation.
String	toString() Returns a String that represents the value of this Object.
void	transform(double[] srcPts, int srcOff, double[] dstPts, int dstOff, int numPts) Transforms an array of double precision coordinates by this transform.
void	transform(double[] srcPts, int srcOff, float[] dstPts, int dstOff, int numPts) Transforms an array of double precision coordinates by this transform, storing the results into an array of floats.
void	transform(float[] srcPts, int srcOff, double[] dstPts, int dstOff, int numPts) Transforms an array of floating point coordinates by this transform, storing the results into an array of doubles.
void	transform(float[] srcPts, int srcOff, float[] dstPts, int dstOff, int numPts) Transforms an array of floating point coordinates by this transform.
Point2D	transform(Point2D ptSrc, Point2D ptDst) Transforms the specified ptSrc and stores the result in ptDst.
void	transform(Point2D[] ptSrc, int srcOff, Point2D[] ptDst, int dstOff, int numPts) Transforms an array of point objects by this transform.
void	translate(double tx, double ty) Concatenates this transform with a translation transformation.

Methods inherited from class java.lang.Object

finalize , getClass , hashCode , notify , notifyAll , wait , wait , wait

Field Detail

TYPE_IDENTITY

public static final int TYPE_IDENTITY

This constant indicates that the transform defined by this object is an identity transform. An identity transform is one in which the output coordinates are always the same as the input coordinates. If this transform is anything other than the identity transform, the type will either be the constant GENERAL_TRANSFORM or a combination of the appropriate flag bits for the various coordinate conversions that this transform performs.

See Also:

TYPE_TRANSLATION, TYPE_UNIFORM_SCALE, TYPE_GENERAL_SCALE, TYPE_FLIP, TYPE_QUADRANT_ROTATION, TYPE_GENERAL_ROTATION, TYPE_GENERAL_TRANSFORM, getType()

TYPE_TRANSLATION

public static final int TYPE_TRANSLATION

This flag bit indicates that the transform defined by this object performs a translation in addition to the conversions indicated by other flag bits. A translation moves the coordinates by a constant amount in x and y without changing the length or angle of vectors.

See Also:

TYPE_IDENTITY, TYPE_UNIFORM_SCALE, TYPE_GENERAL_SCALE, TYPE_FLIP, TYPE_QUADRANT_ROTATION, TYPE_GENERAL_ROTATION, TYPE_GENERAL_TRANSFORM, getType()

TYPE_UNIFORM_SCALE

public static final int TYPE_UNIFORM_SCALE

This flag bit indicates that the transform defined by this object performs a uniform scale in addition to the conversions indicated by other flag bits. A uniform scale multiplies the length of vectors by the same amount in both the x and y directions without changing the angle between vectors. This flag bit is mutually exclusive with the TYPE_GENERAL_SCALE flag.

See Also:

TYPE_IDENTITY, TYPE_TRANSLATION, TYPE_GENERAL_SCALE, TYPE_FLIP, TYPE_QUADRANT_ROTATION, TYPE_GENERAL_ROTATION, TYPE_GENERAL_TRANSFORM, getType()

TYPE_GENERAL_SCALE

public static final int TYPE_GENERAL_SCALE

This flag bit indicates that the transform defined by this object performs a general scale in addition to the conversions indicated by other flag bits. A general scale multiplies the length of vectors by different amounts in the x and y directions without changing the angle between perpendicular vectors. This flag bit is mutually exclusive with the TYPE_UNIFORM_SCALE flag.

See Also:

TYPE_IDENTITY, TYPE_TRANSLATION, TYPE_UNIFORM_SCALE, TYPE_FLIP, TYPE_QUADRANT_ROTATION, TYPE_GENERAL_ROTATION, TYPE_GENERAL_TRANSFORM, getType()

TYPE_MASK_SCALE

public static final int TYPE_MASK_SCALE

This constant is a bit mask for any of the scale flag bits.

See Also:

TYPE_UNIFORM_SCALE, TYPE_GENERAL_SCALE

TYPE_FLIP

public static final int TYPE_FLIP

This flag bit indicates that the transform defined by this object performs a mirror image flip about some axis which changes the normally right handed coordinate system into a left handed system in addition to the conversions indicated by other flag bits. A right handed coordinate system is one where the positive X axis rotates counterclockwise to overlay the positive Y axis similar to the direction that the fingers on your right hand curl when you stare end on at your thumb. A left handed coordinate system is one where the positive X axis rotates clockwise to overlay the positive Y axis similar to the direction that the fingers on your left hand curl. There is no mathematical way to determine the angle of the original flipping or mirroring transformation since all angles of flip are identical given an appropriate adjusting rotation.

See Also:

TYPE_IDENTITY, TYPE_TRANSLATION, TYPE_UNIFORM_SCALE, TYPE_GENERAL_SCALE, TYPE_QUADRANT_ROTATION, TYPE_GENERAL_ROTATION, TYPE_GENERAL_TRANSFORM, getType()

TYPE_QUADRANT_ROTATION

public static final int TYPE_QUADRANT_ROTATION

This flag bit indicates that the transform defined by this object performs a quadrant rotation by some multiple of 90 degrees in addition to the conversions indicated by other flag bits. A rotation changes the angles of vectors by the same amount regardless of the original direction of the vector without changing the length of the vector. This flag bit is mutually exclusive with the TYPE_GENERAL_ROTATION flag.

See Also:

TYPE_IDENTITY, TYPE_TRANSLATION, TYPE_UNIFORM_SCALE, TYPE_GENERAL_SCALE, TYPE_FLIP, TYPE_GENERAL_ROTATION, TYPE_GENERAL_TRANSFORM, getType()

TYPE_GENERAL_ROTATION

public static final int TYPE_GENERAL_ROTATION

This flag bit indicates that the transform defined by this object performs a rotation by an arbitrary angle in addition to the conversions indicated by other flag bits. A rotation changes the angles of vectors by the same amount regardless of the original direction of the vector without changing the length of the vector. This flag bit is mutually exclusive with the TYPE_QUADRANT_ROTATION flag.

See Also:

TYPE_IDENTITY, TYPE_TRANSLATION, TYPE_UNIFORM_SCALE, TYPE_GENERAL_SCALE, TYPE_FLIP, TYPE_QUADRANT_ROTATION, TYPE_GENERAL_TRANSFORM, getType()

TYPE_MASK_ROTATION

public static final int TYPE_MASK_ROTATION

This constant is a bit mask for any of the rotation flag bits.

See Also:

TYPE_QUADRANT_ROTATION, TYPE_GENERAL_ROTATION

TYPE_GENERAL_TRANSFORM

public static final int TYPE_GENERAL_TRANSFORM

This constant indicates that the transform defined by this object performs an arbitrary conversion of the input coordinates. If this transform can be classified by any of the above constants, the type will either be the constant TYPE_IDENTITY or a combination of the appropriate flag bits for the various coordinate conversions that this transform performs.

See Also:

TYPE_IDENTITY, TYPE_TRANSLATION, TYPE_UNIFORM_SCALE, TYPE_GENERAL_SCALE, TYPE_FLIP, TYPE_QUADRANT_ROTATION, TYPE_GENERAL_ROTATION, getType()

Constructor Detail

AffineTransform

public AffineTransform()

Constructs a new AffineTransform representing the Identity transformation.

AffineTransform

public AffineTransform(AffineTransform Tx)

Constructs a new AffineTransform representing a copy of another AffineTransform object.

Parameters:

Tx - the AffineTransform object from which to copy the transformation

AffineTransform

public AffineTransform(float m00,
                       float m10,
                       float m01,
                       float m11,
                       float m02,
                       float m12)

Constructs a new AffineTransform from 6 floating point values representing the 6 specifiable entries of the 3x3 transformation matrix.

AffineTransform

public AffineTransform(float[] flatmatrix)

Constructs a new AffineTransform from an array of floating point values representing either the 4 non-translation or the 6 specifiable entries of the 3x3 transformation matrix. The values are retrieved from the array as { m00 m10 m01 m11 [m02 m12] }.

Parameters:

flatmatrix - The float array containing the values to be set in the new AffineTransform object. The length of the array is assumed to be at least 4. If the length of the array is less than 6, only the first 4 values are taken. If the length of the array is greater than 6, the first 6 values are taken.

AffineTransform

public AffineTransform(double m00,
                       double m10,
                       double m01,
                       double m11,
                       double m02,
                       double m12)

Constructs a new AffineTransform from 6 double precision values representing the 6 specifiable entries of the 3x3 transformation matrix.

AffineTransform

public AffineTransform(double[] flatmatrix)

Constructs a new AffineTransform from an array of double precision values representing either the 4 non-translation or the 6 specifiable entries of the 3x3 transformation matrix. The values are retrieved from the array as { m00 m10 m01 m11 [m02 m12] }.

Parameters:

flatmatrix - The double array containing the values to be set in the new AffineTransform object. The length of the array is assumed to be at least 4. If the length of the array is less than 6, only the first 4 values are taken. If the length of the array is greater than 6, the first 6 values are taken.

Method Detail

getTranslateInstance

public static AffineTransform getTranslateInstance(double tx,
                                                   double ty)

Returns a transform representing a translation transformation. The matrix representing by the returned transform transform will be:

		[   1    0    tx  ]
		[   0    1    ty  ]
		[   0    0    1   ]
 

Parameters:

tx - The distance by which coordinates are translated in the X axis direction

ty - The distance by which coordinates are translated in the Y axis direction

getRotateInstance

public static AffineTransform getRotateInstance(double theta)

Returns a transform representing a rotation transformation. The matrix representing by the returned transform transform will be:

		[   cos(theta)    -sin(theta)    0   ]
		[   sin(theta)     cos(theta)    0   ]
		[       0              0         1   ]
 

Rotating with a positive angle theta rotates points on the positive x axis toward the positive y axis.

Parameters:

theta - The angle of rotation in radians.

getRotateInstance

public static AffineTransform getRotateInstance(double theta,
                                                double x,
                                                double y)

Returns a transform that rotates coordinates around an anchor point. This operation is equivalent to translating the coordinates so that the anchor point is at the origin (S1), then rotating them about the new origin (S2), and finally translating so that the intermediate origin is restored to the coordinates of the original anchor point (S3).

This operation is equivalent to the following sequence of calls:

	    AffineTransform Tx = new AffineTransform();
	    Tx.setToTranslation(x, y);	// S3: final translation
	    Tx.rotate(theta);		// S2: rotate around anchor
	    Tx.translate(-x, -y);	// S1: translate anchor to origin
 

The matrix representing by the returned transform transform will be:

		[   cos(theta)    -sin(theta)    x-x*cos+y*sin  ]
		[   sin(theta)     cos(theta)    y-x*sin-y*cos  ]
		[       0              0               1        ]
 

Rotating with a positive angle theta rotates points on the positive x axis toward the positive y axis.

Parameters:

theta - The angle of rotation in radians.

x - The x coordinate of the anchor point of the rotation

y - The x coordinate of the anchor point of the rotation

getScaleInstance

public static AffineTransform getScaleInstance(double sx,
                                               double sy)

Returns a transform representing a scaling transformation. The matrix representing by the returned transform transform will be:

		[   sx   0    0   ]
		[   0    sy   0   ]
		[   0    0    1   ]
 

Parameters:

sx - The factor by which coordinates are scaled along the X axis direction

sy - The factor by which coordinates are scaled along the Y axis direction

getShearInstance

public static AffineTransform getShearInstance(double shx,
                                               double shy)

Returns a transform representing a shearing transformation. The matrix representing by the returned transform transform will be:

		[   1   shx   0   ]
		[  shy   1    0   ]
		[   0    0    1   ]
 

Parameters:

shx - The multiplier by which coordinates are shifted in the direction of the positive X axis as a factor of their Y coordinate

shy - The multiplier by which coordinates are shifted in the direction of the positive Y axis as a factor of their X coordinate

getType

public int getType()

Retrieves the flag bits describing the conversion properties of this transform. The return value will either be one of the constants TYPE_IDENTITY or TYPE_GENERAL_TRANSFORM, or it will be a combination of the appriopriate flag bits. A valid combination of flag bits is an exclusive OR operation which may combine the TYPE_TRANSLATION flag bit in addition to either of the TYPE_UNIFORM_SCALE or TYPE_GENERAL_SCALE flag bits as well as either of the TYPE_QUADRANT_ROTATION or TYPE_GENERAL_ROTATION flag bits.

Returns:

the OR combination of any of the indicated flags that apply to this transform

See Also:

TYPE_IDENTITY, TYPE_TRANSLATION, TYPE_UNIFORM_SCALE, TYPE_GENERAL_SCALE, TYPE_QUADRANT_ROTATION, TYPE_GENERAL_ROTATION, TYPE_GENERAL_TRANSFORM

getDeterminant

public double getDeterminant()

Returns the determinant of the matrix representation of the transform. The determinant is useful both to determine if the transform can be inverted and also to get a single value representing the combined X and Y scaling of the transform.

If the determinant is non-zero, then this transform will be invertible and the various methods which depend on the inverse transform will not need to throw a NoninvertibleTransformException. If the determinant is zero, then this transform can not be inverted since the transform maps all input coordinates onto a line or a point. If the determinant is near enough to zero, then inverse transform operations may not carry enough precision to produce meaningful results.

If this transform represents a uniform scale, as indicated by the getType method, then the determinant will also represent the square of the uniform scale factor by which all of the points are expanded from or contracted towards the origin. If this transform represents a non-uniform scale or more general transform, then the determinant is not likely to represent a value useful for any other purpose than determining if inverse transforms are possible.

Mathematically, the determinant is calculated using the formula:

		|  m00  m01  m02  |
		|  m10  m11  m12  |  =  m00 * m11 - m01 * m10
		|   0    0    1   |
 

Returns:

the determinant of the matrix used to transform the coordinates

See Also:

getType(), createInverse(), inverseTransform(java.awt.geom.Point2D, java.awt.geom.Point2D), TYPE_UNIFORM_SCALE

getMatrix

public void getMatrix(double[] flatmatrix)

Retrieves the 6 specifiable values in the 3x3 affine transformation matrix into an array of double precisions values. The values are stored into the array as { m00 m10 m01 m11 m02 m12 }.

Parameters:

flatmatrix - The double array used to store the returned values. The length of the array is assumed to be at least 6.

See Also:

getScaleX(), getScaleY(), getShearX(), getShearY(), getTranslateX(), getTranslateY()

getScaleX

public double getScaleX()

Returns the X coordinate scaling element (m00) of the 3x3 affine transformation matrix.

See Also:

getMatrix(double[])

getScaleY

public double getScaleY()

Returns the Y coordinate scaling element (m11) of the 3x3 affine transformation matrix.

See Also:

getMatrix(double[])

getShearX

public double getShearX()

Returns the X coordinate shearing element (m01) of the 3x3 affine transformation matrix.

See Also:

getMatrix(double[])

getShearY

public double getShearY()

Returns the Y coordinate shearing element (m10) of the 3x3 affine transformation matrix.

See Also:

getMatrix(double[])

getTranslateX

public double getTranslateX()

Returns the X coordinate translation element (m02) of the 3x3 affine transformation matrix.

See Also:

getMatrix(double[])

getTranslateY

public double getTranslateY()

Returns the Y coordinate translation element (m12) of the 3x3 affine transformation matrix.

See Also:

getMatrix(double[])

translate

public void translate(double tx,
                      double ty)

Concatenates this transform with a translation transformation. This is equivalent to calling concatenate(T), where T is an AffineTransform represented by the following matrix:

		[   1    0    tx  ]
		[   0    1    ty  ]
		[   0    0    1   ]
 

rotate

public void rotate(double theta)

Concatenates this transform with a rotation transformation. This is equivalent to calling concatenate(R), where R is an AffineTransform represented by the following matrix:

		[   cos(theta)    -sin(theta)    0   ]
		[   sin(theta)     cos(theta)    0   ]
		[       0              0         1   ]
 

Rotating with a positive angle theta rotates points on the positive x axis toward the positive y axis.

Parameters:

theta - The angle of rotation in radians.

rotate

public void rotate(double theta,
                   double x,
                   double y)

Concatenates this transform with a transform that rotates coordinates around an anchor point. This operation is equivalent to translating the coordinates so that the anchor point is at the origin (S1), then rotating them about the new origin (S2), and finally translating so that the intermediate origin is restored to the coordinates of the original anchor point (S3).

This operation is equivalent to the following sequence of calls:

		translate(x, y);	// S3: final translation
		rotate(theta);		// S2: rotate around anchor
		translate(-x, -y);	// S1: translate anchor to origin
 

Rotating with a positive angle theta rotates points on the positive x axis toward the positive y axis.

Parameters:

theta - The angle of rotation in radians.

x - The x coordinate of the anchor point of the rotation

y - The x coordinate of the anchor point of the rotation

scale

public void scale(double sx,
                  double sy)

Concatenates this transform with a scaling transformation. This is equivalent to calling concatenate(S), where S is an AffineTransform represented by the following matrix:

		[   sx   0    0   ]
		[   0    sy   0   ]
		[   0    0    1   ]
 

shear

public void shear(double shx,
                  double shy)

Concatenates this transform with a shearing transformation. This is equivalent to calling concatenate(SH), where SH is an AffineTransform represented by the following matrix:

		[   1   shx   0   ]
		[  shy   1    0   ]
		[   0    0    1   ]
 

Parameters:

shx - The multiplier by which coordinates are shifted in the direction of the positive X axis as a factor of their Y coordinate

shy - The multiplier by which coordinates are shifted in the direction of the positive Y axis as a factor of their X coordinate

setToIdentity

public void setToIdentity()

Resets this transform to the Identity transform.

setToTranslation

public void setToTranslation(double tx,
                             double ty)

Sets this transform to a translation transformation. The matrix representing this transform becomes:

		[   1    0    tx  ]
		[   0    1    ty  ]
		[   0    0    1   ]
 

Parameters:

tx - The distance by which coordinates are translated in the X axis direction

ty - The distance by which coordinates are translated in the Y axis direction

setToRotation

public void setToRotation(double theta)

Sets this transform to a rotation transformation. The matrix representing this transform becomes:

		[   cos(theta)    -sin(theta)    0   ]
		[   sin(theta)     cos(theta)    0   ]
		[       0              0         1   ]
 

Rotating with a positive angle theta rotates points on the positive x axis toward the positive y axis.

Parameters:

theta - The angle of rotation in radians.

setToRotation

public void setToRotation(double theta,
                          double x,
                          double y)

Sets this transform to a translated rotation transformation. This operation is equivalent to translating the coordinates so that the anchor point is at the origin (S1), then rotating them about the new origin (S2), and finally translating so that the intermediate origin is restored to the coordinates of the original anchor point (S3).

This operation is equivalent to the following sequence of calls:

	    setToTranslation(x, y);	// S3: final translation
	    rotate(theta);		// S2: rotate around anchor
	    translate(-x, -y);		// S1: translate anchor to origin
 

The matrix representing this transform becomes:

		[   cos(theta)    -sin(theta)    x-x*cos+y*sin  ]
		[   sin(theta)     cos(theta)    y-x*sin-y*cos  ]
		[       0              0               1        ]
 

Rotating with a positive angle theta rotates points on the positive x axis toward the positive y axis.

Parameters:

theta - The angle of rotation in radians.

x - The x coordinate of the anchor point of the rotation

y - The x coordinate of the anchor point of the rotation

setToScale

public void setToScale(double sx,
                       double sy)

Sets this transform to a scaling transformation. The matrix representing this transform becomes:

		[   sx   0    0   ]
		[   0    sy   0   ]
		[   0    0    1   ]
 

Parameters:

sx - The factor by which coordinates are scaled along the X axis direction

sy - The factor by which coordinates are scaled along the Y axis direction

setToShear

public void setToShear(double shx,
                       double shy)

Sets this transform to a shearing transformation. The matrix representing this transform becomes:

		[   1   shx   0   ]
		[  shy   1    0   ]
		[   0    0    1   ]
 

Parameters:

shx - The multiplier by which coordinates are shifted in the direction of the positive X axis as a factor of their Y coordinate

shy - The multiplier by which coordinates are shifted in the direction of the positive Y axis as a factor of their X coordinate

setTransform

public void setTransform(AffineTransform Tx)

Sets this transform to a copy of the transform in the indicated AffineTransform object.

Parameters:

Tx - the AffineTransform object from which to copy the transform

setTransform

public void setTransform(double m00,
                         double m10,
                         double m01,
                         double m11,
                         double m02,
                         double m12)

Sets this transform to the matrix specified by the 6 double precision values.

concatenate

public void concatenate(AffineTransform Tx)

Concatenates an AffineTransform Tx to this AffineTransform Cx in the most commonly useful way to provide a new user space which is mapped to the former user space by Tx. Cx is updated to perform the combined transformation. Transforming a point p by the updated transform Cx' is equivalent to first transforming p by Tx and then transforming the result by the original transform Cx. In other words, Cx'(p) = Cx(Tx(p)). In matrix notation, if this transform Cx is represented by the matrix [this] and Tx is represented by the matrix [Tx], then this method does the following:

		[this] = [this] x [Tx]
 

Parameters:

Tx - The AffineTransform object to be concatenated with this AffineTransform object.

See Also:

preConcatenate(java.awt.geom.AffineTransform)

preConcatenate

public void preConcatenate(AffineTransform Tx)

Concatenates an AffineTransform Tx to this AffineTransform Cx in a less commonly used way such that Tx modifies the coordinate transformation relative to the absolute pixel space rather than relative to the existing user space. Cx is updated to perform the combined transformation. Transforming a point p by the updated transform Cx' is equivalent to first transforming p by the original transform Cx and then transforming the result by Tx. In other words, Cx'(p) = Tx(Cx(p)). In matrix notation, if this transform Cx is represented by the matrix [this] and Tx is represented by the matrix [Tx], then this method does the following:

		[this] = [Tx] x [this]
 

Parameters:

Tx - The AffineTransform object to be concatenated with this AffineTransform object.

See Also:

concatenate(java.awt.geom.AffineTransform)

createInverse

public AffineTransform createInverse()
                              throws NoninvertibleTransformException

Returns an AffineTransform object representing the inverse transformation. The inverse transform Tx' of this transform Tx is the transform that maps coordinates transformed by Tx back to their original coordinates. In other words, Tx'(Tx(p)) = p = Tx(Tx'(p)).

If this transform maps all coordinates onto a point or a line then it will not have an inverse, since coordinates that do not lie on the destination point or line will not have an inverse mapping. The getDeterminant method can be used to determine if this transform has no inverse, in which case an exception will be thrown if the createInverse method is called.

Returns:

a new AffineTransform object representing the inverse transformation

Throws:

NoninvertibleTransformException - if the matrix cannot be inverted.

See Also:

getDeterminant()

transform

public Point2D transform(Point2D ptSrc,
                         Point2D ptDst)

Transforms the specified ptSrc and stores the result in ptDst. If ptDst is null, a new Point2D object will be allocated before storing. In either case, ptDst containing the transformed point is returned for convenience. Note that ptSrc and ptDst can be the same object in which case the input point will be correctly overwritten with the transformed point.

transform

public void transform(Point2D[] ptSrc,
                      int srcOff,
                      Point2D[] ptDst,
                      int dstOff,
                      int numPts)

Transforms an array of point objects by this transform. If any element of the ptDst array is null, a new Point2D object will be allocated and stored into that element before storing the results.

Note that this method does not take any precautions to avoid problems caused by storing results into Point2D objects that will be used as the source for calculations further down the source array. This method does guarantee that if a given Point2D object is both the source and destination for the same single point transform operation then the results will not be stored until the calculations are complete to avoid storing the results on top of the operands. But if the destination Point2D object for one operation is the same object as the source Point2D object for another operation further down the source array, then the original coordinates in that point will be overwritten before they can be converted.

Parameters:

ptSrc - The array containing the source point objects.

ptDst - The array where the transform point objects are returned.

srcOff - The offset to the first point object to be transformed in the source array.

dstOff - The offset to the location where the first transformed point object is stored in the destination array.

numPts - The number of point objects to be transformed.

transform

public void transform(float[] srcPts,
                      int srcOff,
                      float[] dstPts,
                      int dstOff,
                      int numPts)

Transforms an array of floating point coordinates by this transform. The two coordinate array sections may be exactly the same or overlapping sections of the same array without affecting the validity of the results. This method will ensure that no source coordinates will be overwritten by a previous operation before they can be transformed. The coordinates are stored in the arrays starting at the indicated offset in the order [x0, y0, x1, y1, ..., xn, yn].

Parameters:

ptSrc - The array containing the source point coordinates. Each point is stored as a pair of x,y coordinates.

ptDst - The array where the transformed point coordinates are returned. Each point is stored as a pair of x,y coordinates.

srcOff - The offset to the first point to be transformed in the source array.

dstOff - The offset to the location where the first transformed point is stored in the destination array.

numPts - The number of points to be transformed.

transform

public void transform(double[] srcPts,
                      int srcOff,
                      double[] dstPts,
                      int dstOff,
                      int numPts)

Transforms an array of double precision coordinates by this transform. The two coordinate array sections may be exactly the same or overlapping sections of the same array without affecting the validity of the results. This method will ensure that no source coordinates will be overwritten by a previous operation before they can be transformed. The coordinates are stored in the arrays starting at the indicated offset in the order [x0, y0, x1, y1, ..., xn, yn].

Parameters:

srcPts - The array containing the source point coordinates. Each point is stored as a pair of x,y coordinates.

dstPts - The array where the transformed point coordinates are returned. Each point is stored as a pair of x,y coordinates.

srcOff - The offset to the first point to be transformed in the source array.

dstOff - The offset to the location where the first transformed point is stored in the destination array.

numPts - The number of point objects to be transformed.

transform

public void transform(float[] srcPts,
                      int srcOff,
                      double[] dstPts,
                      int dstOff,
                      int numPts)

Transforms an array of floating point coordinates by this transform, storing the results into an array of doubles. The coordinates are stored in the arrays starting at the indicated offset in the order [x0, y0, x1, y1, ..., xn, yn].

Parameters:

ptSrc - The array containing the source point coordinates. Each point is stored as a pair of x,y coordinates.

ptDst - The array where the transformed point coordinates are returned. Each point is stored as a pair of x,y coordinates.

srcOff - The offset to the first point to be transformed in the source array.

dstOff - The offset to the location where the first transformed point is stored in the destination array.

numPts - The number of points to be transformed.

transform

public void transform(double[] srcPts,
                      int srcOff,
                      float[] dstPts,
                      int dstOff,
                      int numPts)

Transforms an array of double precision coordinates by this transform, storing the results into an array of floats. The coordinates are stored in the arrays starting at the indicated offset in the order [x0, y0, x1, y1, ..., xn, yn].

Parameters:

srcPts - The array containing the source point coordinates. Each point is stored as a pair of x,y coordinates.

dstPts - The array where the transformed point coordinates are returned. Each point is stored as a pair of x,y coordinates.

srcOff - The offset to the first point to be transformed in the source array.

dstOff - The offset to the location where the first transformed point is stored in the destination array.

numPts - The number of point objects to be transformed.

inverseTransform

public Point2D inverseTransform(Point2D ptSrc,
                                Point2D ptDst)
                         throws NoninvertibleTransformException

Inverse transforms the specified ptSrc and stores the result in ptDst. If ptDst is null, a new Point2D object will be allocated before storing. In either case, ptDst containing the transformed point is returned for convenience. Note that ptSrc and ptDst can be the same object in which case the input point will be correctly overwritten with the transformed point.

Parameters:

ptSrc - The point to be inverse transformed.

ptDst - The resulting transformed point.

Throws:

NoninvertibleTransformException - if the matrix cannot be inverted.

inverseTransform

public void inverseTransform(double[] srcPts,
                             int srcOff,
                             double[] dstPts,
                             int dstOff,
                             int numPts)
                      throws NoninvertibleTransformException

Inverse transforms an array of double precision coordinates by this transform. The two coordinate array sections may be exactly the same or overlapping sections of the same array without affecting the validity of the results. This method will ensure that no source coordinates will be overwritten by a previous operation before they can be transformed. The coordinates are stored in the arrays starting at the indicated offset in the order [x0, y0, x1, y1, ..., xn, yn].

Parameters:

srcPts - The array containing the source point coordinates. Each point is stored as a pair of x,y coordinates.

dstPts - The array where the transformed point coordinates are returned. Each point is stored as a pair of x,y coordinates.

srcOff - The offset to the first point to be transformed in the source array.

dstOff - The offset to the location where the first transformed point is stored in the destination array.

numPts - The number of point objects to be transformed.

Throws:

NoninvertibleTransformException - if the matrix cannot be inverted.

deltaTransform

public Point2D deltaTransform(Point2D ptSrc,
                              Point2D ptDst)

Transforms the relative distance vector specified by ptSrc and stores the result in ptDst. A relative distance vector is transformed without applying the translation components of the affine transformation matrix using the following equations:

	[  x' ]   [  m00  m01 (m02) ] [  x  ]   [ m00x + m01y ]
	[  y' ] = [  m10  m11 (m12) ] [  y  ] = [ m10x + m11y ]
	[ (1) ]   [  (0)  (0) ( 1 ) ] [ (1) ]   [     (1)     ]
 

If ptDst is null, a new Point2D object will be allocated before storing. In either case, ptDst containing the transformed point is returned for convenience. Note that ptSrc and ptDst can be the same object in which case the input point will be correctly overwritten with the transformed point.

Parameters:

ptSrc - The distance vector to be delta transformed.

ptDst - The resulting transformed distance vector.

deltaTransform

public void deltaTransform(double[] srcPts,
                           int srcOff,
                           double[] dstPts,
                           int dstOff,
                           int numPts)

Transforms an array of relative distance vectors by this transform. A relative distance vector is transformed without applying the translation components of the affine transformation matrix using the following equations:

	[  x' ]   [  m00  m01 (m02) ] [  x  ]   [ m00x + m01y ]
	[  y' ] = [  m10  m11 (m12) ] [  y  ] = [ m10x + m11y ]
	[ (1) ]   [  (0)  (0) ( 1 ) ] [ (1) ]   [     (1)     ]
 

The two coordinate array sections may be exactly the same or overlapping sections of the same array without affecting the validity of the results. This method will ensure that no source coordinates will be overwritten by a previous operation before they can be transformed. The coordinates are stored in the arrays starting at the indicated offset in the order [x0, y0, x1, y1, ..., xn, yn].

Parameters:

srcPts - The array containing the source distance vectors. Each vector is stored as a pair of relative x,y coordinates.

dstPts - The array where the transformed distance vectors are returned. Each vector is stored as a pair of relative x,y coordinates.

srcOff - The offset to the first vector to be transformed in the source array.

dstOff - The offset to the location where the first transformed vector is stored in the destination array.

numPts - The number of vector coordinate pairs to be transformed.

createTransformedShape

public Shape createTransformedShape(Shape pSrc)

Returns a new Shape object defined by the geometry of the specified Shape argument transformed by this transform.

toString

public String toString()

Returns a String that represents the value of this Object.

Overrides:

toString in class Object

isIdentity

public boolean isIdentity()

Returns true if this AffineTransform is an identity transform.

clone

public Object clone()

Returns a copy of this AffineTransform object.

Overrides:

clone in class Object

equals

public boolean equals(Object obj)

Returns true if this AffineTransform represents the same affine coordinate transform as the given argument.

Overrides:

equals in class Object