Package org.eclipse.swt.graphics
Class Transform
java.lang.Object
org.eclipse.swt.graphics.Resource
org.eclipse.swt.graphics.Transform
Instances of this class represent transformation matrices for
points expressed as (x, y) pairs of floating point numbers.
Application code must explicitly invoke the Transform.dispose()
method to release the operating system resources managed by each instance
when those instances are no longer required.
 Since:
 3.1

Constructor Summary
ConstructorDescriptionConstructs a new identity Transform.Constructs a new Transform given an array of elements that represent the matrix that describes the transformation.Constructs a new Transform given all of the elements that represent the matrix that describes the transformation. 
Method Summary
Modifier and TypeMethodDescriptionvoid
getElements
(float[] elements) Fills the parameter with the values of the transformation matrix that the receiver represents, in the order {m11, m12, m21, m22, dx, dy}.void
identity()
Modifies the receiver such that the matrix it represents becomes the identity matrix.void
invert()
Modifies the receiver such that the matrix it represents becomes the mathematical inverse of the matrix it previously represented.boolean
Returnstrue
if the Transform represents the identity matrix and false otherwise.void
Modifies the receiver such that the matrix it represents becomes the the result of multiplying the matrix it previously represented by the argument.void
rotate
(float angle) Modifies the receiver so that it represents a transformation that is equivalent to its previous transformation rotated by the specified angle.void
scale
(float scaleX, float scaleY) Modifies the receiver so that it represents a transformation that is equivalent to its previous transformation scaled by (scaleX, scaleY).void
setElements
(float m11, float m12, float m21, float m22, float dx, float dy) Modifies the receiver to represent a new transformation given all of the elements that represent the matrix that describes that transformation.void
shear
(float shearX, float shearY) Modifies the receiver so that it represents a transformation that is equivalent to its previous transformation sheared by (shearX, shearY).toString()
Returns a string containing a concise, humanreadable description of the receiver.void
transform
(float[] pointArray) Given an array containing points described by alternating x and y values, modify that array such that each point has been replaced with the result of applying the transformation represented by the receiver to that point.void
translate
(float offsetX, float offsetY) Modifies the receiver so that it represents a transformation that is equivalent to its previous transformation translated by (offsetX, offsetY).Methods inherited from class org.eclipse.swt.graphics.Resource
dispose, getDevice, isDisposed

Constructor Details

Transform
Constructs a new identity Transform.This operation requires the operating system's advanced graphics subsystem which may not be available on some platforms.
 Parameters:
device
 the device on which to allocate the Transform Throws:
IllegalArgumentException
 ERROR_NULL_ARGUMENT  if device is null and there is no current device
 See Also:

Transform
Constructs a new Transform given an array of elements that represent the matrix that describes the transformation.This operation requires the operating system's advanced graphics subsystem which may not be available on some platforms.
 Parameters:
device
 the device on which to allocate the Transformelements
 an array of floats that describe the transformation matrix Throws:
IllegalArgumentException
 ERROR_NULL_ARGUMENT  if device is null and there is no current device, or the elements array is null
 ERROR_INVALID_ARGUMENT  if the elements array is too small to hold the matrix values
 See Also:

Transform
Constructs a new Transform given all of the elements that represent the matrix that describes the transformation.This operation requires the operating system's advanced graphics subsystem which may not be available on some platforms.
 Parameters:
device
 the device on which to allocate the Transformm11
 the first element of the first row of the matrixm12
 the second element of the first row of the matrixm21
 the first element of the second row of the matrixm22
 the second element of the second row of the matrixdx
 the third element of the first row of the matrixdy
 the third element of the second row of the matrix Throws:
IllegalArgumentException
 ERROR_NULL_ARGUMENT  if device is null and there is no current device
 See Also:


Method Details

getElements
public void getElements(float[] elements) Fills the parameter with the values of the transformation matrix that the receiver represents, in the order {m11, m12, m21, m22, dx, dy}. Parameters:
elements
 array to hold the matrix values Throws:
SWTException
 ERROR_GRAPHIC_DISPOSED  if the receiver has been disposed
IllegalArgumentException
 ERROR_NULL_ARGUMENT  if the parameter is null
 ERROR_INVALID_ARGUMENT  if the parameter is too small to hold the matrix values

setElements
public void setElements(float m11, float m12, float m21, float m22, float dx, float dy) Modifies the receiver to represent a new transformation given all of the elements that represent the matrix that describes that transformation. Parameters:
m11
 the first element of the first row of the matrixm12
 the second element of the first row of the matrixm21
 the first element of the second row of the matrixm22
 the second element of the second row of the matrixdx
 the third element of the first row of the matrixdy
 the third element of the second row of the matrix Throws:
SWTException
 ERROR_GRAPHIC_DISPOSED  if the receiver has been disposed

identity
public void identity()Modifies the receiver such that the matrix it represents becomes the identity matrix. Throws:
SWTException
 ERROR_GRAPHIC_DISPOSED  if the receiver has been disposed

isIdentity
public boolean isIdentity()Returnstrue
if the Transform represents the identity matrix and false otherwise. Returns:
true
if the receiver is an identity Transform, andfalse
otherwise

invert
public void invert()Modifies the receiver such that the matrix it represents becomes the mathematical inverse of the matrix it previously represented. Throws:
SWTException
 ERROR_GRAPHIC_DISPOSED  if the receiver has been disposed
 ERROR_CANNOT_INVERT_MATRIX  if the matrix is not invertible

multiply
Modifies the receiver such that the matrix it represents becomes the the result of multiplying the matrix it previously represented by the argument. Parameters:
matrix
 the matrix to multiply the receiver by Throws:
SWTException
 ERROR_GRAPHIC_DISPOSED  if the receiver has been disposed
IllegalArgumentException
 ERROR_NULL_ARGUMENT  if the parameter is null
 ERROR_INVALID_ARGUMENT  if the parameter has been disposed

translate
public void translate(float offsetX, float offsetY) Modifies the receiver so that it represents a transformation that is equivalent to its previous transformation translated by (offsetX, offsetY). Parameters:
offsetX
 the distance to translate in the X directionoffsetY
 the distance to translate in the Y direction Throws:
SWTException
 ERROR_GRAPHIC_DISPOSED  if the receiver has been disposed

scale
public void scale(float scaleX, float scaleY) Modifies the receiver so that it represents a transformation that is equivalent to its previous transformation scaled by (scaleX, scaleY). Parameters:
scaleX
 the amount to scale in the X directionscaleY
 the amount to scale in the Y direction Throws:
SWTException
 ERROR_GRAPHIC_DISPOSED  if the receiver has been disposed

rotate
public void rotate(float angle) Modifies the receiver so that it represents a transformation that is equivalent to its previous transformation rotated by the specified angle. The angle is specified in degrees and for the identity transform 0 degrees is at the 3 o'clock position. A positive value indicates a clockwise rotation while a negative value indicates a counterclockwise rotation. Parameters:
angle
 the angle to rotate the transformation by Throws:
SWTException
 ERROR_GRAPHIC_DISPOSED  if the receiver has been disposed

shear
public void shear(float shearX, float shearY) Modifies the receiver so that it represents a transformation that is equivalent to its previous transformation sheared by (shearX, shearY). Parameters:
shearX
 the shear factor in the X directionshearY
 the shear factor in the Y direction Throws:
SWTException
 ERROR_GRAPHIC_DISPOSED  if the receiver has been disposed

transform
public void transform(float[] pointArray) Given an array containing points described by alternating x and y values, modify that array such that each point has been replaced with the result of applying the transformation represented by the receiver to that point. Parameters:
pointArray
 an array of alternating x and y values to be transformed Throws:
IllegalArgumentException
 ERROR_NULL_ARGUMENT  if the point array is null
SWTException
 ERROR_GRAPHIC_DISPOSED  if the receiver has been disposed

toString
Returns a string containing a concise, humanreadable description of the receiver.
