Class: java.awt.geom.AffineTransform
- public class AffineTransform
- implements Cloneable, Serializable
The
AffineTransform class represents a 2D affine transform
that performs a linear mapping from 2D coordinates to other 2D
coordinates that 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 ]. This matrix 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 ]
Handling 90-Degree Rotations
In some variations of the rotate methods in the
AffineTransform class, a double-precision argument
specifies the angle of rotation in radians.
These methods have special handling for rotations of approximately
90 degrees (including multiples such as 180, 270, and 360 degrees),
so that the common case of quadrant rotation is handled more
efficiently.
This special handling can cause angles very close to multiples of
90 degrees to be treated as if they were exact multiples of
90 degrees.
For small multiples of 90 degrees the range of angles treated
as a quadrant rotation is approximately 0.00000121 degrees wide.
This section explains why such special care is needed and how
it is implemented.
Since 90 degrees is represented as PI/2 in radians,
and since PI is a transcendental (and therefore irrational) number,
it is not possible to exactly represent a multiple of 90 degrees as
an exact double precision value measured in radians.
As a result it is theoretically impossible to describe quadrant
rotations (90, 180, 270 or 360 degrees) using these values.
Double precision floating point values can get very close to
non-zero multiples of PI/2 but never close enough
for the sine or cosine to be exactly 0.0, 1.0 or -1.0.
The implementations of Math.sin() and
Math.cos() correspondingly never return 0.0
for any case other than Math.sin(0.0).
These same implementations do, however, return exactly 1.0 and
-1.0 for some range of numbers around each multiple of 90
degrees since the correct answer is so close to 1.0 or -1.0 that
the double precision significand cannot represent the difference
as accurately as it can for numbers that are near 0.0.
The net result of these issues is that if the
Math.sin() and Math.cos() methods
are used to directly generate the values for the matrix modifications
during these radian-based rotation operations then the resulting
transform is never strictly classifiable as a quadrant rotation
even for a simple case like rotate(Math.PI/2.0),
due to minor variations in the matrix caused by the non-0.0 values
obtained for the sine and cosine.
If these transforms are not classified as quadrant rotations then
subsequent code which attempts to optimize further operations based
upon the type of the transform will be relegated to its most general
implementation.
Because quadrant rotations are fairly common,
this class should handle these cases reasonably quickly, both in
applying the rotations to the transform and in applying the resulting
transform to the coordinates.
To facilitate this optimal handling, the methods which take an angle
of rotation measured in radians attempt to detect angles that are
intended to be quadrant rotations and treat them as such.
These methods therefore treat an angle theta as a quadrant
rotation if either Math.sin(theta) or
Math.cos(theta) returns exactly 1.0 or -1.0.
As a rule of thumb, this property holds true for a range of
approximately 0.0000000211 radians (or 0.00000121 degrees) around
small multiples of Math.PI/2.0.
Methods
-
AffineTransformtop
public AffineTransform()Constructs a newAffineTransformrepresenting the Identity transformation. -
AffineTransformtop
public AffineTransform(double m00, double m10, double m01, double m11, double m02, double m12)Constructs a newAffineTransformfrom 6 double precision values representing the 6 specifiable entries of the 3x3 transformation matrix. -
AffineTransformtop
private AffineTransform(double m00, double m10, double m01, double m11, double m02, double m12, int state) -
AffineTransformtop
public AffineTransform(float m00, float m10, float m01, float m11, float m02, float m12)Constructs a newAffineTransformfrom 6 floating point values representing the 6 specifiable entries of the 3x3 transformation matrix. -
AffineTransformtop
public AffineTransform(AffineTransform Tx)Constructs a newAffineTransformthat is a copy of the specifiedAffineTransformobject. -
AffineTransformtop
public AffineTransform(double[] flatmatrix)Constructs a newAffineTransformfrom an array of double precision values representing either the 4 non-translation entries or the 6 specifiable entries of the 3x3 transformation matrix. The values are retrieved from the array as { m00 m10 m01 m11 [m02 m12]}. -
AffineTransformtop
public AffineTransform(float[] flatmatrix)Constructs a newAffineTransformfrom an array of floating point values representing either the 4 non-translation enries or the 6 specifiable entries of the 3x3 transformation matrix. The values are retrieved from the array as { m00 m10 m01 m11 [m02 m12]}. -
_matroundtop
static private double _matround(double matval) -
calculateTypetop
private void calculateType()This is the utility function to calculate the flag bits when they have not been cached. -
clonetop
public Object clone()Returns a copy of thisAffineTransformobject. -
concatenatetop
public void concatenate(AffineTransform Tx)Concatenates anAffineTransformTxto thisAffineTransformCx in the most commonly useful way to provide a new user space that is mapped to the former user space byTx. Cx is updated to perform the combined transformation. Transforming a point p by the updated transform Cx' is equivalent to first transforming p byTxand then transforming the result by the original transform Cx like this: Cx'(p) = Cx(Tx(p)) In matrix notation, if this transform Cx is represented by the matrix [this] andTxis represented by the matrix [Tx] then this method does the following:[this] = [this] x [Tx] -
createInversetop
public AffineTransform createInverse() throws NoninvertibleTransformExceptionReturns anAffineTransformobject representing the inverse transformation. The inverse transform Tx' of this transform Tx 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
getDeterminantmethod can be used to determine if this transform has no inverse, in which case an exception will be thrown if thecreateInversemethod is called. -
createTransformedShapetop
Returns a new java.awt.Shape object defined by the geometry of the specifiedShapeafter it has been transformed by this transform. -
deltaTransformtop
Transforms the relative distance vector specified byptSrcand stores the result inptDst. 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) ]
IfptDstisnull, a newPoint2Dobject is allocated and then the result of the transform is stored in this object. In either case,ptDst, which contains the transformed point, is returned for convenience. IfptSrcandptDstare the same object, the input point is correctly overwritten with the transformed point. -
deltaTransformtop
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 can be exactly the same or can be overlapping sections of the same array without affecting the validity of the results. This method ensures that no source coordinates are 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]. -
equalstop
public boolean equals(Object obj)Returnstrueif thisAffineTransformrepresents the same affine coordinate transform as the specified argument. -
getDeterminanttop
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 to get a single value representing the combined X and Y scaling of the transform.If the determinant is non-zero, then this transform is invertible and the various methods that depend on the inverse transform do not need to throw a java.awt.geom.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 might not carry enough precision to produce meaningful results.
If this transform represents a uniform scale, as indicated by the
getTypemethod then the determinant also represents 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 purpose other 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 | -
getMatrixtop
public void getMatrix(double[] flatmatrix)Retrieves the 6 specifiable values in the 3x3 affine transformation matrix and places them into an array of double precisions values. The values are stored in the array as { m00 m10 m01 m11 m02 m12 }. An array of 4 doubles can also be specified, in which case only the first four elements representing the non-transform parts of the array are retrieved and the values are stored into the array as { m00 m10 m01 m11 } -
getQuadrantRotateInstancetop
public static AffineTransform getQuadrantRotateInstance(int numquadrants)Returns a transform that rotates coordinates by the specified number of quadrants. This operation is equivalent to calling:AffineTransform.getRotateInstance(numquadrants * Math.PI / 2.0);Rotating by a positive number of quadrants rotates points on the positive X axis toward the positive Y axis. -
getQuadrantRotateInstancetop
public static AffineTransform getQuadrantRotateInstance(int numquadrants, double anchorx, double anchory)Returns a transform that rotates coordinates by the specified number of quadrants around the specified anchor point. This operation is equivalent to calling:AffineTransform.getRotateInstance(numquadrants * Math.PI / 2.0, anchorx, anchory);Rotating by a positive number of quadrants rotates points on the positive X axis toward the positive Y axis. -
getRotateInstancetop
public static AffineTransform getRotateInstance(double theta)Returns a transform representing a rotation transformation. The matrix representing the returned transform is:[ cos(theta) -sin(theta) 0 ] [ sin(theta) cos(theta) 0 ] [ 0 0 1 ]Rotating by a positive angle theta rotates points on the positive X axis toward the positive Y axis. Note also the discussion of Handling 90-Degree Rotations above. -
getRotateInstancetop
public static AffineTransform getRotateInstance(double vecx, double vecy)Returns a transform that rotates coordinates according to a rotation vector. All coordinates rotate about the origin by the same amount. The amount of rotation is such that coordinates along the former positive X axis will subsequently align with the vector pointing from the origin to the specified vector coordinates. If bothvecxandvecyare 0.0, an identity transform is returned. This operation is equivalent to calling:AffineTransform.getRotateInstance(Math.atan2(vecy, vecx)); -
getRotateInstancetop
public static AffineTransform getRotateInstance(double theta, double anchorx, double anchory)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.translate(anchorx, anchory); // S3: final translation Tx.rotate(theta); // S2: rotate around anchor Tx.translate(-anchorx, -anchory); // S1: translate anchor to originThe matrix representing the returned transform is:[ cos(theta) -sin(theta) x-x*cos+y*sin ] [ sin(theta) cos(theta) y-x*sin-y*cos ] [ 0 0 1 ]Rotating by a positive angle theta rotates points on the positive X axis toward the positive Y axis. Note also the discussion of Handling 90-Degree Rotations above. -
getRotateInstancetop
public static AffineTransform getRotateInstance(double vecx, double vecy, double anchorx, double anchory)Returns a transform that rotates coordinates around an anchor point accordinate to a rotation vector. All coordinates rotate about the specified anchor coordinates by the same amount. The amount of rotation is such that coordinates along the former positive X axis will subsequently align with the vector pointing from the origin to the specified vector coordinates. If bothvecxandvecyare 0.0, an identity transform is returned. This operation is equivalent to calling:AffineTransform.getRotateInstance(Math.atan2(vecy, vecx), anchorx, anchory); -
getScaleInstancetop
public static AffineTransform getScaleInstance(double sx, double sy)Returns a transform representing a scaling transformation. The matrix representing the returned transform is:[ sx 0 0 ] [ 0 sy 0 ] [ 0 0 1 ] -
getScaleXtop
public double getScaleX()Returns the X coordinate scaling element (m00) of the 3x3 affine transformation matrix. -
getScaleYtop
public double getScaleY()Returns the Y coordinate scaling element (m11) of the 3x3 affine transformation matrix. -
getShearInstancetop
public static AffineTransform getShearInstance(double shx, double shy)Returns a transform representing a shearing transformation. The matrix representing the returned transform is:[ 1 shx 0 ] [ shy 1 0 ] [ 0 0 1 ] -
getShearXtop
public double getShearX()Returns the X coordinate shearing element (m01) of the 3x3 affine transformation matrix. -
getShearYtop
public double getShearY()Returns the Y coordinate shearing element (m10) of the 3x3 affine transformation matrix. -
getTranslateInstancetop
public static AffineTransform getTranslateInstance(double tx, double ty)Returns a transform representing a translation transformation. The matrix representing the returned transform is:[ 1 0 tx ] [ 0 1 ty ] [ 0 0 1 ] -
getTranslateXtop
public double getTranslateX()Returns the X coordinate of the translation element (m02) of the 3x3 affine transformation matrix. -
getTranslateYtop
public double getTranslateY()Returns the Y coordinate of the translation element (m12) of the 3x3 affine transformation matrix. -
getTypetop
public int getType()Retrieves the flag bits describing the conversion properties of this transform. The return value is either one of the constants TYPE_IDENTITY or TYPE_GENERAL_TRANSFORM, or a combination of the appriopriate flag bits. A valid combination of flag bits is an exclusive OR operation that can 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. -
hashCodetop
public int hashCode()Returns the hashcode for this transform. -
inverseTransformtop
public Point2D inverseTransform(Point2D ptSrc, Point2D ptDst) throws NoninvertibleTransformExceptionInverse transforms the specifiedptSrcand stores the result inptDst. IfptDstisnull, a newPoint2Dobject is allocated and then the result of the transform is stored in this object. In either case,ptDst, which contains the transformed point, is returned for convenience. IfptSrcandptDstare the same object, the input point is correctly overwritten with the transformed point. -
inverseTransformtop
public void inverseTransform(double[] srcPts, int srcOff, double[] dstPts, int dstOff, int numPts) throws NoninvertibleTransformExceptionInverse transforms an array of double precision coordinates by this transform. The two coordinate array sections can be exactly the same or can be overlapping sections of the same array without affecting the validity of the results. This method ensures that no source coordinates are overwritten by a previous operation before they can be transformed. The coordinates are stored in the arrays starting at the specified offset in the order[x0, y0, x1, y1, ..., xn, yn]. -
inverttop
public void invert() throws NoninvertibleTransformExceptionSets this transform to the inverse of itself. The inverse transform Tx' of this transform Tx 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
getDeterminantmethod can be used to determine if this transform has no inverse, in which case an exception will be thrown if theinvertmethod is called. -
isIdentitytop
public boolean isIdentity()Returnstrueif thisAffineTransformis an identity transform. -
preConcatenatetop
public void preConcatenate(AffineTransform Tx)Concatenates anAffineTransformTxto thisAffineTransformCx in a less commonly used way such thatTxmodifies 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 byTxlike this: Cx'(p) = Tx(Cx(p)) In matrix notation, if this transform Cx is represented by the matrix [this] andTxis represented by the matrix [Tx] then this method does the following:[this] = [Tx] x [this] -
quadrantRotatetop
public void quadrantRotate(int numquadrants)Concatenates this transform with a transform that rotates coordinates by the specified number of quadrants. This is equivalent to calling:rotate(numquadrants * Math.PI / 2.0);Rotating by a positive number of quadrants rotates points on the positive X axis toward the positive Y axis. -
quadrantRotatetop
public void quadrantRotate(int numquadrants, double anchorx, double anchory)Concatenates this transform with a transform that rotates coordinates by the specified number of quadrants around the specified anchor point. This method is equivalent to calling:rotate(numquadrants * Math.PI / 2.0, anchorx, anchory);Rotating by a positive number of quadrants rotates points on the positive X axis toward the positive Y axis. -
readObjecttop
private void readObject(ObjectInputStream s) throws ClassNotFoundException, IOException -
rotatetop
public void rotate(double theta)Concatenates this transform with a rotation transformation. This is equivalent to calling concatenate(R), where R is anAffineTransformrepresented by the following matrix:[ cos(theta) -sin(theta) 0 ] [ sin(theta) cos(theta) 0 ] [ 0 0 1 ]Rotating by a positive angle theta rotates points on the positive X axis toward the positive Y axis. Note also the discussion of Handling 90-Degree Rotations above. -
rotatetop
public void rotate(double vecx, double vecy)Concatenates this transform with a transform that rotates coordinates according to a rotation vector. All coordinates rotate about the origin by the same amount. The amount of rotation is such that coordinates along the former positive X axis will subsequently align with the vector pointing from the origin to the specified vector coordinates. If bothvecxandvecyare 0.0, no additional rotation is added to this transform. This operation is equivalent to calling:rotate(Math.atan2(vecy, vecx)); -
rotatetop
public void rotate(double theta, double anchorx, double anchory)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(anchorx, anchory); // S3: final translation rotate(theta); // S2: rotate around anchor translate(-anchorx, -anchory); // S1: translate anchor to originRotating by a positive angle theta rotates points on the positive X axis toward the positive Y axis. Note also the discussion of Handling 90-Degree Rotations above. -
rotatetop
public void rotate(double vecx, double vecy, double anchorx, double anchory)Concatenates this transform with a transform that rotates coordinates around an anchor point according to a rotation vector. All coordinates rotate about the specified anchor coordinates by the same amount. The amount of rotation is such that coordinates along the former positive X axis will subsequently align with the vector pointing from the origin to the specified vector coordinates. If bothvecxandvecyare 0.0, the transform is not modified in any way. This method is equivalent to calling:rotate(Math.atan2(vecy, vecx), anchorx, anchory); -
rotate180top
final private void rotate180() -
rotate270top
final private void rotate270() -
rotate90top
final private void rotate90() -
scaletop
public void scale(double sx, double sy)Concatenates this transform with a scaling transformation. This is equivalent to calling concatenate(S), where S is anAffineTransformrepresented by the following matrix:[ sx 0 0 ] [ 0 sy 0 ] [ 0 0 1 ] -
setToIdentitytop
public void setToIdentity()Resets this transform to the Identity transform. -
setToQuadrantRotationtop
public void setToQuadrantRotation(int numquadrants)Sets this transform to a rotation transformation that rotates coordinates by the specified number of quadrants. This operation is equivalent to calling:setToRotation(numquadrants * Math.PI / 2.0);Rotating by a positive number of quadrants rotates points on the positive X axis toward the positive Y axis. -
setToQuadrantRotationtop
public void setToQuadrantRotation(int numquadrants, double anchorx, double anchory)Sets this transform to a translated rotation transformation that rotates coordinates by the specified number of quadrants around the specified anchor point. This operation is equivalent to calling:setToRotation(numquadrants * Math.PI / 2.0, anchorx, anchory);Rotating by a positive number of quadrants rotates points on the positive X axis toward the positive Y axis. -
setToRotationtop
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 by a positive angle theta rotates points on the positive X axis toward the positive Y axis. Note also the discussion of Handling 90-Degree Rotations above. -
setToRotationtop
public void setToRotation(double vecx, double vecy)Sets this transform to a rotation transformation that rotates coordinates according to a rotation vector. All coordinates rotate about the origin by the same amount. The amount of rotation is such that coordinates along the former positive X axis will subsequently align with the vector pointing from the origin to the specified vector coordinates. If bothvecxandvecyare 0.0, the transform is set to an identity transform. This operation is equivalent to calling:setToRotation(Math.atan2(vecy, vecx)); -
setToRotationtop
public void setToRotation(double theta, double anchorx, double anchory)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(anchorx, anchory); // S3: final translation rotate(theta); // S2: rotate around anchor translate(-anchorx, -anchory); // S1: translate anchor to originThe 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 by a positive angle theta rotates points on the positive X axis toward the positive Y axis. Note also the discussion of Handling 90-Degree Rotations above. -
setToRotationtop
public void setToRotation(double vecx, double vecy, double anchorx, double anchory)Sets this transform to a rotation transformation that rotates coordinates around an anchor point according to a rotation vector. All coordinates rotate about the specified anchor coordinates by the same amount. The amount of rotation is such that coordinates along the former positive X axis will subsequently align with the vector pointing from the origin to the specified vector coordinates. If bothvecxandvecyare 0.0, the transform is set to an identity transform. This operation is equivalent to calling:setToTranslation(Math.atan2(vecy, vecx), anchorx, anchory); -
setToScaletop
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 ] -
setToSheartop
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 ] -
setToTranslationtop
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 ] -
setTransformtop
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. -
setTransformtop
public void setTransform(AffineTransform Tx)Sets this transform to a copy of the transform in the specifiedAffineTransformobject. -
sheartop
public void shear(double shx, double shy)Concatenates this transform with a shearing transformation. This is equivalent to calling concatenate(SH), where SH is anAffineTransformrepresented by the following matrix:[ 1 shx 0 ] [ shy 1 0 ] [ 0 0 1 ] -
stateErrortop
private void stateError() -
toStringtop
public String toString()Returns aStringthat represents the value of this Object. -
transformtop
Transforms the specifiedptSrcand stores the result inptDst. IfptDstisnull, a new java.awt.geom.Point2D object is allocated and then the result of the transformation is stored in this object. In either case,ptDst, which contains the transformed point, is returned for convenience. IfptSrcandptDstare the same object, the input point is correctly overwritten with the transformed point. -
transformtop
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 can be exactly the same or can be overlapping sections of the same array without affecting the validity of the results. This method ensures that no source coordinates are 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]. -
transformtop
public void transform(double[] srcPts, int srcOff, float[] dstPts, int dstOff, int numPts)Transforms an array of double precision coordinates by this transform and stores the results into an array of floats. The coordinates are stored in the arrays starting at the specified offset in the order[x0, y0, x1, y1, ..., xn, yn]. -
transformtop
public void transform(float[] srcPts, int srcOff, double[] dstPts, int dstOff, int numPts)Transforms an array of floating point coordinates by this transform and stores the results into an array of doubles. The coordinates are stored in the arrays starting at the specified offset in the order[x0, y0, x1, y1, ..., xn, yn]. -
transformtop
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 can be exactly the same or can be overlapping sections of the same array without affecting the validity of the results. This method ensures that no source coordinates are overwritten by a previous operation before they can be transformed. The coordinates are stored in the arrays starting at the specified offset in the order[x0, y0, x1, y1, ..., xn, yn]. -
transformtop
Transforms an array of point objects by this transform. If any element of theptDstarray isnull, a newPoint2Dobject is allocated and stored into that element before storing the results of the transformation.Note that this method does not take any precautions to avoid problems caused by storing results into
Point2Dobjects that will be used as the source for calculations further down the source array. This method does guarantee that if a specifiedPoint2Dobject 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. If, however, the destinationPoint2Dobject for one operation is the same object as the sourcePoint2Dobject for another operation further down the source array then the original coordinates in that point are overwritten before they can be converted. -
translatetop
public void translate(double tx, double ty)Concatenates this transform with a translation transformation. This is equivalent to calling concatenate(T), where T is anAffineTransformrepresented by the following matrix:[ 1 0 tx ] [ 0 1 ty ] [ 0 0 1 ] -
updateStatetop
void updateState()Manually recalculates the state of the transform when the matrix changes too much to predict the effects on the state. The following table specifies what the various settings of the state field say about the values of the corresponding matrix element fields. Note that the rules governing the SCALE fields are slightly different depending on whether the SHEAR flag is also set.SCALE SHEAR TRANSLATE m00/m11 m01/m10 m02/m12 IDENTITY 1.0 0.0 0.0 TRANSLATE (TR) 1.0 0.0 not both 0.0 SCALE (SC) not both 1.0 0.0 0.0 TR | SC not both 1.0 0.0 not both 0.0 SHEAR (SH) 0.0 not both 0.0 0.0 TR | SH 0.0 not both 0.0 not both 0.0 SC | SH not both 0.0 not both 0.0 0.0 TR | SC | SH not both 0.0 not both 0.0 not both 0.0 -
writeObjecttop
private void writeObject(ObjectOutputStream s) throws ClassNotFoundException, IOException
Fields
-
APPLY_IDENTITY
static final int APPLY_IDENTITY = 0This constant is used for the internal state variable to indicate that no calculations need to be performed and that the source coordinates only need to be copied to their destinations to complete the transformation equation of this transform. -
APPLY_SCALE
static final int APPLY_SCALE = 2This constant is used for the internal state variable to indicate that the scaling components of the matrix (m00 and m11) need to be factored in to complete the transformation equation of this transform. If the APPLY_SHEAR bit is also set then it indicates that the scaling components are not both 0.0. If the APPLY_SHEAR bit is not also set then it indicates that the scaling components are not both 1.0. If neither the APPLY_SHEAR nor the APPLY_SCALE bits are set then the scaling components are both 1.0, which means that the x and y components contribute to the transformed coordinate, but they are not multiplied by any scaling factor. -
APPLY_SHEAR
static final int APPLY_SHEAR = 4This constant is used for the internal state variable to indicate that the shearing components of the matrix (m01 and m10) need to be factored in to complete the transformation equation of this transform. The presence of this bit in the state variable changes the interpretation of the APPLY_SCALE bit as indicated in its documentation. -
APPLY_TRANSLATE
static final int APPLY_TRANSLATE = 1This constant is used for the internal state variable to indicate that the translation components of the matrix (m02 and m12) need to be added to complete the transformation equation of this transform. -
HI_IDENTITY
static final private int HI_IDENTITY = 0 -
HI_SCALE
static final private int HI_SCALE = 16 -
HI_SHEAR
static final private int HI_SHEAR = 32 -
HI_SHIFT
static final private int HI_SHIFT = 3 -
HI_TRANSLATE
static final private int HI_TRANSLATE = 8 -
TYPE_FLIP
public static final int TYPE_FLIP = 64This 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. -
TYPE_GENERAL_ROTATION
public static final int TYPE_GENERAL_ROTATION = 16This 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 and without changing the length of the vector. This flag bit is mutually exclusive with the TYPE_QUADRANT_ROTATION flag. -
TYPE_GENERAL_SCALE
public static final int TYPE_GENERAL_SCALE = 4This 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. -
TYPE_GENERAL_TRANSFORM
public static final int TYPE_GENERAL_TRANSFORM = 32This 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. -
TYPE_IDENTITY
public static final int TYPE_IDENTITY = 0This 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. -
TYPE_MASK_ROTATION
public static final int TYPE_MASK_ROTATION = 24This constant is a bit mask for any of the rotation flag bits. -
TYPE_MASK_SCALE
public static final int TYPE_MASK_SCALE = 6This constant is a bit mask for any of the scale flag bits. -
TYPE_QUADRANT_ROTATION
public static final int TYPE_QUADRANT_ROTATION = 8This 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 and without changing the length of the vector. This flag bit is mutually exclusive with the TYPE_GENERAL_ROTATION flag. -
TYPE_TRANSLATION
public static final int TYPE_TRANSLATION = 1This 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. -
TYPE_UNIFORM_SCALE
public static final int TYPE_UNIFORM_SCALE = 2This 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. -
TYPE_UNKNOWN
static final private int TYPE_UNKNOWN = -1 -
m00
double m00The X coordinate scaling element of the 3x3 affine transformation matrix. -
m01
double m01The X coordinate shearing element of the 3x3 affine transformation matrix. -
m02
double m02The X coordinate of the translation element of the 3x3 affine transformation matrix. -
m10
double m10The Y coordinate shearing element of the 3x3 affine transformation matrix. -
m11
double m11The Y coordinate scaling element of the 3x3 affine transformation matrix. -
m12
double m12The Y coordinate of the translation element of the 3x3 affine transformation matrix. -
rot90conversion
static final private int[] rot90conversion -
serialVersionUID
static final private long serialVersionUID = 1330973210523860834 -
state
transient int stateThis field keeps track of which components of the matrix need to be applied when performing a transformation. -
type
transient private int typeThis field caches the current transformation type of the matrix.