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Matrix

public class Matrix
extends Object

java.lang.Object
↳	android.graphics.Matrix

The Matrix class holds a 3x3 matrix for transforming coordinates.

Summary

Nested classes
`enum`	`Matrix.ScaleToFit` Controls how the src rect should align into the dst rect for setRectToRect().

Constants
`int`	`MPERSP_0`
`int`	`MPERSP_1`
`int`	`MPERSP_2`
`int`	`MSCALE_X`
`int`	`MSCALE_Y`
`int`	`MSKEW_X`
`int`	`MSKEW_Y`
`int`	`MTRANS_X`
`int`	`MTRANS_Y`

Fields
`public static final Matrix`	`IDENTITY_MATRIX` The identity matrix.

Public constructors
`Matrix()` Create an identity matrix
`Matrix(Matrix src)` Create a matrix that is a (deep) copy of src

Public methods
`final void`	`dump(PrintWriter pw)` Dumps a human-readable shortened string of the matrix into the given stream
`boolean`	`equals(Object obj)` Returns true iff obj is a Matrix and its values equal our values.
`void`	`getValues(float[] values)` Copy 9 values from the matrix into the array.
`int`	`hashCode()` Returns a hash code value for the object.
`boolean`	`invert(Matrix inverse)` If this matrix can be inverted, return true and if inverse is not null, set inverse to be the inverse of this matrix.
`boolean`	`isAffine()` Gets whether this matrix is affine.
`boolean`	`isIdentity()` Returns true if the matrix is identity.
`void`	`mapPoints(float[] dst, int dstIndex, float[] src, int srcIndex, int pointCount)` Apply this matrix to the array of 2D points specified by src, and write the transformed points into the array of points specified by dst.
`void`	`mapPoints(float[] dst, float[] src)` Apply this matrix to the array of 2D points specified by src, and write the transformed points into the array of points specified by dst.
`void`	`mapPoints(float[] pts)` Apply this matrix to the array of 2D points, and write the transformed points back into the array
`float`	`mapRadius(float radius)` Return the mean radius of a circle after it has been mapped by this matrix.
`boolean`	`mapRect(RectF rect)` Apply this matrix to the rectangle, and write the transformed rectangle back into it.
`boolean`	`mapRect(RectF dst, RectF src)` Apply this matrix to the src rectangle, and write the transformed rectangle into dst.
`void`	`mapVectors(float[] vecs)` Apply this matrix to the array of 2D vectors, and write the transformed vectors back into the array.
`void`	`mapVectors(float[] dst, int dstIndex, float[] src, int srcIndex, int vectorCount)` Apply this matrix to the array of 2D vectors specified by src, and write the transformed vectors into the array of vectors specified by dst.
`void`	`mapVectors(float[] dst, float[] src)` Apply this matrix to the array of 2D vectors specified by src, and write the transformed vectors into the array of vectors specified by dst.
`boolean`	`postConcat(Matrix other)` Postconcats the matrix with the specified matrix.
`boolean`	`postRotate(float degrees, float px, float py)` Postconcats the matrix with the specified rotation.
`boolean`	`postRotate(float degrees)` Postconcats the matrix with the specified rotation.
`boolean`	`postScale(float sx, float sy, float px, float py)` Postconcats the matrix with the specified scale.
`boolean`	`postScale(float sx, float sy)` Postconcats the matrix with the specified scale.
`boolean`	`postSkew(float kx, float ky)` Postconcats the matrix with the specified skew.
`boolean`	`postSkew(float kx, float ky, float px, float py)` Postconcats the matrix with the specified skew.
`boolean`	`postTranslate(float dx, float dy)` Postconcats the matrix with the specified translation.
`boolean`	`preConcat(Matrix other)` Preconcats the matrix with the specified matrix.
`boolean`	`preRotate(float degrees)` Preconcats the matrix with the specified rotation.
`boolean`	`preRotate(float degrees, float px, float py)` Preconcats the matrix with the specified rotation.
`boolean`	`preScale(float sx, float sy)` Preconcats the matrix with the specified scale.
`boolean`	`preScale(float sx, float sy, float px, float py)` Preconcats the matrix with the specified scale.
`boolean`	`preSkew(float kx, float ky)` Preconcats the matrix with the specified skew.
`boolean`	`preSkew(float kx, float ky, float px, float py)` Preconcats the matrix with the specified skew.
`boolean`	`preTranslate(float dx, float dy)` Preconcats the matrix with the specified translation.
`boolean`	`rectStaysRect()` Returns true if will map a rectangle to another rectangle.
`void`	`reset()` Set the matrix to identity
`void`	`set(Matrix src)` (deep) copy the src matrix into this matrix.
`boolean`	`setConcat(Matrix a, Matrix b)` Set the matrix to the concatenation of the two specified matrices and return true.
`boolean`	`setPolyToPoly(float[] src, int srcIndex, float[] dst, int dstIndex, int pointCount)` Set the matrix such that the specified src points would map to the specified dst points.
`boolean`	`setRectToRect(RectF src, RectF dst, Matrix.ScaleToFit stf)` Set the matrix to the scale and translate values that map the source rectangle to the destination rectangle, returning true if the the result can be represented.
`void`	`setRotate(float degrees, float px, float py)` Set the matrix to rotate by the specified number of degrees, with a pivot point at (px, py).
`void`	`setRotate(float degrees)` Set the matrix to rotate about (0,0) by the specified number of degrees.
`void`	`setScale(float sx, float sy)` Set the matrix to scale by sx and sy.
`void`	`setScale(float sx, float sy, float px, float py)` Set the matrix to scale by sx and sy, with a pivot point at (px, py).
`void`	`setSinCos(float sinValue, float cosValue, float px, float py)` Set the matrix to rotate by the specified sine and cosine values, with a pivot point at (px, py).
`void`	`setSinCos(float sinValue, float cosValue)` Set the matrix to rotate by the specified sine and cosine values.
`void`	`setSkew(float kx, float ky)` Set the matrix to skew by sx and sy.
`void`	`setSkew(float kx, float ky, float px, float py)` Set the matrix to skew by sx and sy, with a pivot point at (px, py).
`void`	`setTranslate(float dx, float dy)` Set the matrix to translate by (dx, dy).
`void`	`setValues(float[] values)` Copy 9 values from the array into the matrix.
`String`	`toShortString()`
`String`	`toString()` Returns a string representation of the object.

Inherited methods

From class


        
          java.lang.Object

`Object`	`clone()` Creates and returns a copy of this object.
`boolean`	`equals(Object obj)` Indicates whether some other object is "equal to" this one.
`void`	`finalize()` Called by the garbage collector on an object when garbage collection determines that there are no more references to the object.
`final Class<?>`	`getClass()` Returns the runtime class of this `Object`.
`int`	`hashCode()` Returns a hash code value for the object.
`final void`	`notify()` Wakes up a single thread that is waiting on this object's monitor.
`final void`	`notifyAll()` Wakes up all threads that are waiting on this object's monitor.
`String`	`toString()` Returns a string representation of the object.
`final void`	`wait(long timeout, int nanos)` Causes the current thread to wait until another thread invokes the `notify()` method or the `notifyAll()` method for this object, or some other thread interrupts the current thread, or a certain amount of real time has elapsed.
`final void`	`wait(long timeout)` Causes the current thread to wait until either another thread invokes the `notify()` method or the `notifyAll()` method for this object, or a specified amount of time has elapsed.
`final void`	`wait()` Causes the current thread to wait until another thread invokes the `notify()` method or the `notifyAll()` method for this object.

Constants

MPERSP_0

public static final int MPERSP_0

Constant Value: 6 (0x00000006)

MPERSP_1

public static final int MPERSP_1

Constant Value: 7 (0x00000007)

MPERSP_2

public static final int MPERSP_2

Constant Value: 8 (0x00000008)

MSCALE_X

public static final int MSCALE_X

Constant Value: 0 (0x00000000)

MSCALE_Y

public static final int MSCALE_Y

Constant Value: 4 (0x00000004)

MSKEW_X

public static final int MSKEW_X

Constant Value: 1 (0x00000001)

MSKEW_Y

public static final int MSKEW_Y

Constant Value: 3 (0x00000003)

MTRANS_X

public static final int MTRANS_X

Constant Value: 2 (0x00000002)

MTRANS_Y

public static final int MTRANS_Y

Constant Value: 5 (0x00000005)

Fields

IDENTITY_MATRIX

public static final Matrix IDENTITY_MATRIX

The identity matrix. Multiplying by another matrix M returns M. This matrix is immutable, and attempting to modify it will throw an IllegalStateException.

Public constructors

Matrix

public Matrix ()

Create an identity matrix

Matrix

public Matrix (Matrix src)

Create a matrix that is a (deep) copy of src

Parameters
`src`	`Matrix`: The matrix to copy into this matrix

Public methods

dump

public final void dump (PrintWriter pw)

Dumps a human-readable shortened string of the matrix into the given stream

Parameters
`pw`	`PrintWriter`: The `PrintWriter` into which the string representation of the matrix will be written. This value cannot be `null`.

equals

public boolean equals (Object obj)

Returns true iff obj is a Matrix and its values equal our values.

Parameters
`obj`	`Object`: the reference object with which to compare.

Returns
`boolean`	`true` if this object is the same as the obj argument; `false` otherwise.

getValues

public void getValues (float[] values)

Copy 9 values from the matrix into the array.

Parameters
`values`	`float`

hashCode

public int hashCode ()

Returns a hash code value for the object. This method is supported for the benefit of hash tables such as those provided by HashMap.

The general contract of hashCode is:

Whenever it is invoked on the same object more than once during an execution of a Java application, the hashCode method must consistently return the same integer, provided no information used in equals comparisons on the object is modified. This integer need not remain consistent from one execution of an application to another execution of the same application.
If two objects are equal according to the equals(Object) method, then calling the hashCode method on each of the two objects must produce the same integer result.
It is not required that if two objects are unequal according to the equals(java.lang.Object) method, then calling the hashCode method on each of the two objects must produce distinct integer results. However, the programmer should be aware that producing distinct integer results for unequal objects may improve the performance of hash tables.

As much as is reasonably practical, the hashCode method defined by class Object does return distinct integers for distinct objects. (This is typically implemented by converting the internal address of the object into an integer, but this implementation technique is not required by the Java™ programming language.)

Returns
`int`	a hash code value for this object.

invert

public boolean invert (Matrix inverse)

If this matrix can be inverted, return true and if inverse is not null, set inverse to be the inverse of this matrix. If this matrix cannot be inverted, ignore inverse and return false.

Parameters
`inverse`	`Matrix`

Returns
`boolean`

isAffine

public boolean isAffine ()

Gets whether this matrix is affine. An affine matrix preserves straight lines and has no perspective.

Returns
`boolean`	Whether the matrix is affine.

isIdentity

public boolean isIdentity ()

Returns true if the matrix is identity. This maybe faster than testing if (getType() == 0)

Returns
`boolean`

mapPoints

public void mapPoints (float[] dst, 
                int dstIndex, 
                float[] src, 
                int srcIndex, 
                int pointCount)

Apply this matrix to the array of 2D points specified by src, and write the transformed points into the array of points specified by dst. The two arrays represent their "points" as pairs of floats [x, y].

Parameters
`dst`	`float`: The array of dst points (x,y pairs)
`dstIndex`	`int`: The index of the first [x,y] pair of dst floats
`src`	`float`: The array of src points (x,y pairs)
`srcIndex`	`int`: The index of the first [x,y] pair of src floats
`pointCount`	`int`: The number of points (x,y pairs) to transform

mapPoints

public void mapPoints (float[] dst, 
                float[] src)

Parameters
`dst`	`float`: The array of dst points (x,y pairs)
`src`	`float`: The array of src points (x,y pairs)

mapPoints

public void mapPoints (float[] pts)

Apply this matrix to the array of 2D points, and write the transformed points back into the array

Parameters
`pts`	`float`: The array [x0, y0, x1, y1, ...] of points to transform.

mapRadius

public float mapRadius (float radius)

Return the mean radius of a circle after it has been mapped by this matrix. NOTE: in perspective this value assumes the circle has its center at the origin.

Parameters
`radius`	`float`

Returns
`float`

mapRect

public boolean mapRect (RectF rect)

Apply this matrix to the rectangle, and write the transformed rectangle back into it. This is accomplished by transforming the 4 corners of rect, and then setting it to the bounds of those points

Parameters
`rect`	`RectF`: The rectangle to transform.

Returns
`boolean`	the result of calling rectStaysRect()

mapRect

public boolean mapRect (RectF dst, 
                RectF src)

Apply this matrix to the src rectangle, and write the transformed rectangle into dst. This is accomplished by transforming the 4 corners of src, and then setting dst to the bounds of those points.

Parameters
`dst`	`RectF`: Where the transformed rectangle is written.
`src`	`RectF`: The original rectangle to be transformed.

Returns
`boolean`	the result of calling rectStaysRect()

mapVectors

public void mapVectors (float[] vecs)

Apply this matrix to the array of 2D vectors, and write the transformed vectors back into the array. Note: this method does not apply the translation associated with the matrix. Use Matrix#mapPoints(float[]) if you want the translation to be applied.

Parameters
`vecs`	`float`: The array [x0, y0, x1, y1, ...] of vectors to transform.

mapVectors

public void mapVectors (float[] dst, 
                int dstIndex, 
                float[] src, 
                int srcIndex, 
                int vectorCount)

Apply this matrix to the array of 2D vectors specified by src, and write the transformed vectors into the array of vectors specified by dst. The two arrays represent their "vectors" as pairs of floats [x, y]. Note: this method does not apply the translation associated with the matrix. Use Matrix#mapPoints(float[], int, float[], int, int) if you want the translation to be applied.

Parameters
`dst`	`float`: The array of dst vectors (x,y pairs)
`dstIndex`	`int`: The index of the first [x,y] pair of dst floats
`src`	`float`: The array of src vectors (x,y pairs)
`srcIndex`	`int`: The index of the first [x,y] pair of src floats
`vectorCount`	`int`: The number of vectors (x,y pairs) to transform

mapVectors

public void mapVectors (float[] dst, 
                float[] src)

Apply this matrix to the array of 2D vectors specified by src, and write the transformed vectors into the array of vectors specified by dst. The two arrays represent their "vectors" as pairs of floats [x, y]. Note: this method does not apply the translation associated with the matrix. Use Matrix#mapPoints(float[], float[]) if you want the translation to be applied.

Parameters
`dst`	`float`: The array of dst vectors (x,y pairs)
`src`	`float`: The array of src vectors (x,y pairs)

postConcat

public boolean postConcat (Matrix other)

Postconcats the matrix with the specified matrix. M' = other * M

Parameters
`other`	`Matrix`

Returns
`boolean`

postRotate

public boolean postRotate (float degrees, 
                float px, 
                float py)

Postconcats the matrix with the specified rotation. M' = R(degrees, px, py) * M

Parameters
`degrees`	`float`
`px`	`float`
`py`	`float`

Returns
`boolean`

postRotate

public boolean postRotate (float degrees)

Postconcats the matrix with the specified rotation. M' = R(degrees) * M

Parameters
`degrees`	`float`

Returns
`boolean`

postScale

public boolean postScale (float sx, 
                float sy, 
                float px, 
                float py)

Postconcats the matrix with the specified scale. M' = S(sx, sy, px, py) * M

Parameters
`sx`	`float`
`sy`	`float`
`px`	`float`
`py`	`float`

Returns
`boolean`

postScale

public boolean postScale (float sx, 
                float sy)

Postconcats the matrix with the specified scale. M' = S(sx, sy) * M

Parameters
`sx`	`float`
`sy`	`float`

Returns
`boolean`

postSkew

public boolean postSkew (float kx, 
                float ky)

Postconcats the matrix with the specified skew. M' = K(kx, ky) * M

Parameters
`kx`	`float`
`ky`	`float`

Returns
`boolean`

postSkew

public boolean postSkew (float kx, 
                float ky, 
                float px, 
                float py)

Postconcats the matrix with the specified skew. M' = K(kx, ky, px, py) * M

Parameters
`kx`	`float`
`ky`	`float`
`px`	`float`
`py`	`float`

Returns
`boolean`

postTranslate

public boolean postTranslate (float dx, 
                float dy)

Postconcats the matrix with the specified translation. M' = T(dx, dy) * M

Parameters
`dx`	`float`
`dy`	`float`

Returns
`boolean`

preConcat

public boolean preConcat (Matrix other)

Preconcats the matrix with the specified matrix. M' = M * other

Parameters
`other`	`Matrix`

Returns
`boolean`

preRotate

public boolean preRotate (float degrees)

Preconcats the matrix with the specified rotation. M' = M * R(degrees)

Parameters
`degrees`	`float`

Returns
`boolean`

preRotate

public boolean preRotate (float degrees, 
                float px, 
                float py)

Preconcats the matrix with the specified rotation. M' = M * R(degrees, px, py)

Parameters
`degrees`	`float`
`px`	`float`
`py`	`float`

Returns
`boolean`

preScale

public boolean preScale (float sx, 
                float sy)

Preconcats the matrix with the specified scale. M' = M * S(sx, sy)

Parameters
`sx`	`float`
`sy`	`float`

Returns
`boolean`

preScale

public boolean preScale (float sx, 
                float sy, 
                float px, 
                float py)

Preconcats the matrix with the specified scale. M' = M * S(sx, sy, px, py)

Parameters
`sx`	`float`
`sy`	`float`
`px`	`float`
`py`	`float`

Returns
`boolean`

preSkew

public boolean preSkew (float kx, 
                float ky)

Preconcats the matrix with the specified skew. M' = M * K(kx, ky)

Parameters
`kx`	`float`
`ky`	`float`

Returns
`boolean`

preSkew

public boolean preSkew (float kx, 
                float ky, 
                float px, 
                float py)

Preconcats the matrix with the specified skew. M' = M * K(kx, ky, px, py)

Parameters
`kx`	`float`
`ky`	`float`
`px`	`float`
`py`	`float`

Returns
`boolean`

preTranslate

public boolean preTranslate (float dx, 
                float dy)

Preconcats the matrix with the specified translation. M' = M * T(dx, dy)

Parameters
`dx`	`float`
`dy`	`float`

Returns
`boolean`

rectStaysRect

public boolean rectStaysRect ()

Returns true if will map a rectangle to another rectangle. This can be true if the matrix is identity, scale-only, or rotates a multiple of 90 degrees.

Returns
`boolean`

reset

public void reset ()

Set the matrix to identity

set

public void set (Matrix src)

(deep) copy the src matrix into this matrix. If src is null, reset this matrix to the identity matrix.

Parameters
`src`	`Matrix`

setConcat

public boolean setConcat (Matrix a, 
                Matrix b)

Set the matrix to the concatenation of the two specified matrices and return true.

Either of the two matrices may also be the target matrix, that is matrixA.setConcat(matrixA, matrixB); is valid.

In Build.VERSION_CODES.GINGERBREAD_MR1 and below, this function returns true only if the result can be represented. In Build.VERSION_CODES.HONEYCOMB and above, it always returns true.

Parameters
`a`	`Matrix`
`b`	`Matrix`

Returns
`boolean`

setPolyToPoly

public boolean setPolyToPoly (float[] src, 
                int srcIndex, 
                float[] dst, 
                int dstIndex, 
                int pointCount)

Set the matrix such that the specified src points would map to the specified dst points. The "points" are represented as an array of floats, order [x0, y0, x1, y1, ...], where each "point" is 2 float values.

Parameters
`src`	`float`: The array of src [x,y] pairs (points)
`srcIndex`	`int`: Index of the first pair of src values
`dst`	`float`: The array of dst [x,y] pairs (points)
`dstIndex`	`int`: Index of the first pair of dst values
`pointCount`	`int`: The number of pairs/points to be used. Must be [0..4]

Returns
`boolean`	true if the matrix was set to the specified transformation

setRectToRect

public boolean setRectToRect (RectF src, 
                RectF dst, 
                Matrix.ScaleToFit stf)

Set the matrix to the scale and translate values that map the source rectangle to the destination rectangle, returning true if the the result can be represented.

Parameters
`src`	`RectF`: the source rectangle to map from.
`dst`	`RectF`: the destination rectangle to map to.
`stf`	`Matrix.ScaleToFit`: the ScaleToFit option

Returns
`boolean`	true if the matrix can be represented by the rectangle mapping.

setRotate

public void setRotate (float degrees, 
                float px, 
                float py)

Set the matrix to rotate by the specified number of degrees, with a pivot point at (px, py). The pivot point is the coordinate that should remain unchanged by the specified transformation.

Parameters
`degrees`	`float`
`px`	`float`
`py`	`float`

setRotate

public void setRotate (float degrees)

Set the matrix to rotate about (0,0) by the specified number of degrees.

Parameters
`degrees`	`float`

setScale

public void setScale (float sx, 
                float sy)

Set the matrix to scale by sx and sy.

Parameters
`sx`	`float`
`sy`	`float`

setScale

public void setScale (float sx, 
                float sy, 
                float px, 
                float py)

Set the matrix to scale by sx and sy, with a pivot point at (px, py). The pivot point is the coordinate that should remain unchanged by the specified transformation.

Parameters
`sx`	`float`
`sy`	`float`
`px`	`float`
`py`	`float`

setSinCos

public void setSinCos (float sinValue, 
                float cosValue, 
                float px, 
                float py)

Set the matrix to rotate by the specified sine and cosine values, with a pivot point at (px, py). The pivot point is the coordinate that should remain unchanged by the specified transformation.

Parameters
`sinValue`	`float`
`cosValue`	`float`
`px`	`float`
`py`	`float`

setSinCos

public void setSinCos (float sinValue, 
                float cosValue)

Set the matrix to rotate by the specified sine and cosine values.

Parameters
`sinValue`	`float`
`cosValue`	`float`

setSkew

public void setSkew (float kx, 
                float ky)

Set the matrix to skew by sx and sy.

Parameters
`kx`	`float`
`ky`	`float`

setSkew

public void setSkew (float kx, 
                float ky, 
                float px, 
                float py)

Set the matrix to skew by sx and sy, with a pivot point at (px, py). The pivot point is the coordinate that should remain unchanged by the specified transformation.

Parameters
`kx`	`float`
`ky`	`float`
`px`	`float`
`py`	`float`

setTranslate

public void setTranslate (float dx, 
                float dy)

Set the matrix to translate by (dx, dy).

Parameters
`dx`	`float`
`dy`	`float`

setValues

public void setValues (float[] values)

Copy 9 values from the array into the matrix. Depending on the implementation of Matrix, these may be transformed into 16.16 integers in the Matrix, such that a subsequent call to getValues() will not yield exactly the same values.

Parameters
`values`	`float`

toShortString

public String toShortString ()

Returns
`String`

toString

public String toString ()

Returns a string representation of the object. In general, the toString method returns a string that "textually represents" this object. The result should be a concise but informative representation that is easy for a person to read. It is recommended that all subclasses override this method.

The toString method for class Object returns a string consisting of the name of the class of which the object is an instance, the at-sign character `@', and the unsigned hexadecimal representation of the hash code of the object. In other words, this method returns a string equal to the value of:

 getClass().getName() + '@' + Integer.toHexString(hashCode())

Returns
`String`	a string representation of the object.

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Matrix

Summary

Nested classes

Constants

Fields

Public constructors

Public methods

Inherited methods

Constants

MPERSP_0

MPERSP_1

MPERSP_2

MSCALE_X

MSCALE_Y

MSKEW_X

MSKEW_Y

MTRANS_X

MTRANS_Y

Fields

IDENTITY_MATRIX

Public constructors

Matrix

Matrix

Public methods

dump

equals

getValues

hashCode

invert

isAffine

isIdentity

mapPoints

mapPoints

mapPoints

mapRadius

mapRect

mapRect

mapVectors

mapVectors

mapVectors

postConcat

postRotate

postRotate

postScale

postScale

postSkew

postSkew

postTranslate

preConcat

preRotate

preRotate

preScale

preScale

preSkew

preSkew

preTranslate

rectStaysRect

reset

set

setConcat

setPolyToPoly

setRectToRect

setRotate

setRotate

setScale

setScale

setSinCos

setSinCos

setSkew

setSkew

setTranslate

setValues

toShortString

toString