Package com.leia.core

Class MatrixUtils

java.lang.Object

com.leia.core.MatrixUtils

public class MatrixUtils
extends Object

MatrixUtils is a collection of functions for various matrix operations.

Android provides two matrix representations, Matrix and Matrix, MatrixUtils provides methods to convert between the two.

MatrixUtils also provides matrix routines needed for pinch-to-zoom and pan gesture support. This includes a helper function to return a matrix for different ScaleTypes.

Constructor Summary

Constructors

Constructor	Description
MatrixUtils()

Method Summary

Modifier and Type	Method	Description
static float[]	FromMatrix(Matrix matrixIn)	Convert a 3x3 Matrix to a 4x4 Matrix.
static Matrix	GetScaleTypeMatrix(ScaleType scaleType, RectF srcRect, RectF destRect)	Returns a Matrix to transform srcRect to destRect given a specific scaleType.
static Matrix	getTranslationMatrix(InterlacedView view, Matrix scaleTypeMatrix, Matrix localMatrix, float panX, float panY, boolean applyLimits)	Returns a Matrix to translate the contents of a view.
static float[]	getTranslationTransform(InterlacedView view, float[] rectMatrix, float[] localMatrix, float panX, float panY, boolean applyLimits)	Returns an Matrix to translate the contents of a view.
static float[]	getTranslationTransform(InterlacedView view, float panX, float panY, boolean applyLimits)	Returns an Matrix to translate the contents of a view.
static Matrix	getZoomMatrix(InterlacedView view, Matrix scaleTypeMatrix, Matrix localMatrix, float scaleX, float scaleY, float focusX, float focusY, boolean applyLimits)	Returns a Matrix to zoom around a point.
static float[]	getZoomTransform(InterlacedView view, float[] rectMatrix, float[] localMatrix, float scaleX, float scaleY, float focusX, float focusY, boolean applyLimits)	Returns an Matrix to zoom around a point.
static float[]	getZoomTransform(InterlacedView view, float scaleX, float scaleY, float focusX, float focusY, boolean applyLimits)	Returns an Matrix to zoom around a point.
static Matrix	ToMatrix(float[] matrixIn)	Convert a 4x4 Matrix to a 3x3 Matrix.
static PointF	transformPoint(float[] matrix, PointF point)	Returns a 2D point transformed by a matrix.
static PointF	transformPoint(float[] matrix, PointF point, float w)	Returns a 2D point or vector transformed by a matrix.
static PointF	transformVector(float[] matrix, PointF vector)	Returns a 2D vector transformed by a matrix.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

MatrixUtils

public MatrixUtils()

Method Detail

GetScaleTypeMatrix

public static Matrix GetScaleTypeMatrix(ScaleType scaleType,
                                        RectF srcRect,
                                        RectF destRect)

Returns a Matrix to transform srcRect to destRect given a specific scaleType.

Parameters:

scaleType - how to fit srcRect into destRect [FILL | FIT_CENTER | CROP_FILL]

srcRect - source rectangle (e.g. the image)

destRect - destination rectangle (e.g. the view)

getZoomTransform

public static float[] getZoomTransform(InterlacedView view,
                                       float[] rectMatrix,
                                       float[] localMatrix,
                                       float scaleX,
                                       float scaleY,
                                       float focusX,
                                       float focusY,
                                       boolean applyLimits)

Returns an Matrix to zoom around a point.

Parameters:

view - the interlaced view being transformed

rectMatrix - the scaleType matrix used by the view

localMatrix - the current zoom/pan transform

scaleX - x scale factor

scaleY - y scale factor

focusX - the x coordinate of the point to zoom around

focusY - the y coordinate of the point to zoom around

applyLimits - limit the transform to the edges of the view

getZoomTransform

public static float[] getZoomTransform(InterlacedView view,
                                       float scaleX,
                                       float scaleY,
                                       float focusX,
                                       float focusY,
                                       boolean applyLimits)

Returns an Matrix to zoom around a point.
(Convenience method with fewer arguments, using view to get localMatrix and rectMatrix.)

Parameters:

view - the interlaced view being transformed

scaleX - x scale factor

scaleY - y scale factor

focusX - the x coordinate of the point to zoom around

focusY - the y coordinate of the point to zoom around

applyLimits - limit the transform to the edges of the view

getZoomMatrix

public static Matrix getZoomMatrix(InterlacedView view,
                                   Matrix scaleTypeMatrix,
                                   Matrix localMatrix,
                                   float scaleX,
                                   float scaleY,
                                   float focusX,
                                   float focusY,
                                   boolean applyLimits)

Returns a Matrix to zoom around a point.

Parameters:

view - the interlaced view being transformed

scaleTypeMatrix - the scaleType matrix used by the view

localMatrix - the current zoom/pan transform

scaleX - x scale factor

scaleY - y scale factor

focusX - the x coordinate of the point to zoom around

focusY - the y coordinate of the point to zoom around

applyLimits - limit the transform to the edges of the view

getTranslationTransform

public static float[] getTranslationTransform(InterlacedView view,
                                              float[] rectMatrix,
                                              float[] localMatrix,
                                              float panX,
                                              float panY,
                                              boolean applyLimits)

Returns an Matrix to translate the contents of a view.

Parameters:

view - the interlaced view being transformed

rectMatrix - the scaleType matrix used by the view

localMatrix - the current zoom/pan transform

panX - x translation distance

panY - y translation distance

applyLimits - limit the transform to the edges of the view

getTranslationTransform

public static float[] getTranslationTransform(InterlacedView view,
                                              float panX,
                                              float panY,
                                              boolean applyLimits)

Returns an Matrix to translate the contents of a view.
(Convenience method with fewer arguments, using view to get localMatrix and rectMatrix.)

Parameters:

view - the interlaced view being transformed

panX - x translation distance

panY - y translation distance

applyLimits - limit the transform to the edges of the view

getTranslationMatrix

public static Matrix getTranslationMatrix(InterlacedView view,
                                          Matrix scaleTypeMatrix,
                                          Matrix localMatrix,
                                          float panX,
                                          float panY,
                                          boolean applyLimits)

Returns a Matrix to translate the contents of a view.

Parameters:

view - the interlaced view being transformed

scaleTypeMatrix - the scaleType matrix used by the view

localMatrix - the current zoom/pan transform

panX - x translation distance

panY - y translation distance

applyLimits - limit the transform to the edges of the view

transformPoint

public static PointF transformPoint(float[] matrix,
                                    @NonNull
                                    PointF point)

Returns a 2D point transformed by a matrix.

Parameters:

matrix - a 4x4 transform matrix

point - a 2D point to transform

transformPoint

public static PointF transformPoint(float[] matrix,
                                    @NonNull
                                    PointF point,
                                    float w)

Returns a 2D point or vector transformed by a matrix.

Parameters:

matrix - a 4x4 transform matrix

point - a 2D point/vector to transform

w - the w value for (point.x, point.y, 0, w) used for transforming the point/vector

transformVector

public static PointF transformVector(float[] matrix,
                                     @NonNull
                                     PointF vector)

Returns a 2D vector transformed by a matrix.

Parameters:

matrix - a 4x4 transform matrix

vector - a 2D vector to transform

ToMatrix

public static Matrix ToMatrix(float[] matrixIn)

Convert a 4x4 Matrix to a 3x3 Matrix.

Parameters:

matrixIn - a 4x4 Matrix

FromMatrix

public static float[] FromMatrix(Matrix matrixIn)

Convert a 3x3 Matrix to a 4x4 Matrix.

Parameters:

matrixIn - a 3x3 Matrix