affinetransform.java

Hecl编程语言是一个高层次的脚本语言的Java实现。其用意是要小

/*
 * Copyright (C) 2005, 2006 data2c GmbH (www.data2c.com)
 *
 * Author: Wolfgang S. Kechel - [e-mail]
 * 
 * J2ME version of java.awt.geom.AffineTransform.
 */

//#ifndef j2se
package org.awt.geom;

//#ifdef notdef
import java.awt.Shape;
//#endif

/**
 * The <code>AffineTransform</code> 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.
 * <p>
 * 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 <code>(x,&nbsp;y)</code> into
 * destination coordinates <code>(x',&nbsp;y')</code> by considering
 * them to be a column vector and multiplying the coordinate vector
 * by the matrix according to the following process:
 * <pre>
 *	[ x']   [  m00  m01  m02  ] [ x ]   [ m00x + m01y + m02 ]
 *	[ y'] = [  m10  m11  m12  ] [ y ] = [ m10x + m11y + m12 ]
 *	[ 1 ]   [   0    0    1   ] [ 1 ]   [         1         ]
 * </pre>
 */
public class AffineTransform /*implements Cloneable, java.io.Serializable*/ {
    /*
     * This constant is only useful for the cached type field.
     * It indicates that the type has been decached and must be recalculated.
     */
    private static final int TYPE_UNKNOWN = -1;

    /**
     * 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 #TYPE_TRANSLATION
     * @see #TYPE_UNIFORM_SCALE
     * @see #TYPE_GENERAL_SCALE
     * @see #TYPE_FLIP
     * @see #TYPE_QUADRANT_ROTATION
     * @see #TYPE_GENERAL_ROTATION
     * @see #TYPE_GENERAL_TRANSFORM
     * @see #getType
     */
    public static final int TYPE_IDENTITY = 0;

    /**
     * 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 #TYPE_IDENTITY
     * @see #TYPE_UNIFORM_SCALE
     * @see #TYPE_GENERAL_SCALE
     * @see #TYPE_FLIP
     * @see #TYPE_QUADRANT_ROTATION
     * @see #TYPE_GENERAL_ROTATION
     * @see #TYPE_GENERAL_TRANSFORM
     * @see #getType
     */
    public static final int TYPE_TRANSLATION = 1;

    /**
     * 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 #TYPE_IDENTITY
     * @see #TYPE_TRANSLATION
     * @see #TYPE_GENERAL_SCALE
     * @see #TYPE_FLIP
     * @see #TYPE_QUADRANT_ROTATION
     * @see #TYPE_GENERAL_ROTATION
     * @see #TYPE_GENERAL_TRANSFORM
     * @see #getType
     */
    public static final int TYPE_UNIFORM_SCALE = 2;

    /**
     * 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 #TYPE_IDENTITY
     * @see #TYPE_TRANSLATION
     * @see #TYPE_UNIFORM_SCALE
     * @see #TYPE_FLIP
     * @see #TYPE_QUADRANT_ROTATION
     * @see #TYPE_GENERAL_ROTATION
     * @see #TYPE_GENERAL_TRANSFORM
     * @see #getType
     */
    public static final int TYPE_GENERAL_SCALE = 4;

    /**
     * This constant is a bit mask for any of the scale flag bits.
     * @see #TYPE_UNIFORM_SCALE
     * @see #TYPE_GENERAL_SCALE
     */
    public static final int TYPE_MASK_SCALE = (TYPE_UNIFORM_SCALE |
					       TYPE_GENERAL_SCALE);

    /**
     * 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 #TYPE_IDENTITY
     * @see #TYPE_TRANSLATION
     * @see #TYPE_UNIFORM_SCALE
     * @see #TYPE_GENERAL_SCALE
     * @see #TYPE_QUADRANT_ROTATION
     * @see #TYPE_GENERAL_ROTATION
     * @see #TYPE_GENERAL_TRANSFORM
     * @see #getType
     */
    public static final int TYPE_FLIP = 64;
    /* NOTE: TYPE_FLIP was added after GENERAL_TRANSFORM was in public
     * circulation and the flag bits could no longer be conveniently
     * renumbered without introducing binary incompatibility in outside
     * code.
     */

    /**
     * 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 and without
     * changing the length of the vector.
     * This flag bit is mutually exclusive with the TYPE_GENERAL_ROTATION flag.
     * @see #TYPE_IDENTITY
     * @see #TYPE_TRANSLATION
     * @see #TYPE_UNIFORM_SCALE
     * @see #TYPE_GENERAL_SCALE
     * @see #TYPE_FLIP
     * @see #TYPE_GENERAL_ROTATION
     * @see #TYPE_GENERAL_TRANSFORM
     * @see #getType
     */
    public static final int TYPE_QUADRANT_ROTATION = 8;

    /**
     * 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 and without
     * changing the length of the vector.
     * This flag bit is mutually exclusive with the
     * TYPE_QUADRANT_ROTATION flag.
     * @see #TYPE_IDENTITY
     * @see #TYPE_TRANSLATION
     * @see #TYPE_UNIFORM_SCALE
     * @see #TYPE_GENERAL_SCALE
     * @see #TYPE_FLIP
     * @see #TYPE_QUADRANT_ROTATION
     * @see #TYPE_GENERAL_TRANSFORM
     * @see #getType
     */
    public static final int TYPE_GENERAL_ROTATION = 16;

    /**
     * This constant is a bit mask for any of the rotation flag bits.
     * @see #TYPE_QUADRANT_ROTATION
     * @see #TYPE_GENERAL_ROTATION
     */
    public static final int TYPE_MASK_ROTATION = (TYPE_QUADRANT_ROTATION |
						  TYPE_GENERAL_ROTATION);

    /**
     * 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 #TYPE_IDENTITY
     * @see #TYPE_TRANSLATION
     * @see #TYPE_UNIFORM_SCALE
     * @see #TYPE_GENERAL_SCALE
     * @see #TYPE_FLIP
     * @see #TYPE_QUADRANT_ROTATION
     * @see #TYPE_GENERAL_ROTATION
     * @see #getType
     */
    public static final int TYPE_GENERAL_TRANSFORM = 32;

    /**
     * This 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.
     * @see #APPLY_TRANSLATE
     * @see #APPLY_SCALE
     * @see #APPLY_SHEAR
     * @see #state
     */
    static final int APPLY_IDENTITY = 0;

    /**
     * This 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.
     * @see #APPLY_IDENTITY
     * @see #APPLY_SCALE
     * @see #APPLY_SHEAR
     * @see #state
     */
    static final int APPLY_TRANSLATE = 1;

    /**
     * This 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.
     * @see #APPLY_IDENTITY
     * @see #APPLY_TRANSLATE
     * @see #APPLY_SHEAR
     * @see #state
     */
    static final int APPLY_SCALE = 2;

    /**
     * This 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.
     * @see #APPLY_IDENTITY
     * @see #APPLY_TRANSLATE
     * @see #APPLY_SCALE
     * @see #state
     */
    static final int APPLY_SHEAR = 4;

    /*
     * For methods which combine together the state of two separate
     * transforms and dispatch based upon the combination, these constants
     * specify how far to shift one of the states so that the two states 
     * are mutually non-interfering and provide constants for testing the
     * bits of the shifted (HI) state.  The methods in this class use
     * the convention that the state of "this" transform is unshifted and
     * the state of the "other" or "argument" transform is shifted (HI).
     */
    private static final int HI_SHIFT = 3;
    private static final int HI_IDENTITY = APPLY_IDENTITY << HI_SHIFT;
    private static final int HI_TRANSLATE = APPLY_TRANSLATE << HI_SHIFT;
    private static final int HI_SCALE = APPLY_SCALE << HI_SHIFT;
    private static final int HI_SHEAR = APPLY_SHEAR << HI_SHIFT;

    /**
     * The X coordinate scaling element of the 3x3
     * affine transformation matrix.
     * 
     * @serial
     */
    double m00;

    /**
     * The Y coordinate shearing element of the 3x3
     * affine transformation matrix.
     *
     * @serial
     */ 
     double m10;

    /**
     * The X coordinate shearing element of the 3x3
     * affine transformation matrix.
     *
     * @serial
     */
     double m01; 

    /**
     * The Y coordinate scaling element of the 3x3
     * affine transformation matrix.
     * 
     * @serial
     */
     double m11; 

    /**
     * The X coordinate of the translation element of the
     * 3x3 affine transformation matrix.
     * 
     * @serial
     */
     double m02;

    /**
     * The Y coordinate of the translation element of the
     * 3x3 affine transformation matrix.
     *
     * @serial
     */
     double m12;

    /**
     * This field keeps track of which components of the matrix need to
     * be applied when performing a transformation.
     * @see #APPLY_IDENTITY
     * @see #APPLY_TRANSLATE
     * @see #APPLY_SCALE
     * @see #APPLY_SHEAR
     */
    transient int state;

    /**
     * This field caches the current transformation type of the matrix.
     * @see #TYPE_IDENTITY
     * @see #TYPE_TRANSLATION
     * @see #TYPE_UNIFORM_SCALE
     * @see #TYPE_GENERAL_SCALE
     * @see #TYPE_FLIP
     * @see #TYPE_QUADRANT_ROTATION
     * @see #TYPE_GENERAL_ROTATION
     * @see #TYPE_GENERAL_TRANSFORM
     * @see #TYPE_UNKNOWN
     * @see #getType
     */
    private transient int type;

    private AffineTransform(double m00, double m10,
			    double m01, double m11,
			    double m02, double m12,
			    int state) {
	this.m00 = m00;
	this.m10 = m10;
	this.m01 = m01;
	this.m11 = m11;
	this.m02 = m02;
	this.m12 = m12;
	this.state = state;
	this.type = TYPE_UNKNOWN;
    }

    /**
     * Constructs a new <code>AffineTransform</code> representing the
     * Identity transformation.
     */
    public AffineTransform() {
	m00 = m11 = 1.0;
	// m01 = m10 = m02 = m12 = 0.0;		/* Not needed. */
	// state = APPLY_IDENTITY;		/* Not needed. */
	// type = TYPE_IDENTITY;		/* Not needed. */
    }

    /**
     * Constructs a new <code>AffineTransform</code> that is a copy of
     * the specified <code>AffineTransform</code> object.
     * @param Tx the <code>AffineTransform</code> object to copy 
     */
    public AffineTransform(AffineTransform Tx) {
	this.m00 = Tx.m00;
	this.m10 = Tx.m10;
	this.m01 = Tx.m01;
	this.m11 = Tx.m11;
	this.m02 = Tx.m02;
	this.m12 = Tx.m12;
	this.state = Tx.state;
	this.type = Tx.type;
    }

    /**
     * Constructs a new <code>AffineTransform</code> from 6 floating point
     * values representing the 6 specifiable entries of the 3x3
     * transformation matrix.
     * @param m00,&nbsp;m01,&nbsp;m02,&nbsp;m10,&nbsp;m11,&nbsp;m12 the 
     * 6 floating point values that compose the 3x3 transformation matrix
     */
    public AffineTransform(float m00, float m10,
			   float m01, float m11,
			   float m02, float m12) {
	this.m00 = m00;
	this.m10 = m10;
	this.m01 = m01;