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iText, a free Java-PDF library
/*
* $Id: Vector.java 5075 2012-02-27 16:36:18Z blowagie $
*
* This file is part of the iText (R) project.
* Copyright (c) 1998-2012 1T3XT BVBA
* Authors: Kevin Day, Bruno Lowagie, Paulo Soares, et al.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License version 3
* as published by the Free Software Foundation with the addition of the
* following permission added to Section 15 as permitted in Section 7(a):
* FOR ANY PART OF THE COVERED WORK IN WHICH THE COPYRIGHT IS OWNED BY 1T3XT,
* 1T3XT DISCLAIMS THE WARRANTY OF NON INFRINGEMENT OF THIRD PARTY RIGHTS.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE.
* See the GNU Affero General Public License for more details.
* You should have received a copy of the GNU Affero General Public License
* along with this program; if not, see http://www.gnu.org/licenses or write to
* the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
* Boston, MA, 02110-1301 USA, or download the license from the following URL:
* http://itextpdf.com/terms-of-use/
*
* The interactive user interfaces in modified source and object code versions
* of this program must display Appropriate Legal Notices, as required under
* Section 5 of the GNU Affero General Public License.
*
* In accordance with Section 7(b) of the GNU Affero General Public License,
* a covered work must retain the producer line in every PDF that is created
* or manipulated using iText.
*
* You can be released from the requirements of the license by purchasing
* a commercial license. Buying such a license is mandatory as soon as you
* develop commercial activities involving the iText software without
* disclosing the source code of your own applications.
* These activities include: offering paid services to customers as an ASP,
* serving PDFs on the fly in a web application, shipping iText with a closed
* source product.
*
* For more information, please contact iText Software Corp. at this
* address: [email protected]
*/
package com.itextpdf.text.pdf.parser;
import java.util.Arrays;
/**
* Represents a vector (i.e. a point in space). This class is completely
* unrelated to the {@link java.util.Vector} class in the standard JRE.
*
* For many PDF related operations, the z coordinate is specified as 1
* This is to support the coordinate transformation calculations. If it
* helps, just think of all PDF drawing operations as occurring in a single plane
* with z=1.
*/
public class Vector {
/** index of the X coordinate */
public static final int I1 = 0;
/** index of the Y coordinate */
public static final int I2 = 1;
/** index of the Z coordinate */
public static final int I3 = 2;
/** the values inside the vector */
private final float[] vals = new float[]{
0,0,0
};
/**
* Creates a new Vector
* @param x the X coordinate
* @param y the Y coordinate
* @param z the Z coordinate
*/
public Vector(final float x, final float y, final float z) {
vals[I1] = x;
vals[I2] = y;
vals[I3] = z;
}
/**
* Gets the value from a coordinate of the vector
* @param index the index of the value to get (I1, I2 or I3)
* @return a coordinate value
*/
public float get(final int index){
return vals[index];
}
/**
* Computes the cross product of this vector and the specified matrix
* @param by the matrix to cross this vector with
* @return the result of the cross product
*/
public Vector cross(final Matrix by){
float x = vals[I1]*by.get(Matrix.I11) + vals[I2]*by.get(Matrix.I21) + vals[I3]*by.get(Matrix.I31);
float y = vals[I1]*by.get(Matrix.I12) + vals[I2]*by.get(Matrix.I22) + vals[I3]*by.get(Matrix.I32);
float z = vals[I1]*by.get(Matrix.I13) + vals[I2]*by.get(Matrix.I23) + vals[I3]*by.get(Matrix.I33);
return new Vector(x, y, z);
}
/**
* Computes the difference between this vector and the specified vector
* @param v the vector to subtract from this one
* @return the results of the subtraction
*/
public Vector subtract(final Vector v){
float x = vals[I1] - v.vals[I1];
float y = vals[I2] - v.vals[I2];
float z = vals[I3] - v.vals[I3];
return new Vector(x, y, z);
}
/**
* Computes the cross product of this vector and the specified vector
* @param with the vector to cross this vector with
* @return the cross product
*/
public Vector cross(final Vector with){
float x = vals[I2]*with.vals[I3] - vals[I3]*with.vals[I2];
float y = vals[I3]*with.vals[I1] - vals[I1]*with.vals[I3];
float z = vals[I1]*with.vals[I2] - vals[I2]*with.vals[I1];
return new Vector(x, y, z);
}
/**
* Normalizes the vector (i.e. returns the unit vector in the same orientation as this vector)
* @return the unit vector
* @since 5.0.1
*/
public Vector normalize(){
float l = this.length();
float x = vals[I1]/l;
float y = vals[I2]/l;
float z = vals[I3]/l;
return new Vector(x, y, z);
}
/**
* Multiplies the vector by a scalar
* @param by the scalar to multiply by
* @return the result of the scalar multiplication
* @since 5.0.1
*/
public Vector multiply(final float by){
float x = vals[I1] * by;
float y = vals[I2] * by;
float z = vals[I3] * by;
return new Vector(x, y, z);
}
/**
* Computes the dot product of this vector with the specified vector
* @param with the vector to dot product this vector with
* @return the dot product
*/
public float dot(final Vector with){
return vals[I1]*with.vals[I1] + vals[I2]*with.vals[I2] + vals[I3]*with.vals[I3];
}
/**
* Computes the length of this vector
*
* Note: If you are working with raw vectors from PDF, be careful -
* the Z axis will generally be set to 1. If you want to compute the
* length of a vector, subtract it from the origin first (this will set
* the Z axis to 0).
*
* For example:
* aVector.subtract(originVector).length();
*
* @return the length of this vector
*/
public float length(){
return (float)Math.sqrt(lengthSquared());
}
/**
* Computes the length squared of this vector.
*
* The square of the length is less expensive to compute, and is often
* useful without taking the square root.
*
* Note: See the important note under {@link Vector#length()}
*
* @return the square of the length of the vector
*/
public float lengthSquared(){
return vals[I1]*vals[I1] + vals[I2]*vals[I2] + vals[I3]*vals[I3];
}
/**
* @see java.lang.Object#toString()
*/
@Override
public String toString() {
return vals[I1]+","+vals[I2]+","+vals[I3];
}
/**
* Calculates the hashcode using the values.
* @since 5.0.6
*/
@Override
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result + Arrays.hashCode(vals);
return result;
}
/*
* (non-Javadoc)
* @see java.lang.Object#equals(java.lang.Object)
*/
@Override
public boolean equals(final Object obj) {
if (this == obj) {
return true;
}
if (obj == null) {
return false;
}
if (getClass() != obj.getClass()) {
return false;
}
Vector other = (Vector) obj;
if (!Arrays.equals(vals, other.vals)) {
return false;
}
return true;
}
}