Java tutorial
/* * * This file is part of the iText (R) project. Copyright (c) 1998-2019 iText Group NV * 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 * ITEXT GROUP. ITEXT GROUP 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: sales@itextpdf.com */ 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. * <br><br> * 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 * <br> * <b>Note:</b> 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). * <br> * For example: * <code>aVector.subtract(originVector).length();</code> * * @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. * <br><br> * <b>Note:</b> 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; } }