# TextPositionComparator.java

    /*
     * Licensed to the Apache Software Foundation (ASF) under one or more
     * contributor license agreements.  See the NOTICE file distributed with
     * this work for additional information regarding copyright ownership.
     * The ASF licenses this file to You under the Apache License, Version 2.0
     * (the "License"); you may not use this file except in compliance with
     * the License.  You may obtain a copy of the License at
     *
     *      http://www.apache.org/licenses/LICENSE-2.0
     *
     * Unless required by applicable law or agreed to in writing, software
     * distributed under the License is distributed on an "AS IS" BASIS,
     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     * See the License for the specific language governing permissions and
     * limitations under the License.
     */
    package org.apache.pdfbox.text;

    import java.util.Comparator;

    /**
     * This class is a comparator for TextPosition operators.  It handles
     * pages with text in different directions by grouping the text based
     * on direction and sorting in that direction. This allows continuous text
     * in a given direction to be more easily grouped together.
     *
     * @author Ben Litchfield
     */
    public class TextPositionComparator implements Comparator<TextPosition>
    {
        @Override
        public int compare(TextPosition pos1, TextPosition pos2)
        {
            // only compare text that is in the same direction
            int cmp1 = Float.compare(pos1.getDir(), pos2.getDir());
            if (cmp1 != 0)
            {
                return cmp1;
            }

            // get the text direction adjusted coordinates
            float x1 = pos1.getXDirAdj();
            float x2 = pos2.getXDirAdj();

            float pos1YBottom = pos1.getYDirAdj();
            float pos2YBottom = pos2.getYDirAdj();

            // note that the coordinates have been adjusted so 0,0 is in upper left
            float pos1YTop = pos1YBottom - pos1.getHeightDir();
            float pos2YTop = pos2YBottom - pos2.getHeightDir();

            float yDifference = Math.abs(pos1YBottom - pos2YBottom);

            // we will do a simple tolerance comparison
            if (yDifference < .1 ||
                pos2YBottom >= pos1YTop && pos2YBottom <= pos1YBottom ||
                pos1YBottom >= pos2YTop && pos1YBottom <= pos2YBottom)
            {
                return Float.compare(x1, x2);
            }
            else if (pos1YBottom < pos2YBottom)
            {
                return -1;
            }
            else
            {
                return 1;
            }
        }
    }