001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.commons.imaging.formats.png;
018
019/**
020 * Used to specify physical scale when reading or storing image information.
021 */
022public class PhysicalScale {
023   private static final int METER_UNITS = 1;
024   private static final int RADIAN_UNITS = 2;
025   public static final PhysicalScale UNDEFINED = createFromMeters(-1.0, -1.0);
026
027   private final int units;
028   private final double horizontalUnitsPerPixel;
029   private final double verticalUnitsPerPixel;
030
031   private PhysicalScale(final int units, final double horizontalUnitsPerPixel,
032                         final double verticalUnitsPerPixel) {
033      this.units = units;
034      this.horizontalUnitsPerPixel = horizontalUnitsPerPixel;
035      this.verticalUnitsPerPixel = verticalUnitsPerPixel;
036   }
037
038   public static PhysicalScale createFromMeters(final double x, final double y) {
039      return new PhysicalScale(METER_UNITS, x, y);
040   }
041
042   public static PhysicalScale createFromRadians(final double x, final double y) {
043      return new PhysicalScale(RADIAN_UNITS, x, y);
044   }
045
046   public boolean isInMeters() {
047      return METER_UNITS == units;
048   }
049
050   public boolean isInRadians() {
051      return RADIAN_UNITS == units;
052   }
053
054   public double getHorizontalUnitsPerPixel() {
055      return horizontalUnitsPerPixel;
056   }
057
058   public double getVerticalUnitsPerPixel() {
059      return verticalUnitsPerPixel;
060   }
061}