    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.tiff.photometricinterpreters.floatingpoint;
    018
    019import java.awt.Color;
    020
    021/**
    022 * Provides a palette entry for colors associated with a range of values. The return value will be interpolated between the minimum and maximum value for this
    023 * entry.
    024 * <p>
    025 * In keeping with the conventions of many Geographic Information Systems (GIS) and art applications, this instance "covered" values in the range v0 &le; f &lt;
    026 * v1. Thus, a value that exactly matches the upper bound of the range is not considered "covered".
    027 */
    028public final class PaletteEntryForRange implements PaletteEntry {
    029
    030    private final float v0;
    031    private final float v1;
    032    private final float r0;
    033    private final float r1;
    034    private final float g0;
    035    private final float g1;
    036    private final float b0;
    037    private final float b1;
    038    private final float a0;
    039    private final float a1;
    040
    041    /**
    042     * Constructs a palette entry for the range of values v0 &le; f &lt; v1. A single color will be returned for all values in range
    043     *
    044     * @param v0    the lower bounds (inclusive) of the covered range of values
    045     * @param v1    the upper bounds (non-inclusive) of the covered range of value
    046     * @param color the color assigned to value v0
    047     */
    048    public PaletteEntryForRange(final float v0, final float v1, final Color color) {
    049        this.v0 = v0;
    050        this.v1 = v1;
    051        final float deltaV = v1 - v0;
    052        // check for range volation
    053        if (deltaV <= 0 || Float.isNaN(deltaV)) {
    054            throw new IllegalArgumentException("Specified values must be v0<v1");
    055        }
    056        if (color == null) {
    057            throw new IllegalArgumentException("Null colors not allowed");
    058        }
    059
    060        final int argb0 = color.getRGB();
    061        a0 = argb0 >> 24 & 0xff;
    062        r0 = argb0 >> 16 & 0xff;
    063        g0 = argb0 >> 8 & 0xff;
    064        b0 = argb0 & 0xff;
    065
    066        final int argb1 = color.getRGB();
    067        a1 = argb1 >> 24 & 0xff;
    068        r1 = argb1 >> 16 & 0xff;
    069        g1 = argb1 >> 8 & 0xff;
    070        b1 = argb1 & 0xff;
    071    }
    072
    073    /**
    074     * Constructs a palette entry for the range of values v0 &le; f &lt; v1. The return color value will be interpolated between the two specified colors.
    075     *
    076     * @param v0     the lower bounds (inclusive) of the covered range of values
    077     * @param v1     the upper bounds (non-inclusive) of the covered range of value
    078     * @param color0 the color assigned to value v0
    079     * @param color1 the color assigned to value v1
    080     */
    081    public PaletteEntryForRange(final float v0, final float v1, final Color color0, final Color color1) {
    082        this.v0 = v0;
    083        this.v1 = v1;
    084        final float deltaV = v1 - v0;
    085        // check for range volation
    086        if (deltaV <= 0 || Float.isNaN(deltaV)) {
    087            throw new IllegalArgumentException("Specified values must be v0<v1");
    088        }
    089        if (color0 == null || color1 == null) {
    090            throw new IllegalArgumentException("Null colors not allowed");
    091        }
    092        final int argb0 = color0.getRGB();
    093        a0 = argb0 >> 24 & 0xff;
    094        r0 = argb0 >> 16 & 0xff;
    095        g0 = argb0 >> 8 & 0xff;
    096        b0 = argb0 & 0xff;
    097
    098        final int argb1 = color1.getRGB();
    099        a1 = argb1 >> 24 & 0xff;
    100        r1 = argb1 >> 16 & 0xff;
    101        g1 = argb1 >> 8 & 0xff;
    102        b1 = argb1 & 0xff;
    103    }
    104
    105    @Override
    106    public boolean coversSingleEntry() {
    107        return false;
    108    }
    109
    110    @Override
    111    public int getArgb(final float f) {
    112        if (v0 <= f && f <= v1) {
    113            final float t = (f - v0) / (v1 - v0);
    114            final int a = (int) (t * (a1 - a0) + a0 + 0.5);
    115            final int r = (int) (t * (r1 - r0) + r0 + 0.5);
    116            final int g = (int) (t * (g1 - g0) + g0 + 0.5);
    117            final int b = (int) (t * (b1 - b0) + b0 + 0.5);
    118            return ((a << 8 | r) << 8 | g) << 8 | b;
    119        }
    120        return 0;
    121    }
    122
    123    @Override
    124    public Color getColor(final float f) {
    125        if (v0 <= f && f <= v1) {
    126            final float t = (f - v0) / (v1 - v0);
    127            final int a = (int) (t * (a1 - a0) + a0 + 0.5);
    128            final int r = (int) (t * (r1 - r0) + r0 + 0.5);
    129            final int g = (int) (t * (g1 - g0) + g0 + 0.5);
    130            final int b = (int) (t * (b1 - b0) + b0 + 0.5);
    131            return new Color(r, g, b, a);
    132        }
    133        return null;
    134    }
    135
    136    @Override
    137    public float getLowerBound() {
    138        return v0;
    139    }
    140
    141    @Override
    142    public float getUpperBound() {
    143        return v1;
    144    }
    145
    146    @Override
    147    public boolean isCovered(final float f) {
    148        return v0 <= f && f < v1;
    149    }
    150
    151    @Override
    152    public String toString() {
    153        return "PaletteEntry for range " + v0 + ", " + v1;
    154    }
    155}