    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.palette;
    018
    019import org.apache.commons.imaging.ImagingException;
    020
    021/**
    022 * Color palette.
    023 */
    024public interface Palette {
    025
    026    /**
    027     * Gets the color for a given palette index.
    028     *
    029     * @param index the palette index to look up
    030     * @return the color in ARGB format
    031     */
    032    int getEntry(int index);
    033
    034    /**
    035     * Gets the palette index for a given color.
    036     *
    037     * @param rgb the color to look up
    038     * @return the palette index
    039     * @throws ImagingException if it fails to read the palette index
    040     */
    041    int getPaletteIndex(int rgb) throws ImagingException;
    042
    043    /**
    044     * Gets the number of entries in the palette.
    045     *
    046     * @return the number of palette entries
    047     */
    048    int length();
    049
    050}