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.ImageWriteException; 020 021/** 022 * Color palette. 023 */ 024public interface Palette { 025 026 /** 027 * Looks up the palette index for a given color. 028 * @param rgb the color to look up 029 * @return the palette index 030 * @throws ImageWriteException 031 */ 032 int getPaletteIndex(int rgb) throws ImageWriteException; 033 034 /** 035 * Looks up the color for a given palette index. 036 * @param index the palette index to look up 037 * @return the color in ARGB format 038 */ 039 int getEntry(int index); 040 041 /** 042 * The number of entries in the palette. 043 * @return the number of palette entries 044 */ 045 int length(); 046 047}