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 java.util.Collections; 020import java.util.List; 021 022import org.apache.commons.imaging.ImageWriteException; 023 024public class QuantizedPalette implements Palette { 025 private final int precision; 026 private final List<ColorSpaceSubset> subsets; 027 private final ColorSpaceSubset[] straight; 028 029 public QuantizedPalette(final List<ColorSpaceSubset> subsets, final int precision) { 030 this.subsets = subsets == null ? Collections.emptyList() : Collections.unmodifiableList(subsets); 031 this.precision = precision; 032 033 straight = new ColorSpaceSubset[1 << (precision * 3)]; 034 035 for (int i = 0; i < this.subsets.size(); i++) { 036 final ColorSpaceSubset subset = subsets.get(i); 037 subset.setIndex(i); 038 039 for (int u = subset.mins[0]; u <= subset.maxs[0]; u++) { 040 for (int j = subset.mins[1]; j <= subset.maxs[1]; j++) { 041 for (int k = subset.mins[2]; k <= subset.maxs[2]; k++) { 042 final int index = (u << (precision * 2)) 043 | (j << (precision * 1)) 044 | (k << (precision * 0)); 045 straight[index] = subset; 046 } 047 } 048 } 049 } 050 } 051 052 @Override 053 public int getPaletteIndex(final int rgb) throws ImageWriteException { 054 final int precisionMask = (1 << precision) - 1; 055 056 final int index = ((rgb >> (24 - 3 * precision)) & (precisionMask << (precision << 1))) 057 | ((rgb >> (16 - 2 * precision)) & (precisionMask << precision)) 058 | ((rgb >> (8 - precision)) & (precisionMask)); 059 060 return straight[index].getIndex(); 061 } 062 063 @Override 064 public int getEntry(final int index) { 065 final ColorSpaceSubset subset = subsets.get(index); 066 return subset.rgb; 067 } 068 069 @Override 070 public int length() { 071 return subsets.size(); 072 } 073}