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 019import org.apache.commons.imaging.common.BinaryConstant; 020 021public final class PngConstants { 022 023 public static final int COMPRESSION_DEFLATE_INFLATE = 0; 024 025 public static final BinaryConstant PNG_SIGNATURE = new BinaryConstant(new byte[] { (byte) 0x89, 'P', 'N', 'G', '\r', '\n', 0x1A, '\n', }); 026 027 public static final byte COMPRESSION_TYPE_INFLATE_DEFLATE = 0; 028 public static final byte FILTER_METHOD_ADAPTIVE = 0; 029 030 /* 031 * Background color Solid background color to be used when presenting the image if no better option is available. Gamma and chromaticity Gamma 032 * characteristic of the image with respect to the desired output intensity, and chromaticity characteristics of the RGB values used in the image. ICC 033 * profile Description of the color space (in the form of an International Color Consortium (ICC) profile) to which the samples in the image conform. Image 034 * histogram Estimates of how frequently the image uses each palette entry. Physical pixel dimensions Intended pixel size and aspect ratio to be used in 035 * presenting the PNG image. Significant bits The number of bits that are significant in the samples. sRGB color space A rendering intent (as defined by the 036 * International Color Consortium) and an indication that the image samples conform to this color space. Suggested palette A reduced palette that may be 037 * used when the display device is not capable of displaying the full range of colors in the image. Textual data Textual information (which may be 038 * compressed) associated with the image. Time The time when the PNG image was last modified. Transparency Alpha information that allows the reference image 039 * to be reconstructed when the alpha channel is not retained in the PNG image. 040 */ 041 042 public static final String XMP_KEYWORD = "XML:com.adobe.xmp"; 043 044 /** 045 * Parameter key. Used to indicate the PNG compression level to be used. 046 * 047 * <p> 048 * For valid values, see {@link java.util.zip.Deflater}. If no value is specified, it will use the default compression level. 049 * </p> 050 * 051 * @see java.util.zip.Deflater 052 */ 053 public static final String PARAM_KEY_PNG_COMPRESSION_LEVEL = "PNG_COMPRESSION_LEVEL"; 054 055 private PngConstants() { 056 } 057}