1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17 package org.apache.commons.imaging.formats.png;
18
19 import org.apache.commons.imaging.common.BinaryConstant;
20
21 public final class PngConstants {
22
23 public static final int COMPRESSION_DEFLATE_INFLATE = 0;
24
25 public static final BinaryConstant PNG_SIGNATURE = new BinaryConstant(new byte[] { (byte) 0x89, 'P', 'N', 'G', '\r', '\n', 0x1A, '\n', });
26
27 public static final byte COMPRESSION_TYPE_INFLATE_DEFLATE = 0;
28 public static final byte FILTER_METHOD_ADAPTIVE = 0;
29
30 /*
31 * Background color Solid background color to be used when presenting the image if no better option is available. Gamma and chromaticity Gamma
32 * characteristic of the image with respect to the desired output intensity, and chromaticity characteristics of the RGB values used in the image. ICC
33 * 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
34 * histogram Estimates of how frequently the image uses each palette entry. Physical pixel dimensions Intended pixel size and aspect ratio to be used in
35 * 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
36 * International Color Consortium) and an indication that the image samples conform to this color space. Suggested palette A reduced palette that may be
37 * 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
38 * compressed) associated with the image. Time The time when the PNG image was last modified. Transparency Alpha information that allows the reference image
39 * to be reconstructed when the alpha channel is not retained in the PNG image.
40 */
41
42 public static final String XMP_KEYWORD = "XML:com.adobe.xmp";
43
44 /**
45 * Parameter key. Used to indicate the PNG compression level to be used.
46 *
47 * <p>
48 * For valid values, see {@link java.util.zip.Deflater}. If no value is specified, it will use the default compression level.
49 * </p>
50 *
51 * @see java.util.zip.Deflater
52 */
53 public static final String PARAM_KEY_PNG_COMPRESSION_LEVEL = "PNG_COMPRESSION_LEVEL";
54
55 private PngConstants() {
56 }
57 }