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/*
* Copyright 2002-2012 Drew Noakes
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* More information about this project is available at:
*
* http://drewnoakes.com/code/exif/
* http://code.google.com/p/metadata-extractor/
*/
package com.drew.metadata.jpeg;
import com.drew.lang.annotations.NotNull;
import com.drew.lang.annotations.Nullable;
import com.drew.metadata.Directory;
import com.drew.metadata.MetadataException;
import java.util.HashMap;
/**
* Directory of tags and values for the SOF0 Jpeg segment. This segment holds basic metadata about the image.
*
* @author Darrell Silver http://www.darrellsilver.com and Drew Noakes http://drewnoakes.com
*/
public class JpegDirectory extends Directory
{
public static final int TAG_JPEG_COMPRESSION_TYPE = -3;
/** This is in bits/sample, usually 8 (12 and 16 not supported by most software). */
public static final int TAG_JPEG_DATA_PRECISION = 0;
/** The image's height. Necessary for decoding the image, so it should always be there. */
public static final int TAG_JPEG_IMAGE_HEIGHT = 1;
/** The image's width. Necessary for decoding the image, so it should always be there. */
public static final int TAG_JPEG_IMAGE_WIDTH = 3;
/**
* Usually 1 = grey scaled, 3 = color YcbCr or YIQ, 4 = color CMYK
* Each component TAG_COMPONENT_DATA_[1-4], has the following meaning:
* component Id(1byte)(1 = Y, 2 = Cb, 3 = Cr, 4 = I, 5 = Q),
* sampling factors (1byte) (bit 0-3 vertical., 4-7 horizontal.),
* quantization table number (1 byte).
* <p/>
* This info is from http://www.funducode.com/freec/Fileformats/format3/format3b.htm
*/
public static final int TAG_JPEG_NUMBER_OF_COMPONENTS = 5;
// NOTE! Component tag type int values must increment in steps of 1
/** the first of a possible 4 color components. Number of components specified in TAG_JPEG_NUMBER_OF_COMPONENTS. */
public static final int TAG_JPEG_COMPONENT_DATA_1 = 6;
/** the second of a possible 4 color components. Number of components specified in TAG_JPEG_NUMBER_OF_COMPONENTS. */
public static final int TAG_JPEG_COMPONENT_DATA_2 = 7;
/** the third of a possible 4 color components. Number of components specified in TAG_JPEG_NUMBER_OF_COMPONENTS. */
public static final int TAG_JPEG_COMPONENT_DATA_3 = 8;
/** the fourth of a possible 4 color components. Number of components specified in TAG_JPEG_NUMBER_OF_COMPONENTS. */
public static final int TAG_JPEG_COMPONENT_DATA_4 = 9;
@NotNull
protected static final HashMap<Integer, String> _tagNameMap = new HashMap<Integer, String>();
static {
_tagNameMap.put(TAG_JPEG_COMPRESSION_TYPE, "Compression Type");
_tagNameMap.put(TAG_JPEG_DATA_PRECISION, "Data Precision");
_tagNameMap.put(TAG_JPEG_IMAGE_WIDTH, "Image Width");
_tagNameMap.put(TAG_JPEG_IMAGE_HEIGHT, "Image Height");
_tagNameMap.put(TAG_JPEG_NUMBER_OF_COMPONENTS, "Number of Components");
_tagNameMap.put(TAG_JPEG_COMPONENT_DATA_1, "Component 1");
_tagNameMap.put(TAG_JPEG_COMPONENT_DATA_2, "Component 2");
_tagNameMap.put(TAG_JPEG_COMPONENT_DATA_3, "Component 3");
_tagNameMap.put(TAG_JPEG_COMPONENT_DATA_4, "Component 4");
}
public JpegDirectory()
{
this.setDescriptor(new JpegDescriptor(this));
}
@NotNull
public String getName()
{
return "Jpeg";
}
@NotNull
protected HashMap<Integer, String> getTagNameMap()
{
return _tagNameMap;
}
/**
* @param componentNumber The zero-based index of the component. This number is normally between 0 and 3.
* Use getNumberOfComponents for bounds-checking.
* @return the JpegComponent having the specified number.
*/
@Nullable
public JpegComponent getComponent(int componentNumber)
{
int tagType = JpegDirectory.TAG_JPEG_COMPONENT_DATA_1 + componentNumber;
return (JpegComponent)getObject(tagType);
}
public int getImageWidth() throws MetadataException
{
return getInt(JpegDirectory.TAG_JPEG_IMAGE_WIDTH);
}
public int getImageHeight() throws MetadataException
{
return getInt(JpegDirectory.TAG_JPEG_IMAGE_HEIGHT);
}
public int getNumberOfComponents() throws MetadataException
{
return getInt(JpegDirectory.TAG_JPEG_NUMBER_OF_COMPONENTS);
}
}
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