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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.TagDescriptor;
/**
* Provides human-readable string versions of the tags stored in a JpegDirectory.
* Thanks to Darrell Silver (www.darrellsilver.com) for the initial version of this class.
*
* @author Drew Noakes http://drewnoakes.com
*/
public class JpegDescriptor extends TagDescriptor<JpegDirectory>
{
public JpegDescriptor(@NotNull JpegDirectory directory)
{
super(directory);
}
@Nullable
public String getDescription(int tagType)
{
switch (tagType)
{
case JpegDirectory.TAG_JPEG_COMPRESSION_TYPE:
return getImageCompressionTypeDescription();
case JpegDirectory.TAG_JPEG_COMPONENT_DATA_1:
return getComponentDataDescription(0);
case JpegDirectory.TAG_JPEG_COMPONENT_DATA_2:
return getComponentDataDescription(1);
case JpegDirectory.TAG_JPEG_COMPONENT_DATA_3:
return getComponentDataDescription(2);
case JpegDirectory.TAG_JPEG_COMPONENT_DATA_4:
return getComponentDataDescription(3);
case JpegDirectory.TAG_JPEG_DATA_PRECISION:
return getDataPrecisionDescription();
case JpegDirectory.TAG_JPEG_IMAGE_HEIGHT:
return getImageHeightDescription();
case JpegDirectory.TAG_JPEG_IMAGE_WIDTH:
return getImageWidthDescription();
default:
return super.getDescription(tagType);
}
}
@Nullable
public String getImageCompressionTypeDescription()
{
Integer value = _directory.getInteger(JpegDirectory.TAG_JPEG_COMPRESSION_TYPE);
if (value==null)
return null;
// Note there is no 2 or 12
switch (value) {
case 0: return "Baseline";
case 1: return "Extended sequential, Huffman";
case 2: return "Progressive, Huffman";
case 3: return "Lossless, Huffman";
case 5: return "Differential sequential, Huffman";
case 6: return "Differential progressive, Huffman";
case 7: return "Differential lossless, Huffman";
case 8: return "Reserved for JPEG extensions";
case 9: return "Extended sequential, arithmetic";
case 10: return "Progressive, arithmetic";
case 11: return "Lossless, arithmetic";
case 13: return "Differential sequential, arithmetic";
case 14: return "Differential progressive, arithmetic";
case 15: return "Differential lossless, arithmetic";
default:
return "Unknown type: "+ value;
}
}
@Nullable
public String getImageWidthDescription()
{
final String value = _directory.getString(JpegDirectory.TAG_JPEG_IMAGE_WIDTH);
if (value==null)
return null;
return value + " pixels";
}
@Nullable
public String getImageHeightDescription()
{
final String value = _directory.getString(JpegDirectory.TAG_JPEG_IMAGE_HEIGHT);
if (value==null)
return null;
return value + " pixels";
}
@Nullable
public String getDataPrecisionDescription()
{
final String value = _directory.getString(JpegDirectory.TAG_JPEG_DATA_PRECISION);
if (value==null)
return null;
return value + " bits";
}
@Nullable
public String getComponentDataDescription(int componentNumber)
{
JpegComponent value = _directory.getComponent(componentNumber);
if (value==null)
return null;
StringBuilder sb = new StringBuilder();
sb.append(value.getComponentName());
sb.append(" component: Quantization table ");
sb.append(value.getQuantizationTableNumber());
sb.append(", Sampling factors ");
sb.append(value.getHorizontalSamplingFactor());
sb.append(" horiz/");
sb.append(value.getVerticalSamplingFactor());
sb.append(" vert");
return sb.toString();
}
}
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