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/*
* Copyright 2002-2017 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:
*
* https://drewnoakes.com/code/exif/
* https://github.com/drewnoakes/metadata-extractor
*/
package com.drew.imaging.png;
import com.drew.lang.SequentialByteArrayReader;
import com.drew.lang.SequentialReader;
import com.drew.lang.annotations.NotNull;
import java.io.IOException;
/**
* @author Drew Noakes https://drewnoakes.com
*/
public class PngHeader
{
private int _imageWidth;
private int _imageHeight;
private byte _bitsPerSample;
@NotNull
private PngColorType _colorType;
private byte _compressionType;
private byte _filterMethod;
private byte _interlaceMethod;
public PngHeader(@NotNull byte[] bytes) throws PngProcessingException
{
if (bytes.length != 13) {
throw new PngProcessingException("PNG header chunk must have 13 data bytes");
}
SequentialReader reader = new SequentialByteArrayReader(bytes);
try {
_imageWidth = reader.getInt32();
_imageHeight = reader.getInt32();
_bitsPerSample = reader.getInt8();
byte colorTypeNumber = reader.getInt8();
PngColorType colorType = PngColorType.fromNumericValue(colorTypeNumber);
if (colorType == null) {
throw new PngProcessingException("Unexpected PNG color type: " + colorTypeNumber);
}
_colorType = colorType;
_compressionType = reader.getInt8();
_filterMethod = reader.getInt8();
_interlaceMethod = reader.getInt8();
} catch (IOException e) {
// Should never happen
throw new PngProcessingException(e);
}
}
public int getImageWidth()
{
return _imageWidth;
}
public int getImageHeight()
{
return _imageHeight;
}
public byte getBitsPerSample()
{
return _bitsPerSample;
}
@NotNull
public PngColorType getColorType()
{
return _colorType;
}
public byte getCompressionType()
{
return _compressionType;
}
public byte getFilterMethod()
{
return _filterMethod;
}
public byte getInterlaceMethod()
{
return _interlaceMethod;
}
}
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