479 lines
14 KiB
Java
479 lines
14 KiB
Java
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package com.realityinteractive.imageio.tga;
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/*
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* TGAHeader.java
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* Copyright (c) 2003 Reality Interactive, Inc.
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* See bottom of file for license and warranty information.
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* Created on Sep 26, 2003
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*/
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import java.io.IOException;
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import javax.imageio.stream.ImageInputStream;
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/**
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* <p>The header to a TGA image file.</p>
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*
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* <p>See <a href="http://organicbit.com/closecombat/formats/tga.html">format</a>,
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* <a href="http://www.opennet.ru/docs/formats/targa.pdf">format</a> or
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* <a href="http://netghost.narod.ru/gff/graphics/summary/tga.htm">format</a>
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* for header information.</p>
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*
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* @author Rob Grzywinski <a href="mailto:rgrzywinski@realityinteractive.com">rgrzywinski@realityinteractive.com</a>
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* @version $Id: TGAHeader.java,v 1.1 2005/04/12 11:23:53 ornedan Exp $
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* @since 1.0
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*/
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public class TGAHeader
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{
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/**
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* <p>The length of the TGA identifier. This is a <code>byte</code> in
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* length.</p>
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*/
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private int idLength;
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/**
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* <p>The image identifier with length <code>idLength</code>.</p>
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*/
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private byte[] id;
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/**
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* <p>Does this TGA have an associated color map? <code>1</code> indicates
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* that there is a color map. <code>0</code> indicates no color map.</p>
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*/
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private boolean hasColorMap;
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/**
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* <p>The type of image. See the image type constants in {@link com.realityinteractive.imageio.tga.TGAConstants}
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* for allowed values.</p>
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*/
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private int imageType;
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/**
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* <p>An image is compressed if its image type is {@link TGAConstants#RLE_COLOR_MAP},
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* {@link TGAConstants#RLE_TRUE_COLOR}, or {@link TGAConstants#RLE_MONO}.</p>
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*/
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private boolean isCompressed;
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/**
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* <p>The index of the first color map entry.</p>
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*/
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private int firstColorMapEntryIndex;
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/**
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* <p>The total number of color map entries.</p>
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*/
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private int numberColorMapEntries;
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/**
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* <p>The number of bits per color map entry.</p>
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*/
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private int bitsPerColorMapEntry;
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/**
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* <p>The computed size of a color map entry in <code>byte</code>s.</p>
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*/
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private int colorMapEntrySize;
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/**
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* <p>The computed size of the color map field in <code>byte</code>s. This
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* is determined from the <code>numberColorMapEntries</code> and
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* <code>colorMapEntrySize</code>.</p>
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*/
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private int colorMapSize;
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/**
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* <p>The horizontal coordinate for the lower-left corner of the image.</p>
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*/
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private int xOrigin;
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/**
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* <p>The vertical coordinate for the lower-left corner of the image.</p>
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*/
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private int yOrigin;
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/**
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* <p>The width of the image in pixels.</p>
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*/
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private int width;
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/**
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* <p>The height of the image in pixels.</p>
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*/
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private int height;
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/**
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* <p>The number of bits per pixel.</p>
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*/
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private int bitsPerPixel;
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/**
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* <p>The number of attribute bits per pixel.</p>
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*/
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private int imageDescriptor;
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/**
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* <p>The horizontal ordering of the pixels as determined from the image
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* descriptor. By default the order is left to right.</p>
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*/
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// NOTE: true -> left-to-right; false -> right-to-left
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private boolean leftToRight;
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/**
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* <p>The horizontal ordering of the pixels as determined from the image
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* descriptor. By default the order is left to right.</p>
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*/
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// NOTE: true -> bottom-to-top; false -> top-to-bottom
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private boolean bottomToTop;
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/**
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* <p>The offset to the color map data. This value is not defined if there
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* is no color map (see <code>hasColorMap</code>).</p>
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*/
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private int colorMapDataOffset;
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/**
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* <p>The offset to the pixel data.</p>
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*/
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private int pixelDataOffset;
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// =========================================================================
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/**
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* <p>Constructs a TGA header that will be populated by setters or directly
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* (via a static "factory" method).</p>
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*/
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public TGAHeader() {}
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/**
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* <p>Constructs and populates a TGA header from the specified {@link javax.imageio.stream.ImageInputStream}.</p>
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*
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* @param inputStream the <code>ImageInputStream</code> from which the
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* header data is read
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* @throws IOException if there was an I/O error while reading the header
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* data
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*/
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public TGAHeader(final ImageInputStream inputStream)
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throws IOException
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{
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// read the data
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readHeader(inputStream);
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}
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/**
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* <p>Reads and populates the header from the specifed {@link javax.imageio.stream.ImageInputStream}.
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* Any existing values will be over written.</p>
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*
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* <p>The <code>ImageInputStream</code> will be changed as a result of this
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* operation (the offset will be moved).</p>
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*
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* @param inputStream the <code>ImageInputStream</code> from which the
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* header data is read
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* @throws IOException if there was an I/O error while reading the header
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* data
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*/
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public void readHeader(final ImageInputStream inputStream)
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throws IOException
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{
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// read in the header as per the spec
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idLength = inputStream.readUnsignedByte();
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hasColorMap = (inputStream.readUnsignedByte() == 1); // 1 == true, 0 == false
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imageType = inputStream.readUnsignedByte();
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firstColorMapEntryIndex = inputStream.readUnsignedShort();
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numberColorMapEntries = inputStream.readUnsignedShort();
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bitsPerColorMapEntry = inputStream.readByte();
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xOrigin = inputStream.readUnsignedShort();
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yOrigin = inputStream.readUnsignedShort();
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width = inputStream.readUnsignedShort();
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height = inputStream.readUnsignedShort();
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bitsPerPixel = inputStream.readByte();
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imageDescriptor = inputStream.readByte();
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// determine if the image is compressed
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isCompressed = ( (imageType == TGAConstants.RLE_COLOR_MAP) ||
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(imageType == TGAConstants.RLE_TRUE_COLOR) ||
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(imageType == TGAConstants.RLE_MONO) );
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// compute the size of the color map field in bytes
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switch(bitsPerColorMapEntry)
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{
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case 8:
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default:
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colorMapEntrySize = 1;
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break;
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case 15:
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case 16:
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colorMapEntrySize = 2;
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break;
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case 24:
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case 32:
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colorMapEntrySize = 3;
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break;
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}
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colorMapSize = colorMapEntrySize * numberColorMapEntries; // in bytes
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// set the pixel ordering from the imageDescriptor bit mask
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// (bit set indicates false)
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leftToRight = ((imageDescriptor & TGAConstants.LEFT_RIGHT_BIT) == 0);
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bottomToTop = ((imageDescriptor & TGAConstants.BOTTOM_TOP_BIT) == 0);
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// read the image id based whose length is idLength
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if(idLength > 0)
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{
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// allocate the space for the id
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id = new byte[idLength];
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// read the id
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inputStream.read(id, 0, idLength);
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} /* else -- the idLength was not positive */
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// compute the color map and pixel data offsets. The color map data
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// offset is the current offset.
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// NOTE: the conversion to int is OK since the maximum size of the
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// color map data is 65536 bytes.
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final long currentOffset = inputStream.getStreamPosition();
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colorMapDataOffset = (int)currentOffset;
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if(hasColorMap)
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{
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// there is a color map so the pixel data offset is the current
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// offset + the size of the color map data
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pixelDataOffset = colorMapDataOffset + colorMapSize;
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} else /* there is no color map */
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{
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// there is no color map so the pixel data offset is the current
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// offset
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pixelDataOffset = (int)currentOffset;
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}
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}
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/**
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* <p>The length of the TGA identifier. This is a <code>byte</code> in
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* length.</p>
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*/
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public int getIdLength()
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{
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return idLength;
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}
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/**
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* <p>Does this TGA have an associated color map?</p>
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*/
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public boolean hasColorMap()
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{
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return hasColorMap;
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}
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/**
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* <p>Retrieves the type of image. See the image type constants in {@link com.realityinteractive.imageio.tga.TGAConstants}
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* for allowed values.</p>
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*/
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public int getImageType()
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{
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return imageType;
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}
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/**
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* <p>Retrieves a string that represents the image type.</p>
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*/
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public String getImageTypeString()
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{
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switch(imageType)
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{
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case TGAConstants.NO_IMAGE:
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return "NO IMAGE";
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case TGAConstants.COLOR_MAP:
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return "COLOR MAP";
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case TGAConstants.TRUE_COLOR:
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return "TRUE COLOR";
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case TGAConstants.MONO:
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return "MONOCHROME";
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case TGAConstants.RLE_COLOR_MAP:
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return "RLE COMPRESSED COLOR MAP";
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case TGAConstants.RLE_TRUE_COLOR:
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return "RLE COMPRESSED TRUE COLOR";
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case TGAConstants.RLE_MONO:
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return "RLE COMPRESSED MONOCHROME";
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default:
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return "UNKNOWN";
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}
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}
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/**
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* <p>Retrieves if this image is compressed. If the image type is
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* {@link TGAConstants#RLE_COLOR_MAP}, {@link TGAConstants#RLE_TRUE_COLOR},
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* or {@link TGAConstants#RLE_MONO} then the image is compressed.</p>
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*/
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public boolean isCompressed()
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{
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return isCompressed;
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}
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/**
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* <p>Retrieves the index of the first color map entry.</p>
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*/
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public int getFirstColorMapEntryIndex()
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{
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return firstColorMapEntryIndex;
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}
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/**
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* <p>Retrieves ttotal number of color map entries.</p>
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*/
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public int getColorMapLength()
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{
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return numberColorMapEntries;
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}
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/**
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* <p>Retrieves the number of bits per color map entry.</p>
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*/
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public int getBitsPerColorMapEntry()
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{
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return bitsPerColorMapEntry;
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}
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/**
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* <p>Retrieves the horizontal coordinate for the lower-left corner of the
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* image.</p>
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*/
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public int getXOrigin()
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{
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return xOrigin;
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}
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/**
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* <p>Retrieves the vertical coordinate for the lower-left corner of the image.</p>
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*/
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public int getYOrigin()
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{
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return yOrigin;
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}
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/**
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* <p>Retrieves the width of the image in pixels.</p>
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*/
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public int getWidth()
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{
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return width;
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}
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/**
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* <p>Retrieves the height of the image in pixels.</p>
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*/
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public int getHeight()
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{
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return height;
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}
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/**
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* <p>Retrieves the number of bits per pixel.</p>
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*/
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public int getBitsPerPixel()
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{
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return bitsPerPixel;
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}
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/**
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* <p>Retrieves the number of samples per pixel.</p>
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*/
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public int getSamplesPerPixel()
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{
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// FIXME: this is overly simplistic but it is accurate
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return (bitsPerPixel == 32) ? 4 : 3;
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}
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/**
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* <p>Retrieves the number of attribute bits per pixel.</p>
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*/
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public int getImageDescriptor()
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{
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return imageDescriptor;
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}
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/**
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* <p>Returns if this image is left-to-right (<code>true</code>) or right-
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* to-left (<code>false</code>).</p>
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*/
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public boolean isLeftToRight()
|
||
|
|
{
|
||
|
|
return leftToRight;
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* <p>Returns if this image is bottom-to-top (<code>true</code>) or top-to-
|
||
|
|
* bottom (<code>false</code>).</p>
|
||
|
|
*/
|
||
|
|
public boolean isBottomToTop()
|
||
|
|
{
|
||
|
|
return bottomToTop;
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* <p>Retrieves the offset to the color map data. If there is no color
|
||
|
|
* map ({@link #hasColorMap()} returns <code>false</code>) then this is
|
||
|
|
* undefined.</p>
|
||
|
|
*/
|
||
|
|
public int getColorMapDataOffset()
|
||
|
|
{
|
||
|
|
return colorMapDataOffset;
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* <p>Retrieves the offset to the pixel data.</p>
|
||
|
|
*/
|
||
|
|
public int getPixelDataOffset()
|
||
|
|
{
|
||
|
|
return pixelDataOffset;
|
||
|
|
}
|
||
|
|
|
||
|
|
// =========================================================================
|
||
|
|
/**
|
||
|
|
* <p>Retrieves a string useful for debugging.</p>
|
||
|
|
*
|
||
|
|
* @return a string useful for debugging
|
||
|
|
*/
|
||
|
|
public String debugString()
|
||
|
|
{
|
||
|
|
return "TGAHeader[" +
|
||
|
|
"type=" + getImageTypeString() + ", " +
|
||
|
|
(hasColorMap ?
|
||
|
|
("firstColorMapEntryIndex=" + firstColorMapEntryIndex + ", " +
|
||
|
|
"numberColorMapEntries=" + numberColorMapEntries + ", " +
|
||
|
|
"bitsPerColorMapEntry=" + bitsPerColorMapEntry + ", " +
|
||
|
|
"totalColorMapEntrySize=" + colorMapSize + ", " ) :
|
||
|
|
"") +
|
||
|
|
"isCompressed=" + isCompressed + ", " +
|
||
|
|
"xOrigin=" + xOrigin + ", " +
|
||
|
|
"yOrigin=" + yOrigin + ", " +
|
||
|
|
"width=" + width + ", " +
|
||
|
|
"height=" + height + ", " +
|
||
|
|
"bitsPerPixel=" + bitsPerPixel + ", " +
|
||
|
|
"samplesPerPixel=" + getSamplesPerPixel() +
|
||
|
|
"]";
|
||
|
|
}
|
||
|
|
}
|
||
|
|
// =============================================================================
|
||
|
|
/*
|
||
|
|
This library is free software; you can redistribute it and/or
|
||
|
|
modify it under the terms of the GNU Lesser General Public
|
||
|
|
License as published by the Free Software Foundation; either
|
||
|
|
version 2.1 of the License, or (at your option) any later version.
|
||
|
|
|
||
|
|
This library is distributed in the hope that it will be useful,
|
||
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
||
|
|
Lesser General Public License for more details.
|
||
|
|
|
||
|
|
You should have received a copy of the GNU Lesser General Public
|
||
|
|
License along with this library; if not, write to the Free Software
|
||
|
|
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
|
||
|
|
*/
|