274 lines
8.7 KiB
Java
274 lines
8.7 KiB
Java
/* ====================================================================
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Licensed to the Apache Software Foundation (ASF) under one or more
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contributor license agreements. See the NOTICE file distributed with
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this work for additional information regarding copyright ownership.
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The ASF licenses this file to You under the Apache License, Version 2.0
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(the "License"); you may not use this file except in compliance with
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the License. You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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==================================================================== */
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package org.apache.poi.hpsf;
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import org.apache.poi.util.LittleEndian;
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/**
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* <p>Class to manipulate data in the Clipboard Variant ({@link
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* Variant#VT_CF VT_CF}) format.</p>
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*
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* @see SummaryInformation#getThumbnail()
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* @see <a href="https://msdn.microsoft.com/en-us/library/windows/desktop/ms649014(v=vs.85).aspx">Clipboard Operations</a>
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*/
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public final class Thumbnail {
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/**
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* <p>Offset in bytes where the Clipboard Format Tag starts in the
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* <code>byte[]</code> returned by {@link
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* SummaryInformation#getThumbnail()}</p>
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*/
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public static final int OFFSET_CFTAG = 4;
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/**
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* <p>Offset in bytes where the Clipboard Format starts in the
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* <code>byte[]</code> returned by {@link
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* SummaryInformation#getThumbnail()}</p>
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*
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* <p>This is only valid if the Clipboard Format Tag is {@link
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* #CFTAG_WINDOWS}</p>
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*/
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public static final int OFFSET_CF = 8;
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/**
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* <p>Offset in bytes where the Windows Metafile (WMF) image data
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* starts in the <code>byte[]</code> returned by {@link
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* SummaryInformation#getThumbnail()}</p>
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*
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* <p>There is only WMF data at this point in the
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* <code>byte[]</code> if the Clipboard Format Tag is {@link
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* #CFTAG_WINDOWS} and the Clipboard Format is {@link
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* #CF_METAFILEPICT}.</p>
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*
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* <p>Note: The <code>byte[]</code> that starts at
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* <code>OFFSET_WMFDATA</code> and ends at
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* <code>getThumbnail().length - 1</code> forms a complete WMF
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* image. It can be saved to disk with a <code>.wmf</code> file
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* type and read using a WMF-capable image viewer.</p>
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*/
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public static final int OFFSET_WMFDATA = 20;
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/**
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* <p>Clipboard Format Tag - Windows clipboard format</p>
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*
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* <p>A <code>DWORD</code> indicating a built-in Windows clipboard
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* format value</p>
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*/
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public static final int CFTAG_WINDOWS = -1;
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/**
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* <p>Clipboard Format Tag - Macintosh clipboard format</p>
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*
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* <p>A <code>DWORD</code> indicating a Macintosh clipboard format
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* value</p>
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*/
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public static final int CFTAG_MACINTOSH = -2;
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/**
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* <p>Clipboard Format Tag - Format ID</p>
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*
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* <p>A GUID containing a format identifier (FMTID). This is
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* rarely used.</p>
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*/
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public static final int CFTAG_FMTID = -3;
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/**
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* <p>Clipboard Format Tag - No Data</p>
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*
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* <p>A <code>DWORD</code> indicating No data. This is rarely
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* used.</p>
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*/
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public static final int CFTAG_NODATA = 0;
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/**
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* <p>Clipboard Format - Windows metafile format. This is the
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* recommended way to store thumbnails in Property Streams.</p>
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*
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* <p><strong>Note:</strong> This is not the same format used in
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* regular WMF images. The clipboard version of this format has an
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* extra clipboard-specific header.</p>
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*/
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public static final int CF_METAFILEPICT = 3;
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/**
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* <p>Clipboard Format - Device Independent Bitmap</p>
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*/
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public static final int CF_DIB = 8;
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/**
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* <p>Clipboard Format - Enhanced Windows metafile format</p>
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*/
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public static final int CF_ENHMETAFILE = 14;
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/**
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* <p>Clipboard Format - Bitmap</p>
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*/
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public static final int CF_BITMAP = 2;
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/**
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* <p>A <code>byte[]</code> to hold a thumbnail image in ({@link
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* Variant#VT_CF VT_CF}) format.</p>
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*/
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private byte[] _thumbnailData = null;
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/**
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* <p>Default Constructor. If you use it then one you'll have to add
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* the thumbnail <code>byte[]</code> from {@link
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* SummaryInformation#getThumbnail()} to do any useful
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* manipulations, otherwise you'll get a
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* <code>NullPointerException</code>.</p>
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*/
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public Thumbnail()
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{
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super();
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}
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/**
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* <p>Creates a <code>Thumbnail</code> instance and initializes
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* with the specified image bytes.</p>
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*
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* @param thumbnailData The thumbnail data
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*/
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public Thumbnail(final byte[] thumbnailData)
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{
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this._thumbnailData = thumbnailData;
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}
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/**
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* <p>Returns the thumbnail as a <code>byte[]</code> in {@link
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* Variant#VT_CF VT_CF} format.</p>
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*
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* @return The thumbnail value
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* @see SummaryInformation#getThumbnail()
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*/
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public byte[] getThumbnail()
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{
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return _thumbnailData;
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}
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/**
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* <p>Sets the Thumbnail's underlying <code>byte[]</code> in
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* {@link Variant#VT_CF VT_CF} format.</p>
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*
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* @param thumbnail The new thumbnail value
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* @see SummaryInformation#getThumbnail()
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*/
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public void setThumbnail(final byte[] thumbnail)
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{
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this._thumbnailData = thumbnail;
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}
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/**
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* <p>Returns an <code>int</code> representing the Clipboard
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* Format Tag</p>
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*
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* <p>Possible return values are:</p>
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* <ul>
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* <li>{@link #CFTAG_WINDOWS CFTAG_WINDOWS}</li>
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* <li>{@link #CFTAG_MACINTOSH CFTAG_MACINTOSH}</li>
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* <li>{@link #CFTAG_FMTID CFTAG_FMTID}</li>
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* <li>{@link #CFTAG_NODATA CFTAG_NODATA}</li>
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* </ul>
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*
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* @return A flag indicating the Clipboard Format Tag
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*/
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public long getClipboardFormatTag()
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{
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long clipboardFormatTag = LittleEndian.getInt(getThumbnail(),
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OFFSET_CFTAG);
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return clipboardFormatTag;
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}
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/**
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* <p>Returns an <code>int</code> representing the Clipboard
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* Format</p>
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*
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* <p>Will throw an exception if the Thumbnail's Clipboard Format
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* Tag is not {@link Thumbnail#CFTAG_WINDOWS CFTAG_WINDOWS}.</p>
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*
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* <p>Possible return values are:</p>
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*
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* <ul>
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* <li>{@link #CF_METAFILEPICT CF_METAFILEPICT}</li>
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* <li>{@link #CF_DIB CF_DIB}</li>
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* <li>{@link #CF_ENHMETAFILE CF_ENHMETAFILE}</li>
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* <li>{@link #CF_BITMAP CF_BITMAP}</li>
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* </ul>
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*
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* @return a flag indicating the Clipboard Format
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* @throws HPSFException if the Thumbnail isn't CFTAG_WINDOWS
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*/
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public long getClipboardFormat() throws HPSFException
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{
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if (!(getClipboardFormatTag() == CFTAG_WINDOWS))
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throw new HPSFException("Clipboard Format Tag of Thumbnail must " +
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"be CFTAG_WINDOWS.");
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return LittleEndian.getInt(getThumbnail(), OFFSET_CF);
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}
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/**
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* <p>Returns the Thumbnail as a <code>byte[]</code> of WMF data
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* if the Thumbnail's Clipboard Format Tag is {@link
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* #CFTAG_WINDOWS CFTAG_WINDOWS} and its Clipboard Format is
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* {@link #CF_METAFILEPICT CF_METAFILEPICT}</p> <p>This
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* <code>byte[]</code> is in the traditional WMF file, not the
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* clipboard-specific version with special headers.</p>
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*
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* <p>See <a href="http://www.wvware.com/caolan/ora-wmf.html"
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* target="_blank">http://www.wvware.com/caolan/ora-wmf.html</a>
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* for more information on the WMF image format.</p>
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*
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* @return A WMF image of the Thumbnail
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* @throws HPSFException if the Thumbnail isn't CFTAG_WINDOWS and
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* CF_METAFILEPICT
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*/
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public byte[] getThumbnailAsWMF() throws HPSFException
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{
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if (!(getClipboardFormatTag() == CFTAG_WINDOWS))
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throw new HPSFException("Clipboard Format Tag of Thumbnail must " +
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"be CFTAG_WINDOWS.");
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if (!(getClipboardFormat() == CF_METAFILEPICT)) {
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throw new HPSFException("Clipboard Format of Thumbnail must " +
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"be CF_METAFILEPICT.");
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}
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byte[] thumbnail = getThumbnail();
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int wmfImageLength = thumbnail.length - OFFSET_WMFDATA;
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byte[] wmfImage = new byte[wmfImageLength];
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System.arraycopy(thumbnail,
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OFFSET_WMFDATA,
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wmfImage,
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0,
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wmfImageLength);
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return wmfImage;
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}
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}
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