From Bug 38289: Yegor's support for pictures embeded in PPT files

git-svn-id: https://svn.apache.org/repos/asf/jakarta/poi/trunk@369540 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Nick Burch 2006-01-16 18:27:37 +00:00
parent 3ab6d6c4a8
commit c2a41112ab
3 changed files with 178 additions and 0 deletions

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@ -36,6 +36,7 @@ import org.apache.poi.hpsf.DocumentSummaryInformation;
import org.apache.poi.util.LittleEndian; import org.apache.poi.util.LittleEndian;
import org.apache.poi.hslf.record.*; import org.apache.poi.hslf.record.*;
import org.apache.poi.hslf.usermodel.Picture;
/** /**
* This class contains the main functionality for the Powerpoint file * This class contains the main functionality for the Powerpoint file
@ -337,4 +338,34 @@ public class HSLFSlideShow
* Fetch the Current User Atom of the document * Fetch the Current User Atom of the document
*/ */
public CurrentUserAtom getCurrentUserAtom() { return currentUser; } public CurrentUserAtom getCurrentUserAtom() { return currentUser; }
/**
* Read pictures contained in this presentation
*
* @return array with the read pictures ot <code>null</code> if the
* presentation doesn't contain pictures.
*/
public Picture[] getPictures() throws IOException {
byte[] pictstream;
try {
DocumentEntry entry = (DocumentEntry)filesystem.getRoot().getEntry("Pictures");
pictstream = new byte[entry.getSize()];
DocumentInputStream is = filesystem.createDocumentInputStream("Pictures");
is.read(pictstream);
} catch (FileNotFoundException e){
//silently catch exceptions if the presentation doesn't contain pictures
return null;
}
ArrayList p = new ArrayList();
int pos = 0;
while (pos < pictstream.length) {
Picture pict = new Picture(pictstream, pos);
p.add(pict);
pos += Picture.HEADER_SIZE + pict.getSize();
}
return (Picture[])p.toArray(new Picture[p.size()]);
}
} }

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@ -0,0 +1,140 @@
/* ====================================================================
Copyright 2002-2004 Apache Software Foundation
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.
==================================================================== */
package org.apache.poi.hslf.usermodel;
import org.apache.poi.util.LittleEndian;
/**
* Represents a picture in a PowerPoint document.
* <p>
* The information about an image in PowerPoint document is stored in
* two places:
* <li> EscherBSE container in the Document keeps information about image
* type, image index to refer by slides etc.
* <li> "Pictures" OLE stream holds the actual data of the image.
* </p>
* <p>
* Data in the "Pictures" OLE stream is organized as follows:<br>
* For each image there is an entry: 25 byte header + image data.
* Image data is the exact content of the JPEG file, i.e. PowerPoint
* puts the whole jpeg file there without any modifications.<br>
* Header format:
* <li> 2 byte: image type. For JPEGs it is 0x46A0, for PNG it is 0x6E00.
* <li> 2 byte: unknown.
* <li> 4 byte : image size + 17. Looks like shift from the end of
* header but why to add it to the image size?
* <li> next 16 bytes. Unique identifier of this image which is used by
* EscherBSE record.
* </p>
*
* @author Yegor Kozlov
*/
public class Picture {
/**
* Windows Metafile
*/
public static final int WMF = 0x2160;
/**
* Macintosh PICT
*/
public static final int PICT = 0x5420;
/**
* JPEG
*/
public static final int JPEG = 0x46A0;
/**
* PNG
*/
public static final int PNG = 0x6E00;
/**
* Windows DIB (BMP)
*/
public static final int DIB = 0x7A80;
/**
* The size of the header
*/
public static final int HEADER_SIZE = 25;
/**
* Binary data of the picture
*/
protected byte[] pictdata;
/**
* Header which holds information about this picture
*/
protected byte[] header;
/**
* Read a picture from "Pictures" OLE stream
*
* @param pictstream the bytes to read
* @param offset the index of the first byte to read
*/
public Picture(byte[] pictstream, int offset){
header = new byte[Picture.HEADER_SIZE];
System.arraycopy(pictstream, offset, header, 0, header.length);
int size = LittleEndian.getInt(header, 4) - 17;
pictdata = new byte[size];
System.arraycopy(pictstream, offset + Picture.HEADER_SIZE, pictdata, 0, pictdata.length);
}
/**
* @return the binary data of this picture
*/
public byte[] getData(){
return pictdata;
}
/**
* Return image size in bytes
*
* @return the size of the picture in bytes
*/
public int getSize(){
return pictdata.length;
}
/**
* Returns the unique identifier (UID) of this picture.
* The UID is a checksum of the picture data. Its length is 16 bytes
* and it must be unique across the presentation.
*
* @return the unique identifier of this picture
*/
public byte[] getUID(){
byte[] uid = new byte[16];
System.arraycopy(header, 8, uid, 0, uid.length);
return uid;
}
/**
* Returns the type of this picture. Must be one of the static constans defined in this class.
*
* @return type of this picture.
*/
public int getType(){
int type = LittleEndian.getShort(header, 0);
return type;
}
}

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@ -391,4 +391,11 @@ public class SlideShow
* found in the slideshow * found in the slideshow
*/ */
//public MetaSheet[] getMetaSheets() { return _msheets; } //public MetaSheet[] getMetaSheets() { return _msheets; }
/**
* Returns all the pictures attached to the SlideShow
*/
public Picture[] getPictures() throws IOException {
return _hslfSlideShow.getPictures();
}
} }