PDFText2HTML


1   /**
2    * Copyright (c) 2003-2004, www.pdfbox.org
3    * All rights reserved.
4    *
5    * Redistribution and use in source and binary forms, with or without
6    * modification, are permitted provided that the following conditions are met:
7    *
8    * 1. Redistributions of source code must retain the above copyright notice,
9    *    this list of conditions and the following disclaimer.
10   * 2. Redistributions in binary form must reproduce the above copyright notice,
11   *    this list of conditions and the following disclaimer in the documentation
12   *    and/or other materials provided with the distribution.
13   * 3. Neither the name of pdfbox; nor the names of its
14   *    contributors may be used to endorse or promote products derived from this
15   *    software without specific prior written permission.
16   *
17   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
18   * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
20   * DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
21   * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
22   * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
23   * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
24   * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
26   * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27   *
28   * http://www.pdfbox.org
29   *
30   */
31  package org.pdfbox.util;
32  
33  import java.io.IOException  ;
34  
35  import java.util.Iterator  ;
36  import java.util.List  ;
37  
38  import org.pdfbox.pdmodel.PDDocument;
39  
40  /**
41   * Wrap stripped text in simple HTML, trying to form HTML paragraphs.
42   * Paragraphs broken by pages, columns, or figures are not mended.
43   * 
44   * 
45   * @author jjb - http://www.johnjbarton.com
46   * @version  $Revision: 1.3 $
47   */
48  public class PDFText2HTML extends PDFTextStripper 
49  {
50      private static final int INITIAL_PDF_TO_HTML_BYTES = 8192;
51  
52      private TextPosition beginTitle;
53      private TextPosition afterEndTitle;
54      private String   titleGuess;
55      private boolean suppressParagraphs;
56      private boolean onFirstPage = true;
57     
58      /**
59       * Constructor.
60       * 
61       * @throws IOException If there is an error during initialization.
62       */
63      public PDFText2HTML() throws IOException   
64      {
65          titleGuess = "";
66          beginTitle = null;
67          afterEndTitle = null;
68          suppressParagraphs = false;
69      }
70  
71      /**
72       * Write the header to the output document.
73       * 
74       * @throws IOException If there is a problem writing out the header to the document.
75       */
76      protected void writeHeader() throws IOException   
77      {
78          StringBuffer   buf = new StringBuffer  (INITIAL_PDF_TO_HTML_BYTES);
79          buf.append("<html><head>");
80          buf.append("<title>");
81          buf.append(getTitleGuess());
82          buf.append("</title>");
83          buf.append("</head>");
84          buf.append("<body>\n");
85          getOutput().write(buf.toString());
86      }
87     
88      /**
89       * The guess to the document title.
90       * 
91       * @return A string that is the title of this document.
92       */
93      protected String   getTitleGuess() 
94      {
95          return titleGuess;
96      }
97     
98      /**
99       * {@inheritDoc}
100      */
101     protected void flushText() throws IOException   
102     {
103         Iterator   textIter = getCharactersByArticle().iterator();
104       
105         if (onFirstPage) 
106         {
107             guessTitle(textIter);
108             writeHeader();
109             onFirstPage = false;
110         }
111         super.flushText();
112     }
113     
114     /**
115      * {@inheritDoc}
116      */
117     public void endDocument(PDDocument pdf) throws IOException   
118     {
119         output.write("</body></html>");      
120     }
121 
122     /**
123      * This method will attempt to guess the title of the document.
124      * 
125      * @param textIter The characters on the first page.
126      * @return The text position that is guessed to be the title.
127      */
128     protected TextPosition guessTitle(Iterator   textIter) 
129     {
130         float lastFontSize = -1.0f;
131         int stringsInFont = 0;
132         StringBuffer   titleText = new StringBuffer  ();
133         while (textIter.hasNext()) 
134         {
135             Iterator   textByArticle = ((List  )textIter.next()).iterator();
136             while( textByArticle.hasNext() )
137             {
138                 TextPosition position = (TextPosition) textByArticle.next();
139                 float currentFontSize = position.getFontSize();
140                 if (currentFontSize != lastFontSize) 
141                 {
142                     if (beginTitle != null) 
143                     { // font change in candidate title.
144                         if (stringsInFont == 0) 
145                         {
146                             beginTitle = null; // false alarm
147                             titleText.setLength(0);
148                         } 
149                         else 
150                         {
151                             // had a significant font with some words: call it a title
152                             titleGuess = titleText.toString();
153                             afterEndTitle = position;
154                             return beginTitle;
155                         }
156                     } 
157                     else 
158                     { // font change and begin == null
159                         if (currentFontSize > 13.0f) 
160                         { // most body text is 12pt max I guess
161                             beginTitle = position;
162                         }
163                     }
164          
165                     lastFontSize = currentFontSize;
166                     stringsInFont = 0;
167                 } 
168                 stringsInFont++;
169                 if (beginTitle != null)
170                 {
171                     titleText.append(position.getCharacter()+" ");
172                 }
173             }
174         }
175         return beginTitle; // null
176     }
177     
178     /**
179      * Write out the paragraph separator.
180      * 
181      * @throws IOException If there is an error writing to the stream.
182      */
183     protected void startParagraph() throws IOException   
184     {
185         if (! suppressParagraphs) 
186         {
187             getOutput().write("<p>");
188         }
189     }
190     /**
191      * Write out the paragraph separator.
192      * 
193      * @throws IOException If there is an error writing to the stream.
194      */
195     protected void endParagraph() throws IOException   
196     {
197         if (! suppressParagraphs) 
198         {
199             getOutput().write("</p>");
200         }
201     }
202     
203     /**
204      * {@inheritDoc}
205      */
206     protected void writeCharacters(TextPosition position ) throws IOException   
207     {
208         if (position == beginTitle) 
209         {
210             output.write("<H1>");
211             suppressParagraphs = true;
212         } 
213         if (position == afterEndTitle) 
214         {
215             output.write("</H1>");  // end title and start first paragraph
216             suppressParagraphs = false;
217         }
218       
219         String   chars = position.getCharacter();
220 
221         for (int i = 0; i < chars.length(); i++) 
222         {
223             char c = chars.charAt(i);
224             if ((c < 32) || (c > 126)) 
225             {
226                 int charAsInt = c;
227                 output.write("&#" + charAsInt + ";");
228             } 
229             else 
230             {
231                 switch (c) 
232                 {
233                     case 34:
234                         output.write("&quot;");
235                         break;
236                     case 38:
237                         output.write("&amp;");
238                         break;
239                     case 60:
240                         output.write("&lt;");
241                         break;
242                     case 62:
243                         output.write("&gt;");
244                         break;
245                     default:
246                         output.write(c);
247                 }
248             }
249         }
250     }
251     
252     /**
253      * @return Returns the suppressParagraphs.
254      */
255     public boolean isSuppressParagraphs()
256     {
257         return suppressParagraphs;
258     }
259     /**
260      * @param shouldSuppressParagraphs The suppressParagraphs to set.
261      */
262     public void setSuppressParagraphs(boolean shouldSuppressParagraphs)
263     {
264         this.suppressParagraphs = shouldSuppressParagraphs;
265     }
266 }
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