从书签中提取PDF中的文本

Question

I need to extract the text from a PDF right at the place where a bookmark is.

PDFBox extracts the whole page where the bookmark is, as explained here .

But i need to extract the text starting with the bookmark.

Answer 1

I believe iText can handle this.

Rectangle2D bookmarkRect = getRectFromBookmark(someBookmarkThingy);

FilteredTextRenderListener filter = 
  new FilteredTextRenderListener( new LocationTextExtractionStrategy(), 
                                  new RegionTextRenderFilter( bookmarkRect ));

String bookmarkText = PdfTextExtractor.getTextFromPage(reader, pageNum, filter);

someBookmarkThingy will probably be a PdfDictionary of the bookmark in question.

WARNING Bookmarks can actually hold just about any action. They typically hold one of several varieties of GoTo* action.

GoTo actions can specify a rectangle, an upper left corner & zoom factor, just a page, and quite a few other variants. Anything defining a zoom setting will be affected by the size of the window the PDF is being displayed in . That includes all of them except the one that explicitly defines a bounding box for the new view. You'll have to make an educated guess on what a typical window size is and do your conversions from there.

You're probably going to need to read the PDF Specification , particularly section 12.6.4.2 "Go-To Actions". Hmph. What you really need will be the section on Destinations, 12.3.2. Page destinations can be defined thusly:

• [pageRef /XYZ left top zoom]
• [pageRef /Fit]
• [pageRef /FitH top]
• [pageRef /FitV left]
• [pageRef /FitR left bottom right top]
• [pageRef /FitB]
• [pageRef /FitBH top]
• [pageRef /FitBV left]

Have fun!