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From "Hesham G." <heshamgne...@gmail.com>
Subject Re: Spaces are ignored when reading a PDF file
Date Thu, 17 Mar 2016 11:44:56 GMT
Andreas,

You're absolutely right. I am testing it now, but it seems very complicated. 
I hope there might be another easier solution.


Best regards ,
Hesham

------------------------------------------------------------------------
Included message :

> "Hesham G." <heshamgneady@gmail.com> hat am 17. März 2016 um 11:20
> geschrieben:
>
>
> Andreas,
>
> That is very helpful.
>
> I can get the x location of each character using TextPosition.getX(), ex:
> W: 102.88399
> i: 114.18165
> t: 117.660614
> h: 121.55801
> d: 133.09477
> u: 140.3994
> e: 147.60838
>
> So to detect the space between the 2 words "With" & "due" should I make
> subtraction calculations between X of the last letter(h) and the X of the
> first letter (d) and if the number is large than normal then this is a
> space? I think this way might be risky in the detection, or what?
That's the short story. To decide what is normal could be quite tricky. You 
have
to take the following facts into account:

- different fonts have different widths (important if the font before the 
space
isn't the same than the font after the space)
- keep in mind that you have to take a scaling and sometimes a rotation into
account
- the "space" between characters may vary if the text is jusitified

There are certainly some other details which may be important as well, so 
that
you end up with some more or less heuristic.

BR
Andreas

> Best regards ,
> Hesham
>
> ------------------------------------------------------------------------
> Included message :
>
> Hi,
>
> > Frank van der Hulst <drifter.frank@gmail.com> hat am 17. März 2016 um
> > 08:34
> > geschrieben:
> >
> >
> > Spaces don't exist as characters in PDFs. To identify spaces, you have 
> > to
> > compare the X coordinates of adjacent characters against their widths.
> That's not correct, spaces exist but in most cases pdf engines omit them 
> and
> replace spaces by a splitted text with an appropriate positioning.
>
> BTW, latex uses the same strategy. Here is a excerpt from your pdf:
>
>    [ (W) 55 (ith) -383 (due) -384 (r) 18 (egar) 18 (d) -383 (to) -383
> (Article)
> -384 (\(219\),) -416 (the) -384 (competent) -383 (authority) -383 
> (has) -384
> (the) -383 (right) ] TJ
>
> The text is in between the braces and the numbers are used for horizontal
> positioning.
>
> BR
> Andreas
>
> >
> > On Thu, Mar 17, 2016 at 7:12 PM, Hesham G. <heshamgneady@gmail.com> 
> > wrote:
> >
> > > Hello ,
> > >
> > > I have a PDF file created using Latex. I am trying to read and print 
> > > all
> > > letters in that file using PDFBox, but when doing this all spaces in
> > > that
> > > file are ignored. Here is the code I am using:
> > > PDPage page = (PDPage)allPages.get( 0 );
> > > PDStream contents = page.getContents();
> > > if ( contents != null ) {
> > >     PDFTextStripperProcessor pdfTextStripperProcessor = new
> > > PDFTextStripperProcessor();
> > >     pdfTextStripperProcessor.processStream( page, 
> > > page.findResources(),
> > > contents.getStream() );
> > > }
> > >
> > > public class PDFTextStripperProcessor extends PDFTextStripper {
> > >     @Override
> > >     public void processTextPosition( TextPosition text )  {
> > >         System.out.println( text.getCharacter() );
> > >     }
> > > }
> > >
> > > And you can check a one page file sample here to test it:
> > >
> > > https://dl.dropboxusercontent.com/u/10111483/downloads/pdfbox/pdf_latex_spaces_ignored.pdf
> > >
> > > What is the cause of this issue please?
> > >
> > >
> > > Best regards ,
> > > Hesham
>
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