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From Tilman Hausherr <THaush...@t-online.de>
Subject Re: question about creating a PDF - layers and PDPageContentStream
Date Sun, 06 Jan 2019 08:42:38 GMT
See also 
https://stackoverflow.com/questions/53108150/rotate-text-at-45-degree-angle-across-the-center-apache-pdfbox

Tilman

Am 06.01.2019 um 07:40 schrieb Tilman Hausherr:
> Am 05.01.2019 um 21:30 schrieb Don Wills:
>> Hello,
>>
>> I'm a newbie to PDFBox.  It appears to be a very useful tool for what 
>> we're trying to accomplish.
>>
>> FWIW, in the past we have been building our own raw PDF files from 
>> scratch for simple printed output from Java code.  It was tedious, 
>> but with a minimal API on top, it worked.  Thus I have a bit of 
>> knowledge about the structure of a PDF, but not much more.
>>
>> I have noticed that when images, text and graphics are mixed in a 
>> single PDPageContentStream in no particular order, it appears that 
>> the elements are displayed and printed in layers.  From my initial 
>> tests, it appears that graphics (lines and filled polygons) are at 
>> the lowest layer, text is above the graphics, and images are on top 
>> of graphics and text.  Is that correct? Is that a feature or an 
>> accident?  Is that a feature of the PDF spec or PDFBox?  Is that 
>> behavior documented anywhere?
>
>
> It depends on the order in the content stream. This can be chosen freely.
>
> See the PDF specification...
>
>
>>
>> I need to put a watermark on each page of a report.  So for each page 
>> of the report I create a PDPageContentStream, draw the watermark 
>> image on that content stream, close it, and then create a second 
>> PDPageContentStream in APPEND mode for the page that contains the 
>> text, graphics and images of the page.  All seems to work well. Is 
>> that the correct approach, or is there another better method?
>
>
> Yes that is one solution.
>
>
> Another is to append and to use transparency.
>
>
>
>>
>> Also, is there a place where I can search for answers to questions 
>> like this?  I'm sure this particular question has been answered 
>> before.  I couldn't find anything on StackOverflow and I have no idea 
>> how to search the archives of this email list.
>
>
> "pdfbox watermark" finds a few on stackoverflow.
>
>
> Tilman
>
>
>>
>> TIA.
>>
>> Don Wills
>> Portable Software Company
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>
>
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