The method that should be used for determining paragraph
When a document is made accessible one needs to determine the
reading order for the text. This property allows one to control the
method which is used to determine the reading order of the
paragraphs on the page.
You can choose from the following options:
- None - Use the order of layout that already exists on the
- Recursive - Recursively group by rows and columns.
- TopDownLeftRight - Order primarily top to bottom, secondarily
left to right.
- TopDownRightLeft - Order primarily top to bottom, secondarily
right to left.
The None option may seem initially attractive since drawing
sequence and semantic sequence might seem similar. However the
reality is that PDFs are often constructed in peculiar ways; tables
will sometimes be drawn left to right, sometimes top to bottom;
pages will be drawn, then extra sections will be drawn on top of
them to modify the existing structure. In general the other options
will provide more predicable results.
Reading Direction. Some documents contain bi-directional
or right-to-left text like Hebrew and Arabic. If this is the case,
before the operation, you may wish to change the reading direction
and language. This helps ABCpdf analyse the document correctly and
without the change of direction the text may be read backwards.
The following code can be used to set the predominant language
and text direction for Hebrew.
doc.SetInfo(doc.Root, "/Lang:Name", "he-IL"); //
Language-Tag defined in RFC 3066
If your documents are complicated and you require complete
control over the detection process, you can do this using the
techniques detailed in the AccessiblePDF example project which
comes with ABCpdf.