Why does ColumnText ignore the horizontal alignment?

Why does the text appear printed on top of a column, where it is unreadable?

I'm trying to get some rows of text on the left side and some on the right side. For some reason iText seems to ignore the alignment entirely. For example:

// create 200x100 column
ct = new ColumnText(writer.DirectContent);
ct.SetSimpleColumn(0, 0, 200, 100);
ct.AddElement(new Paragraph("entry1"));
ct.AddElement(new Paragraph("entry2"));
ct.AddElement(new Paragraph("entry3"));
ret = ct.Go();
 
ct.SetSimpleColumn(0, 0, 200, 100);
ct.Alignment = Element.ALIGN_RIGHT;
ct.AddElement(new Paragraph("entry4"));
ct.AddElement(new Paragraph("entry5"));
ct.AddElement(new Paragraph("entry6"));
ret = ct.Go();

I've set the alignment of the 2nd column to Element.ALIGN_RIGHT but the text appears printed on top of column one, rendering unreadable text. Like the alignment was still set to left.

Posted on StackOverflow on Aug 9, 2013 by Chuck

To understand what happens, you should learn about the concepts "text mode" and "composite mode".

If you work in text mode, you can define the alignment at the level of the ColumnText object. In other words ct.Alignment = Element.ALIGN_RIGHT; will work in text mode.

If you work in composite mode, the alignment at the column level will be ignored in favor of the alignment of the elements added to the column. In your case, iText will ignore the ALIGN_RIGHT in favor of the alignment of the Paragraph objects added to the column. Looking at your code, I see that you didn't define an alignment for the paragraphs, so the default alignment ALIGN_LEFT is used.

How do you know if you're working in text mode or in composite mode?

By default, ColumnText uses text mode but it switches to composite mode (removing all previously added text) the moment you invoke the AddElement() method.

The concepts text mode and composite mode also applies to PdfPCell.