Your changes are great and thank you very much for that 
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Regarding your reported bug, i found that making vectors is very complicated!
There are two points now, one is that in Persian, characters have a double behavior and sometimes they have to be stuck together. For example, the word "سلام" (which means “hello”) contains the letters of the alphabet س ل ا م, but in writing, these characters are in the stacked form which makes “سلام” .
The second point is the direction of each word itself. I thought you meant miss-direction of all words together in a paragraph, but now I realize that the miss-direction exists even inside the words themselves (e.g. سلام will be written as ملاس and of course not in stacked form). Therefore, with the current approach, words are written in reverse. 
So there are two important objects:
- Words must be written in stacked form, unless the white-space character separates them.
- Each word must be written from right to left.
I’m not sure if by changing the font itself we can solve any above mentioned issues, (sometime it works, even in Microsoft Word we have something like that) but at least i can try it with different fonts.