Re: usability questions about Arabic script on UML sequence diagrams

[Yanic Inghelbrecht <yanic dot inghelbrecht at avondschool dot be>]

Hi Imed,

Thank you very much for your view on these issues!

I had already implemented the support for right-to-left scripts and 
diagram layout, but I wasn't sure if a) it was useful and b) I had made 
the right choices. Luckily you confirmed that I'm on the right track.

> Paying some attention to the Arabic language will also buy you the
> support for nearly all semetic languages or languages using the Arabic
> script, that is Farsi, Urdu, Hebrew, etc.
Great!

-----

Issue 1 (language related)
> I'm almost sure that developers in the Arab world use English in
> porgramming for portability reasons and to make it easier to
> communicate with non-Arabic speaking users. This may not be good news
> though, since you'll have to worry about bidirectional text which may
> be a bit confusing at times.
That certainly makes sense.

Also, I'm using the built-in support for bidi-text of the Java platform, 
so I hope it works the way it should (i.e. no confusion required on my 
part :o).

-----

Issue 2 (direction related)
> I cannot speak for everyone on this, but I, for one, find it more
> natural to read diagrams from right-to-left. I would say this is a
> plus to have, but if it gives a headaches to implement, then most
> Arabic-speaking developers would still live with a left-to-right
> diagram.
Actually, the diagrams were exported from the program!

Adapting the layout algorithms was pretty straightforward (in 
retrospect), although confusing at times. At some point I decided to 
first change all left/right references in comments and variables to 
leading/trailing, before continuing. That made it a lot easier to reason 
about the algorithms and adapt them. The biggest source of confusion was 
that the coordinate system of Java2D remains the same regardless of 
left/right or leading/trailing,  i.e. adding to the x-coordinate always 
moves things to the right.

-----

Issue 3 (font related)
> I get this comment quite often and I still don't know why the text,
> despite the small size, is very readable for me and I didn't get
> confused on any word. I guess, the human brain does not need to look
> at individual letters but only a few and the general shape of the word
> to recognise it. I'm sure this would be more problematic with
> unfamiliar words like transliterated Latin names.
>
> I would say, the text is very readable as is, but you may want to add
> a font-sizing option to be on the safe side.
Ah, that's good news (but font-sizing is already present in the program 
as well).

I was wondering if I should make the space between the bottom of the 
text and the underline a setting the user can change?

The last couple of days, I've been adding support for multi-line text 
(e.g. in comments). I've run into another issue that I hope the 
community could help me with :

-----

Issue 4 (justification related)

At first, justification of multi-line texts seemed simple : always pick 
leading justification. However, mixed script complicates the matter.

Each line can have its own base direction (left-to-right or 
right-to-left). I simply layout each line according to its own leading 
direction (i.e. right for Arabic script, left for English, etc.). How it 
is decided what the base direction is of a line which mixes Arabic and 
English script, I have no idea. I just get the base direction via a 
library call for each line so I'm guessing it's ok.

When showing the diagram, I can give each line its own justification 
according to its script :

http://www.freeimagehosting.net/uploads/522ce4d984.jpg

a) Would you prefer all lines in a text to be justified the same way 
regardless of their script (based on user locale), or would you prefer 
each line to get its own justification based on its script (as in the 
above image)?

When editing text, aligning individual lines according to their script 
is not feasible I think. So I would have to pick one direction and align 
all lines the same way.

b) Would you prefer I pick this according to the user locale (i.e. 
leading justification)? So an Arab developer could see both Arabic and 
English lines right-justified whilst I would see them left-justified? 
(note : once editing is over, I could justify each line individually 
according to its script as mention in issue 4a above).

Thanks in advance for any view you (or someone else) can give on this 
matter.

Best regards,
Yanic Inghelbrecht