[reportlab-users] RTL Patch Committed

[Yoann Roman]

Andy Robinson wrote...

> 2009/11/24 Yoann Roman <yroman-reportlab at altalang.com>:

>> Based on what I've read, it seems Pango can do this glyph selection

>> given the text and font. I just haven't confirmed this or if there's 

>> a way to get the information back out in a usable form to RL.

> 

> I am not even sure we would have a use for the info.  When making PDF,

> we do not render text at all; we just pass a string to the PDF

> 'textout' operator, which is stored in the PDF and then somehow

> rendered on someone else's monitor later.  So we're at someone else's

> mercy about how it all looks in the end (Adobe? MS/Apple/Gnome?)


Ah. For some reason, I kept thinking you outputted a code point to 
font glyph mapping somewhere.


> When I have time and have learned to recognise some phrases, I'll get

> back to absolute basics:   make up a 'hello world' phrase in Farsi or

> Pashto as Postscript, run it through Acrobat Distiller, and see what

> kind of PDF comes out of it.  If it looks right from the glyph

> selection viewpoint, then we can look at what kind of font

> declarations need to go with it.


I've tried a similar approach, but I've never been able to decode the 
PDFs Acrobat generates. Is there a tool you use to interpret Acrobat's 
PDFs into something more human-legible?


> We also have to think of our non-PDF output.  When making bitmap

> charts, we currently use libart under the hood, and we have extra bits

> of code to extract and pass curves to it from FreeType.    Probably

> all of this needs 'modernising' for ReportLab 3000 to use fully

> Unicode-aware rendering tools.


Pango uses HarfBuzz, which supposedly started from FreeType and can 
apparently be integrated back into it. HarfBuzz is actually developed 
in part by the author of Fribidi:
http://www.freedesktop.org/wiki/Software/HarfBuzz

I don't know much about HarfBuzz or FreeType; I just remembered having 
seen a reference to FreeType when digging around for RTL support.

-- 
Yoann Roman