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From thomas.dewe...@kodak.com
Subject Re: Batik 1.7 text rendering issues
Date Tue, 05 Aug 2008 10:12:18 GMT
Hi John,

"John C. Turnbull" <ozemale@ozemail.com.au> wrote on 08/04/2008 09:17:36 

> I am looking at Batik for the first time and I have done a little 
> bit of experimentation with the ?text-rendering? attribute yielding 
> some puzzling results.
> I would have thought that the option ?optimizeLegibility? would 
> produce the ?nicest? text or at least the most readable but it seems
> that Batik does not use anti-aliasing at all with this option set. 

   Right, when you use optimizeLegibility we render the text relying
on the font hinting to improve legibility at small font sizes.
The level/quality of the hinting varies a bit from font to font so
it may not be ideal.

> However, when I specify the option ?geometricPrecision? which I 
> would have thought would result in plainer text, I do see anti-
> aliasing and the text is much more readable 

   Setting 'geometricPrecision' means that the rendered text should follow
the raw geometry of the text as closely as possible (hinting 
effectively distorts the outlines of the text to align it with the 
pixel grid).  It also means that we can't take advantage of 
cached glyphs in most cases since a glyph at x="10.1" will render
differently from a glyph at x="10.6" due to anti-aliasing.

>(although still not as readable or as clear as I would like it 
> to be on an LCD screen).
   The very latest versions of the JDK offer options to do
'sub pixel' rendering, however currently Batik doesn't try to
make use of them.

> Is this is the intended behavior or am I misreading this whole 
> issue?  I am using Java 6 Update 10 on Windows Vista.

   AFAIK Batik's behavior is correct with respect to the
SVG specification.

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