Re: Font Metrics

Hi Dylan,

"Dylan Browne" <dylanmango-solutions.com>
wrote on 04/03/2007 10:19:30 
AM:

> If I am rendering a specified font in SVG, say Verdana,
is there anyway 
to
> ascertain information about the font rendering. What I
need to get hold 
of
> is the ascent and descent so I am able to layout text
correctly.
> 
> I am guessing to be able to do this I need to get hold
of the Font 
Metrics
> object, and to do that would require access to the
Graphics object?

   The Graphics object won't help that much actually.  If
you are using
a "Platform Font" then you can just use the
Standard Java API's to get
the font metrics.  If you are using an SVG Font, this is
quite a bit
more complex as the construction of an SVG Font Instance
requires a
text element hooked into the CSS cascade.   In fact the
easiest way
to get this would be to build an SVG text element and then
get the
Font associated with the GVT Graphics node.

   The method:
           BridgeContext.getGraphicsNode(Element)

   Can be used to get the batik.gvt.TextNode that is
associated
with an SVG Text Element.  From that you can get the 
AttributedCharacterIterator, from which you can get the Font
by
looking get the value for the TextAttribute:
       
batik.gvt.text.GVTAttributedCharacterIterator.GVT_FONT.

> I am creating my SVG using Batik DOM, so am also
guessing this is not
> possible? In which case I should define my own font, or
use a true 
> type font and convert it to SVG font using ttf2SVG?

   It is possible although as you can see from the sketch
above
it's not real easy (unless you are only concerned with
Platform
fonts).

> Hope my questions make sense, and thanks in advance for
any help.

   Good luck!

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