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From The Web Maestro <the.webmaes...@gmail.com>
Subject Re: Intermediate Format Performance: Necessary changes to IFPainter interface
Date Tue, 03 Feb 2009 15:35:03 GMT
Sounds exciting! Cool!

On Tue, Feb 3, 2009 at 2:31 AM, Jeremias Maerki <dev@jeremias-maerki.ch> wrote:
> Oh, yes, I almost forgot: I'm removing the "dy" parameter for now since
> it's not supported anyway until we support different writing-modes.
> Doesn't make sense to keep that around until then.
> On 03.02.2009 11:10:03 Jeremias Maerki wrote:
>> I'm getting near to finishing my work on the new intermediate format.
>> Logically, performance tests have to show whether the goals have been
>> achieved. Generally, they have:
>> - Rendering directly from the new intermediate is a lot faster than from
>> the old area tree XML format.
>> - The new intermediate files are also a lot smaller.
>> - New output formats are much easier to implement than the old Renderers.
>> However, the performance tests showed that the improvement for the
>> PostScript output was rather small (and that's one of the most important
>> formats in that context). The cause was my simplistic approach to glyph
>> positioning (using the xshow operator). It causes at least one
>> DecimalFormat.format() call per glyph even if the text has no kerning,
>> letter/wordspacing or justification. So I had to revise my decision to
>> simply carry a "dx" (from SVG) property with glyph offsets. Adding SVG's
>> letter-spacing and word-spacing attributes made it possible to keep dx
>> to null in many cases. Furthermore, a custom text painting operator in
>> PostScript (similar to PDF's TJ) allowed much more compact PostScript
>> code and brought the performance back in the region of PDF and AFP.
>> So, IFPainter.drawText will get two new parameters letterSpacing and
>> wordSpacing. I'm currently updating the rest of the output formats in a
>> similar way (for example, PDF gets to use the Tc operator for
>> letter-spacing). AFP will also profit from that. I'll commit when
>> everything's working again.
>> I'll also publish performance figures when this is done.
>> Jeremias Maerki
> Jeremias Maerki


The Web Maestro
<the.webmaestro@gmail.com> - <http://ourlil.com/>
My religion is simple. My religion is kindness.
- HH The 14th Dalai Lama of Tibet

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