Re: Pango Perf & Basic QnA

[Behdad Esfahbod <behdad behdad org>]

On 04/28/2010 12:14 PM, Jason Talley wrote:

> 1 - Currently, I'm not doing anything w/ a fontmap/font_description.
> Is there something I need to do to load the fonts, cache, etc that
> might help this issue?  Thus far, I've not had to do anything beyond
> build/install fontconfig.  Maybe thats the sign of a good library,
> but...

Is your fontconfig cache uptodate?


> 2 - Is the expected way to handle things to keep a context around for
> the life of the text?  Our old system (non international friendly)
> used FT to simply render each glyph on the fly as needed.  A page that
> once rendered in milliseconds now takes tens of seconds when using the
> above function for each block of text.

That doesn't sound right.  You are only expected to keep a fontmap around.
That said, I highly recommend switching over to pangocairo.  pangoft2 is not
maintained anymore.


> 3 - what is the purpose of the fontmap?

It abstracts and caches the fonts available on your system.


> 4 - what's the life expectancy of a layout?  Of a context?

The layout does caching as long as the text and attributes don't change.
However, note that you are expected to pass paragraph at a time to
PangoLayout.  If you do that for each glyph, that's definitely not the way
it's supposed to be done.

behdad

> I can't really fault our drawing engine as the same page loads quickly
> when simply rendering w/ FT (a la FT_Load_Glyph)
> 
> Apologies for html text -- I'll look for a gmail setting to disable.
> 
> Thanks.