Re: [Devel] Cache Manager

[David Turner]

Hi Mike,

> 
> I'm currently testing to find the fastest method to retrieve characters. 
> Using the cache manager I cache the lower half of the character set on boot 
> up. I've used a truetype font and a .fon file. Using the .fon file  is much 
> faster than the truetype font but not 'apparently' for the reason I thought. 
> After tracing through the code, I've noticed that the rendering process also 
> allocates bitmap memory for a character in the .fon file of which I thought 
> it would not. I though it would just use the bitmaps in the font file. 
> Anyway, since the cache system is caching for both fonts, I was wondering why 
> using the truetype file was so much slower. Am I doing something incorrectly?
> 

You'll probably need to give us a few more details about your
system and program so that we can answer it. Could you tell us:

 - are you using the bytecode interpreter or the auto-hinter (the
   latter can be much slower than the former for some fonts) ?

 - did you try to load without hinting (use FT_LOAD_NO_HINTING)
   does this change speed dramatically ??

 - is loading the 256 characters through the cache manager really
   slower than loading them directly through the FT2 API ? If not,
   there probably isn't anything wrong with the cache manager.

 - at what size are you loading the characters. Monochrome or
   anti-aliased ?

 - what cache size are you using (since it is customizable),
   what kind of glyph images are you caching (FT_Glyph of small
   bitmaps ??)

 - which version of FreeType 2 are you using ?

 - what's your system. A MHz count could be useful to compare
   it with other working systems that use FT2 without too
   much trouble (even at 16 MHz !! ;-)


> An additional question: Is the font system capable of scaling a bitmap font? 
> And where would I look for this?

We don't provide that for now, I don't know if doing it is such a good idea,
since it sounds more a graphics feature than anything else.. Anyway, if you
have some code to contribute, we'll probably review it to see if it can be 
incorporated within FT2.

Otherwise, you'll need to look for the functionality in your favorite
graphics lib or code your own..

Regards,

- David