Re: [Freetype] How to use freetype2's cache system for bold, italic and rotation and ...

[David Turner]

Hello,

> wjj263 a écrit :
> 
> Without using cache, I can render embolded characters by functions relating 
> to FT_Outline.
> But when I used the cache system, only regular characters are rendered. It 
> seems that the cache system in freetype2 can not cope with bold, italic and
> rotation.
> Can you give me some good ideas about how to use cache in freetype2 ?
> 

You basically need to create a new cache class to be used by the cache
manager. For now, this is a bit difficult due to the cache sub-system's
design but doable nonetheless..

> BTW: I noticed that FT_Outline_Embolden(...) is an experimental function. 
> Using this function is quite differet with the introduced idea in tutorial. 
> Is there
> any good idea for using other function for bold and italic?
>

There are several ways to do that:

  - tweak the bitmap to artifically "embolden" it. Works with
    any font format, quality may not be very satisfying except
    for small character pixels sizes..

  - tweak the outline like FT_Outline_Embolden. Again, the quality
    will vary greatly depending on the font used, and most type
    designers will throw flames at you because you'll only have
    created a very low-quality "bold" version..

    finding a good and efficient algorithm is another challenge
    (and we want one that works well with fixed-point maths..)

Regards,

- David