Re: [Devel] Problems with bbox code and cubic bezier curves

[Just van Rossum]

Tom Kacvinsky wrote:

> Hi Just,
> 
> >
> > But I don't understand *why* to *ever* worry about an exact bounding box? 
> > If 
> > the outlines are decent, the cbox is fine, and if the outlines are not so 
> > decent, then the cbox may be too large, but why should FT care?
> 
> I'll give you an example (and it shouldn't surprise you, considering the topic
> has been opened on the OpenType list):
> 
> Getting AFM data from OpenType/CFF fonts.  The AFM ought to have decent glyph
> bbox info for post processing by tools like afm2tfm, etc...

Not knowing tfm's at all, so I have to ask: why isn't the cbox good enough even
for those purposes? (I just checked, the AFM spec indeed mumbles something about
"flattened paths", so strictly speaking you are absolutely right.)

But this also proves my other point: for such tools speed is not an issue, so a
"simple" implentation using floats and sqrt's etc. would be good enough. No need
to fiddle with fixed point math, splitting curves, etc.

> Now, I know TTX will do what I want when I get around to it,

(Erm, all I support right now are cboxes ;-)

Just