Re: converting svg glyph to path data for use in scheme

[David Kastrup]

Urs Liska <address@hidden> writes:

> Am 13.12.2015 um 14:09 schrieb Graham Breed:
>> On 13/12/15 12:48, N. Andrew Walsh wrote:
>>> Take a look at conversions.ly (sorry; mround is the equivalend
>>> function in
>>> the spreadsheet I use to do the same thing). Those functions will
>>> convert
>>> the input (given as a fraction comprising two integers) into Lily's
>>> semitone values. That should allow you to convert between
>>> just-intonation
>>> ratios an the nearest note name. Urs has some comments in there
>>> explaining
>>> a bit how it works.
>>
>> Converting from ratios to cents is easy.  Converting between ratios
>> and cents requires a function from cents to ratios.  That's a lot more
>> difficult because information is lost.  You got us excited by
>> suggesting that had been solved.
>
> Well, this is because conversion from cent to ratio isn't part of the
> objective currently.

Guile has

(rationalize (inexact->exact (atan 0 -1)) #e1e-6)

so you can try converting irrational numbers to ratios.  However,
figuring out the precision to use may be tricky and there is no "prefer
simple ratios" option.  All you have to work with is the eps argument.

-- 
David Kastrup