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

[David Kastrup]

"Trevor Daniels" <address@hidden> writes:

> David Kastrup wrote Monday, December 14, 2015 11:32 AM
>
>
>> 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.
>
> One way to approach this would be via continued fractions.

Well, that's what `rationalize' does.

-- 
David Kastrup