Re: Lilypond on iPhone

[Graham Percival]

On Thu, Feb 04, 2010 at 08:53:22PM +0000, Dave Addey wrote:
>    1) How do you rate my chances of getting Lilypond to compile for the
>    ARM-based iPhone OS, especially given the number of libraries it depends
>    on?

Compiling on an ARM-based chip?  No problem.  Debian's been
compiling lilypond on arm for years.

On the iphone OS?  Almost zero.  You'd certainly need to jailbreak
your phone, but even then I'm pessimistic about porting all the
font-related libraries to whateve environment you get with a
jailbroken iphone OS.

That said, I've heard that iphoneOS is a variant of OSX, and
people manage to compile it on OSX (after a lot of trouble), so
maybe I'm overly pessimistic here.

>    2) Would there be any licensing issues in using Lilypond (and dependent
>    libraries) in a paid app on a closed platform such as the iPhone?

Yes.  LilyPond is GPL.  If it's compiled directly into your app,
you'd need to distribute source for lilypond and your app.

GPL software on the iphone is a grey area in general.  Some people
interpret the GPL as requiring that the user be able to compile
your software (which is not possible unless the user has an iphone
developer license, costing $99).  Other people say that as long as
the source is available, it's fine.  Note that the iphone has no
provision for distributing app sources, so you'd need to add a
special button to your app which extracts the source (which you
distrbuted as part of your app) and saves it in a location for the
user.

If you run lilypond as a service (which AFAIK isn't possible in
the non-multitasking iphone OS), then you'd be fine.

>    3) What's the likely performance of rendering .ly files on a lower-powered
>    (and lower-memory) device such as an iPhone or iPod Touch? Is it likely to
>    take seconds, minutes or hours?

4 bars?  I'd say a few seconds.  A page of music with no tweaks?
Maybe a minute.

>    4) If performance is likely to be a no-go, what are my best alternative?
>    Server-side PDF generation for delivery to a device?

Server-side PDF generation would work, although we recently
switched to GPLv3 so you'd need to double-check how that works for
web apps.  You'll want to look into security, since lilypond
doesn't do any such checking.  Do a few mailist searches; the
question pops up from time to time and I don't feel like repeating
myself for an 8th time.

>    Any thoughts or ideas much appreciated.  I've a fair bit of experience in
>    Mac open-source development (I wrote much of the audio code for
>    Handbrake), but I'm new to Lilypond, so would be starting from scratch in
>    compiling it.

Trying to guess at your intentions, you'd probably be better off
different software.  I vaguely recall some kind of KDE applet that
did music notation... muscore or something like that?  In any
case, I really doubt that lilypond is the right tool for this job.


BTW, thanks for your work on Handbrake!  It was very handy when I
moved from my parent's house to different city for university in
Canada.  :)

Cheers,
- Graham