On May 4, 2005, at 9:51 PM, Erik Osheim wrote:
I've been developing a curses-based music player in python for the
pretty good these days. I have added keybindings to control volume in
linux using the ossaudiodev module found in python.
I wanted to do the same thing under OS X which I am now trying to
fully support. After some digging, it looked to me like Carbon.Snd was
the ticket. However, I can't find any documentation on this module; I
did some digging in Apple provided docs, and was able to get a
semi-working, semi-broken version of volume control going (mutes one
ear, controls the volume of the other), but I am not sure this will do
it.
My questions are:
1. Does anyone have a good idea how to go about doing this best on OS
X? I am not going to be able to support OS 9 (too many unix
dependencies) so if there is a cleaner way to do it than Carbon I
would be interested.
The best way to do it on OS X is to use CoreAudio, but none of that �
is wrapped in Python.� You can, however, find an Objective-C �
framework that wraps what you need (MTCoreAudio should be able to do �
it, but there might be something easier) and just call into that with �
PyObjC.
There are a couple other ways, but they're all really, really old and �
deprecated and they often behave pretty strangely.
2. Is there anywhere to get better docs on things like ae*, Carbon.*,
etc? It seems like python for mac is incredibly powerful but arcane,
and between no documentation and no doc strings I have a hard time
figuring out what I can do with it.
The first thing you should do is look for another way to do it, with �
PyObjC or some POSIX API (but probably PyObjC).� There's a very �
straightforward translation between Objective-C and Python, so you �
use Apple's Cocoa docs when developing with PyObjC.
If there is no way to do what you need with just PyObjC, you should �
consider just writing a little Objective-C wrapper that does what you �
need to do (calling into Carbon, CoreFoundation etc.), and call into �
that from PyObjC.� Use the Apple documentation.� Unfortunately this �
does require knowing C, but the ONLY documentation and the ONLY �
supported APIs are for C and Objective-C.� Most of the time, in my �
experience, it's just quicker to write and debug the code (i.e. �
QuickTime related stuff) in Objective-C and call into it from PyObjC.
If you still feel the need to try and do it with "pure Python", then �
read the Apple documentation for the relevant function(s) in C, and �
then guess at how it would be done from Python.� Everything in �
Carbon.* is automatically generated, but there are a bunch of special �
cases and the rules are a bit strange.� These modules would sooner go �
away than become documented.� Don't be surprised if there's a bug in �
the wrapper or some function call sequence is impossible because the �
wrapper won't let you pass NULL somewhere, etc.� Writing code using �
undocumented modules that may be broken is no fun.
-bob
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