Modulealsa-mixer-0.3.0.1Haskell2010

Sound.ALSA.Mixer

This library provides bindings to the Advanced Linux Sound Architecture (ALSA) library API. The portability of this library is limited to systems with ALSA (i.e., Linux systems). The functions in this library throw errors of type T on failure.

8 types
12 values

Packagealsa-mixer-0.3.0.1
Exports20
LanguageHaskell2010
LicenceBSD-3-Clause
SourceMixer.hs

Types

8 declarations

datadata Control

Control represents one of the controls belonging to an ALSA mixer element. Each control has a number of playback and capture channels. The control may also have a switch and/or a volume capability associated with it. The capability can be common to both playback and capture, or there can be separate capabilities for each.

Constructors

Control
- index :: CUInt
- name :: String
- switch :: Either Switch (Maybe Switch, Maybe Switch)
- volume :: Either Volume (Maybe Volume, Maybe Volume)

newtypenewtype Mixer

datadata Channel

Unknown FrontLeft SND_MIXER_SCHN_MONO FrontRight RearLeft RearRight FrontCenter Woofer SideLeft SideRight RearCenter Last

Instances4Enum, Eq, Read, Show

Enum ChannelDefined in alsa-mixer-0.3.0.1 · Sound.ALSA.Mixer.Internal
Eq ChannelDefined in alsa-mixer-0.3.0.1 · Sound.ALSA.Mixer.Internal
Read ChannelDefined in alsa-mixer-0.3.0.1 · Sound.ALSA.Mixer.Internal
Show ChannelDefined in alsa-mixer-0.3.0.1 · Sound.ALSA.Mixer.Internal

datadata PerChannel e

PerChannel represents a capability that with either a separate value for each channel or with a common value for all channels.

Constructors

Joined
- getJoined :: IO e
- setJoined :: e -> IO ()
- joinedChannels :: [Channel]
PerChannel
- getPerChannel :: IO [(Channel, e)]
- setPerChannel :: [(Channel, e)] -> IO ()
- perChannels :: [Channel]

datadata Volume

Volume represents a volume capability. There may be a separate value per channel, but each capability has only one range.

Constructors

Volume
- getRange :: IO (CLong, CLong)
  Returns the minimum and maximum volumes (unitless).
- setRange :: (CLong, CLong) -> IO ()
  Sets the minimum and maximum volumes (unitless).
- getRangeDb :: IO (CLong, CLong)
  Returns the minimum and maximum volumes in hundredths of a decibel.
- value :: PerChannel CLong
  Volume values for each channel.
- dB :: PerChannel CLong
  Volume values for each channel in hundredths of a decibel.

typetype Switch = PerChannel Bool

Switch represents a switch capability for controls and channels that can be muted and unmuted.

newtypenewtype CUInt

Haskell type representing the C unsigned int type. (The concrete types of Foreign.C.Types#platform are platform-specific.)

Instances14Bounded, Enum, Eq, Integral, Num, Ord, …

Bounded CUIntDefined in ghc-internal-9.1003.0 · GHC.Internal.Foreign.C.Types
Enum CUIntDefined in ghc-internal-9.1003.0 · GHC.Internal.Foreign.C.Types
Eq CUIntDefined in ghc-internal-9.1003.0 · GHC.Internal.Foreign.C.Types
Integral CUIntDefined in ghc-internal-9.1003.0 · GHC.Internal.Foreign.C.Types
Num CUIntDefined in ghc-internal-9.1003.0 · GHC.Internal.Foreign.C.Types
Ord CUIntDefined in ghc-internal-9.1003.0 · GHC.Internal.Foreign.C.Types
Read CUIntDefined in ghc-internal-9.1003.0 · GHC.Internal.Foreign.C.Types
Real CUIntDefined in ghc-internal-9.1003.0 · GHC.Internal.Foreign.C.Types
Show CUIntDefined in ghc-internal-9.1003.0 · GHC.Internal.Foreign.C.Types
Ix CUIntDefined in ghc-internal-9.1003.0 · GHC.Internal.Foreign.C.Types
Bits CUIntDefined in ghc-internal-9.1003.0 · GHC.Internal.Foreign.C.Types
FiniteBits CUIntDefined in ghc-internal-9.1003.0 · GHC.Internal.Foreign.C.Types
Storable CUIntDefined in ghc-internal-9.1003.0 · GHC.Internal.Foreign.C.Types
NFData CUIntDefined in deepseq-1.5.0.0 · Control.DeepSeq

newtypenewtype CLong

Haskell type representing the C long type. (The concrete types of Foreign.C.Types#platform are platform-specific.)

Instances14Bounded, Enum, Eq, Integral, Num, Ord, …

Bounded CLongDefined in ghc-internal-9.1003.0 · GHC.Internal.Foreign.C.Types
Enum CLongDefined in ghc-internal-9.1003.0 · GHC.Internal.Foreign.C.Types
Eq CLongDefined in ghc-internal-9.1003.0 · GHC.Internal.Foreign.C.Types
Integral CLongDefined in ghc-internal-9.1003.0 · GHC.Internal.Foreign.C.Types
Num CLongDefined in ghc-internal-9.1003.0 · GHC.Internal.Foreign.C.Types
Ord CLongDefined in ghc-internal-9.1003.0 · GHC.Internal.Foreign.C.Types
Read CLongDefined in ghc-internal-9.1003.0 · GHC.Internal.Foreign.C.Types
Real CLongDefined in ghc-internal-9.1003.0 · GHC.Internal.Foreign.C.Types
Show CLongDefined in ghc-internal-9.1003.0 · GHC.Internal.Foreign.C.Types
Ix CLongDefined in ghc-internal-9.1003.0 · GHC.Internal.Foreign.C.Types
Bits CLongDefined in ghc-internal-9.1003.0 · GHC.Internal.Foreign.C.Types
FiniteBits CLongDefined in ghc-internal-9.1003.0 · GHC.Internal.Foreign.C.Types
Storable CLongDefined in ghc-internal-9.1003.0 · GHC.Internal.Foreign.C.Types
NFData CLongDefined in deepseq-1.5.0.0 · Control.DeepSeq

Functions

0 declarations

Mixers

valuecontrols :: Mixer -> IO [Control]

All the Control objects associated with a particular Mixer.

valuewithMixer :: String -> (Mixer -> IO a) -> IO a

Perform an IO action with the named mixer. An exception of type T will be thrown if the named mixer cannot be found. A mixer named "default" should always exist.

Controls

valuegetControlByName

:: Mixer
Mixer
-> String
Control name
-> IO (Maybe Control)

Get the named Control, if it exists, from the named Mixer.

valuecommon :: Either a (Maybe a, Maybe a) -> Maybe a

For a given capability, which may be for either playback or capture, or common to both, return the common capability if it exists.

valueplayback :: Either a (Maybe a, Maybe a) -> Maybe a

For a given capability, which may be for either playback or capture, or common to both, return the playback capability if it exists.

valuecapture :: Either a (Maybe a, Maybe a) -> Maybe a

For a given capability, which may be for either playback or capture, or common to both, return the capture capability if it exists.

PerChannels

valuechannels :: PerChannel e -> [Channel]

All channels supported by a PerChannel object.

valueallChannels :: [Channel]

valuejoined :: PerChannel e -> Bool

True if the PerChannel object has a common value for all channels.

valueperChannel :: PerChannel e -> Bool

True if the PerChannel object has a separate value for each channel.

valuegetChannel :: Channel -> PerChannel x -> IO (Maybe x)

Get the value associated with a particular channel, if that channel exists.

valuesetChannel :: Channel -> PerChannel x -> x -> IO ()

Set the value associated with a particular channel, if that channel exists.

Examples

0 declarations

Getting and setting the volume of a Control

This example demonstrates the method of accessing the volume of a Control. The example function reads the volume and increases it by the value supplied.

  changeVolumeBy :: CLong -> IO ()
  changeVolumeBy i =
      withMixer "default" $ \mixer ->
        do Just control <- getControlByName mixer "Master"
           let Just playbackVolume = playback $ volume control
           (min, max) <- getRange playbackVolume
           Just vol <- getChannel FrontLeft $ value $ playbackVolume
           when ((i > 0 && vol < max) || (i < 0 && vol > min))
             $ setChannel FrontLeft (value $ playbackVolume) $ vol + i

Getting and setting the switch of a Control

This example demonstrates the method of accessing the switch of a Control. The example function reads the value of the switch and toggles it.

  toggleMute :: IO ()
  toggleMute =
      withMixer "default" $ \mixer ->
        do Just control <- getControlByName mixer "Master"
           let Just playbackSwitch = playback $ switch control
           Just sw <- getChannel FrontLeft playbackSwitch
           setChannel FrontLeft playbackSwitch $ not sw