Public Member Functions | List of all members
BMidiLocalProducer Class Reference

A producer endpoint that is created by your own application. More...

Inherits BMidiProducer.

Public Member Functions

 BMidiLocalProducer (const char *name=NULL)
 Creates a new local producer endpoint. More...
 
virtual void Connected (BMidiConsumer *cons)
 Invoked when a new consumer is connected to this producer. More...
 
virtual void Disconnected (BMidiConsumer *cons)
 Invoked when a consumer is disconnected from this producer. More...
 
void SprayChannelPressure (uchar channel, uchar pressure, bigtime_t time=0) const
 Sends a Channel Pressure event to all connected consumers. More...
 
void SprayControlChange (uchar channel, uchar controlNumber, uchar controlValue, bigtime_t time=0) const
 Sends a Controller Change event to all connected consumers. More...
 
void SprayData (void *data, size_t length, bool atomic=false, bigtime_t time=0) const
 Sends raw MIDI data downstream to all connected consumers. More...
 
void SprayKeyPressure (uchar channel, uchar note, uchar pressure, bigtime_t time=0) const
 Sends a Polyphonic Pressure (Aftertouch) event to all connected consumers. More...
 
void SprayNoteOff (uchar channel, uchar note, uchar velocity, bigtime_t time=0) const
 Sends a Note Off event to all connected consumers. More...
 
void SprayNoteOn (uchar channel, uchar note, uchar velocity, bigtime_t time=0) const
 Sends a Note On event to all connected consumers. More...
 
void SprayPitchBend (uchar channel, uchar lsb, uchar msb, bigtime_t time=0) const
 Sends a Pitch Bend event to all connected consumers. More...
 
void SprayProgramChange (uchar channel, uchar programNumber, bigtime_t time=0) const
 Sends a Program Change event to all connected consumers. More...
 
void SpraySystemCommon (uchar status, uchar data1, uchar data2, bigtime_t time=0) const
 Sends a System Common event to the connected consumers. More...
 
void SpraySystemExclusive (void *data, size_t length, bigtime_t time=0) const
 Sends a System Exclusive event to all connected consumers. More...
 
void SpraySystemRealTime (uchar status, bigtime_t time=0) const
 Sends a Real Time event to the connected consumers. More...
 
void SprayTempoChange (int32 beatsPerMinute, bigtime_t time=0) const
 Sends a Tempo Change event to the connected consumers. More...
 
- Public Member Functions inherited from BMidiProducer
status_t Connect (BMidiConsumer *cons)
 Connects a consumer to this producer. More...
 
BListConnections () const
 Returns a list with all connected consumers. More...
 
status_t Disconnect (BMidiConsumer *cons)
 Disconnects a consumer from this producer. More...
 
bool IsConnected (BMidiConsumer *cons) const
 Determines whether a consumer is connected to this producer. More...
 
- Public Member Functions inherited from BMidiEndpoint
status_t Acquire ()
 Increments the endpoint's reference count. More...
 
status_t GetProperties (BMessage *properties) const
 Reads the properties of the endpoint. More...
 
int32 ID () const
 Returns the ID of the endpoint. More...
 
bool IsConsumer () const
 Determines whether this endpoint is a BMidiConsumer. More...
 
bool IsLocal () const
 Determines whether this endpoint represents a local object. More...
 
bool IsPersistent () const
 Not used. More...
 
bool IsProducer () const
 Determines whether this endpoint is a BMidiProducer. More...
 
bool IsRemote () const
 Determines whether this endpoint is a proxy for a remote object. More...
 
bool IsValid () const
 Determines whether the endpoint still exists. More...
 
const char * Name () const
 Returns the name of the endpoint. More...
 
status_t Register ()
 Publishes the endpoint on the roster. More...
 
status_t Release ()
 Decrements the endpoint's reference count. More...
 
void SetName (const char *name)
 Changes the name of the endpoint. More...
 
status_t SetProperties (const BMessage *properties)
 Changes the properties of the endpoint. More...
 
status_t Unregister ()
 Hides the endpoint from the roster/. More...
 

Detailed Description

A producer endpoint that is created by your own application.

You create a BMidiLocalProducer if you want your application to send MIDI events. You use the various spray functions to send events to all connected consumers. If no consumers are connected to the producer, any calls to the spray functions are ignored.

Most spray functions accept a channel argument. Even though MIDI channels are really numbered 1 through 16, the spray functions work with channels 0 through 15. You can also specify the performance time for the event using the time argument. Specify 0 (or any time in the past) to perform the event "now", i.e. as soon as possible. You can also schedule events to be performed in the future, by passing a time such as system_time() + 5000000, which means 5 seconds from now.

Unlike BMidiLocalConsumer, which should be subclassed almost always, you hardly ever need to derive a class from BMidiLocalProducer. The only reason for subclassing is when you need to know when the producer gets connected or disconnected.

Also unlike consumers, local producers have no thread of control directly associated with them. If you want to send out the MIDI events from a different thread, you will have to create one yourself.

Constructor & Destructor Documentation

◆ BMidiLocalProducer()

BMidiLocalProducer::BMidiLocalProducer ( const char *  name = NULL)

Creates a new local producer endpoint.

The new endpoint is not visible to other applications until you Register() it. You can tell the constructor what the name of the new producer will be. If you pass NULL (or use the default argument), then the producer's name will be an empty string. It won't be NULL, since endpoint names cannot be NULL. There is no guarantee that the endpoint will be successfully created. For example, the Midi Server may not be running. Therefore, you should always call IsValid() after creating a new endpoint to make sure that everything went okay. If not, Release() the object to reclaim memory and abort gracefully.

if (!prod->IsValid())
{
prod->Release();
...exit gracefully...
}

Member Function Documentation

◆ Connected()

void BMidiLocalProducer::Connected ( BMidiConsumer cons)
virtual

Invoked when a new consumer is connected to this producer.

Although typical notifications (i.e. from BMidiRoster's "watching" facility) are only sent if it is some other app that is performing the operation, Connected() is also called if you are making the connection yourself. If you override this hook, you don't have to call the default implementation, because that does nothing.

Parameters
consThe newly connected consumer. The reference count of the consumer object is not increased, so you should not Release() it. However, if you want to keep track of the consumer beyond this function, you should first Acquire() it, and Release() it when you are done.
See also
Disconnected()

◆ Disconnected()

void BMidiLocalProducer::Disconnected ( BMidiConsumer cons)
virtual

Invoked when a consumer is disconnected from this producer.

See also
Connected()

◆ SprayChannelPressure()

void BMidiLocalProducer::SprayChannelPressure ( uchar  channel,
uchar  pressure,
bigtime_t  time = 0 
) const

Sends a Channel Pressure event to all connected consumers.

See also
BMidiLocalConsumer::ChannelPressure()

◆ SprayControlChange()

void BMidiLocalProducer::SprayControlChange ( uchar  channel,
uchar  controlNumber,
uchar  controlValue,
bigtime_t  time = 0 
) const

Sends a Controller Change event to all connected consumers.

See also
Midi2Defs.h
BMidiLocalConsumer::ControlChange()

◆ SprayData()

void BMidiLocalProducer::SprayData ( void *  data,
size_t  length,
bool  atomic = false,
bigtime_t  time = 0 
) const

Sends raw MIDI data downstream to all connected consumers.

Typically you won't have to call SprayData(); the other spray functions will do just fine. If you do call it, remember that you retain ownership of the data and that you are responsible for freeing it at some point. (Even though data is not declared const, the function does not change it.) With atomic set to false, you can send a MIDI message in segments (perhaps for a large sysex dump). However, when you do this, you are on your own. The Midi Kit only tags the data as being non-atomic, but offers no] additional support.

The default implementation of BMidiLocalConsumer completely ignores such events. To handle non-atomic MIDI data, you should override the BMidiLocalConsumer::Data() hook and process the MIDI event yourself. All of BMidiLocalProducer's other spray functions always send atomic data.

Parameters
datathe MIDI event data.
lengthbyte size of the data buffer.
atomicwhether the data buffer contains a single complete MIDI event.
timethe required performance time of the event.
See also
BMidiLocalConsumer::Data()

◆ SprayKeyPressure()

void BMidiLocalProducer::SprayKeyPressure ( uchar  channel,
uchar  note,
uchar  pressure,
bigtime_t  time = 0 
) const

Sends a Polyphonic Pressure (Aftertouch) event to all connected consumers.

See also
BMidiLocalConsumer::KeyPressure()

◆ SprayNoteOff()

void BMidiLocalProducer::SprayNoteOff ( uchar  channel,
uchar  note,
uchar  velocity,
bigtime_t  time = 0 
) const

Sends a Note Off event to all connected consumers.

See also
BMidiLocalConsumer::NoteOff()

◆ SprayNoteOn()

void BMidiLocalProducer::SprayNoteOn ( uchar  channel,
uchar  note,
uchar  velocity,
bigtime_t  time = 0 
) const

Sends a Note On event to all connected consumers.

See also
BMidiLocalConsumer::NoteOn()

◆ SprayPitchBend()

void BMidiLocalProducer::SprayPitchBend ( uchar  channel,
uchar  lsb,
uchar  msb,
bigtime_t  time = 0 
) const

Sends a Pitch Bend event to all connected consumers.

See also
BMidiLocalConsumer::PitchBend()

◆ SprayProgramChange()

void BMidiLocalProducer::SprayProgramChange ( uchar  channel,
uchar  programNumber,
bigtime_t  time = 0 
) const

Sends a Program Change event to all connected consumers.

See also
BMidiLocalConsumer::ProgramChange()

◆ SpraySystemCommon()

void BMidiLocalProducer::SpraySystemCommon ( uchar  status,
uchar  data1,
uchar  data2,
bigtime_t  time = 0 
) const

Sends a System Common event to the connected consumers.

The status byte must be one of the following:

0xF1 B_MIDI_TIME_CODE data1 only
0xF2 B_SONG_POSITION data1 and data2
0xF3 B_SONG_SELECT data1 only
0xF5 B_CABLE_MESSAGE data1 only
0xF6 B_TUNE_REQUEST no data
0xF7 B_SYS_EX_END no data
See also
BMidiLocalConsumer::SystemCommon()

◆ SpraySystemExclusive()

void BMidiLocalProducer::SpraySystemExclusive ( void *  data,
size_t  length,
bigtime_t  time = 0 
) const

Sends a System Exclusive event to all connected consumers.

You retain ownership of the data and are responsible for freeing it. Even though data is not declared const, the function does not change it. Even though the amount of data may be quite large, this function always sends sysex messages as an atomic block of data.

See also
BMidiLocalConsumer::SystemExclusive()

◆ SpraySystemRealTime()

void BMidiLocalProducer::SpraySystemRealTime ( uchar  status,
bigtime_t  time = 0 
) const

Sends a Real Time event to the connected consumers.

The status byte must be one of the following:

0xf8B_TIMING_CLOCK
0xfaB_START
0xfbB_CONTINUE
0xfcB_STOP
0xfeB_ACTIVE_SENSING
0xffB_SYSTEM_RESET

Because of their high priority, the MIDI specification allows real time messages to "interleave" with other MIDI messages. A large sysex dump, for example, may be interrupted by a real time event. The Midi Kit, however, doesn't care. If you (or another producer) have just sent a big system exclusive to a consumer, any following real time message will simply have to wait until the consumer has dealt with the sysex.

See also
BMidiLocalConsumer::SystemRealTime()

◆ SprayTempoChange()

void BMidiLocalProducer::SprayTempoChange ( int32  bpm,
bigtime_t  time = 0 
) const

Sends a Tempo Change event to the connected consumers.

This kind of Tempo Change event is not really part of the MIDI spec, rather it is an extension from the SMF (Standard MIDI File) format.

See also
BMidiLocalConsumer::TempoChange()