wxMidiMessage Class Reference

Abstract class representing a MIDI message. More...

#include <wxMidi.h>

Inheritance diagram for wxMidiMessage:

Public Member Functions
	wxMidiMessage ()
	Constructor.
virtual	~wxMidiMessage ()
	Destructor.
virtual void	SetTimestamp (wxMidiTimestamp timestamp)=0
	Set the message timestamp value. More...
virtual wxMidiTimestamp	GetTimestamp ()=0
wxMidiMsgType	GetType ()
	Returns either wxMIDI_SHORT_MSG, or wxMIDI_SYSEX_MSG, identifying the type of the message object. More...
virtual wxByte	GetStatus ()=0
	Returns the status byte of the message. More...

Protected Attributes
wxMidiMsgType	m_type

Detailed Description

Abstract class representing a MIDI message.

In wxMidi, messages are represented by a wxMidiMessage object. It is an abstract class from which the specific Midi messages derive. It contains information about the type and status byte of the MIDI message. In addition, it provides a timestamp value that is used by devices dealing with MIDI timing, such as sequencers.

See also

wxMidiShortMessage, wxMidiSysExMessage

Member Function Documentation

GetStatus()

virtual wxByte wxMidiMessage::GetStatus ( )

pure virtual

Returns the status byte of the message.

For a wxSysExMessage status byte is always 0xF0 but the end of sysex message (0xF7) is also included in the message data. According MIDI standard the most significant bit of the status byte is always 1 so the range of status values goes from 0x80 to 0xFF.

Values lower than 0xF0 identify channel messages, with the four lower bits specifying the channel (0-15); for example, status byte 0x93 is a NoteOn for channel 3:

Message	Status byte
Note-Off Event	0x8n
Note-On Event	0x9n
Polyphonic Key Pressure	0xAn
Control Change	0xBn
Program Change	0xCn
Channel Pressure	0xDn
Pitch Bend	0xEn

Values 0xF0 to 0xFF are for system messages and are no intended for a specific channel:

Message	Status byte
Begin System Exclusive	0xF0
MIDI Time Code	0xF1
Song Position Pointer	0xF2
Song Select	0xF3
Tune Request	0xF6
End System Exclusive	0xF7
Real-time Clock	0xF8
Undefined	0xF9
Start	0xFA
Continue	0xFB
Stop	0xFC
Undefined	0xFD
Active Sensing	0xFE
System Reset	0xFF

Implemented in wxMidiSysExMessage, and wxMidiShortMessage.

GetType()

wxMidiMsgType wxMidiMessage::GetType ( )

inline

Returns either wxMIDI_SHORT_MSG, or wxMIDI_SYSEX_MSG, identifying the type of the message object.

SetTimestamp()

virtual void wxMidiMessage::SetTimestamp ( wxMidiTimestamp  timestamp )

pure virtual

Set the message timestamp value.

On output to a wxMidiOutDevice opened with non-zero latency, the timestamp will determine the time to begin sending the message. If the wxMidiOutDevice was opened with a latency value of zero, timestamps will be ignored and messages will be delivered inmediatelly.

Parameters

timestamp

The timestamp value. It is milliseconds elapsed since the wxMidi package initialization. Current time can be obtained by calling wxMidi::GetTime().

Implemented in wxMidiSysExMessage, and wxMidiShortMessage.

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The documentation for this class was generated from the following file:

• /datos/cecilio/lm/projects/wxmidi/src/wxMidi.h