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C# MIDI Toolkit

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18 Apr 2007MIT18 min read 3.1M   41.7K   303  
A toolkit for creating MIDI applications with C#.
/*
 * Created by: Leslie Sanford
 * 
 * Contact: jabberdabber@hotmail.com
 * 
 * Last modified: 09/29/2004
 */

using System;
using System.Threading;

namespace Multimedia.Midi
{
	/// <summary>
	/// Provides functionality for controlling playback.
	/// </summary>
	public class MasterClock : MidiClock
	{
        #region MasterClock Members

        #region Fields

        // Indicates whether or not the master mode is enabled.
        private bool masterEnabled = false;

        /// <summary>
        /// The MIDI sender for sending system realtime messages.
        /// </summary>
        protected IMidiSender midiSender;

        // Keeps track of the number of ticks that have occurred - used for 
        // determining when to send clock messages.
        private int tickCounter;

        // Number of ticks per MIDI clock.
        private int ticksPerClock;

        #region System Realtime Messages

        private SysRealtimeMessage startMessage = 
            new SysRealtimeMessage(SysRealtimeType.Start);
        private SysRealtimeMessage stopMessage = 
            new SysRealtimeMessage(SysRealtimeType.Stop);
        private SysRealtimeMessage continueMessage = 
            new SysRealtimeMessage(SysRealtimeType.Continue);
        private SysRealtimeMessage clockMessage = 
            new SysRealtimeMessage(SysRealtimeType.Clock);

        #endregion        

        #endregion

        #region Construction

        /// <summary>
        /// Initializes a new instance of the MasterClock class with the 
        /// specified MIDI sender and tick generator.
        /// </summary>
        /// <param name="midiSender">
        /// The MIDI sender used for sending system realtime messages.
        /// </param>
        /// <param name="tickGenerator">
        /// The tick generator the MIDI clock will control.
        /// </param>
		public MasterClock(IMidiSender midiSender, 
            TickGenerator tickGenerator) : base(tickGenerator)
		{
            this.midiSender = midiSender;
		}

        #endregion

        #region Methods

        /// <summary>
        /// Starts the MIDI clock.
        /// </summary>
        /// <remarks>
        /// If the master mode is enabled, the MIDI clock will send a start
        /// system realtime message to its slaves.
        /// </remarks>
        public override void Start()
        {
            // If the master mode is not enabled, use base class functionality.
            if(!MasterEnabled)
            {
                base.Start();
                return;
            }
             
            // Guard.
            if(IsRunning())
                return;

            // It is possible that the tick resolution has changed, recalculate
            // the number of ticks per clock.
            ticksPerClock = tickGenerator.Ppqn / TickGenerator.PpqnMin;

            // Register tick handler.
            tickGenerator.Tick += new EventHandler(TickHandler);            

            // Raise starting event.
            OnStarting();

            // Send start message.
            midiSender.Send(startMessage);

            // Pause to let slave device prepare for playback.
            Thread.Sleep(1);

            tickGenerator.Start();
        }

        /// <summary>
        /// Continues the MIDI clock.
        /// </summary>
        /// <remarks>
        /// If the master mode is enabled, the MIDI clock will send a continue
        /// system realtime message to its slaves.
        /// </remarks>
        public override void Continue()
        {
            // If the master mode is not enabled, use base class functionality.
            if(!MasterEnabled)
            {
                base.Continue();
                return;
            }

            // Guard.
            if(IsRunning())
                return;

            // It is possible that the tick resolution has changed, recalculate
            // the number of ticks per clock.
            ticksPerClock = tickGenerator.Ppqn / TickGenerator.PpqnMin;

            // Register tick handler.
            tickGenerator.Tick += new EventHandler(TickHandler);

            // Raise continuing event.
            OnContinuing();

            // Send continue message.
            midiSender.Send(continueMessage);            

            // Pause to let slave device prepare for playback.
            Thread.Sleep(1);

            tickGenerator.Start();
        }

        /// <summary>
        /// Stops the MIDI clock.
        /// </summary>
        /// <remarks>
        /// If the master mode is enabled, the MIDI clock will send a stop
        /// system realtime message to its slaves.
        /// </remarks>
        public override void Stop()
        {
            // If the master mode is not enabled, use base class functionality.
            if(!MasterEnabled)
            {
                base.Stop();
                return;
            }

            // Guard.
            if(!IsRunning())
                return;

            tickGenerator.Stop();

            // Remove tick handler from tick generator.
            tickGenerator.Tick -= new EventHandler(TickHandler);            

            // Send stop message.
            midiSender.Send(stopMessage); 

            // Raise stopping event.
            OnStopping();
        }

        /// <summary>
        /// Sends song position pointer to its slaves.
        /// </summary>
        /// <param name="spp">
        /// The sont position pointer.
        /// </param>
        /// <remarks>
        /// If the master mode is not enabled, this method has no effect.
        /// </remarks>
        public void SendSongPositionPointer(SongPositionPointer spp)
        {
            // Guard.
            if(!MasterEnabled)
                return;

            // Keep track of whether or not the clock is running.
            bool wasRunning = IsRunning();

            // If the clock is running, stop it momentarily. It is better not
            // to change the position while a sequencer is running.
            if(wasRunning)
                Stop();

            // Send song position pointer.
            midiSender.Send(spp.ToMessage());

            // If the clock was running, resume running.
            if(wasRunning)
                Continue();
        }

        /// <summary>
        /// Disposes of the MIDI clock.
        /// </summary>
        /// <param name="disposing">
        /// Indicates whether or not to dispose the MIDI clock.
        /// </param>
        protected override void Dispose(bool disposing)
        {
            if(disposing)
            {
                if(IsRunning())
                {
                    tickGenerator.Stop();
                    tickGenerator.Tick -= new EventHandler(TickHandler);
                }

                base.Dispose(disposing);
            }
        }

        /// <summary>
        /// Handles tick events.
        /// </summary>
        /// <param name="sender">
        /// The tick generator responsible for the event.
        /// </param>
        /// <param name="e">
        /// Information about the event.
        /// </param>
        private void TickHandler(object sender, EventArgs e)
        {
            // Keep track of the number of ticks that have occurred since the
            // last clock message.
            tickCounter++;

            // If it is time to send a clock message.
            if(tickCounter == ticksPerClock)
            {
                // Send clock message.
                midiSender.Send(clockMessage);

                // Reset counter.
                tickCounter = 0;
            }
        }

        #endregion

        #region Properties

        /// <summary>
        /// Gets or sets a value indicating whether or not the master mode is
        /// enabled.
        /// </summary>
        /// <remarks>
        /// When the master mode is enabled, system realtime messages are sent
        /// to slave devices for controlling playback.
        /// </remarks>
        public bool MasterEnabled
        {
            get
            {
                return masterEnabled;
            }
            set
            {
                if(masterEnabled == value)
                    return;

                Stop();

                masterEnabled = value;
            }
        }

        #endregion       

        #endregion
	}
}

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License

This article, along with any associated source code and files, is licensed under The MIT License


Written By
United States United States
Aside from dabbling in BASIC on his old Atari 1040ST years ago, Leslie's programming experience didn't really begin until he discovered the Internet in the late 90s. There he found a treasure trove of information about two of his favorite interests: MIDI and sound synthesis.

After spending a good deal of time calculating formulas he found on the Internet for creating new sounds by hand, he decided that an easier way would be to program the computer to do the work for him. This led him to learn C. He discovered that beyond using programming as a tool for synthesizing sound, he loved programming in and of itself.

Eventually he taught himself C++ and C#, and along the way he immersed himself in the ideas of object oriented programming. Like many of us, he gotten bitten by the design patterns bug and a copy of GOF is never far from his hands.

Now his primary interest is in creating a complete MIDI toolkit using the C# language. He hopes to create something that will become an indispensable tool for those wanting to write MIDI applications for the .NET framework.

Besides programming, his other interests are photography and playing his Les Paul guitars.

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