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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: 10/29/2004
 */

using System;

namespace Multimedia.Midi
{
	/// <summary>
	/// Provides functionality for updating playback settings.
	/// </summary>
	internal class MidiChaser : MidiMessageVisitor
	{
        #region MidiChaser Members

        #region Fields

        // The MIDI sender to use for sending MIDI messages.
        private IMidiSender midiSender;

        // The tick generator to use for setting the tempo.
        private TickGenerator tickGenerator;

        // For storing control change messages.
        private ChannelMessage[] controllers;

        // For storing the channel pressure message.
        private ChannelMessage channelPressureMessage = null;

        // For storing the poly pressure message.
        private ChannelMessage polyPressureMessage = null;

        // For storing the program change message.
        private ChannelMessage programChangeMessage = null;

        // For storing the pitch bend message.
        private ChannelMessage pitchBendMessage = null;

        // For storing the tempo change message.
        private MetaMessage tempoChangeMessage = null;

        #endregion

        #region Construction

        /// <summary>
        /// Initializes a new instance of the MidiChaser class with the 
        /// specified MIDI sender and tick generator.
        /// </summary>
        /// <param name="midiSender">
        /// The MIDI sender to use for sending MIDI messages.
        /// </param>
        /// <param name="tickGenerator">
        /// The tick generator to use for setting the tempo.
        /// </param>
		public MidiChaser(IMidiSender midiSender, TickGenerator tickGenerator)
		{
            this.midiSender = midiSender;
            this.tickGenerator = tickGenerator;

            controllers = new ChannelMessage[ShortMessage.DataValueMax];

            Initialize();
		}

        #endregion

        #region Methods

        /// <summary>
        /// Adds a MIDI message to the chaser to use for updating the playback
        /// settings later.
        /// </summary>
        /// <param name="message">
        /// The MIDI message to add to the chaser.
        /// </param>
        /// <remarks>
        /// Only certain MIDI messages are accepted by the chaser. If the
        /// message is not accepted, no operation occurs.
        /// </remarks>
        public void Add(IMidiMessage message)
        {
            message.Accept(this);           
        }

        /// <summary>
        /// Update playback settings based on the stored set of MIDI messages.
        /// </summary>
        public void Chase()
        {
            if(channelPressureMessage != null)
                midiSender.Send(channelPressureMessage);

            if(polyPressureMessage != null)
                midiSender.Send(polyPressureMessage);

            if(programChangeMessage != null)
                midiSender.Send(programChangeMessage);

            if(pitchBendMessage != null)
                midiSender.Send(pitchBendMessage);

            for(int i = 0; i < controllers.Length; i++)
            {
                if(controllers[i] != null)
                    midiSender.Send((ChannelMessage)controllers[i]);
            }

            if(tempoChangeMessage != null)
            {
                TempoChange tChange = new TempoChange(tempoChangeMessage);

                tickGenerator.Tempo = tChange.Tempo;
            }

            Initialize();
        }

        /// <summary>
        /// Visits channel messages.
        /// </summary>
        /// <param name="message">
        /// The channel message to visit.
        /// </param>
        /// <remarks>
        /// This method should not be called by an outside source.
        /// </remarks>
        public override void Visit(ChannelMessage message)
        {
            if(message.Command == ChannelCommand.ChannelPressure)
            {
                channelPressureMessage = message;
            }
            else if(message.Command == ChannelCommand.PolyPressure)
            {
                polyPressureMessage = message;
            }
            else if(message.Command == ChannelCommand.ProgramChange)
            {       
                programChangeMessage = message;
            }
            else if(message.Command == ChannelCommand.PitchWheel)
            {
                pitchBendMessage = message;
            }
            else if(message.Command == ChannelCommand.Controller)
            {    
                controllers[message.Data1] = message;
            }
        }

        /// <summary>
        /// Visits meta messages.
        /// </summary>
        /// <param name="message">
        /// The meta message to visit.
        /// </param>
        /// <remarks>
        /// This method should not be called by an outside source.
        /// </remarks>
        public override void Visit(MetaMessage message)
        {
            if(message.Type == MetaType.Tempo)
            {
                tempoChangeMessage = message;
            }
        }

        /// <summary>
        /// Initializes the MIDI chaser.
        /// </summary>
        private void Initialize()
        {
            channelPressureMessage = null;
            polyPressureMessage = null;
            programChangeMessage = null;
            pitchBendMessage = null;

            for(int i = 0; i < controllers.Length; i++)
            {
                controllers[i] = null;
            }

            tempoChangeMessage = null;
        }

        #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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