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DRKB - это самая большая и удобная в использовании база знаний по Дельфи в рунете, составленная Виталием Невзоровым

Как проиграть ноту?

01.01.2007

This is a simple class that plays a formatted musical string. It is reminiscent of the old GWBASIC days whereby one could play a string of notes via the PC speaker. I know that WAV and MIDI files are available in todays technology, but sometimes one does not need all that overhead. The class is useful for certain types of alarms (specially if the user has his sound card volume muted) or simple "Cell Phone" like jingles. The trick of the matter in Delphi is that the standard DELPHI implementation of BEEP takes no arguments and has only one sound. However the WIN API BEEP() takes two arguments.

ie.

BOOL Beep(

         DWORD dwFreq,     // sound frequency, in hertz

         DWORD dwDuration  // sound duration, in milliseconds

        );

Parameters

dwFreq

  Windows NT:

  Specifies the frequency, in hertz, of the sound. This parameter   must be in the range 37 through 32,767 (0x25        through 0x7FFF).

  Windows 95:

  The parameter is ignored.

dwDuration

  Windows NT:

  Specifies the duration, in milliseconds, of the sound.

  Windows 95:

  The parameter is ignored.

As can be seen it appears that BEEP() is NOT supported on WIN95, but is OK from there upwards. (I have not tested it on WIN95, but assume you will just get a monotone ???? - anyone for comment)

It is easily called by prefixing the unit

ie. Windows.Beep(Freq,Duration)

The format of the "Music String" is a comma delimited (",<" terminated) string in the following formats. (The string is CASE-INSENSITIVE and [] means optional with defaults).

A..G[+ or -][0..5][/BEATS] and

@[/BEATS]

Where A..G   is the Note to be played.

     + or - is optional Sharp or Flat designator respectively. (default is normal NULL)

     0..5   is optional Octave range (default = 1)

     /BEATS is number of 100ms to hold the note (default = 1)

where @      is a musical pause

     /BEATS is the number of beats to pause for (default = 1)

where ,<     is the END OF STRING terminator.

Properties:

DefaultOctave                        : Used if no 0..5 designator specified in format. (System Default = 1)  

BetweenNotesPause        : Use to set number MS gap between notes (faster or slower default = 100ms)

Simple Example:

procedure TForm1.Button3Click(Sender: TObject);
var
 
Organ: TMusicPlayer;
begin
 
Organ := TMusicPlayer.Create;
 
Organ.Play('A,C,C+,D/3,C,A,C,A,@,F,D/4,<');
 
Organ.Play('A,A3/2,G4,G/3,@/2,D-0/4,<');
 
Organ.Free;
end;

Any enhancements or additional ideas welcome. Happy jingeling.

unit Music;
interface
 
uses
Windows, SysUtils;
 
// ===========================================================================
// Mike Heydon May 2002
// Simple Music Player Class Win98/2000 (Win95 not supported)
// Implements Notes A,A#/Bb,C,C#/Db,D,D#,Eb,E,F,F#/Gb,G,G#/Ab
// Caters for Octaves 0..5
// In Between Note Pause setable.
// Defailt Octave setable.
//
// Based on Frequency Matrix
//
//         Octave0   Octave1   Octave2   Octave3   Octave4   Octave5
// A       55.000    110.000   220.000   440.000   880.000   1760.000
// A#/Bb   58.270    116.541   233.082   466.164   932.328   1864.655
// B       61.735    123.471   246.942   493.883   987.767   1975.533
// C       65.406    130.813   261.626   523.251   1046.502  2093.005
// C#/Db   69.296    138.591   277.183   554.365   1108.731  2217.461
// D       73.416    146.832   293.665   587.330   1174.659  2349.318
// D#/Eb   77.782    155.563   311.127   622.254   1244.508  2489.016
// E       82.407    164.814   329.628   659.255   1318.510  2637.020
// F       87.307    174.614   349.228   698.456   1396.913  2793.826
// F#/Gb   92.499    184.997   369.994   739.989   1479.978  2959.955
// G       97.999    195.998   391.995   783.991   1567.982  3135.963
// G#/Ab   103.826   207.652   415.305   830.609   1661.219  3322.438
//
// @ = Pause
// < = End of Music String Marker
//
// ===========================================================================
 
type
 
TOctaveNumber = 0..5;
 
TNoteNumber = -1..11;
 
 
TMusicPlayer = class(TObject)
 
private
   
Octave,
     
FDefaultOctave: TOctaveNumber;
   
NoteIdx: TNoteNumber;
   
FBetweenNotesPause,
     
Duration: integer;
 
protected
   
function ParseNextNote(var MS: string): boolean;
 
public
   
constructor Create;
    procedure
Play(const MusicString: string);
    property
DefaultOctave: TOctaveNumber read FDefaultOctave
      write
FDefaultOctave;
    property
BetweenNotesPause: integer read FBetweenNotesPause
      write
FBetweenNotesPause;
 
end;
 
 
// ---------------------------------------------------------------------------
implementation
 
const
  MAXSTRING
= 2048; // ASCIIZ String max length
 
  MHERTZ
: array[0..11, 0..5] of integer = // Array of Note MHertz
 
((55, 110, 220, 440, 880, 1760), // A
   
(58, 117, 233, 466, 932, 1865), // A+ B-
   
(62, 123, 247, 494, 988, 1976), // B
   
(65, 131, 262, 523, 1047, 2093), // C
   
(69, 139, 277, 554, 1109, 2217), // C+ D-
   
(73, 147, 294, 587, 1175, 2349), // D
   
(78, 156, 311, 622, 1245, 2489), // D+ E-
   
(82, 165, 330, 659, 1319, 2637), // E
   
(87, 1745, 349, 698, 1397, 2794), // F
   
(92, 185, 370, 740, 1480, 2960), // F+ G-
   
(98, 196, 392, 784, 1568, 3136), // G
   
(105, 208, 415, 831, 1661, 3322) // G+ A-
   
);
 
 
// =======================================
 
// Create the object and set defaults
 
// =======================================
 
constructor TMusicPlayer.Create;
begin
 
FDefaultOctave := 1;
 
FBetweenNotesPause := 100;
end;
 
// ===========================================================
// Parse the next note and set Octave,NoteIdx and Duration
// ===========================================================
 
function TMusicPlayer.ParseNextNote(var MS: string): boolean;
var
  NS
: string; // Note String
 
Beats,
   
CommaPos: integer;
 
Retvar: boolean;
begin
 
Retvar := false; // Assume Error Condition
 
Beats := 1;
 
Duration := 0;
 
NoteIdx := 0;
 
Octave := FDefaultOctave;
 
CommaPos := pos(',', MS);
 
 
if (CommaPos > 0) then
 
begin
    NS
:= trim(copy(MS, 1, CommaPos - 1)); // Next Note info
    MS
:= copy(MS, CommaPos + 1, MAXSTRING); // Remove note from music string
 
   
if (length(NS) >= 1) and (NS[1] in ['@'..'G']) then
   
begin
     
Retvar := true; // Valid Note - set return type true
 
     
// Resolve NoteIdx
     
NoteIdx := byte(NS[1]) - 65; // Map 'A'..'G' into 0..11 or -1
      NS
:= copy(NS, 2, MAXSTRING); // Remove the Main Note ID
 
     
// Handle the @ Pause first
     
if NoteIdx = -1 then
     
begin
       
if (length(NS) >= 1) and (NS[1] = '/') then
         
Beats := StrToIntDef(copy(NS, 2, MAXSTRING), 1);
       
Sleep(100 * Beats);
       
Retvar := false; // Nothing to play
        NS
:= ''; // Stop further processing
     
end;
 
     
// Resolve Sharp or Flast
     
if (length(NS) >= 1) and (NS[1] in ['+', '-']) then
     
begin
       
if NS[1] = '+' then // # Sharp
          inc
(NoteIdx)
       
else if NS[1] = '-' then // b Flat
          dec
(NoteIdx);
 
       
if NoteIdx = -1 then
         
NoteIdx := 11; // Roll A Flat to G Sharp
        NS
:= copy(NS, 2, MAXSTRING); // Remove Flat/Sharp ID
     
end;
 
     
// Resolve Octave Number - Default := FDefaultOctave
     
if (length(NS) >= 1) and (NS[1] in ['0'..'5']) then
     
begin
       
Octave := byte(NS[1]) - 48; // map '0'..'5' to 0..5 decimal
        NS
:= copy(NS, 2, MAXSTRING); // Remove Octave Number
     
end;
 
     
// Resolve Number of Beats - Default = 1
     
if (length(NS) >= 1) and (NS[1] = '/') then
       
Beats := StrToIntDef(copy(NS, 2, MAXSTRING), 1);
 
     
Duration := 100 * Beats;
   
end;
 
end
 
else
    MS
:= ''; // Signal end of music string
 
 
Result := Retvar;
end;
 
// ===================================
// Play the passed music string
// ===================================
 
procedure
TMusicPlayer.Play(const MusicString: string);
var
  MS
: string; // Music String
begin
  MS
:= trim(UpperCase(MusicString));
 
 
while (MS <> '') do
 
begin
   
if ParseNextNote(MS) then
   
begin
     
Windows.Beep(MHERTZ[NoteIdx, Octave], Duration);
     
Sleep(FBetweenNotesPause);
   
end;
 
end;
end;
 
end.

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