Metronome
You are encouraged to solve this task according to the task description, using any language you may know.
The task is to implement a metronome.
The metronome should be capable of producing high and low audio beats, accompanied by a visual beat indicator, and the beat pattern and tempo should be configurable.
For the purpose of this task, it is acceptable to play sound files for production of the beat notes, and an external player may be used.
However, the playing of the sounds should not interfere with the timing of the metronome.
The visual indicator can simply be a blinking red or green area of the screen (depending on whether a high or low beat is being produced), and the metronome can be implemented using a terminal display, or optionally, a graphical display, depending on the language capabilities.
If the language has no facility to output sound, then it is permissible for this to implemented using just the visual indicator.
AutoHotkey
Rather basic implementation, but meets the requirements and is reasonably accurate. <lang AHK>bpm = 120 ; Beats per minute pattern = 4/4 ; duration = 100 ; Milliseconds beats = 0 ; internal counter
Gui -Caption
StringSplit, p, pattern, /
Start := A_TickCount
Loop { Gui Color, 0xFF0000 Gui Show, w200 h200 Na SoundBeep 750, duration beats++ Sleep 1000 * 60 / bpm - duration Loop % p1 -1 { Gui Color, 0x00FF00 Gui Show, w200 h200 Na SoundBeep, , duration beats++ Sleep 1000 * 60 / bpm - duration } }
Esc:: MsgBox % "Metronome beeped " beats " beats, over " (A_TickCount-Start)/1000 " seconds. " ExitApp</lang>
BBC BASIC
<lang bbcbasic> BeatPattern$ = "HLLL"
Tempo% = 100
*font Arial,36
REPEAT
FOR beat% = 1 TO LEN(BeatPattern$)
IF MID$(BeatPattern$, beat%, 1) = "H" THEN
SOUND 1,-15,148,1
ELSE
SOUND 1,-15,100,1
ENDIF
VDU 30
COLOUR 2
PRINT LEFT$(BeatPattern$,beat%-1);
COLOUR 9
PRINT MID$(BeatPattern$,beat%,1);
COLOUR 2
PRINT MID$(BeatPattern$,beat%+1);
WAIT 6000/Tempo%
NEXT
UNTIL FALSE</lang>
C
Using usleep with self correcting delays. Audio is the bell character, which will definitely drive one insane (but I'm ok: my computer doesn't have the bell device). Invoke with ./a.out [beats_per_minute], default to 60.
<lang c>#include <stdio.h>
- include <stdlib.h>
- include <unistd.h>
- include <stdint.h>
- include <signal.h>
- include <time.h>
- include <sys/time.h>
struct timeval start, last;
inline int64_t tv_to_u(struct timeval s) { return s.tv_sec * 1000000 + s.tv_usec; }
inline struct timeval u_to_tv(int64_t x) { struct timeval s; s.tv_sec = x / 1000000; s.tv_usec = x % 1000000; return s; }
void draw(int dir, int64_t period, int64_t cur, int64_t next) { int len = 40 * (next - cur) / period; int s, i;
if (len > 20) len = 40 - len; s = 20 + (dir ? len : -len);
printf("\033[H"); for (i = 0; i <= 40; i++) putchar(i == 20 ? '|': i == s ? '#' : '-'); }
void beat(int delay) { struct timeval tv = start; int dir = 0; int64_t d = 0, corr = 0, slp, cur, next = tv_to_u(start) + delay; int64_t draw_interval = 20000; printf("\033[H\033[J"); while (1) { gettimeofday(&tv, 0); slp = next - tv_to_u(tv) - corr; usleep(slp); gettimeofday(&tv, 0);
putchar(7); /* bell */ fflush(stdout);
printf("\033[5;1Hdrift: %d compensate: %d (usec) ", (int)d, (int)corr); dir = !dir;
cur = tv_to_u(tv); d = cur - next; corr = (corr + d) / 2; next += delay;
while (cur + d + draw_interval < next) { usleep(draw_interval); gettimeofday(&tv, 0); cur = tv_to_u(tv); draw(dir, delay, cur, next); fflush(stdout); } } }
int main(int c, char**v) { int bpm;
if (c < 2 || (bpm = atoi(v[1])) <= 0) bpm = 60; if (bpm > 600) { fprintf(stderr, "frequency %d too high\n", bpm); exit(1); }
gettimeofday(&start, 0); last = start; beat(60 * 1000000 / bpm);
return 0; }</lang>
Common Lisp
Depends on quicklisp and OpenAL. <lang lisp>(ql:quickload '(cl-openal cl-alc))
(defparameter *short-max* (- (expt 2 15) 1)) (defparameter *2-pi* (* 2 pi))
(defun make-sin (period)
"Create a generator for a sine wave of the given PERIOD." (lambda (x) (sin (* *2-pi* (/ x period)))))
(defun make-tone (length frequency sampling-frequency)
"Create a vector containing sound information of the given LENGTH,
FREQUENCY, and SAMPLING-FREQUENCY."
(let ((data (make-array (truncate (* length sampling-frequency))
:element-type '(signed-byte 16)))
(generator (make-sin (/ sampling-frequency frequency))))
(dotimes (i (length data))
(setf (aref data i)
(truncate (* *short-max* (funcall generator i)))))
data))
(defun internal-time-ms ()
"Get the process's real time in ms." (* 1000 (/ (get-internal-real-time) internal-time-units-per-second)))
(defun spin-wait (next-real-time)
"Wait until the process's real time has reached the given time." (loop while (< (internal-time-ms) next-real-time)))
(defun upload (buffer data sampling-frequency)
"Upload the given vector DATA to a BUFFER at the given SAMPLING-FREQUENCY."
(cffi:with-pointer-to-vector-data (data-ptr data)
(al:buffer-data buffer :mono16 data-ptr (* 2 (length data))
sampling-frequency)))
(defun metronome (beats/minute pattern &optional (sampling-frequency 44100))
"Play a metronome until interrupted."
(let ((ms/beat (/ 60000 beats/minute)))
(alc:with-device (device)
(alc:with-context (context device)
(alc:make-context-current context)
(al:with-buffer (low-buffer)
(al:with-buffer (high-buffer)
(al:with-source (source)
(al:source source :gain 0.5)
(flet ((play-it (buffer)
(al:source source :buffer buffer)
(al:source-play source))
(upload-it (buffer time frequency)
(upload buffer
(make-tone time frequency sampling-frequency)
sampling-frequency)))
(upload-it low-buffer 0.1 440)
(upload-it high-buffer 0.15 880)
(let ((next-scheduled-tone (internal-time-ms)))
(loop
(loop for symbol in pattern do
(spin-wait next-scheduled-tone)
(incf next-scheduled-tone ms/beat)
(case symbol
(l (play-it low-buffer))
(h (play-it high-buffer)))
(princ symbol))
(terpri)))))))))))</lang>
CL-USER> (metronome 100 '(h l l l)) HLLL HLL; Evaluation aborted on NIL.
EchoLisp
<lang scheme>
- available preloaded sounds are
- ok, ko, tick, tack, woosh, beep, digit .
(lib 'timer)
(define (metronome) (blink) (play-sound 'tack)) (at-every 1000 'metronome) ;; every 1000 msec
- CTRL-C to stop
</lang>
Factor
<lang factor>USING: accessors calendar circular colors.constants colors.hsv command-line continuations io kernel math math.parser namespaces openal.example sequences system timers ui ui.gadgets ui.pens.solid ; IN: rosetta-code.metronome
- bpm>duration ( bpm -- duration ) 60 swap / seconds ;
- blink-gadget ( gadget freq -- )
1.0 1.0 1.0 <hsva> <solid> >>interior relayout-1 ;
- blank-gadget ( gadget -- )
COLOR: white <solid> >>interior relayout-1 ;
- play-note ( gadget freq -- )
[ blink-gadget ] [ 0.3 play-sine blank-gadget ] 2bi ;
- metronome-iteration ( gadget circular -- )
[ first play-note ] [ rotate-circular ] bi ;
TUPLE: metronome-gadget < gadget bpm notes timer ;
- <metronome-gadget> ( bpm notes -- gadget )
\ metronome-gadget new swap >>notes swap >>bpm ;
- metronome-quot ( gadget -- quot )
dup notes>> <circular> [ metronome-iteration ] 2curry ;
- metronome-timer ( gadget -- timer )
[ metronome-quot ] [ bpm>> bpm>duration ] bi every ;
M: metronome-gadget graft* ( gadget -- )
[ metronome-timer ] keep timer<< ;
M: metronome-gadget ungraft*
timer>> stop-timer ;
M: metronome-gadget pref-dim* drop { 200 200 } ;
- metronome-defaults ( -- bpm notes ) 60 { 440 220 330 } ;
- metronome-ui ( bpm notes -- ) <metronome-gadget> "Metronome" open-window ;
- metronome-example ( -- ) metronome-defaults metronome-ui ;
- validate-args ( int-args -- )
[ length 2 < ] [ [ 0 <= ] any? ] bi or [ "args error" throw ] when ;
- (metronome-cmdline) ( args -- bpm notes )
[ string>number ] map dup validate-args unclip swap ;
- metronome-cmdline ( -- bpm notes )
command-line get [ metronome-defaults ] [ (metronome-cmdline) ] if-empty ;
- print-defaults ( -- )
metronome-defaults swap prefix [ " " write ] [ number>string write ] interleave nl ;
- metronome-usage ( -- )
"Usage: metronome [BPM FREQUENCIES...]" print "Arguments must be non-zero" print "Example: metronome " write print-defaults flush ;
- metronome-main ( -- )
[ [ metronome-cmdline metronome-ui ] [ drop metronome-usage 1 exit ] recover ] with-ui ;
MAIN: metronome-main</lang>
F#
<lang fsharp>open System open System.Threading // You can use .wav files for your clicks. // If used, make sure they are in the same file // as this program's executable file. let high_pitch =
new System.Media.SoundPlayer("Ping Hi.wav")
let low_pitch =
new System.Media.SoundPlayer("Ping Low.wav")
let factor x y = x / y // Notice that exact bpm would not work by using // Thread.Sleep() as there are additional function calls // that would consume a miniscule amount of time. // This number may need to be adjusted based on the cpu. let cpu_error = -750.0 let print = function | 1 -> high_pitch.Play(); printf "\nTICK " | _ -> low_pitch.Play(); printf "tick " let wait (time:int) =
Thread.Sleep(time)
// Composition of functions let tick = float>>factor (60000.0+cpu_error)>>int>>wait let rec play beats_per_measure current_beat beats_per_minute =
match current_beat, beats_per_measure with
| a, b ->
current_beat |> print
beats_per_minute |> tick
if a <> b then
beats_per_minute |> play beats_per_measure (current_beat + 1)
[<EntryPointAttribute>] let main (args : string[]) =
let tempo, beats = int args.[0], int args.[1] Seq.initInfinite (fun i -> i + 1) |> Seq.iter (fun _ -> tempo |> play beats 1 |> ignore) 0 </lang>
Sample run:
$ metronome 120 6 TICK tick tick tick tick tick TICK tick tick tick tick tick TICK tick tick tick tick tick TICK tick tick tick tick tick TICK tick tick^C
Go
As with the Perl example, just simple text output. It would be reasonably simple (but covered better in other tasks) to change bpm and bpb into command line arguments, make it a function/object, and/or substitute sound production instead of text output.
time.Ticker's documentation says that it
"adjusts the intervals or drops ticks to make up for slow receivers".
So, as long as the output or sound production finishes before the next tick,
the timing will be reliable and will not drift which is the gist of this task.
<lang go>package main
import ( "fmt" "time" )
func main() { var bpm = 72.0 // Beats Per Minute var bpb = 4 // Beats Per Bar
d := time.Duration(float64(time.Minute) / bpm) fmt.Println("Delay:", d) t := time.NewTicker(d) i := 1 for _ = range t.C { i-- if i == 0 { i = bpb fmt.Printf("\nTICK ") } else { fmt.Printf("tick ") } } }</lang>
- Output:
Delay: 833.333333ms TICK tick tick tick TICK tick tick tick TICK tick ^C
Haskell
<lang Haskell>import Control.Concurrent import Control.Concurrent.MVar import System.Process (runCommand)
-- This program works only on the GHC compiler because of the use of -- threadDelay
data Beep = Stop | Hi | Low
type Pattern = [Beep]
type BeatsPerMinute = Int
minute = 60000000 -- 1 minute = 60,000,000 microseconds
-- give one of the following example patterns to the metronome function
pattern4_4 = [Hi, Low, Low, Low] pattern2_4 = [Hi, Low] pattern3_4 = [Hi, Low, Low] pattern6_8 = [Hi, Low, Low, Low, Low, Low]
-- use this version if you can't play audio, use Windows or don't -- have audio files to play -- beep :: Beep -> IO () -- beep Stop = return () -- beep Hi = putChar 'H' -- beep Low = putChar 'L'
-- use this version if you can and want to play audio on Linux using -- Alsa. Change the name of the files to those of your choice
beep Stop = return () beep Hi = putChar 'H' >> runCommand "aplay hi.wav &> /dev/null" >> return () beep Low = putChar 'L' >> runCommand "aplay low.wav &> /dev/null" >> return ()
tick :: MVar Pattern -> BeatsPerMinute -> IO () tick b i = do
t <- readMVar b
case t of
[Stop] -> return ()
x -> do
mapM_ (\v -> forkIO (beep v) >> threadDelay (minute `div` i)) t
tick b i
metronome :: Pattern -> BeatsPerMinute -> IO () metronome p i = do
putStrLn "Press any key to stop the metronome." b <- newMVar p _ <- forkIO $ tick b i _ <- getChar putMVar b [Stop]</lang>
J
The explicit version (nbars,t) MET (barlengths;bpm) prints a bell character every beat, accompanied by a sequence of slashes, spaces, and backspaces to create a little animation. It includes a beat hand and a measure (or bar) hand.
MET can take several barlengths and bpm values, in which case it will cycle through them individually at each measure, creating (perhaps) interesting patterns. It will stop when nbars measures have been cycled through, or at the end of the current measure if the time limit is exceeded. The clock is self correcting.
MET returns the total number of measures, beats, and elapsed time.
If you leave out the left arguments, it will set them to infinity, so you can go insane without worrying about the metronome ever stopping.
<lang j>
MET=: _ _&$: :(4 : 0)
'BEL BS LF CR'=. 7 8 10 13 { a.
'`print stime delay'=. 1!:2&4`(6!:1)`(6!:3)
ticker=. 2 2$'\ /'
'small large'=. (BEL,2#BS) ; 5#BS
clrln=. CR,(79#' '),CR
x=. 2 ({.,) x
y=. _1 |.&.> 2 ({.,) y
'i j'=. 0
print 'bpb \ bpm \ ' , 2#BS
delay 1
x=. ({. , ('ti t'=. stime) + {:) x
while. x *./@:> i,t do.
'bpb bpm'=. {.@> y=. 1 |.&.> y
dl=. 60 % bpm
print clrln,(":bpb),' ',(ticker {~ 2 | i=. >: i),' ',(":bpm),' '
for. i. bpb do.
print small ,~ ticker {~ 2 | j=. >: j
delay 0 >. (t=. t + dl) - stime
end.
end.
print clrln i , j , t - ti
)
NB. Basic tacit version; this is probably considered bad coding style. At least I removed the "magic constants". Sort of.
NB. The above version is by far superior.
'BEL BS LF'=: 7 8 10 { a.
'`print delay'=: 1!:2&4`(6!:3)
met=: _&$: :((] ({:@] [ LF print@[ (-.@{.@] [ delay@[ print@] (BEL,2#BS) , (2 2$'\ /') {~ {.@])^:({:@])) 1 , <.@%) 60&% [ print@('\ '"_))
</lang>
- Output:
16 60 MET 4;120 4 / 120 / NB. Variable measure lengths, and corresponding bpm: 21 _ MET 4 3 4 5 ; 120 100 120 150 NB. _ is infinity. 5 \ 150 / NB. returns: 21 84 39.2 (21 measures, 84 beats, 39.2 seconds) MET 4 8;120 240 NB. It can almost make music! bpb \ bpm \
Liberty BASIC
Requires two supplied wav files for accentuated & standard sounds. <lang lb> WindowWidth =230
WindowHeight =220
button #w.b1 "Start", [start], LR, 110, 90, 55, 20 button #w.b2 "Tempo", [tempo], LR, 180, 90, 55, 20 button #w.b3 "Pattern", [pattern], LR, 40, 90, 55, 20
open "Metronome" for graphics_nsb_nf as #w
#w "trapclose quit" #w "down" #w "fill darkblue ; backcolor darkblue ; color white"
tempo = 60 ' per minute interval =1000 /(tempo /60) ' timer works in ms tickCount = 0 ' cycle counter running = 1 ' flag for state bar$ = "HLLL" ' initially strong-weak-weak-weak count = len( bar$)
wait
sub quit w$
close #w$ end
end sub
[start]
if running =1 then
running =0
#w.b1 "Stop"
#w.b2 "!disable"
#w.b3 "!disable"
else
running =1
#w.b1 "Start"
#w.b2 "!enable"
#w.b3 "!enable"
end if
if running =0 then timer interval, [tick] else timer 0
wait
[tempo]
prompt "New tempo 30...360"; tempo$ tempo =val( tempo$) tempo =min( tempo, 360) tempo =max( tempo, 30) interval =int( 1000 /(tempo /60)) wait
[pattern]
prompt "New Pattern, eg 'HLLL' "; bar$ count =len( bar$) if count <2 or count >8 then goto [pattern]
wait
[tick]
'beep and flash #w "place 115 40"
if mid$( bar$, tickCount +1, 1) ="H" then
playwave "mHi.wav", async
#w "backcolor blue ; color white ; circlefilled "; 20 -tickCount *2
else
playwave "mLo.wav", async
#w "backcolor cyan ; circlefilled "; 20 -tickCount *2
end if
#w "place 50 140 ; backcolor darkblue ; color white" #w "\ "; tempo; " beats /min." #w "place 85 160" #w "\"; bar$
#w "place 85 120" #w "\Beat # "; tickCount +1
#w "place 115 40" #w "color darkblue"
tickCount =( tickCount +1) mod count
#w "flush"
wait</lang>
Perl 6
This code only uses textual output, but any noise-generating commands may be substituted; as long as they are executed synchronously, and do not run longer than the specified duration, the timing loop will compensate, since the sequence operator is determining a list of absolute times for each sleep to target. <lang perl6>sub MAIN ($beats-per-minute = 72, $beats-per-bar = 4) {
my $duration = 60 / $beats-per-minute; my $base-time = now + $duration; my $i;
for $base-time, $base-time + $duration ... * -> $next-time {
if $i++ %% $beats-per-bar {
print "\nTICK";
}
else {
print " tick";
}
sleep $next-time - now;
}
}</lang> Sample run:
$ metronome 120 6 TICK tick tick tick tick tick TICK tick tick tick tick tick TICK tick tick tick tick tick TICK tick tick tick tick tick TICK tick tick^C
PicoLisp
A short beep (440 Hz, 40 msec) is produced in a child process, while a "pendulum" is swinging left and right. Hitting any key will stop it. <lang PicoLisp>(de metronome (Bpm)
(if (fork)
(let Pid @
(for Pendulum '(" /" . ("^H^H\\ " "^H^H /" .))
(tell Pid 'call "/usr/bin/beep" "-f" 440 "-l" 40)
(prin Pendulum)
(T (key (*/ 30000 Bpm)) (tell Pid 'bye)) )
(prinl) )
(wait) ) )</lang>
Test: <lang PicoLisp>: (metronome 60)
/
-> NIL # A key was hit</lang>
PureBasic
Metronome features:
- A periodic graphical-metronomimic image.
- The wav file is included within the resulting executable as raw data.
- A milliseconds between each click field in order to assess accuracy.
- Volumn controls for when you just can't stand it anymore!
<lang PureBasic>Structure METRONOMEs
msPerBeat.i BeatsPerMinute.i BeatsPerCycle.i volume.i canvasGadget.i w.i h.i originX.i originY.i radius.i activityStatus.i
EndStructure
Enumeration ;gadgets
#TEXT_MSPB ;milliseconds per beat #STRING_MSPB ;milliseconds per beat #TEXT_BPM ;beats per minute #STRING_BPM ;beats per minute #TEXT_BPC ;beats per cycle #STRING_BPC ;beats per cycle #BUTTON_VOLM ;volume - #BUTTON_VOLP ;volume + #BUTTON_START ;start #SPIN_BPM #CANVAS_METRONOME
EndEnumeration
Enumeration ;sounds
#SOUND_LOW #SOUND_HIGH
EndEnumeration
- WINDOW = 0 ;window
Procedure handleError(Value, text.s)
If Not Value: MessageRequester("Error", text): End: EndIf
EndProcedure
Procedure drawMetronome(*m.METRONOMEs, Angle.f, cycleCount = 0)
Protected CircleX, CircleY, circleColor
If StartDrawing(CanvasOutput(*m\canvasGadget))
Box(0, 0, *m\w, *m\h, RGB(0, 0, 0))
CircleX = Int(*m\radius * Cos(Radian(Angle)))
CircleY = Int(*m\radius * Sin(Radian(Angle)))
If Angle = 90
If cycleCount: circleColor = RGB(255, 0, 0): Else: circleColor = RGB(0, 255, 0): EndIf
LineXY(*m\originX, *m\originY, *m\originX, *m\originY - CircleY, RGB(255, 255, 0))
Circle(*m\originX + CircleX, *m\originY - CircleY - *m\radius * 0.15, 10, circleColor)
Else
LineXY(*m\originX, *m\originY - *m\radius * 1.02, *m\originX, *m\originY - *m\radius, RGB(255, 255, 0))
LineXY(*m\originX, *m\originY, *m\originX + CircleX, *m\originY - CircleY, RGB(255, 255, 0))
EndIf
StopDrawing()
ProcedureReturn 1
EndIf
EndProcedure
Procedure.i Metronome(*m.METRONOMEs)
Protected milliseconds = Int((60 * 1000) / *m\BeatsPerMinute)
Protected msPerFrame, framesPerBeat
Protected i, j, cycleCount, startTime, frameEndTime, delayTime, delayError, h.f
;calculate metronome angles for each frame of animation
If *m\BeatsPerMinute < 60
framesPerBeat = Round(milliseconds / 150, #PB_Round_Nearest)
Else
framesPerBeat = Round((*m\BeatsPerMinute - 420) / -60, #PB_Round_Nearest)
EndIf
If framesPerBeat < 1
framesPerBeat = 1
Dim metronomeFrameAngle.f(1, framesPerBeat)
metronomeFrameAngle(0, 1) = 90
metronomeFrameAngle(1, 1) = 90
Else
Dim metronomeFrameAngle.f(1, framesPerBeat * 2)
For j = 1 To framesPerBeat
h = 45 / framesPerBeat
metronomeFrameAngle(0, j) = 90 - h * (j - 1)
metronomeFrameAngle(0, framesPerBeat + j) = 45 + h * (j - 1)
metronomeFrameAngle(1, j) = 90 + h * (j - 1)
metronomeFrameAngle(1, framesPerBeat + j) = 135 - h * (j - 1)
Next
framesPerBeat * 2
EndIf
msPerFrame = milliseconds / framesPerBeat
PlaySound(#SOUND_HIGH)
startTime = ElapsedMilliseconds()
Repeat
For i = 0 To 1
frameEndTime = startTime + msPerFrame
For j = 1 To framesPerBeat
drawMetronome(*m, metronomeFrameAngle(i, j), cycleCount)
;check for thread exit
If *m\activityStatus < 0
*m\activityStatus = 0
ProcedureReturn
EndIf
delayTime = frameEndTime - ElapsedMilliseconds()
If (delayTime - delayError) >= 0
Delay(frameEndTime - ElapsedMilliseconds() - delayError) ;wait the remainder of frame
ElseIf delayTime < 0
delayError = - delayTime
EndIf
frameEndTime + msPerFrame
Next
;check for thread exit
If *m\activityStatus < 0
*m\activityStatus = 0
ProcedureReturn
EndIf
While (ElapsedMilliseconds() - startTime) < milliseconds: Wend
SetGadgetText(*m\msPerBeat, Str(ElapsedMilliseconds() - startTime))
cycleCount + 1: cycleCount % *m\BeatsPerCycle
If cycleCount = 0
PlaySound(#SOUND_HIGH)
Else
PlaySound(#SOUND_LOW)
EndIf
startTime + milliseconds
Next
ForEver
EndProcedure
Procedure startMetronome(*m.METRONOMEs, MetronomeThread) ;start up the thread with new values
*m\BeatsPerMinute = Val(GetGadgetText(#STRING_BPM)) *m\BeatsPerCycle = Val(GetGadgetText(#STRING_BPC)) *m\activityStatus = 1 If *m\BeatsPerMinute MetronomeThread = CreateThread(@Metronome(), *m) EndIf ProcedureReturn MetronomeThread
EndProcedure
Procedure stopMetronome(*m.METRONOMEs, MetronomeThread) ;if the thread is running: stop it
If IsThread(MetronomeThread) *m\activityStatus = -1 ;signal thread to stop EndIf drawMetronome(*m, 90)
EndProcedure
Define w = 360, h = 360, ourMetronome.METRONOMEs
- initialize the metronome
With ourMetronome
\msPerBeat = #STRING_MSPB \canvasGadget = #CANVAS_METRONOME \volume = 10 \w = w \h = h \originX = w / 2 \originY = h / 2 \radius = 100
EndWith
ourMetronome\canvasGadget = #CANVAS_METRONOME
- initialize sounds
handleError(InitSound(), "Sound system is Not available") handleError(CatchSound(#SOUND_LOW, ?sClick, ?eClick - ?sClick), "Could Not CatchSound") handleError(CatchSound(#SOUND_HIGH, ?sClick, ?eClick - ?sClick), "Could Not CatchSound") SetSoundFrequency(#SOUND_HIGH, 50000) SoundVolume(#SOUND_LOW, ourMetronome\volume) SoundVolume(#SOUND_HIGH, ourMetronome\volume)
- setup window & GUI
Define Style, i, wp, gh
Style = #PB_Window_SystemMenu | #PB_Window_ScreenCentered | #PB_Window_MinimizeGadget handleError(OpenWindow(#WINDOW, 0, 0, w + 200 + 12, h + 4, "Metronome", Style), "Not OpenWindow") SetWindowColor(#WINDOW, $505050)
If LoadFont(0, "tahoma", 9, #PB_Font_HighQuality | #PB_Font_Bold)
SetGadgetFont(#PB_Default, FontID(0))
EndIf
i = 3: wp = 10: gh = 22 TextGadget(#TEXT_MSPB, w + wp, gh * i, 100, gh, "MilliSecs/Beat ", #PB_Text_Center) StringGadget(#STRING_MSPB, w + wp + 108, gh * i, 90, gh, "0", #PB_String_ReadOnly): i + 2 TextGadget(#TEXT_BPM, w + wp, gh * i, 100, gh,"Beats/Min ", #PB_Text_Center) StringGadget(#STRING_BPM, w + wp + 108, gh * i, 90, gh, "120", #PB_String_Numeric): i + 2 GadgetToolTip(#STRING_BPM, "Valid range is 20 -> 240") TextGadget(#TEXT_BPC, w + wp, gh * i, 100, gh,"Beats/Cycle ", #PB_Text_Center) StringGadget(#STRING_BPC, w + wp + 108, gh * i, 90, gh, "4", #PB_String_Numeric): i + 2 GadgetToolTip(#STRING_BPC, "Valid range is 1 -> BPM") ButtonGadget(#BUTTON_START, w + wp, gh * i, 200, gh, "Start", #PB_Button_Toggle): i + 2 ButtonGadget(#BUTTON_VOLM, w + wp, gh * i, 100, gh, "-Volume") ButtonGadget(#BUTTON_VOLP, w + wp + 100, gh * i, 100, gh, "+Volume") CanvasGadget(ourMetronome\canvasGadget, 0, 0, ourMetronome\w, ourMetronome\h, #PB_Image_Border) drawMetronome(ourMetronome, 90)
Define msg, GID, MetronomeThread, Value Repeat ;the control loop for our application
msg = WaitWindowEvent(1)
GID = EventGadget()
etp = EventType()
If GetAsyncKeyState_(#VK_ESCAPE): End: EndIf ;remove when app is o.k.
Select msg
Case #PB_Event_CloseWindow
End
Case #PB_Event_Gadget
Select GID
Case #STRING_BPM
If etp = #PB_EventType_LostFocus
Value = Val(GetGadgetText(#STRING_BPM))
If Value > 390
Value = 390
ElseIf Value < 20
Value = 20
EndIf
SetGadgetText(#STRING_BPM, Str(Value))
EndIf
Case #STRING_BPC
If etp = #PB_EventType_LostFocus
Value = Val(GetGadgetText(#STRING_BPC))
If Value > Val(GetGadgetText(#STRING_BPM))
Value = Val(GetGadgetText(#STRING_BPM))
ElseIf Value < 1
Value = 1
EndIf
SetGadgetText(#STRING_BPC, Str(Value))
EndIf
Case #BUTTON_VOLP, #BUTTON_VOLM ;change volume
If GID = #BUTTON_VOLP And ourMetronome\volume < 100
ourMetronome\volume + 10
ElseIf GID = #BUTTON_VOLM And ourMetronome\volume > 0
ourMetronome\volume - 10
EndIf
SoundVolume(#SOUND_LOW, ourMetronome\volume)
SoundVolume(#SOUND_HIGH, ourMetronome\volume)
Case #BUTTON_START ;the toggle button for start/stop
Select GetGadgetState(#BUTTON_START)
Case 1
stopMetronome(ourMetronome, MetronomeThread)
MetronomeThread = startMetronome(ourMetronome, MetronomeThread)
SetGadgetText(#BUTTON_START,"Stop")
Case 0
stopMetronome(ourMetronome, MetronomeThread)
SetGadgetText(#BUTTON_START,"Start")
EndSelect
EndSelect
EndSelect
ForEver End
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Python
<lang Python>
- lang Python
import time
def main(bpm = 72, bpb = 4):
sleep = 60.0 / bpm
counter = 0
while True:
counter += 1
if counter % bpb:
print 'tick'
else:
print 'TICK'
time.sleep(sleep)
main()
</lang>
Racket
<lang Racket>
- lang racket
(require racket/gui)
(define msec 500) (define sounds '("hi.wav" "lo.wav")) (define colors '("red" "green"))
(define f
(new frame% [label "Metronome"] [width 200] [height 200]))
(define c
(new (class canvas%
(define brushes
(map (λ(c) (new brush% [color c] [style 'solid])) colors))
(define cur 0)
(define/override (on-paint)
(send* (send this get-dc)
(clear)
(set-brush (list-ref brushes cur))
(draw-rectangle 0 0 200 200)))
(define/public (flip!)
(set! cur (modulo (add1 cur) (length sounds)))
(play-sound (list-ref sounds cur) #f)
(on-paint))
(super-new))
[parent f]))
(define (flip)
(define init (current-inexact-milliseconds))
(define next (+ msec init))
(define ticks 1)
(let loop ()
(when (> (current-inexact-milliseconds) next)
(set! ticks (add1 ticks))
(set! next (+ init (* msec ticks)))
(queue-callback (λ() (send c flip!))))
(sleep 0.01)
(loop)))
(send* f (center) (show #t)) (void (thread flip)) </lang>
REXX
These REXX program examples are modeled after the Perl 6 example.
textual visual, no sound
<lang rexx>/*REXX program simulates a visual (textual) metronome (with no sound). */ parse arg bpm bpb dur . /*obtain optional arguments from the CL*/ if bpm== | bpm=="," then bpm=72 /*the number of beats per minute. */ if bpb== | bpb=="," then bpb= 4 /* " " " " " bar. */ if dur== | dur=="," then dur= 5 /*duration of the run in seconds. */ call time 'Reset' /*reset the REXX elapsed timer. */ bt=1/bpb /*calculate a tock-time interval. */
do until et>=dur; et=time('Elasped') /*process tick-tocks for the duration*/
say; call charout ,'TICK' /*show the first tick for the period. */
es=et+1 /*bump the elapsed time "limiter". */
$t=et+bt
do until e>=es; e=time('Elapsed')
if e<$t then iterate /*time for tock? */
call charout , ' tock' /*show a "tock". */
$t=$t+bt /*bump the TOCK time.*/
end /*until e≥es*/
end /*until et≥dur*/
/*stick a fork in it, we're all done. */</lang>
output when using the default inputs: <per> TICK tock tock tock tock TICK tock tock tock tock TICK tock tock tock tock TICK tock tock tock tock TICK tock tock tock tock TICK tock tock tock tock
with sound, REGINA only
This REXX version only executes when using the Regina REXX interpreter. <lang rexx>/*REXX program simulates a metronome (with sound). Regina REXX only. */ parse arg bpm bpb dur tockf tockd tickf tickd . /*obtain optional arguments from the CL*/ if bpm== | bpm=="," then bpm= 72 /*the number of beats per minute. */ if bpb== | bpb=="," then bpb= 4 /* " " " " " bar. */ if dur== | dur=="," then dur= 5 /*duration of the run in secs*/ if tockf== | tockf=="," then tockf=400 /*frequency " " tock sound " HZ. */ if tockd== | tockd=="," then tockd= 20 /*duration " " " " " msec*/ if tickf== | tickf=="," then tickf=600 /*frequency " " tick " " HZ. */ if tickd== | tickd=="," then tickd= 10 /*duration " " " " " msec*/ call time 'Reset' /*reset the REXX elapsed timer. */ bt=1/bpb /*calculate a tock─time interval. */
do until et>=dur; et=time('Elasped') /*process tick-tocks for the duration*/
call beep tockf, tockd /*sound a beep for the "TOCK". */
es=et+1 /*bump the elapsed time "limiter". */
$t=et+bt
do until e>=es; e=time('Elapsed')
if e<$t then iterate /*time for tock? */
call beep tickf, tickd /*sound a "tick". */
$t=$t+bt /*bump the TOCK time.*/
end /*until e≥es*/
end /*until et≥dur*/
/*stick a fork in it, we're all done. */</lang>
with sound, PC/REXX only
<lang rexx>/*REXX program simulates a metronome (with sound). PC/REXX or Personal REXX only.*/ parse arg bpm bpb dur tockf tockd tickf tickd . /*obtain optional arguments from the CL*/ if bpm== | bpm=="," then bpm= 72 /*the number of beats per minute. */ if bpb== | bpb=="," then bpb= 4 /* " " " " " bar. */ if dur== | dur=="," then dur= 5 /*duration of the run in secs*/ if tockf== | tockf=="," then tockf=400 /*frequency " " tock sound " HZ. */ if tockd== | tockd=="," then tockd= .02 /*duration " " " " " sec.*/ if tickf== | tickf=="," then tickf=600 /*frequency " " tick " " HZ. */ if tickd== | tickd=="," then tickd= .01 /*duration " " " " " sec.*/ call time 'Reset' /*reset the REXX elapsed timer. */ bt=1/bpb /*calculate a tock─time interval. */
do until et>=dur; et=time('Elasped') /*process tick-tocks for the duration*/
call sound tockf, tockd /*sound a beep for the "TOCK". */
es=et+1 /*bump the elapsed time "limiter". */
$t=et+bt
do until e>=es; e=time('Elapsed')
if e<$t then iterate /*time for tock? */
call sound tickf, tickd /*sound a tick. */
$t=$t+bt /*bump the TOCK time.*/
end /*until e≥es*/
end /*until et≥dur*/
/*stick a fork in it, we're all done. */</lang>
Tcl
This code only rings the bell on the high beat, which occurs at the start of the bar. <lang tcl>package require Tcl 8.5
lassign $argv bpm bpb if {$argc < 2} {set bpb 4} if {$argc < 1} {set bpm 60}
fconfigure stdout -buffering none set intervalMS [expr {round(60000.0 / $bpm)}] set ctr 0
proc beat {} {
global intervalMS ctr bpb
after $intervalMS beat ;# Reschedule first, to encourage minimal drift
if {[incr ctr] == 1} {
puts -nonewline "\r\a[string repeat { } [expr {$bpb+4}]]\rTICK"
} else {
puts -nonewline "\rtick[string repeat . [expr {$ctr-1}]]"
}
if {$ctr >= $bpb} {
set ctr 0
}
}
- Run the metronome until the user uses Ctrl+C...
beat vwait forever</lang> It might be executed like this: <lang bash>tclsh8.5 metronome.tcl 90 4</lang>