pynotation

pynotation writes music out as notes on a staff in a Pyctures scene, and lights the notes as they play. It is for any age and any level: you give it a tune in one line and sheet music appears; you play the tune and each note lights as it sounds; you can play along on a keyboard and it tells you how you did. It is the Python sibling of notation.js, and goes with synths for sound and pydials for a keyboard on the screen.

Start with four small scenes

Each one is a whole program. Run one with pyctures run scene.py.

1. A tune, written out.

from pyctures import *
from pynotation import *

show_notes("E4 D4 C4 D4 E4 E4 E4:2", "quarter", title="Mary had a little lamb")

def draw():
    background("midnightblue")

The notes are written the way play_notes takes them: a note is a letter and a number ("C4" is middle C, "F#3", "Bb5"), - is a rest, :2 makes a note last two steps, and "quarter" says how long a step is. The key, the clef and the bars are worked out for you.

2. Play it, and watch it go.

from pyctures import *
from synths import *
from pynotation import *

page = show_notes("C4 C4 G4 G4 A4 A4 G4:2 F4 F4 E4 E4 D4 D4 C4:2", "quarter", tempo=100)
page.on_note = lambda note: print("now playing", note.name)

def on_mouse_down(x, y):
    page.play()

def draw():
    background("midnightblue")
    text("Click here to play", width / 2, height - 30, "white", 18, "centre")

page.play() plays the music through synths and follows it: the notes that are sounding turn orange, a line moves through the bar, and the page turns when the music reaches the next line. page.on_note is called as each note begins. page.stop() stops it.

3. Follow a song.

from pyctures import *
from synths import *
from pynotation import *

song = play_song("songs/night_drive.json")
show_notes("songs/night_drive.json", channels=[3, 1], follow=song)     # the tune and the bass, a staff each

def draw():
    background("#0b1020")

A tracker song is turned into written music: you choose which channels to show. As the song plays, the page follows it. Tap a bar and the song jumps there. That is the picture at the top of this page.

4. Play along.

from pyctures import *
from synths import *
from pydials import *
from pynotation import *

lead = make_synth("keys")
page = show_notes("E4 D4 C4 D4 E4 E4 E4:2", "quarter")
page.play_along("wait", synth=lead)
keyboard(page, octave=4, octaves=1)        # a pydials keyboard plays the page

def draw():
    background("#12261e")
    text("%d right, %d wrong" % (page.result.right, page.result.wrong), width / 2, height / 2, "white", 20, "centre")

The line waits at each note until you play it. The key to press is lit. A right note turns green; a wrong one shows in red for a moment where you played it. "time" in place of "wait" keeps going at the tempo whether you are ready or not.

The scenes in examples/ are ready to run: twinkle.py, song.py and play_along.py.

What you can show

The options are those of notation.js, spelled Python's way: key, time, clef, tempo, title, at, x, y, width, height, zoom, paper, colours, scroll, lines, bar_numbers, follow, hear, seek, line, voice, synth, and for a song channels, instruments, drums, grand and rows_per_beat. How a tracker song becomes written music is told there too.

The page

How it is made

The page writes the music out and draws it. Python never touches the page (it may be in a worker, or on another computer). show_notes sends one command, which makes the page of music in the browser from notation.js (the package carries the very file that is the JavaScript library), and Python keeps a small object that stands for it. What happens there comes back with the next frame.

The sound library keeps the time. page.play() asks the page for the notes as play_notes takes them, plays them through synths at a moment on the sound clock, and tells the page that moment: the page then lights the notes and moves the line by itself, every frame, with no more commands. A song is followed from song.position, which Python hands on as it changes, and the page moves smoothly between.

A keyboard from pydials tied to the page (keyboard(page)) plays it in the page itself, so a key is marked the moment it is touched.

Tests

python -m pytest tests

tests/test_runtime.py is the Python half with no browser: the commands it sends and what it does with what the page reports. tests/test_browser.py runs scenes with pyctures run in a muted Chromium (it needs Playwright): every example draws its music, a tune Python plays is followed in the page and each note is told to Python in time, and a learner plays along on a pydials keyboard. The page's half is tested in notation.js.

Licence

MIT, © John Wylie. The music symbols' outlines are from the Leland font, © MuseScore BVBA, under the SIL Open Font Licence 1.1: see LICENSE-GLYPHS.