Adding a music activity and using gcomprismusic.py module

If you wish to add an activity relating to music to gcompris, consider importing the module gcomprismusic.py This module contains several useful classes of objects that will not only make it easier for you to make your activity, but also help GCompris maintain a more uniform music platform.

The following music objects are currently included in the module:

• Piano Keyboard
• Music Note
  • Eighth Note
  • Quarter Note
  • Half Note
  • Whole Note
• Musical Staff
  • Bass Clef
  • Treble Clef

The module was developed in 2012 by Beth Hadley through Google Summer of Code. It can always be improved, added to, and adjusted.

The documentation provided below will help you get started using the module. It provides coding examples, with pictures, that will help you create music objects.

Beth Hadley welcomes comments, ideas, contributions, and questions regarding the gcomprismusic module or GCompris music activities. Send her an email at bethmhadley@gmail.com

How to import the gcomprismusic module

The gcomprismusic.py module is located in the piano_composition-activity. There are certain resources that support the module, and these are permanently located under the resources folder of the piano_composition activity. Thus, you must execute the following instructions to properly import the gcomprismusic module.

• create your new activity (see Beginner if you need help)
• open init_path.sh and find the pythonplugindir line. Replace this line with something like:

   pythonplugindir=$path/../piano_composition-activity:$path/../name_of_your_activity-activity
  

  save and close this file
• add a resources folder to your activity folder
• create a symbolic link in this resources folder that references the piano_composition resources file. If you are unsure of this step, just go into the play_piano activity folder, click on resources, and copy the piano_composition folder and paste that into your resources folder
• open the python file for your activity, name_of_your_activity, and find at the top where all the import statements are. add the following line to the import statements:

  from gcomprismusic import *
  

• run your activity, and ensure that it works (you should see a screen that says "This is the first plugin in GCompris coded in the Python Programming language." If there are errors, enjoy troubleshooting or contact Beth.

General Reference

Once you've imported the module, you may call or invoke all methods and classes. Instructions and examples are provided below for your reference.

• Each note is assigned a number, stored internally as numID This is to prevent issues with converting between different language translations of note names. Each note is also assigned a color, according to NOTE_COLOR_SCHEME The following table represents this:

  English Name	Northern European Name	numID	Color
  C	C	1
  C sharp / D flat (C♯ / D♭)	Cis / Des	-1
  D	D	2
  D sharp / E flat (D♯ / E♭)	Dis / Es	-2
  E	E	3
  F	F	4
  F sharp / G flat (F♯ / G♭)	Fis / Ges	-3
  G	G	5
  G sharp / A flat (G♯ / G♭)	Gis / As	-4
  A	A	6
  A sharp / B flat (A♯ / B♭)	Ais / B	-5
  B	H	7
  C (higher octave)	C (higher octave)	8

  
  

• getKeyNameFromID(numID, sharpNotation=True)

  get the name of the key that corresponds to the numID given. optionally set sharpNotation = True for sharp notation, or sharpNotation = False for flat notation
  
  >>> getKeyNameFromID(1)
  C
  >>> getKeyNameFromID(-3, sharpNotation=True)
  F#
  >>> getKeyNameFromID(-5, sharpNotation=False)
  Bb
  

• getIDFromKeyName(keyName)

  get the name of the key that corresponds to the numID given
  
  >>> getIDFromKeyName('C')
  1
  >>> getIDFromKeyName('D#')
  -2
  >>> getIDFromKeyName('Eb')
  -2
  

Staff Classes

There are two staff subclasses, both of which inherit from the master Staff Class:

• TrebleStaff
• BassStaff

To create these objects, the __init__ functions require the following arguments:

1. x: starting x position of the staff
2. y: starting y position of the staff
3. canvasRoot: the rootitem of the canvas
4. numStaves: the number of staves you'd like to create

An example of instantiating each object is below. Note that you must call the drawStaff() method to draw the staff to the canvas.

>>> self.staff1 = TrebleStaff(50, 30, self.rootitem, numStaves=1)
>>> self.staff2 = BassStaff(50, 130, self.rootitem, numStaves=2)

Staff Formatting Attributes

Attribute Name	Default Value	Description
endx	390	rightend location of staff lines
verticalDistanceBetweenStaves	115	vertical distance between musical staves
staffLineSpacing	13	vertical distance between lines in staff
staffLineThickness	2.0	thickness of staff lines
numStaves	from __init__	number of staves to draw

Music Notation Formatting

Attribute Name	Default Value	Description
initialNoteX	30	starting X position of first note
noteSpacingX	26	#distance between each note when appended to staff
currentLineNum	1	the line number you're currently writing notes to
currentNoteType	4	the note type you're currently using to write to the musical staff, could be 4 (quarter), 8 (eighth), 2 (half) or 1 (whole)

Note & Playback

Attribute Name	Default Value	Description
initialNoteX	30	starting X position of first note
colorCodeNotes	True	color notes according to NOTE_COLOR_SCHEME
labelBeatNumbers	False	label the beat numbers for each note above the note (used in play_rhythm-activity)
drawPlayingLine	False	draw vertical line on staff to follow the beat as the composition is being played
notReadyToPlay	False	#set to True when staff is not ready to play composition (something else is going on for example)
noteList	[]	list of note objects written to staff
staffName	'trebleClef' or 'bassClef'	name of the staff
positionDict	{set values}	a dictionary mapping the notes to the appropriate y coordinate on the staff

Methods

• drawStaff()

  draw the staff, including staff lines and staff clefs
  
  >>> self.newStaff = TrebleStaff(100, 80, self.rootitem, numStaves=4)
  >>> self.newStaff.drawStaff(self)
  

  

• drawNote(self,note)

  determine the correct x & y coordinate for the next note, and writes this note as an image to the staff. An alert is triggered if no more room is left on the staff. Color-codes the note or draws beat numbers if appropriate.
  
  >>> self.newStaff = TrebleStaff(50, 50, self.rootitem, numStaves=4)
  >>> self.newStaff.drawStaff()
  >>> self.newStaff.drawNote(QuarterNote(1, 'trebleClef', self.newStaff.rootitem))
  >>> self.newStaff.drawNote(EighthNote(5, 'trebleClef', self.newStaff.rootitem))
  >>> self.newStaff.drawNote(WholeNote(-3, 'trebleClef', self.newStaff.rootitem))
  

  

• writeLabel(self, text, note)

  writes the text below the note, such as labeling the note name, in color-code if self.colorCodeNotes = True
  
  >>> self.newStaff = TrebleStaff(50, 50, self.rootitem, numStaves=1)
  >>> self.newStaff.endx = 200
  >>> self.newStaff.rootitem.scale(2.0, 2.0)
  >>> self.newStaff.drawStaff()
  >>> n2 = HalfNote(5, 'trebleClef', self.newStaff.rootitem)
  >>> self.newStaff.drawNote(n2)
  >>> self.newStaff.writeLabel('G', n2)
  

  

• eraseOneNote(self, widget=None, target=None, event=None)

  removes the last note in the staff's noteList, updates self.currentLineNum if necessary, and updates self.currentNoteXCoordinate
  
  >>> self.newStaff.eraseOneNote()
  

• eraseAllNotes(self, widget=None, target=None, event=None)

  remove all notes from staff, deleting them from self.noteList, and restores self.currentLineNumto 1 and self.currentNoteXCoordinate to the starting position
  
  >>> self.newStaff.eraseAllNotes()
  

• clear(self, widget=None, target=None, event=None)

  clear all notes and clefs on the staff (for preparaiton of a clef change)
  
  >>> self.newStaff.clear()
  

  

• playComposition(self, widget=None, target=None, event=None, playingLineOnly=False)

  plays entire composition. establish timers, one per note, called after different durations according to noteType. Only way to stop playback after calling this method and during play is self.eraseAllNotes()
  
  >>> self.newStaff.playComposition()
  

• stringToNotation(self, melodyString)

  parse the melody string and write the notes to the staff. The melody must be in a very simple format. It is one line, and begins the clef, either 'trebleClef' or 'bassClef' Then, each following note is seperated with a space and the note name (English system, sharp=#,flat=b, C (second octave is 2C rather than just C) written first followed by the note duration (8=eighth,4=quarter,2=half,1=whole)
  
  >>> self.staff1 = TrebleStaff(50, 30, self.rootitem, numStaves=1)
  >>> self.staff1.endx = 200
  >>> self.staff1.rootitem.scale(2.0, 2.0)
  >>> self.staff1.drawStaff()
  >>> self.staff1.stringToNotation('trebleClef C4 G2 F#4 Ab4 2C2')
  
  >>> self.staff2 = BassStaff(50, 130, self.rootitem, numStaves=1)
  >>> self.staff2.endx = 200
  >>> self.staff2.rootitem.scale(2.0, 2.0)
  >>> self.staff2.drawStaff()
  >>> self.staff2.stringToNotation('bassClef Eb2 F4 C#8 Bb4 C2')
  



• drawScale(self, scaleName, includeNoteNames=True)

  return a note's vertical coordinate based on the note's name. This is unique to each type of clef (different for bass and treble)
  
  scaleNames currently supported: 'C Major'
  
  >>> self.staff2 = TrebleStaff(50, 50, self.rootitem, numStaves=1)
  >>> self.staff2.endx = 300
  >>> self.staff2.rootitem.scale(2.0, 2.0)
  >>> self.staff2.drawStaff()
  >>> self.staff2.drawScale('C Major')
  



• colorCodeAllNotes(self)

  color notes according to NOTE_COLOR_SCHEME
          
  >>> self.newStaff.colorCodeAllNotes()
  

• colorCodeAllNotes(self)

  color notes according to NOTE_COLOR_SCHEME
          
  >>> self.newStaff.colorCodeAllNotes()
  

• colorAllNotes(self, color)

  color all notes a certain color ('black', 'red', 'blue', etc.)
          
  >>> self.newStaff.colorAllNotes('black')
  

• getNoteXCoordinate(self)

  determines the x coordinate of the next note to be written to the staff, with consideration for the maximum staff line length.Increments self.currentLineNumand sets self.currentNoteXCoordinate
  

• getNoteYCoordinate(self)

  return a note's vertical coordinate based on the note's name. This is unique to each type of clef (different for bass and treble)
  

Note Classes

There are four types of notes classes, all of which subclass the Note class.

• Eighth Note
• Quarter Note
• Half Note
• Whole Note

To create these objects, the __init__ functions require the following arguments:

• numID: The numerical id number that corresponds to this note (see table above for note number correspondance)
• staffType: 'trebleClef' or 'bassClef', whichever clef this note will belong to
• rootitem: the rootitem of the canvas where you'd like this note to appear (use the staff's rootitem if you'd like the note to appear in the staff)
• sharpNotation=Trueoptional argument, pass in False if you'd like this note to always display with flat notation. Default is to display with flat notation

An example of creating notes (these will not appear on the page until you call the drawNote() method)

>>> n2 = HalfNote(5, 'trebleClef', self.rootitem)
>>> n2 = HalfNote(5, 'trebleClef', self.staff.rootitem)
>>> n2 = EighthNote(-1, 'trebleClef', self.rootitem)
>>> n2 = QuarterNote(3, 'trebleClef', self.staff.rootitem)

Each note has an x and y coordinate, set to 0,0 initially but updated when it is drawn to the canvas.

Property Name	Value(s)/Default	Description
x	0	x-position of note when written to canvas (updated when .draw() is called
y	0	y-position of note when written to canvas (updated when .draw() is called
staffType	from __init__	the staffType ('trebleClef' or 'bassClef' this note corresponds to
sharpNotation	from __init__	toggle to switch note between sharp notation and flat notation, if applicable	-	noteType	8,4,2,1	the number that corresponds to the note name (eighth note = 8, quarter note = 4, half note = 2, whole note = 1
beatNums	'+','1','1,2','1,2,3,4'	the beat numbers that correspond to the notes (in order above: eighth, quarter, half, whole)




Methods

• draw(self, x,y)

  places note image in canvas at x,y
  
  >>> n2 = QuarterNote(5, 'trebleClef', self.rootitem)
  >>> n2.rootitem.scale(2.0, 2.0)
  >>> n2.draw(100, 100)
  

  

• play(self, widget=None, target=None, event=None)

  plays the note pitch. Each pitch is stored in the resources
  folder as an .ogg file (these are not synthesized)
  
  >>> self.newStaff = TrebleStaff(100, 80, self.rootitem, numStaves=4)
  >>> self.newStaff.drawStaff(self)