Chain¶

class maelzel.core.chain.Chain(items=None, offset=None, label='', properties=None, parent=None, _init=True)[source]¶

Bases: MContainer

A Chain is a sequence of Notes, Chords or other Chains

Parameters:

items (Union[Sequence[MEvent | Chain | str], str, None]) – the items of this Chain. The start time of any object, if given, is interpreted as relative to the start of the chain.
offset (Union[float, Rational, Fraction, None]) – offset of the chain itself relative to its parent
label (str) – a label for this chain
properties (Optional[dict[str, Any]]) – any properties for this chain. Properties can be anything, they are a way for the user to attach data to an object

Attributes Summary

`dur`	The duration of this sequence
`end`	The end time of this object.
`items`	The items in this chain, a list of events of other chains
`label`	a label can be used to identify an object within a group of objects
`offset`	Optional offset, in quarternotes.
`parent`	The parent of this object.
`playargs`	playargs are set via `setPlay()` and are used to customize playback (instr, gain, …).
`properties`	User-defined properties as a dict (None by default).
`symbols`	A list of all symbols added via `addSymbol()` (None by default)

Methods Summary

`absOffset`()	Returns the absolute offset of this object in quarternotes
`absorbInitialOffset`([removeRedundantOffsets])	Moves the offset of the first event to the offset of the chain itself
`addSpanner`(spanner[, endobj])	Adds a spanner symbol across this object
`addSymbol`(args, *kws)	rtype: `Self`
`addSymbolAt`(location, symbol)	Adds a symbol at the given location
`addText`(text[, placement, italic, weight, ...])	Add a text annotation to this object
`append`(item)	Append an item to this chain
`asVoice`([removeOffsets])	Create a Voice as a copy of this Chain
`automate`(param, breakpoints[, relative, ...])	rtype: `None`
`beamBreak`(location)	Add a 'soft' beam break at the given location
`childOffset`(child)	Returns the offset of child within this chain
`clone`([items, offset, label, properties])	Clone this object, changing parameters if needed
`copy`()	Returns a copy of this object
`cropped`(start, end)	Returns a copy of this chain, cropped to the given beat range
`cycle`(totaldur[, crop])	Cycle over the items of self for the given total duration
`dump`([indents, forcetext])	Dump this chain, recursively
`durSecs`()	Returns the duration in seconds according to the active score
`eventAt`(location[, margin, split])	The event present at the given location
`events`([instr, delay, args, gain, chan, ...])	Returns the SynthEvents needed to play this object
`eventsBetween`(start, end[, partial])	Events between the given time range
`eventsWithOffset`([start, end, partial])	Recurse the events in self and resolves each event's offset
`extend`(items)	Extend this chain with items
`fillGaps`([recurse])	Fill any gaps with rests, inplace
`firstEvent`()	The first event in this chain, recursively
`firstOffset`()	Returns the offset (relative to the start of this chain) of the first event in this chain
`flat`([forcecopy])	A flat version of this Chain
`flatEvents`()	A list of flat events, with explicit absolute offsets set
`getPlay`(key[, default, recursive])	Get a playback attribute previously set via `MObj.setPlay()`
`getProperty`(key[, default])	Get a property of this objects
`getSymbol`(classname)	Get a symbol of a given class, if present
`hasOffsets`()	True if self has an explicit offset and all items as well (recursively)
`invertPitch`(pivot)	Invert the pitch of this object
`isFlat`()	Is self flat?
`isRest`()	Is this object a Rest?
`itemsBetween`(start, end[, partial])	Items between the given time range
`itemsWithOffset`()	Iterate over the items of this chain with their absolute offset
`itemsWithRelativeOffset`()	Iterate over the items of this chain with their relative offset
`lastEvent`()	The last event in this chain, recursively
`matchOrfanSpanners`([removeUnmatched])	Match unmatched spanners
`meanPitch`()	The mean pitch of this object
`mergeTiedEvents`()	Merge tied events inplace
`nextEvent`(event)	Returns the next event after event
`nextItem`(item)	Returns the next item after item
`parentAbsOffset`()	The absolute offset of the parent
`pitchRange`()	The pitch range of this object, if applicable
`pitchTransform`(pitchmap)	Apply a pitch-transform to this object, returns a copy
`play`([instr, delay, args, gain, chan, ...])	Plays this object.
`plot`(**kws)	rtype: `Axes`
`previousEvent`(event)	Returns the event before the given event
`previousItem`(item)	Returns the item (an event or a chain) previous to the given one
`quantizePitch`([step])	Returns a new object, with pitch rounded to step
`quantizedScore`([scorestruct, config, ...])	Returns a QuantizedScore representing this object
`rec`([outfile, sr, verbose, wait, nchnls, ...])	Record the output of .play as a soundfile
`recurse`([reverse])	Yields all events (Notes/Chords) in this chain, recursively
`relOffset`()	Resolve the offset of this object, relative to its parent
`remap`(deststruct[, sourcestruct])	Remap times (offset, dur) from source scorestruct to destination scorestruct
`removeRedundantOffsets`()	Remove over-specified start times in this Chain (in place)
`render`([backend, renderoptions, ...])	Renders this object as notation
`resolveEnd`()	Returns the resolved end of this object, relative to its parent
`scorestruct`([resolve])	Returns the ScoreStruct active for this obj or its parent (recursively)
`scoringEvents`([groupid, config, parentOffset])	Returns the scoring events corresponding to this object.
`scoringParts`([config])	Returns this object as a list of scoring UnquantizedParts.
`setPlay`(**kws)	Set any playback attributes, returns self
`setProperty`(key, value)	Set a property, returns self
`show`([fmt, external, backend, scorestruct, ...])	Show this as notation.
`splitAt`(location[, tie, beambreak, nomerge])	Split any event present at the given absolute offset (in place)
`splitEventsAtMeasures`([scorestruct, ...])	Splits items in self at measure offsets, inplace (recursively)
`splitEventsAtOffsets`(offsets[, tie, nomerge])	Splits items in self at the given offsets, inplace (recursively)
`stack`()	Stack events to the left INPLACE, making offsets explicit
`timeRangeSecs`([parentOffset, scorestruct])	The absolute time range, in seconds
`timeScale`(factor[, offset])	Create a copy with modified timing by applying a linear transformation
`timeShift`(timeoffset)	Return a copy of this object with an added offset
`timeShiftInPlace`(timeoffset)	Shift the time of this by the given offset (inplace)
`timeTransform`(timemap[, inplace])	Apply a time-transform to this object
`transpose`(interval)	Transpose this object by the given interval
`transposeByRatio`(ratio)	Transpose this by a given frequency ratio, if applicable
`unquantizedScore`([title])	Create a maelzel.scoring.UnquantizedScore from this object
`withExplicitOffset`([forcecopy])	Copy of self with explicit offset
`write`(outfile[, backend, resolution])	Export to multiple formats

Attributes Documentation

dur¶: The duration of this sequence

end¶

The end time of this object.

Will be None if this object has no explicit offset. Use :meth:`

items: list[MEvent | Chain]¶: The items in this chain, a list of events of other chains

label: str¶: a label can be used to identify an object within a group of objects

offset: F | None¶

Optional offset, in quarternotes. Specifies the start time relative to its parent

It can be None, which indicates that within a container this object would start after the previous object. For an object without a parent, the offset is an absolute offset.

parent¶

The parent of this object.

This attribute is set by the parent when an object is added to it. For example, when adding a Note to a Chain, the Chain is set as the parent of the Note. This enables the Note to query information about the parent, like its absolute position or if a score structure has been set upstream

playargs: PlayArgs | None¶: playargs are set via setPlay() and are used to customize playback (instr, gain, …). None by default

properties: dict[str, Any] | None¶: User-defined properties as a dict (None by default). Set them via setProperty()

symbols: list[_symbols.Symbol] | None¶: A list of all symbols added via addSymbol() (None by default)

Methods Documentation

absOffset()¶

Returns the absolute offset of this object in quarternotes

If this object is embedded (has a parent) in a container, its absolute offset depends on the offset of its parent, recursively. If the object has no parent then the absolute offset is just the resolved offset

Return type:: Fraction
Returns:: the absolute start position of this object

absorbInitialOffset(removeRedundantOffsets=True)[source]¶

Moves the offset of the first event to the offset of the chain itself

Parameters:: removeRedundantOffsets – remove redundant offsets.

Example

Notice how the offset of the first note is now None and the chain itself has an offset of 0.5

>>> ch = Chain([
...     "4C:1:offset=0.5",
...     "4E:1",
...     "4G:1"
... ])
>>> ch.dump()
Chain - beat: 0, offset: None, dur: 3.5
location  beat   offset      dur         name
0:0.5     0.5    0.5         1           4C
0:1.5     1.5    (1.5)       1           4E
0:2.5     2.5    (2.5)       1           4G
>>> ch._absorbInternalOffset()
>>> ch.dump()
Chain - beat: 1/2, offset: 0.5, dur: 3
location  beat   offset      dur         name
0:0.5     0.5    (0)         1           4C
0:1.5     1.5    (1)         1           4E
0:2.5     2.5    (2)         1           4G

addSpanner(spanner, endobj=None)[source]¶

Adds a spanner symbol across this object

A spanner is a slur, line or any other symbol attached to two or more objects. A spanner always has a start and an end.

Parameters:

spanner (str | Spanner) – a Spanner object or a spanner description (one of ‘slur’, ‘<’, ‘>’, ‘trill’, ‘bracket’, etc. - see maelzel.core.symbols.makeSpanner() When passing a string description, prepend it with ‘~’ to create an end spanner
endobj (Optional[MEvent]) – the object where this spanner ends. If not given, the last event of this chain

Return type:

Self

Returns:

self (allows to chain calls)

Example

>>> chain = Chain([
... Note("4C", 1),
... Note("4D", 0.5),
... Note("4E")   # This ends the hairpin spanner
... ])
>>> chain.addSpanner('slur')

This is the same as:

>>> chain[0].addSpanner('slur', chain[-1])

addSymbol(*args, **kws)¶

Return type:: Self

addSymbolAt(location, symbol)[source]¶

Adds a symbol at the given location

If there is no event starting at the given location, the quantized part is split at the location when rendering and the symbol is added to the event. This allows to add ‘soft’ symbols at any location without the need to modify the events themselves. If there actually is an event starting at the given offset, the symbol is added to the event directly.

Parameters:

location (Union[float, Rational, Fraction, tuple[int, Union[float, Rational, Fraction]]]) – the location to add the symbol at
symbol (Symbol) – the symbol to add

Return type:

Self

Returns:

self

Example

>>> chain = Chain([
... Note("4C", 2),
... Note("4E", 1)
])
>>> chain.addSymbolAt(1, symbols.Fermata())

See also

Chain.beamBreak()

addText(text, placement='above', italic=False, weight='normal', fontsize=None, fontfamily='', box='')¶

Add a text annotation to this object

This is a shortcut to self.addSymbol(symbols.Text(...)). Use that for in-depth customization.

Parameters:

text (str) – the text annotation
placement – where to place the annotation (‘above’, ‘below’)
italic – if True, use italic as font style
weight – ‘normal’ or ‘bold’
fontsize (Optional[int]) – the size of the annotation
fontfamily – the font family to use. It is probably best to leave this unset
box – the enclosure shape, or ‘’ for no box around the text. Possible shapes are ‘square’, ‘circle’, ‘rounded’

Return type:

Self

Returns:

self

append(item)[source]¶

Append an item to this chain

Parameters:: item (MEvent) – the item to add
Return type:: None

asVoice(removeOffsets=True)[source]¶

Create a Voice as a copy of this Chain

Parameters:: removeOffsets – if True, remove any redundant offsets in the returned voice
Return type:: Voice

automate(param, breakpoints, relative=True, interpolation='linear')[source]¶

Return type:: None

beamBreak(location)[source]¶

Add a ‘soft’ beam break at the given location

A soft beam break does not modify the actual events in this Chain/Voice. It adds a beam break to the quantized score when rendering. Any syncopation at the given location will be broken for rendering but stays unmodified as an event. This is similar to performing:

>>> chain.splitAt(location).addSymbol(symbols.BeamBreak())

But the Chain/Voice itself remains unmodified: the operation is only performed at the quantized score

Parameters:: location (Union[float, Rational, Fraction, tuple[int, Union[float, Rational, Fraction]]]) – the location to add a beam break to
Return type:: Self
Returns:: self

See also

Chain.addSymbolAt()

childOffset(child)[source]¶

Returns the offset of child within this chain

raises ValueError if self is not a parent of child

Parameters:: child (MObj) – the object whose offset is to be determined
Return type:: Fraction
Returns:: The offset of this child within this chain

clone(items=None, offset=UNSET, label=None, properties=None)[source]¶

Clone this object, changing parameters if needed

Parameters:: **kws – any keywords passed to the constructor
Return type:: Chain
Returns:: a clone of this object, with the given arguments changed

Example:

>>> from maelzel.core import *
>>> a = Note("C4+", dur=1)
>>> b = a.clone(dur=0.5)

copy()[source]¶

Returns a copy of this object

Return type:: Self

cropped(start, end)[source]¶

Returns a copy of this chain, cropped to the given beat range

Returns None if there are no events in this chain within the given time range

Parameters:

start (Union[Fraction, Rational, float, tuple[int, Union[float, Rational, Fraction]]]) – start of the beat range
end (Union[Fraction, Rational, float, tuple[int, Union[float, Rational, Fraction]]]) – end of the beat range

Return type:

Optional[Self]

Returns:

a Chain cropped at the given beat range

cycle(totaldur, crop=False)[source]¶

Cycle over the items of self for the given total duration

Parameters:

totaldur (Fraction) – the total duration of the resulting sequence
crop – if True, crop last item if it exceeds the given total duration

Return type:

Self

Returns:

a copy of self representing cycles of its items

dump(indents=0, forcetext=False)[source]¶

Dump this chain, recursively

Values inside parenthesis are implicit. For example if an object inside this chain does not have an explicit .offset, its withExplicitTimes offset will be shown within parenthesis

Parameters:

indents – the number of indents to use
forcetext – if True, force print output instea of html, even when running inside jupyter

Return type:

None

durSecs()¶

Returns the duration in seconds according to the active score

Return type:: Fraction
Returns:: the duration of self in seconds

eventAt(location, margin=Fraction(1, 8), split=False)[source]¶

The event present at the given location

Parameters:

location (Union[float, Rational, Fraction, tuple[int, Union[float, Rational, Fraction]]]) – the beat or a tuple (measureindex, beatoffset). If a beat is given, it is interpreted as an absoute offset
margin – a time margin (in quarternotes) from the given location. This can help in corner cases
split – if True split the event at the given offset. This will modify the event itself, which will remain split after this call.

Return type:

MEvent | None

Returns:

the event present at the given location, or None if no event was found. An explicit rest will be returned if found but empty space will return None

events(instr=None, delay=None, args=None, gain=None, chan=None, pitchinterpol=None, fade=None, fadeshape=None, position=None, skip=None, end=None, sustain=None, workspace=None, transpose=0.0, **kwargs)¶

Returns the SynthEvents needed to play this object

All these attributes here can be set previously via playargs (or using setPlay())

Parameters:

gain (Optional[float]) – modifies the own amplitude for playback/recording (0-1)
delay (Optional[float]) – delay in seconds, added to the start of the object As opposed to the .offset attribute of each object, which is defined in quarternotes, the delay is always in seconds
instr (Optional[str]) – which instrument to use (see defPreset, definedPresets). Use “?” to select from a list of defined presets.
chan (Optional[int]) – the channel to output to. Channels start at 1
pitchinterpol (Optional[str]) – ‘linear’, ‘cos’, ‘freqlinear’, ‘freqcos’
fade (Union[float, tuple[float, float], None]) – fade duration in seconds, can be a tuple (fadein, fadeout)
fadeshape (Optional[str]) – ‘linear’ | ‘cos’
args (Optional[dict[str, float]]) – named arguments passed to the note. A dict {paramName: value}
position (Optional[float]) – the panning position (0=left, 1=right)
skip (Optional[float]) – start playback at the given offset (in quarternotes), relative to the start of the object. Allows to play a fragment of the object (NB: this trims the playback of the object. Use delay to offset the playback in time while keeping the playback time unmodified)
end (Optional[float]) – end time of playback, in quarternotes. Allows to play a fragment of the object by trimming the end of the playback
sustain (Optional[float]) – a time added to the playback events to facilitate overlapping/legato between notes, or to allow one-shot samples to play completely without being cropped.
workspace (Optional[Workspace]) – a Workspace. If given, overrides the current workspace. It’s scorestruct is used to determine the mapping between beat-time and real-time.
transpose (float) – an interval to transpose any pitch

Return type:

list[SynthEvent]

Returns:

A list of SynthEvents (see SynthEvent)

Example

>>> from maelzel.core import *
>>> n = Note(60, dur=1).setPlay(instr='piano')
>>> n.events(gain=0.5)
[SynthEvent(delay=0.000, gain=0.5, chan=1, fade=(0.02, 0.02), instr=piano)
 bps 0.000s:  60, 1.000000
     1.000s:  60, 1.000000]
>>> play(n.events(chan=2))

eventsBetween(start, end, partial=True)[source]¶

Events between the given time range

If partial is false, only events which lie completey within the given range are included. Gracenotes at the edges are always included. The returned events are the actual events in this Chain or subchains: they are NOT copies.

Parameters:

start (Union[Fraction, Rational, float, tuple[int, Union[float, Rational, Fraction]]]) – absolute start location (a beat or a score location)
end (Union[Fraction, Rational, float, tuple[int, Union[float, Rational, Fraction]]]) – absolute end location (a beat or score location)
partial – include also events wich are partially included within the given time range

Return type:

list[MEvent]

Returns:

a list of the events within the given time range

eventsWithOffset(start=None, end=None, partial=True)[source]¶

Recurse the events in self and resolves each event’s offset

Parameters:

start (Union[Fraction, Rational, float, tuple[int, Union[float, Rational, Fraction]], None]) – absolute start beat/location. Filters the returned event pairs to events within this time range
end (Union[Fraction, Rational, float, tuple[int, Union[float, Rational, Fraction]], None]) – absolute end beat/location. Filters the returned event pairs to events within the given range
partial – only used if either start or end are given, this controls how events are matched. If True, events only need to be defined within the time range. Otherwise, events need to be fully included within the time range

Return type:

list[tuple[MEvent, Fraction]]

Returns:

a list of pairs, where each pair has the form (event, offset), the offset being: the absolute offset of the event. Event themselves are not modified

Example

>>> from maelzel.core import *
>>> chain = Chain([
... "4C:0.5",
... "4D",
... Chain(["4E:0.5"], offset=2)
... ], offset=1)

extend(items)[source]¶

Extend this chain with items

Parameters:: items (list[MEvent]) – a list of items to append to this chain
Return type:: None

Note

Items passed are marked as children of this chain (their .parent attribute is modified)

fillGaps(recurse=True)[source]¶

Fill any gaps with rests, inplace

A gap is produced when an event within a chain has an explicit offset later than the offset calculated by stacking the previous objects in terms of their duration

Parameters:: recurse – if True, fill gaps within subchains
Return type:: None

firstEvent()[source]¶

The first event in this chain, recursively

Return type:: MEvent | None

firstOffset()[source]¶

Returns the offset (relative to the start of this chain) of the first event in this chain

Return type:: Fraction | None

flat(forcecopy=False)[source]¶

A flat version of this Chain

A Chain can contain other Chains. This method flattens all objects inside this Chain and any sub-chains to a flat chain of events (notes/chords/clips).

If this Chain is already flat (it does not contain any Chains), self is returned unmodified (unless forcecopy=True).

Note

All items in the returned Chain will have an explicit .offset attribute. To remove any redundant .offset call Chain.removeRedundantOffsets()

Parameters:: forcecopy – all items in the returned Chain are a copy of self, even if self is already flat
Return type:: Self
Returns:: a flat chain

See also

Chain.isFlat()

flatEvents()[source]¶

A list of flat events, with explicit absolute offsets set

The returned events are a clone of the events in this chain, not the actual events themselves

Return type:: list[MEvent]
Returns:: a list of events (Notes, Chords, Clips, …) with explicit offset

getPlay(key, default=None, recursive=True)¶

Get a playback attribute previously set via MObj.setPlay()

Parameters:

key (str) – the key (see setPlay for possible keys)
default – the value to return if the given key has not been set
recursive – if True, search the given attribute up the parent chain

Returns:

either the value previously set, or default otherwise.

getProperty(key, default=None)¶

Get a property of this objects

Any MObj can have multiple properties. A property is a key:value pair, where the key is a string and the value can be anything. Properties can be used to attach information to an object, to tag it in any way needed.

Properties are set via MObj.setProperty(). The MObj.properties attribute can be queries directly, but bear in mind that if no properties have been set, this attribute is ``None`` by default.

Parameters:

key (str) – the property to query
default – returned value if the property has not been set

Returns:

the value of the property, or the default value

See also

setProperty(), properties

getSymbol(classname)¶

Get a symbol of a given class, if present

This is only supported for symbol classes which are exclusive (notehead, color, ornament, etc.). For symbols like ‘articulation’, which can be present multiple times, query the symbols attribute directly (NB: symbols might be None if no symbols have been set):

if note.symbols:
    articulations = [s for s in note.symbols
                     if s.name == 'articulation']

Parameters:: classname (str) – the class of the symbol. Possible values are ‘articulation’, ‘text’, ‘notehead’, ‘color’, ‘ornament’, ‘fermata’, ‘notatedpitch’. See XXX (TODO) for a complete list
Return type:: Symbol | None
Returns:: a symbol of the given class, or None

hasOffsets()[source]¶

True if self has an explicit offset and all items as well (recursively)

Return type:: bool
Returns:: True if all items in self have explicit offsets

invertPitch(pivot)¶

Invert the pitch of this object

Parameters:: pivot (Union[int, float, str]) – the point around which to invert pitches
Return type:: Self
Returns:: the inverted object

>>> from maelzel.core import *
>>> series = Chain("4Bb 4E 4F# 4Eb 4F 4A 5D 5C# 4G 4G# 4B 5C".split())
>>> inverted = series.invertPitch("4F#")
>>> print(" ".join(_.name.ljust(4) for _ in series))
... print(" ".join(_.name.ljust(4) for _ in inverted))
4A#  4E   4F#  4D#  4F   4A   5D   5C#  4G   4G#  4B   5C
4D   4G#  4F#  4A   4G   4D#  3A#  3B   4F   4E   4C#  4C
>>> Score([series, inverted])

../_images/dodecaphonic-series-1-inverted.png

isFlat()[source]¶

Is self flat?

A flat chain/voice contains only events, not other containers

Return type:: bool

isRest()¶

Is this object a Rest?

Rests are used as separators between objects inside an Chain or a Track

Return type:: bool

itemsBetween(start, end, partial=True)[source]¶

Items between the given time range

An item is either an event (Note, Chord, Clip, etc.) or another Chain.

If partial is false, only items which lie completey within the given range are included. Gracenotes at the edges are always included

Parameters:

start (Union[Fraction, Rational, float, tuple[int, Union[float, Rational, Fraction]]]) – absolute start location (a beat or a score location)
end (Union[Fraction, Rational, float, tuple[int, Union[float, Rational, Fraction]]]) – absolute end location (a beat or score location)
partial – include also events wich are partially included within the given time range

Return type:

list[MEvent | Chain]

Returns:

a list of the items within the given time range

itemsWithOffset()[source]¶

Iterate over the items of this chain with their absolute offset

Returns:: an iterator over tuple[item, offset], where an item can be an event or a Chain, and offset is the absolute offset

See also

Chain.eventsWithOffset()

itemsWithRelativeOffset()[source]¶

Iterate over the items of this chain with their relative offset

Return type:: Iterator[tuple[MEvent | Chain, Fraction]]
Returns:: an iterator over tuple[item, offset], where an item can be an event or a Chain, and offset is the offset relative to this chain

See also

Chain.eventsWithOffset()

lastEvent()[source]¶

The last event in this chain, recursively

Return type:: MEvent | None

matchOrfanSpanners(removeUnmatched=False)[source]¶

Match unmatched spanners

When adding spanners to objects, it is possible to create a spanner without a partner spanner. As long as there are as many start spanners as end spanners for a specific spanner class, these “orfan” spanners are matched. This method makes the matches explicit, as if they had been created with a partner spanner.

Parameters:: removeUnmatched – if True, any spanners which cannot be matched will be removed
Return type:: None

meanPitch()[source]¶

The mean pitch of this object

Returns:: The mean pitch of this object

mergeTiedEvents()[source]¶

Merge tied events inplace

Two events can be merged if they are tied and the second event does not provide any extra information (does not have an individual amplitude, dynamic, does not start a gliss, etc.)

Return type:: None
Returns:: True if self was modified

nextEvent(event)[source]¶

Returns the next event after event

Return type:: MEvent | None

Example

>>> from maelzel.core import *
>>> chain = Chain(['4C', '4D', Chain(['4E', '4F'])])
>>> chain.eventAfter(chain[1])
4E
>>> chain.itemAfter(chain[1])
Chain([4E, 4F])

nextItem(item)[source]¶

Returns the next item after item

An item can be an event (note, chord) or another chain

Parameters:: item (MEvent | Chain) – the item to find its next item
Return type:: MEvent | Chain | None
Returns:: the item following item or None if the given item is not in this container, or it has no item after it

Example

>>> from maelzel.core import *
>>> chain = Chain(['4C', '4D', Chain(['4E', '4F'])])
>>> chain.eventAfter(chain[1])
4E
>>> chain.itemAfter(chain[1])
Chain([4E, 4F])

parentAbsOffset()¶

The absolute offset of the parent

Return type:: Fraction
Returns:: the absolute offset of the parent if this object has a parent, else 0

pitchRange()[source]¶

The pitch range of this object, if applicable

This is useful in order to assign this object to a proper Voice when distributing objects among voices

Return type:: tuple[float, float] | None
Returns:: either None or a tuple (lowest pitch, highest pitch)

pitchTransform(pitchmap)[source]¶

Apply a pitch-transform to this object, returns a copy

Parameters:: pitchmap (Callable[[float], float]) – a function mapping pitch to pitch
Return type:: Self
Returns:: the object after the transform

play(instr=None, delay=None, args=None, gain=None, chan=None, pitchinterpol=None, fade=None, fadeshape=None, position=None, skip=None, end=None, whenfinished=None, sustain=None, workspace=None, transpose=0, config=None, display=False, **kwargs)¶

Plays this object.

Play is always asynchronous (to block, use some sleep funcion). By default, play() schedules this event to be renderer in realtime.

Note

To record events offline, see the example below

Parameters:

gain (Optional[float]) – modifies the own amplitude for playback/recording (0-1)
delay (Optional[float]) – delay in seconds, added to the start of the object As opposed to the .offset attribute of each object, which is defined in symbolic (beat) time, the delay is always in real (seconds) time
instr (Optional[str]) – which instrument to use (see defPreset, definedPresets). Use “?” to select from a list of defined presets.
chan (Optional[int]) – the channel to output to. Channels start at 1
pitchinterpol (Optional[str]) – ‘linear’, ‘cos’, ‘freqlinear’, ‘freqcos’
fade (Union[float, tuple[float, float], None]) – fade duration in seconds, can be a tuple (fadein, fadeout)
fadeshape (Optional[str]) – ‘linear’ | ‘cos’
args (Optional[dict[str, float]]) – arguments passed to the note. A dict {paramName: value}
position (Optional[float]) – the panning position (0=left, 1=right)
skip (Optional[float]) – amount of time (in quarternotes) to skip. Allows to play a fragment of the object (NB: this trims the playback of the object. Use delay to offset the playback in time while keeping the playback time unmodified)
end (Optional[float]) – end time of playback. Allows to play a fragment of the object by trimming the end of the playback
sustain (Optional[float]) – a time added to the playback events to facilitate overlapping/legato between notes, or to allow one-shot samples to play completely without being cropped.
workspace (Optional[Workspace]) – a Workspace. If given, overrides the current workspace. It’s scorestruct is used to to determine the mapping between beat-time and real-time.
transpose (float) – add a transposition interval to the pitch of this object
config (Optional[CoreConfig]) – if given, overrides the current config
whenfinished (Optional[Callable]) – function to be called when the playback is finished. Only applies to realtime rendering
display – if True and running inside Jupyter, display the resulting synth’s html

Return type:

SynthGroup

Returns:

A SynthGroup

See also

Example

Play a note

>>> from maelzel.core import *
>>> note = Note(60).play(gain=0.1, chan=2)

Play multiple objects synchronised

>>> play(
... Note(60, 1.5).events(gain=0.1, position=0.5)
... Chord("4E 4G", 2, start=1.2).events(instr='piano')
... )

Or using play as a context managger:

>>> with play():
...     Note(60, 1.5).play(gain=0.1, position=0.5)
...     Chord("4E 4G", 2, start=1.2).play(instr='piano')
...     ...

Render offline

>>> with render("out.wav", sr=44100) as r:
...     Note(60, 5).play(gain=0.1, chan=2)
...     Chord("4E 4G", 3).play(instr='piano')

plot(**kws)¶

Return type:: Axes

previousEvent(event)[source]¶

Returns the event before the given event

Parameters:: event (MEvent) – the event to query
Return type:: MEvent | None
Returns:: the event before the given event, or None if no event is found. Raises ValueError if event is not part of this container

previousItem(item)[source]¶

Returns the item (an event or a chain) previous to the given one

Parameters:: item (MEvent | Chain) – the item to query.
Return type:: MEvent | Chain | None
Returns:: the item previous to item

See also

Chain.previousEvent()

quantizePitch(step=0.25)[source]¶: Returns a new object, with pitch rounded to step

quantizedScore(scorestruct=None, config=None, quantizationProfile=None, enharmonicOptions=None, nestedTuplets=None)¶

Returns a QuantizedScore representing this object

Parameters:

scorestruct (Optional[ScoreStruct]) – if given it will override the scorestructure active for this object
config (Optional[CoreConfig]) – if given will override the active config
quantizationProfile (Union[str, QuantizationProfile, None]) – if given it is used to customize the quantization process. Otherwise, a profile is constructed based on the config. It is also possible to pass the name of a quantization preset (possible values: ‘lowest’, ‘low’, ‘medium’, ‘high’, ‘highest’, see maelzel.scoring.quant.QuantizationProfile.fromPreset())
enharmonicOptions (Optional[EnharmonicOptions]) – if given it is used to customize enharmonic respelling. Otherwise, the enharmonic options used for respelling are constructed based on the config
nestedTuplets (Optional[bool]) – if given, overloads the config value ‘quant.nestedTuplets’. This is used to disallow nested tuplets, mainly for rendering musicxml since there are some music editors (MuseScore, for example) which fail to import nested tuplets. This can be set at the config level as getConfig()['quant.nestedTuplets'] = False

Return type:

QuantizedScore

Returns:

a quantized score. To render such a quantized score as notation call its render() method

A QuantizedScore contains a list of QuantizedParts, which each consists of list of QuantizedMeasures. To access the recursive notation structure of each measure call its asTree() method

rec(outfile='', sr=None, verbose=None, wait=None, nchnls=None, instr=None, delay=None, args=None, gain=None, position=None, extratime=None, workspace=None, **kws)¶

Record the output of .play as a soundfile

Parameters:

outfile – the outfile where sound will be recorded. Can be None, in which case a filename will be generated. Use ‘?’ to open a save dialog
sr (Optional[int]) – the sampling rate (config key: ‘rec.sr’)
wait (Optional[bool]) – if True, the operation blocks until recording is finishes (config ‘rec.block’)
nchnls (Optional[int]) – if given, use this as the number of channels to record.
gain (Optional[float]) – modifies the own amplitude for playback/recording (0-1)
delay (Optional[float]) – delay in seconds, added to the start of the object As opposed to the .start attribute of each object, which is defined in symbolic (beat) time, the delay is always in real (seconds) time
instr (Optional[str]) – which instrument to use (see defPreset, definedPresets). Use “?” to select from a list of defined presets.
args (Optional[dict[str, float]]) – named arguments passed to the note. A dict {paramName: value}
position (Optional[float]) – the panning position (0=left, 1=right)
workspace (Optional[Workspace]) – if given it overrides the active workspace
extratime (Optional[float]) – extratime added to the recording (config key: ‘rec.extratime’)
verbose (Optional[bool]) – if True, display synthesis output
**kws – any keyword passed to .play

Return type:

OfflineRenderer

Returns:

the offline renderer used. If no outfile was given it is possible to access the renderer soundfile via OfflineRenderer.lastOutfile()

Example

>>> from maelzel.core import *
>>> # a simple note
>>> chord = Chord("4C 4E 4G", dur=8).setPlay(gain=0.1, instr='piano')
>>> renderer = chord.rec(wait=True)
>>> renderer.lastOutfile()
'/home/testuser/.local/share/maelzel/recordings/tmpashdas.wav'

See also

OfflineRenderer

recurse(reverse=False)[source]¶

Yields all events (Notes/Chords) in this chain, recursively

This method guarantees that the yielded events are the actual objects included in this chain or its sub-chains. This is usefull when used in combination with methods like addSpanner, which modify the objects themselves.

Parameters:: reverse – if True, recurse the chain in reverse
Return type:: Iterator[MEvent]
Returns:: an iterator over all notes/chords within this chain and its sub-chains, where for each event a tuple (event: MEvent, offset: F) is returned. The offset is relative to the offset of this chain, so in order to determine the absolute offset for each returned event one needs to add the absolute offset of this chain

relOffset()¶

Resolve the offset of this object, relative to its parent

If this object has no parent the offset is an absolute offset.

The .offset attribute holds the explicit offset. If this attribute is unset (None) this object might ask its parent to determine the offset based on the durations of any previous objects

Return type:: Fraction
Returns:: the offset, in quarter notes. If no explicit or implicit offset and the object has no parent it returns 0.

See also

MObj.absOffset()

remap(deststruct, sourcestruct=None)[source]¶

Remap times (offset, dur) from source scorestruct to destination scorestruct

The absolute time remains the same

Parameters:

deststruct (ScoreStruct) – the destination scorestruct
sourcestruct (ScoreStruct) – the source scorestructure, or None to use the resolved scoresturct

Return type:

_MObjT

Returns:

a clone of self remapped to the destination scorestruct

removeRedundantOffsets()[source]¶

Remove over-specified start times in this Chain (in place)

Return type:: None

render(backend='', renderoptions=None, scorestruct=None, config=None, quantizationProfile=None)¶

Renders this object as notation

First the object is quantized to abstract notation, then it is passed to the backend to render it for the specific format (lilypond, musicxml, …), which is then used to generate a document (pdf, png, …)

Parameters:

backend – the backend to use, one of ‘lilypond’, ‘musicxml’. If not given, defaults to the config key ‘show.backend’
renderoptions (Optional[RenderOptions]) – the render options to use. If not given, these are generated from the active config
scorestruct (Optional[ScoreStruct]) – if given, overrides the scorestruct set within the active Workspace and any scorestruct attached to this object
config (Optional[CoreConfig]) – if given, overrides the active config
quantizationProfile (Union[str, QuantizationProfile, None]) – if given, it is used to customize the quantization process and will override any config option related to quantization. A QuantizationProfile can be created from a config via maelzel.core.config.CoreConfig.makeQuantizationProfileFromPreset().

Return type:

Renderer

Returns:

a scoring.render.Renderer. This can be used to write the rendered structure to an image (png, pdf) or as a musicxml or lilypond file.

Example

>>> from maelzel.core import *
>>> voice = Voice(...)
# Render with the settings defined in the config
>>> voice.render()
# Customize the rendering process
>>> from maelzel.scoring.renderer import RenderOptions
>>> from maelzel.scoring.quant import QuantizationProfile
>>> quantprofile = QuantizationProfile.simple(
...     possibleDivisionsByTempo={80: []
...     })

resolveEnd()¶

Returns the resolved end of this object, relative to its parent

An object’s offset can be explicit (set in the .offset attributes) or implicit, as calculated from the context of the parent. For example, inside a Chain, the offset of an event depends on the offsets and durations of the objects preceding it.

Note

To calculate the absolute end of an object, use obj.absOffset() + obj.resolveEnd

Return type:: Fraction
Returns:: the resolved end of this object, relative to its parent. If this object has no parent, the relative end and the absolute end are the same

See also

MObj.relOffset(), MObj.absOffset()

scorestruct(resolve=False)¶

Returns the ScoreStruct active for this obj or its parent (recursively)

If this object has no parent None is returned. If resolve is True and this object has no associated scorestruct, the active scorestruct is returned

Parameters:: resolve – if True and this obj (or its parent, recursively) has no associated scorestruct, the active scorestruct is returned
Return type:: ScoreStruct | None
Returns:: the associated scorestruct or the active struct if resolve is True and this object has no associated struct (either directly or through its parent)

Example

>>> from maelzel.core import *
>>> n = Note("4C", 1)
>>> voice = Voice([n])
>>> score = Score([voice])
>>> score.setScoreStruct(ScoreStruct(timesig=(3, 4), tempo=72))
>>> n.scorestruct()
ScoreStruct(timesig=(3, 4), tempo=72)

scoringEvents(groupid='', config=None, parentOffset=None)[source]¶

Returns the scoring events corresponding to this object.

The scoring events returned always have an absolute offset

Parameters:

groupid – if given, all events are given this groupid
config (Optional[CoreConfig]) – the configuration used (None to use the active config)
parentOffset (Optional[Fraction]) – if given will override the parent’s offset

Return type:

list[Notation]

Returns:

the scoring notations representing this object

scoringParts(config=None)[source]¶

Returns this object as a list of scoring UnquantizedParts.

Parameters:: config (Optional[CoreConfig]) – if given, this config instead of the active config will be used
Return type:: list[UnquantizedPart]
Returns:: a list of unquantized parts

This method is used internally to generate the parts which constitute a given MObj prior to rendering, but might be of use itself so it is exposed here.

An maelzel.scoring.UnquantizedPart is an intermediate format used by the scoring package to represent notated events. It represents a list of non-simultaneous Notations, unquantized and independent of any score structure

setPlay(**kws)¶

Set any playback attributes, returns self

Parameters:: **kws – any argument passed to play() (delay, dur, chan, gain, fade, instr, pitchinterpol, fadeshape, params, priority, position).
Return type:: Self
Returns:: self. This allows to chain this to any constructor (see example)

Attribute	Type	Descr
instr	str	The instrument preset to use
delay	float	Delay in seconds, added to the start of the object
chan	int	The channel to output to, channels start at 1
fade	float	The fade time; can also be a tuple (fadein, fadeout)
fadeshape	str	One of ‘linear’, ‘cos’, ‘scurve’
pitchinterpol	str	One of ‘linear’, ‘cos’, ‘freqlinear’, ‘freqcos’
gain	float	A gain factor applied to the amplitud of this object. Dynamic argument (kgain)
position	float	Dynamic argument. Panning position (0=left, 1=right). Dynamic argument (kpos)
skip	float	Skip time of playback; allows to play a fragment of the object. NB: set the delay to the -skip to start playback at the original time but from the timepoint specified by the skip param
end	float	End time of playback; counterpart of `skip`, allow to trim playback of the object
sustain	float	An extra sustain time. This is useful for sample based instruments
transpose	float	Transpose the pitch of this object only for playback
glisstime	float	The duration (in beats) of the glissando for events with glissando. A short glisstime can be used for legato playback in non-percusive instruments
priority	int	The order of evaluation. Events scheduled with a higher priority are evaluated later in the chain
args	dict	Named arguments passed to the playback instrument
gliss	float/ bool	An object can be set to have a playback only gliss. It is equivalent to having a gliss., but the gliss is not displayed as notation.

Example:

# a piano note
>>> from maelzel.core import *
# Create a note with predetermined instr and panning position
>>> note = Note("C4+25", dur=0.5).setPlay(instr="piano", position=1)
# When .play is called, the note will play with the preset instr and position
>>> note.play()

See also

addSymbol(), playargs

setProperty(key, value)¶

Set a property, returns self

Any MObj can have user-defined properties. These properties are optional: before any property is created the .properties attribute is None. This method creates the dict if it is still None and sets the property.

Parameters:

key (str) – the key to set
value – the value of the property

Return type:

Self

Returns:

self (similar to setPlay or setSymbol, to allow for chaining calls)

Example

>>> from maelzel.core import *
>>> n = Note("4C", 1)
>>> n.setProperty('foo', 'bar')
4C:1♩
>>> # To query a property do:
>>> n.getProperty('foo')
bar
>>> # Second Method: query the properties attribute directly.
>>> # WARNING: if no properties were set, this attribute would be None
>>> if n.properties:
...     foo = n.properties.get('foo')
...     print(foo)
bar

See also

getProperty(), properties

show(fmt=None, external=None, backend='', scorestruct=None, config=None, resolution=None)¶

Show this as notation.

Parameters:

external (Optional[bool]) – True to force opening the image in an external image viewer, even when inside a jupyter notebook. If False, show will display the image inline if inside a notebook environment. To change the default, modify config[‘openImagesInExternalApp’]
backend – backend used when rendering to png/pdf. One of ‘lilypond’, ‘musicxml’. If not given, use default (see config[‘show.backend’])
fmt (Optional[str]) – one of ‘png’, ‘pdf’, ‘ly’. None to use default.
scorestruct (Optional[ScoreStruct]) – if given overrides the current/default score structure
config (Optional[CoreConfig]) – if given overrides the current/default config
resolution (Optional[int]) – dpi resolution when rendering to an image, overrides the config key ‘show.pngResolution’

Return type:

None

splitAt(location, tie=True, beambreak=False, nomerge=False)[source]¶

Split any event present at the given absolute offset (in place)

The parts resulting from the split operation will be part of this chain/voice.

To split at a relative offset, substract the absolute offset of this Chain from the given offset

Parameters:

location (Union[Fraction, Rational, float, tuple[int, Union[float, Rational, Fraction]]]) – the absolute offset to split at, or a score location (measureindex, measureoffset)
tie – tie the parts of an event together if the split intersects an event
beambreak – if True, add a BeamBreak symbol to the given event
nomerge – if True, enforce that the items splitted cannot be merged at a later stage (they are marked with a NoMerge symbol)

Return type:

MEvent | None

Returns:

if an event was split, returns the part of the event starting at the given offset. Otherwise returns None.

splitEventsAtMeasures(scorestruct=None, startindex=0, stopindex=0)[source]¶

Splits items in self at measure offsets, inplace (recursively)

After this method is called, no event extends for longer than a measure, as defined in the given scorestruct or this object’s scorestruct.

Note

To avoid modifying self, create a copy first: newchain = self.copy().splitEventsAtMeasure(...)

Parameters:

scorestruct (Optional[ScoreStruct]) – if given, overrides any active scorestruct for this object
startindex – the first measure index to use
stopindex – the last measure index to use. 0=len(measures). The stopindex is not included (similar to how python’s builtin range behaves`

Return type:

None

splitEventsAtOffsets(offsets, tie=True, nomerge=False)[source]¶

Splits items in self at the given offsets, inplace (recursively)

The offsets are absolute. Split items are by default tied together. This method is useful for the case where a part of an event needs to be adressed in some way. For example, a symbol needs to be added to a part of a note (a crescendo hairpin which starts in the middle of an event).

Parameters:

offsets (list[Union[float, Rational, Fraction, tuple[int, Union[float, Rational, Fraction]]]]) – the offsets to split items at (either absolute offsets or score locations as tuple (measureindex, measureoffset)
tie – if True, parts of an item are tied together
nomerge – if True, add event breaks to prevent events from being merged

Return type:

None

stack()[source]¶

Stack events to the left INPLACE, making offsets explicit

Return type:: Fraction
Returns:: the total duration of self

timeRangeSecs(parentOffset=None, scorestruct=None)¶

The absolute time range, in seconds

Parameters:

parentOffset (Optional[Fraction]) – if given, use this offset as parent offset. This is useful if the parent’s offset has already been calculated
scorestruct (Optional[ScoreStruct]) – use this scorestruct to calculate absolute time. This is useful if the scorestruct is already known.

Return type:

tuple[Fraction, Fraction]

Returns:

a tuple (absolute start time in seconds, absolute end time in seconds)

timeScale(factor, offset=0)¶

Create a copy with modified timing by applying a linear transformation

Parameters:

factor (Union[float, Rational, Fraction]) – a factor which multiplies all durations and start times
offset (Union[float, Rational, Fraction]) – an offset added to all start times

Return type:

Self

Returns:

the modified object

timeShift(timeoffset)[source]¶

Return a copy of this object with an added offset

Parameters:: timeoffset (Union[float, Rational, Fraction]) – a delta time added
Return type:: Self
Returns:: a copy of this object shifted in time by the given amount

timeShiftInPlace(timeoffset)[source]¶

Shift the time of this by the given offset (inplace)

Parameters:: timeoffset (Union[float, Rational, Fraction]) – the time delta (in quarterNotes)
Return type:: None

timeTransform(timemap, inplace=False)[source]¶

Apply a time-transform to this object

Parameters:

timemap (Callable[[Fraction], Fraction]) – a function mapping old time to new time
inplace – if True changes are applied inplace

Return type:

Self

Returns:

the resulting object (self if inplace)

Note

time is conceived as abstract ‘beat’ time, measured in quarter-notes. The actual time will be also determined by any tempo changes in the active score structure.

transpose(interval)¶

Transpose this object by the given interval

Parameters:: interval (int | float) – the interval in semitones
Return type:: Self
Returns:: the transposed object

transposeByRatio(ratio)¶

Transpose this by a given frequency ratio, if applicable

A ratio of 2 equals to transposing an octave higher.

Parameters:: ratio (float) – the ratio to transpose by
Return type:: _MObjT
Returns:: a copy of this object, transposed by the given ratio

Example

>>> from maelzel.core import *
>>> n = Note("4C")
# A transposition by a ratio of 2 results in a pitch an octave higher
>>> n.transposeByRatio(2)
5C

unquantizedScore(title='')¶

Create a maelzel.scoring.UnquantizedScore from this object

Parameters:: title – the title of the resulting score (if given)
Return type:: UnquantizedScore
Returns:: the Arrangement representation of this object

An UnquantizedScore is a list of UnquantizedPart, which is itself a list of Notation. An Arrangement represents an unquantized score, meaning that the Notations within each part are not split into measures, nor organized in beats. To generate a quantized score see quantizedScore()

This method is mostly used internally when an object is asked to be represented as a score. In this case, an Arrangement is created first, which is then quantized, generating a QuantizedScore

See also

quantizedScore(), QuantizedScore

withExplicitOffset(forcecopy=False)[source]¶

Copy of self with explicit offset

If self already has explicit offset, self itself is returned.

Parameters:: forcecopy – if forcecopy, a copy of self will be returned even if self already has explicit times
Return type:: Self
Returns:: a clone of self with explicit times

Example

The offset and dur shown as the first two columns are the resolved times. When an event has an explicit offset, these are shown as part of the event repr. See for example the second note, 4C, which in the first version does not have any explicit times and is shown as “4C” and in the second version it appears as “4C:2.5♩:offset=0.5”

>>> from maelzel.core import *
>>> chain = Chain([Rest(0.5), Note("4C"), Chord("4D 4E", offset=3)])
>>> chain.dump()
Chain
  offset: 0      dur: 0.5    | Rest:0.5♩
  offset: 0.5    dur: 2.5    | 4C
  offset: 3      dur: 1      | ‹4D 4E offset=3›
>>> chain.withExplicitTimes().dump()
Chain
  offset: 0      dur: 0.5    | Rest:0.5♩:offset=0
  offset: 0.5    dur: 2.5    | 4C:2.5♩:offset=0.5
  offset: 3      dur: 1      | ‹4D 4E 1♩ offset=3›

write(outfile, backend='', resolution=None)¶

Export to multiple formats

Formats supported: pdf, png, musicxml (extension: .xml or .musicxml), lilypond (.ly), midi (.mid or .midi) and pickle

Parameters:

outfile (str) – the path of the output file. The extension determines the format. Formats available are pdf, png, lilypond, musicxml, midi, csd and pickle.
backend – the backend used when writing as pdf or png. If not given, the default defined in the active config is used (key: ‘show.backend’). Possible backends: lilypond; musicxml (uses MuseScore to render musicxml as image so MuseScore needs to be installed)
resolution (Optional[int]) – image DPI (only valid if rendering to an image) - overrides the config key ‘show.pngResolution’

Return type:

None

Formats¶

pdf, png: will render the object as notation and save that to the given format
lilypond: .ly extension. Will render the object as notation and save it as lilypond text
midi: .mid or .midi extension. At the moment this is done via lilypond, so the midi
produced follows the quantization process used for rendering to notation. Notice that midi cannot reproduce many features of a maelzel object, like microtones, and many complex rhythms will not be translated correctly
pickle: the object is serialized using the pickle module. This allows to load it
via pickle.load: myobj = pickle.load(open('myobj.pickle'))