music21.layout

The layout.py module contains two types of objects that specify the layout on page (or screen) for Scores and other Stream objects. There are two main types of Layout objects: (1) layout describing elements and (2) layout defining Streams.

(1) ScoreLayout, PageLayout, SystemLayout, and StaffLayout objects describe the size of pages, the geometry of page and system margins, the distance between staves, etc. The model for these layout objects is taken directly (perhaps too directly?) from MusicXML. These objects all inherit from a BaseLayout class, primarily as an aid to finding all of these objects as a group. ScoreLayouts give defaults for each page, system, and staff. Thus, they contain PageLayout, SystemLayout, and currently one or more StaffLayout objects (but probably just one. MusicXML allows more than StaffLayout object because multiple staves can be in a Part. Music21 uses the concept of a PartStaff for a Part that is played by the same performer as another. e.g., the left hand of the Piano is a PartStaff paired with the right hand).

PageLayout and SystemLayout objects also have a property, ‘isNew’, which, if set to True, signifies that a new page or system should begin here. In theory, one could define new dimensions for a page or system in the middle of the system or page without setting isNew to True, in which case these measurements would start applying on the next page. In practice, there’s really one good place to use these Layout objects and that’s in the first part in a score at offset 0 of the first measure on a page or system (or for ScoreLayout, at the beginning of a piece outside any parts). But it’s not an error to put them in other places, such as at offset 0 of the first measure of a page or system in all the other parts. In fact, MusicXML tends to do this, and it ends up not being a waste if a program extracts a single part from the middle of a score.

These objects are standard Music21Object types, but many properties such as .duration, .beat, will probably not apply.

When exporting to MusicXML (which is currently the only format in which music21 can and does preserve these markings), many MusicXML readers will ignore these tags (or worse, add a new page or system when PageLayout and SystemLayout objects are found but also add theme wherever they want). In Finale, this behavior disappears if the MusicXML document notes that it <supports> new-page and new-system markings. Music21 will add the appropriate <supports> tags if the containing Stream has .definesExplicitPageBreaks and .definesExplicitSystemBreaks set to True. When importing a score that has the <supports> tag set, music21 will set .definesExplicitXXXXBreaks to True for the outer score and the inner parts. However, this means that if the score is manipulated enough that the prior layout information is obsolete, programs will need to set these properties to False or move the Layout tags accordingly.

(2) The second set of objects are Stream subclasses that can be employed when a program needs to easily iterate around the systems and pages defined through the layout objects just described, or to get the exact position on a page (or a graphical representation of a page) for a particular measure or system. (Individual notes coming soon). Normal Score streams can be changed into LayoutStreams by calling divideByPages(s) on them. A Score that was organized: Score->Part->Measure would then become: LayoutScore->Page->System->Staff->Measure.

The new LayoutScore has methods that enable querying what page or system a measure is in, and specifically where on a page a measure is (or the dimensions of every measure in the piece). However do not call .show() on a LayoutScore – the normal score it’s derived from will work just fine. Nor does calling .show() on a Page or System work yet, but once the LayoutStream has been created, code like this can be done:

s = stream.Stream(…) ls = layout.divideByPages(s) pg2sys3 = ls.pages[1].systems[2] # n.b.! 1, 2 measureStart, measureEnd = pg2sys3.measureStart, pg2sys3.measureEnd scoreExcerpt = s.measures(measureStart, measureEnd) scoreExcerpt.show() # will show page 2, system 3

Note that while the coordinates given by music21 for a musicxml score (based on margins, staff size, etc.) generally reflect what is actually in a musicxml producer, unfortunately, x-positions are far less accurately produced by most editors. For instance, Finale scores with measure sizes that have been manually adjusted tend to show their unadjusted measure width and not their actual measure width in the MusicXML.

SmartScore Pro tends to produce very good MusicXML layout data.

ScoreLayout

class music21.layout.ScoreLayout(*, scalingMillimeters: int | float | None = None, scalingTenths: int | float | None = None, musicFont: str | None = None, wordFont: str | None = None, pageLayout: PageLayout | None = None, systemLayout: SystemLayout | None = None, staffLayoutList: list[music21.layout.StaffLayout] | None = None, **keywords)

Parameters for configuring a score’s layout.

PageLayout objects may be found on Measure or Part Streams.

>>> pl = layout.PageLayout(pageNumber=4, leftMargin=234, rightMargin=124,
...                        pageHeight=4000, pageWidth=3000, isNew=True)
>>> pl.pageNumber
4
>>> pl.rightMargin
124
>>> pl.leftMargin
234
>>> pl.isNew
True

This object represents both <print new-page> and <page-layout> elements in musicxml. The appearance tag is handled in the .style for the stream (it was here in v7 and before, but did nothing).

Note that the appearance and style elements are subject to change during and after the v8 releases.

ScoreLayout bases

• LayoutBase

• Music21Object

• ProtoM21Object

ScoreLayout read-only properties

Read-only properties inherited from Music21Object:

beat beatDuration beatStr

beatStrength hasEditorialInformation

hasStyleInformation measureNumber

Read-only properties inherited from ProtoM21Object:

classSet

classes

ScoreLayout read/write properties

Read/write properties inherited from Music21Object:

activeSite derivation duration editorial

id offset priority

quarterLength seconds style

ScoreLayout methods

ScoreLayout.tenthsToMillimeters(tenths)

given the scalingMillimeters and scalingTenths, return the value in millimeters of a number of musicxml “tenths” where a tenth is a tenth of the distance from one staff line to another

returns 0.0 if either of scalingMillimeters or scalingTenths is undefined.

>>> sl = layout.ScoreLayout(scalingMillimeters=2.0, scalingTenths=10)
>>> print(sl.tenthsToMillimeters(10))
2.0
>>> print(sl.tenthsToMillimeters(17))  # printing to round
3.4

Methods inherited from Music21Object:

__eq__() clearCache() containerHierarchy() contextSites() getAllContextsByClass() getContextByClass() getOffsetBySite() getOffsetInHierarchy()

getSpannerSites() informSites() mergeAttributes() next() previous() purgeLocations() purgeOrphans()

setOffsetBySite() show() sortTuple() splitAtDurations() splitAtQuarterLength() splitByQuarterLengths() write()

Methods inherited from ProtoM21Object:

isClassOrSubclass()

ScoreLayout instance variables

Instance variables inherited from Music21Object:

classSortOrder groups

isStream

sites

PageLayout

class music21.layout.PageLayout(*, pageNumber: int | None = None, leftMargin: int | float | None = None, rightMargin: int | float | None = None, topMargin: int | float | None = None, bottomMargin: int | float | None = None, pageHeight: int | float | None = None, pageWidth: int | float | None = None, isNew: bool | None = None, **keywords)

Parameters for configuring a page’s layout.

PageLayout objects may be found on Measure or Part Streams.

>>> pl = layout.PageLayout(pageNumber=4, leftMargin=234, rightMargin=124,
...                        pageHeight=4000, pageWidth=3000, isNew=True)
>>> pl.pageNumber
4
>>> pl.rightMargin
124
>>> pl.leftMargin
234
>>> pl.isNew
True

This object represents both <print new-page> and <page-layout> elements in musicxml.

PageLayout bases

• LayoutBase

• Music21Object

• ProtoM21Object

PageLayout read-only properties

Read-only properties inherited from Music21Object:

beat beatDuration beatStr

beatStrength hasEditorialInformation

hasStyleInformation measureNumber

Read-only properties inherited from ProtoM21Object:

classSet

classes

PageLayout read/write properties

Read/write properties inherited from Music21Object:

activeSite derivation duration editorial

id offset priority

quarterLength seconds style

PageLayout methods

Methods inherited from Music21Object:

__eq__() clearCache() containerHierarchy() contextSites() getAllContextsByClass() getContextByClass() getOffsetBySite() getOffsetInHierarchy()

getSpannerSites() informSites() mergeAttributes() next() previous() purgeLocations() purgeOrphans()

setOffsetBySite() show() sortTuple() splitAtDurations() splitAtQuarterLength() splitByQuarterLengths() write()

Methods inherited from ProtoM21Object:

isClassOrSubclass()

PageLayout instance variables

Instance variables inherited from Music21Object:

classSortOrder groups

isStream

sites

SystemLayout

class music21.layout.SystemLayout(*, leftMargin: int | float | None = None, rightMargin: int | float | None = None, distance: int | float | None = None, topDistance: int | float | None = None, isNew: bool | None = None, **keywords)

Object that configures or alters a system’s layout.

SystemLayout objects may be found on Measure or Part Streams.

Importantly, if isNew is True then this object indicates that a new system should start here.

>>> sl = layout.SystemLayout(leftMargin=234, rightMargin=124, distance=3, isNew=True)
>>> sl.distance
3
>>> sl.rightMargin
124
>>> sl.leftMargin
234
>>> sl.isNew
True

SystemLayout bases

• LayoutBase

• Music21Object

• ProtoM21Object

SystemLayout read-only properties

Read-only properties inherited from Music21Object:

beat beatDuration beatStr

beatStrength hasEditorialInformation

hasStyleInformation measureNumber

Read-only properties inherited from ProtoM21Object:

classSet

classes

SystemLayout read/write properties

Read/write properties inherited from Music21Object:

activeSite derivation duration editorial

id offset priority

quarterLength seconds style

SystemLayout methods

Methods inherited from Music21Object:

__eq__() clearCache() containerHierarchy() contextSites() getAllContextsByClass() getContextByClass() getOffsetBySite() getOffsetInHierarchy()

getSpannerSites() informSites() mergeAttributes() next() previous() purgeLocations() purgeOrphans()

setOffsetBySite() show() sortTuple() splitAtDurations() splitAtQuarterLength() splitByQuarterLengths() write()

Methods inherited from ProtoM21Object:

isClassOrSubclass()

SystemLayout instance variables

Instance variables inherited from Music21Object:

classSortOrder groups

isStream

sites

StaffLayout

class music21.layout.StaffLayout(*, distance: int | float | None = None, staffNumber: int | float | None = None, staffSize: int | float | None = None, staffLines: int | None = None, hidden: bool | None = None, staffType: StaffType = StaffType.REGULAR, **keywords)

Object that configures or alters the distance between one staff and another in a system.

StaffLayout objects may be found on Measure or Part Streams.

The musicxml equivalent <staff-layout> lives in the <defaults> and in <print> attributes.

>>> sl = layout.StaffLayout(distance=3, staffNumber=1, staffSize=113, staffLines=5)
>>> sl.distance
3

The “number” attribute refers to which staff number in a part group this refers to. Thus, it’s not necessary in music21, but we store it if it’s there. (defaults to None)

>>> sl.staffNumber
1

staffLines specifies the number of lines for a non 5-line staff.

>>> sl.staffLines
5

staffSize is a percentage of the base staff size, so this defines a staff 13% larger than normal. Note that it is always converted to a floating point number.

>>> sl.staffSize
113.0
>>> sl
<music21.layout.StaffLayout distance 3, staffNumber 1, staffSize 113.0, staffLines 5>

StaffLayout can also specify the staffType:

>>> sl.staffType = stream.enums.StaffType.OSSIA

There is one other attribute, ‘.hidden’ which has three settings:

• None - inherit from previous StaffLayout object, or False if no object exists

• False - not hidden – show as a default staff

• True - hidden – for playback only staves, or for a hidden/optimized-out staff

Note: (TODO: .hidden None is not working; always gives False)

StaffLayout bases

• LayoutBase

• Music21Object

• ProtoM21Object

StaffLayout read-only properties

Read-only properties inherited from Music21Object:

beat beatDuration beatStr

beatStrength hasEditorialInformation

hasStyleInformation measureNumber

Read-only properties inherited from ProtoM21Object:

classSet

classes

StaffLayout read/write properties

Read/write properties inherited from Music21Object:

activeSite derivation duration editorial

id offset priority

quarterLength seconds style

StaffLayout methods

Methods inherited from Music21Object:

__eq__() clearCache() containerHierarchy() contextSites() getAllContextsByClass() getContextByClass() getOffsetBySite() getOffsetInHierarchy()

getSpannerSites() informSites() mergeAttributes() next() previous() purgeLocations() purgeOrphans()

setOffsetBySite() show() sortTuple() splitAtDurations() splitAtQuarterLength() splitByQuarterLengths() write()

Methods inherited from ProtoM21Object:

isClassOrSubclass()

StaffLayout instance variables

StaffLayout.staffType

What kind of staff is this as a stream.enums.StaffType.

>>> sl = layout.StaffLayout()
>>> sl.staffType
<StaffType.REGULAR: 'regular'>
>>> sl.staffType = stream.enums.StaffType.CUE
>>> sl.staffType
<StaffType.CUE: 'cue'>

Instance variables inherited from Music21Object:

classSortOrder groups

isStream

sites

LayoutBase

class music21.layout.LayoutBase(id: str | int | None = None, groups: Groups | None = None, sites: Sites | None = None, duration: Duration | None = None, activeSite: stream.Stream | None = None, style: Style | None = None, editorial: Editorial | None = None, offset: OffsetQL = 0.0, quarterLength: OffsetQLIn | None = None, **keywords)

A base class for all Layout objects, defining a classSortOrder and also an inheritance tree.

>>> scoreLayout = layout.ScoreLayout()
>>> isinstance(scoreLayout, layout.LayoutBase)
True

LayoutBase bases

• Music21Object

• ProtoM21Object

LayoutBase read-only properties

Read-only properties inherited from Music21Object:

beat beatDuration beatStr

beatStrength hasEditorialInformation

hasStyleInformation measureNumber

Read-only properties inherited from ProtoM21Object:

classSet

classes

LayoutBase read/write properties

Read/write properties inherited from Music21Object:

activeSite derivation duration editorial

id offset priority

quarterLength seconds style

LayoutBase methods

Methods inherited from Music21Object:

__eq__() clearCache() containerHierarchy() contextSites() getAllContextsByClass() getContextByClass() getOffsetBySite() getOffsetInHierarchy()

getSpannerSites() informSites() mergeAttributes() next() previous() purgeLocations() purgeOrphans()

setOffsetBySite() show() sortTuple() splitAtDurations() splitAtQuarterLength() splitByQuarterLengths() write()

Methods inherited from ProtoM21Object:

isClassOrSubclass()

LayoutBase instance variables

Instance variables inherited from Music21Object:

classSortOrder groups

isStream

sites

LayoutScore

class music21.layout.LayoutScore(givenElements=None, **keywords)

Designation that this Score is divided into Pages, Systems, Staves (=Parts), Measures, etc.

Used for computing location of notes, etc.

If the score does not change between calls to the various getPosition calls, it is much faster as it uses a cache.

LayoutScore bases

• Opus

• Stream

• StreamCore

• Music21Object

• ProtoM21Object

LayoutScore read-only properties

LayoutScore.pages

Read-only properties inherited from Opus:

scores

Read-only properties inherited from Stream:

beat beatDuration beatStr beatStrength flat

highestOffset highestTime isGapless lowestOffset notes

notesAndRests pitches secondsMap spanners voices

Read-only properties inherited from StreamCore:

spannerBundle

Read-only properties inherited from Music21Object:

hasEditorialInformation

hasStyleInformation

measureNumber

Read-only properties inherited from ProtoM21Object:

classSet

classes

LayoutScore read/write properties

Read/write properties inherited from Stream:

atSoundingPitch clef duration elements

finalBarline keySignature metadata

seconds staffLines timeSignature

Read/write properties inherited from Music21Object:

activeSite derivation editorial

id offset priority

quarterLength style

LayoutScore methods

LayoutScore.getAllMeasurePositionsInDocument(returnFormat='tenths', printUpdates=False)

returns a list of dictionaries, where each dictionary gives the measure number and other information, etc. in the document.

# >>> g = corpus.parse(‘luca/gloria’) # >>> gl = layout.divideByPages(g) # >>> gl.getAllMeasurePositionsInDocument()

LayoutScore.getMarginsAndSizeForPageId(pageId)

return a namedtuple of (top, left, bottom, right, width, height) margins for a given pageId in tenths

Default of (100, 100, 100, 100, 850, 1100) if undefined

>>> g = corpus.parse('luca/gloria')
>>> m22 = g.parts[0].getElementsByClass(stream.Measure)[22]
>>> m22.getElementsByClass(layout.PageLayout).first().leftMargin = 204.0
>>> gl = layout.divideByPages(g)
>>> gl.getMarginsAndSizeForPageId(1)
PageSize(top=171.0, left=204.0, right=171.0, bottom=171.0, width=1457.0, height=1886.0)

LayoutScore.getPageAndSystemNumberFromMeasureNumber(measureNumber)

Given a layoutScore from divideByPages and a measureNumber returns a tuple of (pageId, systemId). Note that pageId is probably one less than the page number, assuming that the first page number is 1, the pageId for the first page will be 0.

Similarly, the first systemId on each page will be 0

>>> lt = corpus.parse('demos/layoutTest.xml')
>>> l = layout.divideByPages(lt, fastMeasures=True)
>>> l.getPageAndSystemNumberFromMeasureNumber(80)
(3, 3)

LayoutScore.getPositionForStaff(pageId, systemId, staffId)

return a tuple of (top, bottom) for a staff, specified by a given pageId, systemId, and staffId in tenths of a staff-space.

This distance is specified with respect to the top of the system.

Staff scaling (<staff-details> in musicxml inside an <attributes> object) is taken into account, but not non-five-line staves. Thus, a normally sized staff is always of height 40 (4 spaces of 10-tenths each)

>>> lt = corpus.parse('demos/layoutTest.xml')
>>> ls = layout.divideByPages(lt, fastMeasures=True)

The first staff (staff 0) of each page/system always begins at height 0 and should end at height 40 if it is a 5-line staff (not taken into account) with no staffSize changes

>>> ls.getPositionForStaff(0, 0, 0)
(0.0, 40.0)
>>> ls.getPositionForStaff(1, 0, 0)
(0.0, 40.0)

The second staff (staff 1) begins at the end of staff 0 (40.0) + the appropriate staffDistance and adds the height of the staff. Staff 1 here has a size of 80 which means 80% of the normal staff size. 40 * 0.8 = 32.0:

>>> ls.getPositionForStaff(0, 0, 1)
(133.0, 165.0)

The third staff (staff 2) begins after the second staff (staff 1) but is a normal size staff

>>> ls.getPositionForStaff(0, 0, 2)
(266.0, 306.0)

The first staff (staff 0) of the second system (system 1) also begins at 0 and as a normally-sized staff, has height of 40:

>>> ls.getPositionForStaff(0, 1, 0)
(0.0, 40.0)

The spacing between the staves has changed in the second system, but the staff height has not:

>>> ls.getPositionForStaff(0, 1, 1)
(183.0, 215.0)
>>> ls.getPositionForStaff(0, 1, 2)
(356.0, 396.0)

In the third system (system 2), the staff distance reverts to the distance of system 0, but the staffSize is now 120 or 48 tenths (40 * 1.2 = 48)

>>> ls.getPositionForStaff(0, 2, 1)
(117.0, 165.0)

Page 1 (0), System 4 (3), Staff 2 (1) is a hidden (“optimized”) system. Thus, its staffLayout notes this:

>>> staffLayout031 = ls.pages[0].systems[3].staves[1].staffLayout
>>> staffLayout031
<music21.layout.StaffLayout distance None, staffNumber None, staffSize 80, staffLines None>
>>> staffLayout031.hidden
True

Thus, the position for this staff will have the same top and bottom, and the position for the next staff will have the same top as the previous staff:

>>> ls.getPositionForStaff(0, 3, 0)
(0.0, 40.0)
>>> ls.getPositionForStaff(0, 3, 1)
(40.0, 40.0)
>>> ls.getPositionForStaff(0, 3, 2)
(133.0, 173.0)

Tests for a score with PartStaff objects: >>> lt = corpus.parse(‘demos/layoutTestMore.xml’) >>> ls = layout.divideByPages(lt, fastMeasures = True) >>> ls.getPositionForStaff(0, 0, 0) (0.0, 40.0) >>> ls.getPositionForStaff(0, 0, 1) (133.0, 173.0) >>> ls.getPositionForStaff(0, 0, 2) (235.0, 275.0)

>>> ls.getPositionForStaff(0, 2, 0)
(0.0, 40.0)
>>> ls.getPositionForStaff(0, 2, 1)
(40.0, 40.0)
>>> ls.getPositionForStaff(0, 2, 2)
(40.0, 40.0)

System 4 has the top staff hidden, which has been causing problems:

>>> ls.getPositionForStaff(0, 4, 0)
(0.0, 0.0)
>>> ls.getPositionForStaff(0, 4, 1)
(0.0, 40.0)

LayoutScore.getPositionForStaffMeasure(staffId, measureNumber, returnFormat='tenths')

Given a layoutScore from divideByPages, a staffId, and a measureNumber, returns a tuple of ((top, left), (bottom, right), pageId) allowing an exact position for the measure on the page. If returnFormat is “tenths”, then it will be returned in tenths.

If returnFormat is “float”, returns each as a number from 0 to 1 where 0 is the top or left of the page, and 1 is the bottom or right of the page.

>>> lt = corpus.parse('demos/layoutTest.xml')
>>> ls = layout.divideByPages(lt, fastMeasures = True)

The first measure of staff one begins at 336 tenths from the top (125 for the margin top and 211 for the top-staff-distance). It begins 170.0 from the left (100 for the page-margin-left, 70 for staff-margin-left). It ends 40.0 below that (staffHeight) and 247.0 to the right (measure width)

>>> ls.getPositionForStaffMeasure(0, 1)
((336.0, 170.0), (376.0, 417.0), 0)

The other staves for the same measure are below this one:

>>> ls.getPositionForStaffMeasure(1, 1)
((469.0, 170.0), (501.0, 417.0), 0)
>>> ls.getPositionForStaffMeasure(2, 1)
((602.0, 170.0), (642.0, 417.0), 0)

If float is requested for returning, then the numbers are the fraction of the distance across the page.

>>> ls.getPositionForStaffMeasure(0, 1, returnFormat='float')
((0.152..., 0.0996...), (0.170..., 0.244...), 0)

Moving over the page boundary:

>>> ls.getPositionForStaffMeasure(0, 23)
((1703.0, 1345.0), (1743.0, 1606.0), 0)
>>> ls.getPositionForStaffMeasure(1, 23)  # hidden
((1743.0, 1345.0), (1743.0, 1606.0), 0)
>>> ls.getPositionForStaffMeasure(0, 24)
((195.0, 100.0), (235.0, 431.0), 1)
>>> ls.getPositionForStaffMeasure(1, 24)
((328.0, 100.0), (360.0, 431.0), 1)

LayoutScore.getPositionForSystem(pageId: int, systemId: int) → SystemSize

first systems on a page use a different positioning.

returns a Named tuple of the (top, left, right, and bottom) where each unit is relative to the page margins

N.B. right is NOT the width – it is different. It is the offset to the right margin. weird, inconsistent, but most useful. Bottom, however, is the hard part to compute.

>>> lt = corpus.parse('demos/layoutTestMore.xml')
>>> ls = layout.divideByPages(lt, fastMeasures = True)
>>> ls.getPositionForSystem(0, 0)
SystemSize(top=211.0, left=70.0, right=0.0, bottom=696.0)
>>> ls.getPositionForSystem(0, 1)
SystemSize(top=810.0, left=0.0, right=0.0, bottom=1173.0)
>>> ls.getPositionForSystem(0, 2)
SystemSize(top=1340.0, left=67.0, right=92.0, bottom=1610.0)
>>> ls.getPositionForSystem(0, 3)
SystemSize(top=1724.0, left=0.0, right=0.0, bottom=2030.0)
>>> ls.getPositionForSystem(0, 4)
SystemSize(top=2144.0, left=0.0, right=0.0, bottom=2583.0)

LayoutScore.getStaffDistanceFromPrevious(pageId, systemId, staffId)

return the distance of this staff from the previous staff in the same system

for staffId = 0, this is always 0.0

TODO:tests, now that this is out from previous

LayoutScore.getStaffHiddenAttribute(pageId: int, systemId: int, staffId: int) → bool

returns the staffLayout.hidden attribute for a staffId, or if it is not defined, recursively search through previous staves until one is found.

>>> lt = corpus.parse('demos/layoutTestMore.xml')
>>> ls = layout.divideByPages(lt, fastMeasures = True)
>>> ls.getStaffHiddenAttribute(0, 0, 0)
False
>>> ls.getStaffHiddenAttribute(0, 0, 1)
False
>>> ls.getStaffHiddenAttribute(0, 1, 1)
True
>>> ls.getStaffHiddenAttribute(0, 2, 1)
True
>>> ls.getStaffHiddenAttribute(0, 3, 1)
False

LayoutScore.getStaffSizeFromLayout(pageId: int, systemId: int, staffId: int) → float

Get the currently active staff-size for a given pageId, systemId, and staffId.

Note that this does not take into account the hidden state of the staff, which, if True, makes the effective size 0.0 – see getStaffHiddenAttribute

>>> lt = corpus.parse('demos/layoutTest.xml')
>>> ls = layout.divideByPages(lt, fastMeasures=True)
>>> ls.getStaffSizeFromLayout(0, 0, 0)
40.0
>>> ls.getStaffSizeFromLayout(0, 0, 1)
32.0
>>> ls.getStaffSizeFromLayout(0, 0, 2)
40.0
>>> ls.getStaffSizeFromLayout(0, 1, 1)
32.0
>>> ls.getStaffSizeFromLayout(0, 2, 1)
48.0
>>> ls.getStaffSizeFromLayout(0, 3, 1)
32.0

LayoutScore.getSystemBeforeThis(pageId: int, systemId: int) → tuple[int | None, int]

given a pageId and systemId, get the (pageId, systemId) for the previous system.

return (None, None) if it’s the first system on the first page

This test score has five systems on the first page, three on the second, and two on the third

>>> lt = corpus.parse('demos/layoutTestMore.xml')
>>> ls = layout.divideByPages(lt, fastMeasures = True)
>>> systemId = 1
>>> pageId = 2  # last system, last page
>>> while pageId is not None:
...    pageId, systemId = ls.getSystemBeforeThis(pageId, systemId)
...    (pageId, systemId)
(2, 0) (1, 2) (1, 1) (1, 0) (0, 4) (0, 3) (0, 2) (0, 1) (0, 0) (None, -1)

LayoutScore.measurePositionWithinSystem(measureNumber, pageId=None, systemId=None)

Given a measure number, find the start and end X positions (with respect to the system margins) for the measure.

if pageId and systemId are given, then it will speed up the search. But not necessary

no staffId is needed since (at least for now) all measures begin and end at the same X position

>>> l = corpus.parse('demos/layoutTest.xml')
>>> ls = layout.divideByPages(l, fastMeasures = True)
>>> ls.measurePositionWithinSystem(1, 0, 0)
(0.0, 247.0)
>>> ls.measurePositionWithinSystem(2, 0, 0)
(247.0, 544.0)
>>> ls.measurePositionWithinSystem(3, 0, 0)
(544.0, 841.0)

Measure positions reset at the start of a new system

>>> ls.measurePositionWithinSystem(6)
(0.0, 331.0)
>>> ls.measurePositionWithinSystem(7)
(331.0, 549.0)

LayoutScore.show(fmt=None, app=None, **keywords)

Borrows stream.Score.show

>>> lp = layout.Page()
>>> ls = layout.LayoutScore()
>>> ls.append(lp)
>>> ls.show('text')
{0.0} <music21.layout.Page p.1>

Methods inherited from Opus:

getNumbers() getScoreByNumber()

getScoreByTitle() mergeScores()

write()

Methods inherited from Stream:

__eq__() __getitem__() activateVariants() addGroupForElements() allPlayingWhileSounding() analyze() append() attachIntervalsBetweenStreams() attachMelodicIntervals() augmentOrDiminish() beatAndMeasureFromOffset() chordify() clear() cloneEmpty() containerInHierarchy() elementOffset() expandRepeats() explode() extendDuration() extendTies() extractContext() findConsecutiveNotes() findGaps() first() flatten() flattenUnnecessaryVoices() getElementAfterElement() getElementAtOrBefore() getElementBeforeOffset() getElementById() getElementsByClass() getElementsByGroup() getElementsByOffset() getElementsNotOfClass() getInstrument() getInstruments()

getOverlaps() getTimeSignatures() hasElement() hasElementOfClass() hasMeasures() hasPartLikeStreams() hasVoices() haveAccidentalsBeenMade() index() insert() insertAndShift() insertIntoNoteOrChord() invertDiatonic() isSequence() isTwelveTone() isWellFormedNotation() iter() last() lyrics() makeAccidentals() makeBeams() makeImmutable() makeMeasures() makeMutable() makeNotation() makeRests() makeTies() makeVoices() measure() measureOffsetMap() measures() melodicIntervals() mergeAttributes() mergeElements() metronomeMarkBoundaries() offsetMap()

playingWhenAttacked() plot() pop() quantize() recurse() recurseRepr() remove() removeByClass() removeByNotOfClass() repeatAppend() repeatInsert() replace() scaleDurations() scaleOffsets() setDerivationMethod() setElementOffset() shiftElements() showVariantAsOssialikePart() simultaneousAttacks() sliceAtOffsets() sliceByBeat() sliceByGreatestDivisor() sliceByQuarterLengths() sort() sorted() splitAtDurations() splitAtQuarterLength() splitByClass() storeAtEnd() stripTies() template() toSoundingPitch() toWrittenPitch() transferOffsetToElements() transpose() voicesToParts()

Methods inherited from StreamCore:

asTimespans() asTree() coreAppend() coreCopyAsDerivation()

coreElementsChanged() coreGatherMissingSpanners() coreGetElementByMemoryLocation() coreGuardBeforeAddElement()

coreInsert() coreSelfActiveSite() coreSetElementOffset() coreStoreAtEnd()

Methods inherited from Music21Object:

clearCache() containerHierarchy() contextSites() getAllContextsByClass() getContextByClass() getOffsetBySite()

getOffsetInHierarchy() getSpannerSites() informSites() next() previous()

purgeLocations() purgeOrphans() setOffsetBySite() sortTuple() splitByQuarterLengths()

Methods inherited from ProtoM21Object:

isClassOrSubclass()

LayoutScore instance variables

Instance variables inherited from Stream:

autoSort definesExplicitPageBreaks

definesExplicitSystemBreaks isFlat

isSorted recursionType

Instance variables inherited from Music21Object:

classSortOrder groups

isStream

sites

Page

class music21.layout.Page(givenElements=None, **keywords)

Designation that all the music in this Stream belongs on a single notated page.

Page bases

• Opus

• Stream

• StreamCore

• Music21Object

• ProtoM21Object

Page read-only properties

Page.systems

Read-only properties inherited from Opus:

scores

Read-only properties inherited from Stream:

beat beatDuration beatStr beatStrength flat

highestOffset highestTime isGapless lowestOffset notes

notesAndRests pitches secondsMap spanners voices

Read-only properties inherited from StreamCore:

spannerBundle

Read-only properties inherited from Music21Object:

hasEditorialInformation

hasStyleInformation

measureNumber

Read-only properties inherited from ProtoM21Object:

classSet

classes

Page read/write properties

Read/write properties inherited from Stream:

atSoundingPitch clef duration elements

finalBarline keySignature metadata

seconds staffLines timeSignature

Read/write properties inherited from Music21Object:

activeSite derivation editorial

id offset priority

quarterLength style

Page methods

Page.show(fmt=None, app=None, **keywords)

Borrows stream.Score.show

>>> ls = layout.System()
>>> lp = layout.Page()
>>> lp.append(ls)
>>> lp.show('text')
{0.0} <music21.layout.System 0: p.0, sys.0>

Methods inherited from Opus:

getNumbers() getScoreByNumber()

getScoreByTitle() mergeScores()

write()

Methods inherited from Stream:

__eq__() __getitem__() activateVariants() addGroupForElements() allPlayingWhileSounding() analyze() append() attachIntervalsBetweenStreams() attachMelodicIntervals() augmentOrDiminish() beatAndMeasureFromOffset() chordify() clear() cloneEmpty() containerInHierarchy() elementOffset() expandRepeats() explode() extendDuration() extendTies() extractContext() findConsecutiveNotes() findGaps() first() flatten() flattenUnnecessaryVoices() getElementAfterElement() getElementAtOrBefore() getElementBeforeOffset() getElementById() getElementsByClass() getElementsByGroup() getElementsByOffset() getElementsNotOfClass() getInstrument() getInstruments()

getOverlaps() getTimeSignatures() hasElement() hasElementOfClass() hasMeasures() hasPartLikeStreams() hasVoices() haveAccidentalsBeenMade() index() insert() insertAndShift() insertIntoNoteOrChord() invertDiatonic() isSequence() isTwelveTone() isWellFormedNotation() iter() last() lyrics() makeAccidentals() makeBeams() makeImmutable() makeMeasures() makeMutable() makeNotation() makeRests() makeTies() makeVoices() measure() measureOffsetMap() measures() melodicIntervals() mergeAttributes() mergeElements() metronomeMarkBoundaries() offsetMap()

playingWhenAttacked() plot() pop() quantize() recurse() recurseRepr() remove() removeByClass() removeByNotOfClass() repeatAppend() repeatInsert() replace() scaleDurations() scaleOffsets() setDerivationMethod() setElementOffset() shiftElements() showVariantAsOssialikePart() simultaneousAttacks() sliceAtOffsets() sliceByBeat() sliceByGreatestDivisor() sliceByQuarterLengths() sort() sorted() splitAtDurations() splitAtQuarterLength() splitByClass() storeAtEnd() stripTies() template() toSoundingPitch() toWrittenPitch() transferOffsetToElements() transpose() voicesToParts()

Methods inherited from StreamCore:

asTimespans() asTree() coreAppend() coreCopyAsDerivation()

coreElementsChanged() coreGatherMissingSpanners() coreGetElementByMemoryLocation() coreGuardBeforeAddElement()

coreInsert() coreSelfActiveSite() coreSetElementOffset() coreStoreAtEnd()

Methods inherited from Music21Object:

clearCache() containerHierarchy() contextSites() getAllContextsByClass() getContextByClass() getOffsetBySite()

getOffsetInHierarchy() getSpannerSites() informSites() next() previous()

purgeLocations() purgeOrphans() setOffsetBySite() sortTuple() splitByQuarterLengths()

Methods inherited from ProtoM21Object:

isClassOrSubclass()

Page instance variables

Instance variables inherited from Stream:

autoSort definesExplicitPageBreaks

definesExplicitSystemBreaks isFlat

isSorted recursionType

Instance variables inherited from Music21Object:

classSortOrder groups

isStream

sites

System

class music21.layout.System(givenElements=None, **keywords)

Designation that all the music in this Stream belongs on a single notated system.

Attribute systemNumbering says at what point the numbering of systems resets. It can be either “Score” (default), “Opus”, or “Page”.

System bases

• Score

• Stream

• StreamCore

• Music21Object

• ProtoM21Object

System read-only properties

System.staves

Read-only properties inherited from Score:

parts

Read-only properties inherited from Stream:

beat beatDuration beatStr beatStrength flat

highestOffset highestTime isGapless lowestOffset notes

notesAndRests pitches secondsMap spanners voices

Read-only properties inherited from StreamCore:

spannerBundle

Read-only properties inherited from Music21Object:

hasEditorialInformation

hasStyleInformation

measureNumber

Read-only properties inherited from ProtoM21Object:

classSet

classes

System read/write properties

Read/write properties inherited from Stream:

atSoundingPitch clef duration elements

finalBarline keySignature metadata

seconds staffLines timeSignature

Read/write properties inherited from Music21Object:

activeSite derivation editorial

id offset priority

quarterLength style

System methods

Methods inherited from Score:

expandRepeats() implode() makeNotation()

measure() measureOffsetMap() measures()

partsToVoices() sliceByGreatestDivisor()

Methods inherited from Stream:

__eq__() __getitem__() activateVariants() addGroupForElements() allPlayingWhileSounding() analyze() append() attachIntervalsBetweenStreams() attachMelodicIntervals() augmentOrDiminish() beatAndMeasureFromOffset() chordify() clear() cloneEmpty() containerInHierarchy() elementOffset() explode() extendDuration() extendTies() extractContext() findConsecutiveNotes() findGaps() first() flatten() flattenUnnecessaryVoices() getElementAfterElement() getElementAtOrBefore() getElementBeforeOffset() getElementById() getElementsByClass() getElementsByGroup() getElementsByOffset() getElementsNotOfClass() getInstrument() getInstruments()

getOverlaps() getTimeSignatures() hasElement() hasElementOfClass() hasMeasures() hasPartLikeStreams() hasVoices() haveAccidentalsBeenMade() index() insert() insertAndShift() insertIntoNoteOrChord() invertDiatonic() isSequence() isTwelveTone() isWellFormedNotation() iter() last() lyrics() makeAccidentals() makeBeams() makeImmutable() makeMeasures() makeMutable() makeRests() makeTies() makeVoices() melodicIntervals() mergeAttributes() mergeElements() metronomeMarkBoundaries() offsetMap() playingWhenAttacked() plot() pop()

quantize() recurse() recurseRepr() remove() removeByClass() removeByNotOfClass() repeatAppend() repeatInsert() replace() scaleDurations() scaleOffsets() setDerivationMethod() setElementOffset() shiftElements() show() showVariantAsOssialikePart() simultaneousAttacks() sliceAtOffsets() sliceByBeat() sliceByQuarterLengths() sort() sorted() splitAtDurations() splitAtQuarterLength() splitByClass() storeAtEnd() stripTies() template() toSoundingPitch() toWrittenPitch() transferOffsetToElements() transpose() voicesToParts() write()

Methods inherited from StreamCore:

asTimespans() asTree() coreAppend() coreCopyAsDerivation()

coreElementsChanged() coreGatherMissingSpanners() coreGetElementByMemoryLocation() coreGuardBeforeAddElement()

coreInsert() coreSelfActiveSite() coreSetElementOffset() coreStoreAtEnd()

Methods inherited from Music21Object:

clearCache() containerHierarchy() contextSites() getAllContextsByClass() getContextByClass() getOffsetBySite()

getOffsetInHierarchy() getSpannerSites() informSites() next() previous()

purgeLocations() purgeOrphans() setOffsetBySite() sortTuple() splitByQuarterLengths()

Methods inherited from ProtoM21Object:

isClassOrSubclass()

System instance variables

Instance variables inherited from Stream:

autoSort definesExplicitPageBreaks

definesExplicitSystemBreaks isFlat

isSorted recursionType

Instance variables inherited from Music21Object:

classSortOrder groups

isStream

sites

Staff

class music21.layout.Staff(givenElements=None, **keywords)

Designation that all the music in this Stream belongs on a single Staff.

Staff bases

• Part

• Stream

• StreamCore

• Music21Object

• ProtoM21Object

Staff read-only properties

Read-only properties inherited from Stream:

beat beatDuration beatStr beatStrength flat

highestOffset highestTime isGapless lowestOffset notes

notesAndRests pitches secondsMap spanners voices

Read-only properties inherited from StreamCore:

spannerBundle

Read-only properties inherited from Music21Object:

hasEditorialInformation

hasStyleInformation

measureNumber

Read-only properties inherited from ProtoM21Object:

classSet

classes

Staff read/write properties

Read/write properties inherited from Part:

partAbbreviation

partName

Read/write properties inherited from Stream:

atSoundingPitch clef duration elements

finalBarline keySignature metadata

seconds staffLines timeSignature

Read/write properties inherited from Music21Object:

activeSite derivation editorial

id offset priority

quarterLength style

Staff methods

Methods inherited from Part:

makeAccidentals()

mergeAttributes()

Methods inherited from Stream:

__eq__() __getitem__() activateVariants() addGroupForElements() allPlayingWhileSounding() analyze() append() attachIntervalsBetweenStreams() attachMelodicIntervals() augmentOrDiminish() beatAndMeasureFromOffset() chordify() clear() cloneEmpty() containerInHierarchy() elementOffset() expandRepeats() explode() extendDuration() extendTies() extractContext() findConsecutiveNotes() findGaps() first() flatten() flattenUnnecessaryVoices() getElementAfterElement() getElementAtOrBefore() getElementBeforeOffset() getElementById() getElementsByClass() getElementsByGroup() getElementsByOffset() getElementsNotOfClass() getInstrument() getInstruments()

getOverlaps() getTimeSignatures() hasElement() hasElementOfClass() hasMeasures() hasPartLikeStreams() hasVoices() haveAccidentalsBeenMade() index() insert() insertAndShift() insertIntoNoteOrChord() invertDiatonic() isSequence() isTwelveTone() isWellFormedNotation() iter() last() lyrics() makeBeams() makeImmutable() makeMeasures() makeMutable() makeNotation() makeRests() makeTies() makeVoices() measure() measureOffsetMap() measures() melodicIntervals() mergeElements() metronomeMarkBoundaries() offsetMap() playingWhenAttacked() plot()

pop() quantize() recurse() recurseRepr() remove() removeByClass() removeByNotOfClass() repeatAppend() repeatInsert() replace() scaleDurations() scaleOffsets() setDerivationMethod() setElementOffset() shiftElements() show() showVariantAsOssialikePart() simultaneousAttacks() sliceAtOffsets() sliceByBeat() sliceByGreatestDivisor() sliceByQuarterLengths() sort() sorted() splitAtDurations() splitAtQuarterLength() splitByClass() storeAtEnd() stripTies() template() toSoundingPitch() toWrittenPitch() transferOffsetToElements() transpose() voicesToParts() write()

Methods inherited from StreamCore:

asTimespans() asTree() coreAppend() coreCopyAsDerivation()

coreElementsChanged() coreGatherMissingSpanners() coreGetElementByMemoryLocation() coreGuardBeforeAddElement()

coreInsert() coreSelfActiveSite() coreSetElementOffset() coreStoreAtEnd()

Methods inherited from Music21Object:

clearCache() containerHierarchy() contextSites() getAllContextsByClass() getContextByClass() getOffsetBySite()

getOffsetInHierarchy() getSpannerSites() informSites() next() previous()

purgeLocations() purgeOrphans() setOffsetBySite() sortTuple() splitByQuarterLengths()

Methods inherited from ProtoM21Object:

isClassOrSubclass()

Staff instance variables

Instance variables inherited from Stream:

autoSort definesExplicitPageBreaks

definesExplicitSystemBreaks isFlat

isSorted recursionType

Instance variables inherited from Music21Object:

classSortOrder groups

isStream

sites

PageSize

class music21.layout.PageSize(top, left, right, bottom, width, height)

StaffGroup

class music21.layout.StaffGroup(*spannedElements, name: str | None = None, barTogether: Literal[True, False, None, 'Mensurstrich'] = True, abbreviation: str | None = None, symbol: Literal['bracket', 'line', 'brace', 'square'] | None = None, **keywords)

A StaffGroup defines a collection of one or more Part objects, specifying that they should be shown together with a bracket, brace, or other symbol, and may have a common name.

>>> p1 = stream.Part()
>>> p2 = stream.Part()
>>> p1.append(note.Note('C5', type='whole'))
>>> p1.append(note.Note('D5', type='whole'))
>>> p2.append(note.Note('C3', type='whole'))
>>> p2.append(note.Note('D3', type='whole'))
>>> p3 = stream.Part()
>>> p3.append(note.Note('F#4', type='whole'))
>>> p3.append(note.Note('G#4', type='whole'))
>>> s = stream.Score()
>>> s.insert(0, p1)
>>> s.insert(0, p2)
>>> s.insert(0, p3)
>>> staffGroup1 = layout.StaffGroup([p1, p2],
...      name='Marimba', abbreviation='Mba.', symbol='brace')
>>> staffGroup1.barTogether = 'Mensurstrich'
>>> s.insert(0, staffGroup1)
>>> staffGroup2 = layout.StaffGroup([p3],
...      name='Xylophone', abbreviation='Xyl.', symbol='bracket')
>>> s.insert(0, staffGroup2)
>>> s.show()

StaffGroup bases

• Spanner

• Music21Object

• ProtoM21Object

StaffGroup read-only properties

Read-only properties inherited from Music21Object:

beat beatDuration beatStr

beatStrength hasEditorialInformation

hasStyleInformation measureNumber

Read-only properties inherited from ProtoM21Object:

classSet

classes

StaffGroup read/write properties

StaffGroup.barTogether

Get or set the barTogether value, with either Boolean values or yes or no strings. Or the string ‘Mensurstrich’ which indicates barring between staves but not in staves.

Currently Mensurstrich is not supported by most exporters.

>>> sg = layout.StaffGroup()
>>> sg.barTogether = 'yes'
>>> sg.barTogether
True
>>> sg.barTogether = 'Mensurstrich'
>>> sg.barTogether
'Mensurstrich'

StaffGroup.symbol

Get or set the symbol value, with either Boolean values or yes or no strings.

>>> sg = layout.StaffGroup()
>>> sg.symbol = 'Brace'
>>> sg.symbol
'brace'

Read/write properties inherited from Music21Object:

activeSite derivation duration editorial

id offset priority

quarterLength seconds style

StaffGroup methods

Methods inherited from Spanner:

__getitem__() addSpannedElements() fill() getFirst() getLast()

getSpannedElementIds() getSpannedElements() getSpannedElementsByClass() hasSpannedElement() isFirst()

isLast() purgeLocations() purgeOrphans() replaceSpannedElement()

Methods inherited from Music21Object:

__eq__() clearCache() containerHierarchy() contextSites() getAllContextsByClass() getContextByClass() getOffsetBySite()

getOffsetInHierarchy() getSpannerSites() informSites() mergeAttributes() next() previous() setOffsetBySite()

show() sortTuple() splitAtDurations() splitAtQuarterLength() splitByQuarterLengths() write()

Methods inherited from ProtoM21Object:

isClassOrSubclass()

StaffGroup instance variables

Instance variables inherited from Music21Object:

classSortOrder groups

isStream

sites

SystemSize

class music21.layout.SystemSize(top, left, right, bottom)

Functions

music21.layout.divideByPages(scoreIn: Score, printUpdates: bool = False, fastMeasures: bool = False) → LayoutScore

Divides a score into a series of smaller scores according to page breaks. Only searches for PageLayout.isNew or SystemLayout.isNew on the first part. Returns a new LayoutScore object.

If fastMeasures is True, then the newly created System objects do not have Clef signs, Key Signatures, or necessarily all the applicable spanners in them. On the other hand, the position (on the page) information will be just as correct with fastMeasures = True and it will run much faster on large scores (because our spanner gathering algorithm is currently O(n^2); something TODO: to fix.)

>>> lt = corpus.parse('demos/layoutTest.xml')
>>> len(lt.parts)
3
>>> len(lt.parts[0].getElementsByClass(stream.Measure))
80

Divide the score up into layout.Page objects

>>> layoutScore = layout.divideByPages(lt, fastMeasures=True)
>>> len(layoutScore.pages)
4
>>> lastPage = layoutScore.pages[-1]
>>> lastPage.measureStart
64
>>> lastPage.measureEnd
80

the layoutScore is a subclass of stream.Opus:

>>> layoutScore
<music21.layout.LayoutScore ...>
>>> 'Opus' in layoutScore.classes
True

Pages are subclasses of Opus also, since they contain Scores

>>> lastPage
<music21.layout.Page ...>
>>> 'Opus' in lastPage.classes
True

Each page now has Systems not parts.

>>> firstPage = layoutScore.pages[0]
>>> len(firstPage.systems)
4
>>> firstSystem = firstPage.systems[0]
>>> firstSystem.measureStart
1
>>> firstSystem.measureEnd
5

Systems are a subclass of Score:

>>> firstSystem
<music21.layout.System ...>
>>> isinstance(firstSystem, stream.Score)
True

Each System has staves (layout.Staff objects) not parts, though Staff is a subclass of Part

>>> secondStaff = firstSystem.staves[1]
>>> print(len(secondStaff.getElementsByClass(stream.Measure)))
5
>>> secondStaff
<music21.layout.Staff ...>
>>> isinstance(secondStaff, stream.Part)
True

music21.layout.getPageRegionMeasureNumbers(scoreIn)

music21.layout.getRegionMeasureNumbers(scoreIn, region='Page')

get a list where each entry is a 2-tuplet whose first number refers to the first measure on a page and whose second number is the last measure on the page.

music21.layout.getSystemRegionMeasureNumbers(scoreIn)