class QTextBoundaryFinder¶

The QTextBoundaryFinder class provides a way of finding Unicode text boundaries in a string. More…

Synopsis¶

Methods¶

def __init__()
def boundaryReasons()
def isAtBoundary()
def isValid()
def position()
def setPosition()
def string()
def toEnd()
def toNextBoundary()
def toPreviousBoundary()
def toStart()
def type()

Note

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Detailed Description¶

QTextBoundaryFinder allows to find Unicode text boundaries in a string, accordingly to the Unicode text boundary specification (see Unicode Standard Annex #14 and Unicode Standard Annex #29 ).

QTextBoundaryFinder can operate on a QString in four possible modes depending on the value of BoundaryType.

Units of Unicode characters that make up what the user thinks of as a character or basic unit of the language are here called Grapheme clusters. The two unicode characters ‘A’ + diaeresis do for example form one grapheme cluster as the user thinks of them as one character, yet it is in this case represented by two unicode code points (see https://www.unicode.org/reports/tr29/#Grapheme_Cluster_Boundaries ).

Word boundaries are there to locate the start and end of what a language considers to be a word (see https://www.unicode.org/reports/tr29/#Word_Boundaries ).

Line break boundaries give possible places where a line break might happen and sentence boundaries will show the beginning and end of whole sentences (see https://www.unicode.org/reports/tr29/#Sentence_Boundaries and https://www.unicode.org/reports/tr14/ ).

The first position in a string is always a valid boundary and refers to the position before the first character. The last position at the length of the string is also valid and refers to the position after the last character.

class BoundaryType¶

Constant	Description
QTextBoundaryFinder.Grapheme	Finds a grapheme which is the smallest boundary. It including letters, punctuation marks, numerals and more.
QTextBoundaryFinder.Word	Finds a word.
QTextBoundaryFinder.Line	Finds possible positions for breaking the text into multiple lines.
QTextBoundaryFinder.Sentence	Finds sentence boundaries. These include periods, question marks etc.

class BoundaryReason¶

Constant	Description
QTextBoundaryFinder.NotAtBoundary	(inherits `enum.Flag`) The boundary finder is not at a boundary position.
QTextBoundaryFinder.BreakOpportunity	The boundary finder is at a break opportunity position. Such a break opportunity might also be an item boundary (either StartOfItem, EndOfItem, or combination of both), a mandatory line break, or a soft hyphen.
QTextBoundaryFinder.StartOfItem	The boundary finder is at the start of a grapheme, a word, a sentence, or a line.
QTextBoundaryFinder.EndOfItem	The boundary finder is at the end of a grapheme, a word, a sentence, or a line.
QTextBoundaryFinder.MandatoryBreak	The boundary finder is at the end of line (can occur for a Line boundary type only).
QTextBoundaryFinder.SoftHyphen	The boundary finder is at the soft hyphen (can occur for a Line boundary type only).

__init__()¶

Constructs an invalid QTextBoundaryFinder object.

__init__(other)

Parameters:: other – QTextBoundaryFinder

Copies the QTextBoundaryFinder object, other.

__init__(type, string)

Parameters:

type – BoundaryType
string – str

Creates a QTextBoundaryFinder object of type operating on string.

__init__(type, str[, buffer=None[, bufferSize=0]])

Parameters:

type – BoundaryType
str – str
buffer – unsigned char
bufferSize – int

Creates a QTextBoundaryFinder object of type operating on string.

buffer is an optional working buffer of size bufferSize you can pass to the QTextBoundaryFinder . If the buffer is large enough to hold the working data required (bufferSize >= length + 1), it will use this instead of allocating its own buffer.

Warning

QTextBoundaryFinder does not create a copy of string. It is the application programmer’s responsibility to ensure the array is allocated for as long as the QTextBoundaryFinder object stays alive. The same applies to buffer.

boundaryReasons()¶

Return type:: Combination of BoundaryReason

Returns the reasons for the boundary finder to have chosen the current position as a boundary.

isAtBoundary()¶

Return type:: bool

Returns true if the object’s position() is currently at a valid text boundary.

isValid()¶

Return type:: bool

Returns true if the text boundary finder is valid; otherwise returns false. A default QTextBoundaryFinder is invalid.

position()¶

Return type:: int

Returns the current position of the QTextBoundaryFinder .

The range is from 0 (the beginning of the string) to the length of the string inclusive.

See also

setPosition()

setPosition(position)¶

Parameters:: position – int

Sets the current position of the QTextBoundaryFinder to position.

If position is out of bounds, it will be bound to only valid positions. In this case, valid positions are from 0 to the length of the string inclusive.

See also

position()

string()¶

Return type:: str

Returns the string the QTextBoundaryFinder object operates on.

toEnd()¶

Moves the finder to the end of the string. This is equivalent to setPosition (string.length()).

See also

setPosition() position()

toNextBoundary()¶

Return type:: int

Moves the QTextBoundaryFinder to the next boundary position and returns that position.

Returns -1 if there is no next boundary.

toPreviousBoundary()¶

Return type:: int

Moves the QTextBoundaryFinder to the previous boundary position and returns that position.

Returns -1 if there is no previous boundary.

toStart()¶

Moves the finder to the start of the string. This is equivalent to setPosition (0).

See also

setPosition() position()

type()¶

Return type:: BoundaryType

Returns the type of the QTextBoundaryFinder .