QTextLayout¶
The
QTextLayout
class is used to lay out and render text. More…
Synopsis¶
Functions¶
def
additionalFormats
()def
beginLayout
()def
boundingRect
()def
cacheEnabled
()def
clearAdditionalFormats
()def
clearFormats
()def
clearLayout
()def
createLine
()def
cursorMoveStyle
()def
draw
(p, pos[, selections=list()[, clip=QRectF()]])def
drawCursor
(p, pos, cursorPosition)def
drawCursor
(p, pos, cursorPosition, width)def
endLayout
()def
font
()def
formats
()def
isValidCursorPosition
(pos)def
leftCursorPosition
(oldPos)def
lineAt
(i)def
lineCount
()def
lineForTextPosition
(pos)def
maximumWidth
()def
minimumWidth
()def
nextCursorPosition
(oldPos[, mode=SkipCharacters])def
position
()def
preeditAreaPosition
()def
preeditAreaText
()def
previousCursorPosition
(oldPos[, mode=SkipCharacters])def
rightCursorPosition
(oldPos)def
setAdditionalFormats
(overrides)def
setCacheEnabled
(enable)def
setCursorMoveStyle
(style)def
setFlags
(flags)def
setFont
(f)def
setFormats
(overrides)def
setPosition
(p)def
setPreeditArea
(position, text)def
setRawFont
(rawFont)def
setText
(string)def
setTextOption
(option)def
text
()def
textOption
()
Detailed Description¶
It offers many features expected from a modern text layout engine, including Unicode compliant rendering, line breaking and handling of cursor positioning. It can also produce and render device independent layout, something that is important for WYSIWYG applications.
The class has a rather low level API and unless you intend to implement your own text rendering for some specialized widget, you probably won’t need to use it directly.
QTextLayout
can be used with both plain and rich text.
QTextLayout
can be used to create a sequence ofQTextLine
instances with given widths and can position them independently on the screen. Once the layout is done, these lines can be drawn on a paint device.The text to be laid out can be provided in the constructor or set with
setText()
.The layout can be seen as a sequence of
QTextLine
objects; usecreateLine()
to create aQTextLine
instance, andlineAt()
orlineForTextPosition()
to retrieve created lines.Here is a code snippet that demonstrates the layout phase:
leading = fontMetrics.leading() height = 0 widthUsed = 0 textLayout.beginLayout() while True: line = textLayout.createLine() if not line.isValid(): break line.setLineWidth(lineWidth) height += leading line.setPosition(QPointF(0, height)) height += line.height() widthUsed = qMax(widthUsed, line.naturalTextWidth()) textLayout.endLayout()The text can then be rendered by calling the layout’s
draw()
function:painter = QPainter(self) textLayout.draw(painter, QPoint(0, 0))For a given position in the text you can find a valid cursor position with
isValidCursorPosition()
,nextCursorPosition()
, andpreviousCursorPosition()
.The
QTextLayout
itself can be positioned withsetPosition()
; it has aboundingRect()
, and aminimumWidth()
and amaximumWidth()
.See also
- class PySide2.QtGui.QTextLayout¶
PySide2.QtGui.QTextLayout(text)
PySide2.QtGui.QTextLayout(text, font[, paintdevice=None])
PySide2.QtGui.QTextLayout(b)
- param font:
- param paintdevice:
- param b:
- param text:
str
Constructs an empty text layout.
See also
- PySide2.QtGui.QTextLayout.CursorMode¶
Constant
Description
QTextLayout.SkipCharacters
QTextLayout.SkipWords
- PySide2.QtGui.QTextLayout.additionalFormats()¶
- Return type:
Note
This function is deprecated.
Use
formats()
instead.
- PySide2.QtGui.QTextLayout.beginLayout()¶
Begins the layout process.
Warning
This will invalidate the layout, so all existing
QTextLine
objects that refer to the previous contents should now be discarded.See also
- PySide2.QtGui.QTextLayout.boundingRect()¶
- Return type:
The smallest rectangle that contains all the lines in the layout.
- PySide2.QtGui.QTextLayout.cacheEnabled()¶
- Return type:
bool
Returns
true
if the complete layout information is cached; otherwise returnsfalse
.See also
- PySide2.QtGui.QTextLayout.clearAdditionalFormats()¶
Note
This function is deprecated.
Use
clearFormats()
instead.
- PySide2.QtGui.QTextLayout.clearFormats()¶
Clears the list of additional formats supported by the text layout.
See also
- PySide2.QtGui.QTextLayout.clearLayout()¶
Clears the line information in the layout. After having called this function,
lineCount()
returns 0.Warning
This will invalidate the layout, so all existing
QTextLine
objects that refer to the previous contents should now be discarded.
- PySide2.QtGui.QTextLayout.createLine()¶
- Return type:
Returns a new text line to be laid out if there is text to be inserted into the layout; otherwise returns an invalid text line.
The text layout creates a new line object that starts after the last line in the layout, or at the beginning if the layout is empty. The layout maintains an internal cursor, and each line is filled with text from the cursor position onwards when the
setLineWidth()
function is called.Once
setLineWidth()
is called, a new line can be created and filled with text. Repeating this process will lay out the whole block of text contained in theQTextLayout
. If there is no text left to be inserted into the layout, theQTextLine
returned will not be valid ( isValid() will return false).
- PySide2.QtGui.QTextLayout.cursorMoveStyle()¶
- Return type:
The cursor movement style of this
QTextLayout
. The default isLogicalMoveStyle
.See also
- PySide2.QtGui.QTextLayout.draw(p, pos[, selections=list()[, clip=QRectF()]])¶
- Parameters:
pos –
PySide2.QtCore.QPointF
selections –
clip –
PySide2.QtCore.QRectF
Draws the whole layout on the painter
p
at the position specified bypos
. The rendered layout includes the givenselections
and is clipped within the rectangle specified byclip
.
- PySide2.QtGui.QTextLayout.drawCursor(p, pos, cursorPosition)¶
- Parameters:
pos –
PySide2.QtCore.QPointF
cursorPosition – int
This is an overloaded function.
Draws a text cursor with the current pen at the given
position
using thepainter
specified. The corresponding position within the text is specified bycursorPosition
.
- PySide2.QtGui.QTextLayout.drawCursor(p, pos, cursorPosition, width)
- Parameters:
pos –
PySide2.QtCore.QPointF
cursorPosition – int
width – int
Draws a text cursor with the current pen and the specified
width
at the givenposition
using thepainter
specified. The corresponding position within the text is specified bycursorPosition
.
- PySide2.QtGui.QTextLayout.endLayout()¶
Ends the layout process.
See also
- PySide2.QtGui.QTextLayout.font()¶
- Return type:
Returns the current font that is used for the layout, or a default font if none is set.
See also
- PySide2.QtGui.QTextLayout.formats()¶
- Return type:
Returns the list of additional formats supported by the text layout.
See also
- PySide2.QtGui.QTextLayout.isValidCursorPosition(pos)¶
- Parameters:
pos – int
- Return type:
bool
/ Returns
true
if positionpos
is a valid cursor position.In a Unicode context some positions in the text are not valid cursor positions, because the position is inside a Unicode surrogate or a grapheme cluster.
A grapheme cluster is a sequence of two or more Unicode characters that form one indivisible entity on the screen. For example the latin character `Ä’ can be represented in Unicode by two characters, `A’ (0x41), and the combining diaresis (0x308). A text cursor can only validly be positioned before or after these two characters, never between them since that wouldn’t make sense. In indic languages every syllable forms a grapheme cluster.
- PySide2.QtGui.QTextLayout.leftCursorPosition(oldPos)¶
- Parameters:
oldPos – int
- Return type:
int
Returns the cursor position to the left of
oldPos
, next to it. It’s dependent on the visual position of characters, after bi-directional reordering.
- PySide2.QtGui.QTextLayout.lineAt(i)¶
- Parameters:
i – int
- Return type:
Returns the
i
-th line of text in this text layout.See also
- PySide2.QtGui.QTextLayout.lineCount()¶
- Return type:
int
Returns the number of lines in this text layout.
See also
- PySide2.QtGui.QTextLayout.lineForTextPosition(pos)¶
- Parameters:
pos – int
- Return type:
Returns the line that contains the cursor position specified by
pos
.See also
- PySide2.QtGui.QTextLayout.maximumWidth()¶
- Return type:
float
The maximum width the layout could expand to; this is essentially the width of the entire text.
Warning
This function only returns a valid value after the layout has been done.
See also
- PySide2.QtGui.QTextLayout.minimumWidth()¶
- Return type:
float
The minimum width the layout needs. This is the width of the layout’s smallest non-breakable substring.
Warning
This function only returns a valid value after the layout has been done.
See also
- PySide2.QtGui.QTextLayout.nextCursorPosition(oldPos[, mode=SkipCharacters])¶
- Parameters:
oldPos – int
mode –
CursorMode
- Return type:
int
Returns the next valid cursor position after
oldPos
that respects the given cursormode
. Returns value ofoldPos
, ifoldPos
is not a valid cursor position.
- PySide2.QtGui.QTextLayout.position()¶
- Return type:
The global position of the layout. This is independent of the bounding rectangle and of the layout process.
See also
- PySide2.QtGui.QTextLayout.preeditAreaPosition()¶
- Return type:
int
Returns the position of the area in the text layout that will be processed before editing occurs.
See also
- PySide2.QtGui.QTextLayout.preeditAreaText()¶
- Return type:
str
Returns the text that is inserted in the layout before editing occurs.
See also
- PySide2.QtGui.QTextLayout.previousCursorPosition(oldPos[, mode=SkipCharacters])¶
- Parameters:
oldPos – int
mode –
CursorMode
- Return type:
int
Returns the first valid cursor position before
oldPos
that respects the given cursormode
. Returns value ofoldPos
, ifoldPos
is not a valid cursor position.
- PySide2.QtGui.QTextLayout.rightCursorPosition(oldPos)¶
- Parameters:
oldPos – int
- Return type:
int
Returns the cursor position to the right of
oldPos
, next to it. It’s dependent on the visual position of characters, after bi-directional reordering.See also
- PySide2.QtGui.QTextLayout.setAdditionalFormats(overrides)¶
- Parameters:
overrides –
Note
This function is deprecated.
Use
setFormats()
instead.See also
- PySide2.QtGui.QTextLayout.setCacheEnabled(enable)¶
- Parameters:
enable – bool
Enables caching of the complete layout information if
enable
is true; otherwise disables layout caching. UsuallyQTextLayout
throws most of the layouting information away after a call toendLayout()
to reduce memory consumption. If you however want to draw the laid out text directly afterwards enabling caching might speed up drawing significantly.See also
- PySide2.QtGui.QTextLayout.setCursorMoveStyle(style)¶
- Parameters:
style –
CursorMoveStyle
Sets the visual cursor movement style to the given
style
. If theQTextLayout
is backed by a document, you can ignore this and use the option inQTextDocument
, this option is for widgets likeQLineEdit
or custom widgets without aQTextDocument
. Default value isLogicalMoveStyle
.See also
- PySide2.QtGui.QTextLayout.setFlags(flags)¶
- Parameters:
flags – int
- PySide2.QtGui.QTextLayout.setFont(f)¶
- Parameters:
Sets the layout’s font to the given
font
. The layout is invalidated and must be laid out again.See also
- PySide2.QtGui.QTextLayout.setFormats(overrides)¶
- Parameters:
overrides –
Sets the additional formats supported by the text layout to
formats
. The formats are applied with preedit area text in place.See also
- PySide2.QtGui.QTextLayout.setPosition(p)¶
- Parameters:
Moves the text layout to point
p
.See also
- PySide2.QtGui.QTextLayout.setPreeditArea(position, text)¶
- Parameters:
position – int
text – str
Sets the
position
andtext
of the area in the layout that is processed before editing occurs. The layout is invalidated and must be laid out again.See also
- PySide2.QtGui.QTextLayout.setRawFont(rawFont)¶
- Parameters:
rawFont –
PySide2.QtGui.QRawFont
Sets a raw font, to be used with
glyphRuns
. Note that this only supports the needs of WebKit. Use of this function with e.g.draw
will result in undefined behaviour.
- PySide2.QtGui.QTextLayout.setText(string)¶
- Parameters:
string – str
Sets the layout’s text to the given
string
. The layout is invalidated and must be laid out again.Notice that when using this
QTextLayout
as part of aQTextDocument
this method will have no effect.See also
- PySide2.QtGui.QTextLayout.setTextOption(option)¶
- Parameters:
option –
PySide2.QtGui.QTextOption
Sets the text option structure that controls the layout process to the given
option
.See also
- PySide2.QtGui.QTextLayout.textOption()¶
- Return type:
Returns the current text option used to control the layout process.
See also
© 2022 The Qt Company Ltd. Documentation contributions included herein are the copyrights of their respective owners. The documentation provided herein is licensed under the terms of the GNU Free Documentation License version 1.3 as published by the Free Software Foundation. Qt and respective logos are trademarks of The Qt Company Ltd. in Finland and/or other countries worldwide. All other trademarks are property of their respective owners.