QTextCursor¶

PyQt5.QtGui.QTextCursor

Description¶

The QTextCursor class offers an API to access and modify QTextDocuments.

Text cursors are objects that are used to access and modify the contents and underlying structure of text documents via a programming interface that mimics the behavior of a cursor in a text editor. QTextCursor contains information about both the cursor’s position within a QTextDocument and any selection that it has made.

QTextCursor is modeled on the way a text cursor behaves in a text editor, providing a programmatic means of performing standard actions through the user interface. A document can be thought of as a single string of characters. The cursor’s current position() then is always either between two consecutive characters in the string, or else before the very first character or after the very last character in the string. Documents can also contain tables, lists, images, and other objects in addition to text but, from the developer’s point of view, the document can be treated as one long string. Some portions of that string can be considered to lie within particular blocks (e.g. paragraphs), or within a table’s cell, or a list’s item, or other structural elements. When we refer to “current character” we mean the character immediately before the cursor position() in the document. Similarly, the “current block” is the block that contains the cursor position().

A QTextCursor also has an anchor() position. The text that is between the anchor() and the position() is the selection. If anchor() == position() there is no selection.

The cursor position can be changed programmatically using setPosition() and movePosition(); the latter can also be used to select text. For selections see selectionStart(), selectionEnd(), hasSelection(), clearSelection(), and removeSelectedText().

If the position() is at the start of a block, atBlockStart() returns true; and if it is at the end of a block, atBlockEnd() returns true. The format of the current character is returned by charFormat(), and the format of the current block is returned by blockFormat().

Formatting can be applied to the current text document using the setCharFormat(), mergeCharFormat(), setBlockFormat() and mergeBlockFormat() functions. The ‘set’ functions will replace the cursor’s current character or block format, while the ‘merge’ functions add the given format properties to the cursor’s current format. If the cursor has a selection, the given format is applied to the current selection. Note that when only a part of a block is selected, the block format is applied to the entire block. The text at the current character position can be turned into a list using createList().

Deletions can be achieved using deleteChar(), deletePreviousChar(), and removeSelectedText().

Text strings can be inserted into the document with the insertText() function, blocks (representing new paragraphs) can be inserted with insertBlock().

Existing fragments of text can be inserted with insertFragment() but, if you want to insert pieces of text in various formats, it is usually still easier to use insertText() and supply a character format.

Various types of higher-level structure can also be inserted into the document with the cursor:

Lists are ordered sequences of block elements that are decorated with bullet points or symbols. These are inserted in a specified format with insertList().
Tables are inserted with the insertTable() function, and can be given an optional format. These contain an array of cells that can be traversed using the cursor.
Inline images are inserted with insertImage(). The image to be used can be specified in an image format, or by name.
Frames are inserted by calling insertFrame() with a specified format.

Actions can be grouped (i.e. treated as a single action for undo/redo) using beginEditBlock() and endEditBlock().

Cursor movements are limited to valid cursor positions. In Latin writing this is between any two consecutive characters in the text, before the first character, or after the last character. In some other writing systems cursor movements are limited to “clusters” (e.g. a syllable in Devanagari, or a base letter plus diacritics). Functions such as movePosition() and deleteChar() limit cursor movement to these valid positions.

See also

Rich Text Processing.

Enums¶

MoveMode

If the anchor() is kept where it is and the position() is moved, the text in between will be selected.

Member	Value	Description
KeepAnchor	1	Keeps the anchor where it is.
MoveAnchor	0	Moves the anchor to the same position as the cursor itself.

MoveOperation

See also

movePosition().

Member	Value	Description
Down	12	Move down one line.
End	11	Move to the end of the document.
EndOfBlock	15	Move to the end of the current block.
EndOfLine	13	Move to the end of the current line.
EndOfWord	14	Move to the end of the current word.
Left	9	Move left one character.
NextBlock	16	Move to the beginning of the next block.
NextCell	21	Move to the beginning of the next table cell inside the current table. If the current cell is the last cell in the row, the cursor will move to the first cell in the next row.
NextCharacter	17	Move to the next character.
NextRow	23	Move to the first new cell of the next row in the current table.
NextWord	18	Move to the next word.
NoMove	0	Keep the cursor where it is
PreviousBlock	6	Move to the start of the previous block.
PreviousCell	22	Move to the beginning of the previous table cell inside the current table. If the current cell is the first cell in the row, the cursor will move to the last cell in the previous row.
PreviousCharacter	7	Move to the previous character.
PreviousRow	24	Move to the last cell of the previous row in the current table.
PreviousWord	8	Move to the beginning of the previous word.
Right	19	Move right one character.
Start	1	Move to the start of the document.
StartOfBlock	4	Move to the start of the current block.
StartOfLine	3	Move to the start of the current line.
StartOfWord	5	Move to the start of the current word.
Up	2	Move up one line.
WordLeft	10	Move left one word.
WordRight	20	Move right one word.

SelectionType

This enum describes the types of selection that can be applied with the select() function.

Member	Value	Description
BlockUnderCursor	2	Selects the block of text under the cursor.
Document	3	Selects the entire document.
LineUnderCursor	1	Selects the line of text under the cursor.
WordUnderCursor	0	Selects the word under the cursor. If the cursor is not positioned within a string of selectable characters, no text is selected.

Methods¶

__init__(): Constructs a null cursor.

__init__(QTextDocument): Constructs a cursor pointing to the beginning of the document.

__init__(QTextFrame): Constructs a cursor pointing to the beginning of the frame.

__init__(QTextBlock): Constructs a cursor pointing to the beginning of the block.

__init__(QTextCursor): Constructs a new cursor that is a copy of cursor.

anchor() → int: Returns the anchor position; this is the same as position() unless there is a selection in which case position() marks one end of the selection and marks the other end. Just like the cursor position, the anchor position is between characters.

See also

position(), setPosition(), movePosition(), selectionStart(), selectionEnd().

atBlockEnd() → bool: Returns true if the cursor is at the end of a block; otherwise returns false.

See also

atBlockStart(), atEnd().

atBlockStart() → bool: Returns true if the cursor is at the start of a block; otherwise returns false.

See also

atBlockEnd(), atStart().

atEnd() → bool: Returns true if the cursor is at the end of the document; otherwise returns false.

See also

atStart(), atBlockEnd().

atStart() → bool: Returns true if the cursor is at the start of the document; otherwise returns false.

See also

atBlockStart(), atEnd().

beginEditBlock()

Indicates the start of a block of editing operations on the document that should appear as a single operation from an undo/redo point of view.

For example:

# QTextCursor cursor(textDocument);
# cursor.beginEditBlock();
# cursor.insertText("Hello");
# cursor.insertText("World");
# cursor.endEditBlock();

# textDocument->undo();

The call to undo() will cause both insertions to be undone, causing both “World” and “Hello” to be removed.

It is possible to nest calls to and endEditBlock(). The top-most pair will determine the scope of the undo/redo operation.

See also

endEditBlock().

block() → QTextBlock: Returns the block that contains the cursor.

blockCharFormat() → QTextCharFormat

Returns the block character format of the block the cursor is in.

The block char format is the format used when inserting text at the beginning of an empty block.

See also

setBlockCharFormat().

blockFormat() → QTextBlockFormat: Returns the block format of the block the cursor is in.

See also

setBlockFormat(), charFormat().

blockNumber() → int

Returns the number of the block the cursor is in, or 0 if the cursor is invalid.

Note that this function only makes sense in documents without complex objects such as tables or frames.

charFormat() → QTextCharFormat: Returns the format of the character immediately before the cursor position(). If the cursor is positioned at the beginning of a text block that is not empty then the format of the character immediately after the cursor is returned.

See also

setCharFormat(), insertText(), blockFormat().

clearSelection()

Clears the current selection by setting the anchor to the cursor position.

Note that it does not delete the text of the selection.

See also

removeSelectedText(), hasSelection().

columnNumber() → int

Returns the position of the cursor within its containing line.

Note that this is the column number relative to a wrapped line, not relative to the block (i.e. the paragraph).

You probably want to call positionInBlock() instead.

See also

positionInBlock().

createList(QTextListFormat) → QTextList: Creates and returns a new list with the given format, and makes the current paragraph the cursor is in the first list item.

See also

insertList(), currentList().

createList(Style) → QTextList

This is an overloaded function.

Creates and returns a new list with the given style, making the cursor’s current paragraph the first list item.

The style to be used is defined by the Style enum.

See also

insertList(), currentList().

currentFrame() → QTextFrame: Returns a pointer to the current frame. Returns 0 if the cursor is invalid.

See also

insertFrame().

currentList() → QTextList: Returns the current list if the cursor position() is inside a block that is part of a list; otherwise returns 0.

See also

insertList(), createList().

currentTable() → QTextTable: Returns a pointer to the current table if the cursor position() is inside a block that is part of a table; otherwise returns 0.

See also

insertTable().

deleteChar(): If there is no selected text, deletes the character at the current cursor position; otherwise deletes the selected text.

See also

deletePreviousChar(), hasSelection(), clearSelection().

deletePreviousChar(): If there is no selected text, deletes the character before the current cursor position; otherwise deletes the selected text.

See also

deleteChar(), hasSelection(), clearSelection().

document() → QTextDocument: Returns the document this cursor is associated with.

endEditBlock(): Indicates the end of a block of editing operations on the document that should appear as a single operation from an undo/redo point of view.

See also

beginEditBlock().

__eq__(QTextCursor) → bool: TODO

__ge__(QTextCursor) → bool: TODO

__gt__(QTextCursor) → bool: TODO

hasComplexSelection() → bool

Returns true if the cursor contains a selection that is not simply a range from selectionStart() to selectionEnd(); otherwise returns false.

Complex selections are ones that span at least two cells in a table; their extent is specified by selectedTableCells().

hasSelection() → bool: Returns true if the cursor contains a selection; otherwise returns false.

insertBlock(): Inserts a new empty block at the cursor position() with the current blockFormat() and charFormat().

See also

setBlockFormat().

insertBlock(QTextBlockFormat)

This is an overloaded function.

Inserts a new empty block at the cursor position() with block format format and the current charFormat() as block char format.

See also

setBlockFormat().

insertBlock(QTextBlockFormat, QTextCharFormat): TODO

insertFragment(QTextDocumentFragment): Inserts the text fragment at the current position().

insertFrame(QTextFrameFormat) → QTextFrame

Inserts a frame with the given format at the current cursor position(), moves the cursor position() inside the frame, and returns the frame.

If the cursor holds a selection, the whole selection is moved inside the frame.

See also

hasSelection().

insertHtml(str)

Inserts the text html at the current position(). The text is interpreted as HTML.

Note: When using this function with a style sheet, the style sheet will only apply to the current block in the document. In order to apply a style sheet throughout a document, use setDefaultStyleSheet() instead.

insertImage(QTextImageFormat): Inserts the image defined by format at the current position().

insertImage(str)

This is an overloaded function.

Convenience method for inserting the image with the given name at the current position().

# QImage img = ...
# textDocument->addResource(QTextDocument::ImageResource, QUrl("myimage"), img);
# cursor.insertImage("myimage");

insertImage(QTextImageFormat, Position)

This is an overloaded function.

Inserts the image defined by the given format at the cursor’s current position with the specified alignment.

See also

position().

insertImage(QImage, name: str = '')

This is an overloaded function.

Convenience function for inserting the given image with an optional name at the current position().

insertList(QTextListFormat) → QTextList: Inserts a new block at the current position and makes it the first list item of a newly created list with the given format. Returns the created list.

See also

currentList(), createList(), insertBlock().

insertList(Style) → QTextList

This is an overloaded function.

Inserts a new block at the current position and makes it the first list item of a newly created list with the given style. Returns the created list.

insertTable(int, int) → QTextTable: TODO

insertTable(int, int, QTextTableFormat) → QTextTable: TODO

insertText(str)

Inserts text at the current position, using the current character format.

If there is a selection, the selection is deleted and replaced by text, for example:

# cursor.clearSelection();
# cursor.movePosition(QTextCursor::NextWord, QTextCursor::KeepAnchor);
# cursor.insertText("Hello World");

This clears any existing selection, selects the word at the cursor (i.e. from position() forward), and replaces the selection with the phrase “Hello World”.

Any ASCII linefeed characters (\n) in the inserted text are transformed into unicode block separators, corresponding to insertBlock() calls.

See also

charFormat(), hasSelection().

insertText(str, QTextCharFormat): TODO

isCopyOf(QTextCursor) → bool: Returns true if this cursor and other are copies of each other, i.e. one of them was created as a copy of the other and neither has moved since. This is much stricter than equality.

See also

operator=(), operator==().

isNull() → bool: Returns true if the cursor is null; otherwise returns false. A null cursor is created by the default constructor.

joinPreviousEditBlock()

Like beginEditBlock() indicates the start of a block of editing operations that should appear as a single operation for undo/redo. However unlike beginEditBlock() it does not start a new block but reverses the previous call to endEditBlock() and therefore makes following operations part of the previous edit block created.

For example:

# QTextCursor cursor(textDocument);
# cursor.beginEditBlock();
# cursor.insertText("Hello");
# cursor.insertText("World");
# cursor.endEditBlock();

# ...

# cursor.joinPreviousEditBlock();
# cursor.insertText("Hey");
# cursor.endEditBlock();

# textDocument->undo();

The call to undo() will cause all three insertions to be undone.

See also

beginEditBlock(), endEditBlock().

keepPositionOnInsert() → bool

Returns whether the cursor should keep its current position when text gets inserted at the position of the cursor.

The default is false;

See also

setKeepPositionOnInsert().

__le__(QTextCursor) → bool: TODO

__lt__(QTextCursor) → bool: TODO

mergeBlockCharFormat(QTextCharFormat): Modifies the block char format of the current block (or all blocks that are contained in the selection) with the block format specified by modifier.

See also

setBlockCharFormat().

mergeBlockFormat(QTextBlockFormat): Modifies the block format of the current block (or all blocks that are contained in the selection) with the block format specified by modifier.

See also

setBlockFormat(), blockFormat().

mergeCharFormat(QTextCharFormat): Merges the cursor’s current character format with the properties described by format modifier. If the cursor has a selection, this function applies all the properties set in modifier to all the character formats that are part of the selection.

See also

hasSelection(), setCharFormat().

movePosition(MoveOperation, mode: MoveMode = MoveAnchor, n: int = 1) → bool: TODO

__ne__(QTextCursor) → bool: TODO

position() → int: Returns the absolute position of the cursor within the document. The cursor is positioned between characters.

See also

setPosition(), movePosition(), anchor(), positionInBlock().

positionInBlock() → int

Returns the relative position of the cursor within the block. The cursor is positioned between characters.

This is equivalent to position() - block().position().

See also

position().

removeSelectedText(): If there is a selection, its content is deleted; otherwise does nothing.

See also

hasSelection().

select(SelectionType): Selects text in the document according to the given selection.

selectedTableCells() → (int, int, int, int): If the selection spans over table cells, firstRow is populated with the number of the first row in the selection, firstColumn with the number of the first column in the selection, and numRows and numColumns with the number of rows and columns in the selection. If the selection does not span any table cells the results are harmless but undefined.

selectedText() → str

Returns the current selection’s text (which may be empty). This only returns the text, with no rich text formatting information. If you want a document fragment (i.e. formatted rich text) use selection() instead.

Note: If the selection obtained from an editor spans a line break, the text will contain a Unicode U+2029 paragraph separator character instead of a newline \n character. Use QString::replace() to replace these characters with newlines.

selection() → QTextDocumentFragment

Returns the current selection (which may be empty) with all its formatting information. If you just want the selected text (i.e. plain text) use selectedText() instead.

Note: Unlike toPlainText(), selectedText() may include special unicode characters such as QChar::ParagraphSeparator.

See also

toPlainText().

selectionEnd() → int: Returns the end of the selection or position() if the cursor doesn’t have a selection.

See also

selectionStart(), position(), anchor().

selectionStart() → int: Returns the start of the selection or position() if the cursor doesn’t have a selection.

See also

selectionEnd(), position(), anchor().

setBlockCharFormat(QTextCharFormat): Sets the block char format of the current block (or all blocks that are contained in the selection) to format.

See also

blockCharFormat().

setBlockFormat(QTextBlockFormat): Sets the block format of the current block (or all blocks that are contained in the selection) to format.

See also

blockFormat(), mergeBlockFormat().

setCharFormat(QTextCharFormat): Sets the cursor’s current character format to the given format. If the cursor has a selection, the given format is applied to the current selection.

See also

charFormat(), hasSelection(), mergeCharFormat().

setKeepPositionOnInsert(bool)

Defines whether the cursor should keep its current position when text gets inserted at the current position of the cursor.

If b is true, the cursor keeps its current position when text gets inserted at the positing of the cursor. If b is false, the cursor moves along with the inserted text.

The default is false.

Note that a cursor always moves when text is inserted before the current position of the cursor, and it always keeps its position when text is inserted after the current position of the cursor.

See also

keepPositionOnInsert().

setPosition(int, mode: MoveMode = MoveAnchor): Moves the cursor to the absolute position in the document specified by pos using a MoveMode specified by m. The cursor is positioned between characters.

See also

position(), movePosition(), anchor().

setVerticalMovementX(int)

Sets the visual x position for vertical cursor movements to x.

The vertical movement x position is cleared automatically when the cursor moves horizontally, and kept unchanged when the cursor moves vertically. The mechanism allows the cursor to move up and down on a visually straight line with proportional fonts, and to gently “jump” over short lines.

A value of -1 indicates no predefined x position. It will then be set automatically the next time the cursor moves up or down.

See also

verticalMovementX().

setVisualNavigation(bool)

Sets visual navigation to b.

Visual navigation means skipping over hidden text paragraphs. The default is false.

See also

visualNavigation(), movePosition().

swap(QTextCursor): TODO

verticalMovementX() → int

Returns the visual x position for vertical cursor movements.

A value of -1 indicates no predefined x position. It will then be set automatically the next time the cursor moves up or down.

See also

setVerticalMovementX().

visualNavigation() → bool

Returns true if the cursor does visual navigation; otherwise returns false.

Visual navigation means skipping over hidden text paragraphs. The default is false.

See also

setVisualNavigation(), movePosition().