TextIter

class TextIter(*args, **kwargs)

An iterator for the contents of a GtkTextBuffer.

You may wish to begin by reading the text widget conceptual overview, which gives an overview of all the objects and data types related to the text widget and how they work together.

Methods

class TextIter
assign(other: TextIter) → None

Assigns the value of other to iter.

This function is not useful in applications, because iterators can be assigned with GtkTextIter i = j;.

The function is used by language bindings.

Parameters:

other – another GtkTextIter

backward_char() → bool

Moves backward by one character offset.

Returns True if movement was possible; if iter was the first in the buffer (character offset 0), this function returns False for convenience when writing loops.

backward_chars(count: int) → bool

Moves count characters backward, if possible.

If count would move past the start or end of the buffer, moves to the start or end of the buffer.

The return value indicates whether the iterator moved onto a dereferenceable position; if the iterator didn’t move, or moved onto the end iterator, then False is returned. If count is 0, the function does nothing and returns False.

Parameters:

count – number of characters to move

backward_cursor_position() → bool

Like forward_cursor_position, but moves backward.

backward_cursor_positions(count: int) → bool

Moves up to count cursor positions.

See forward_cursor_position for details.

Parameters:

count – number of positions to move

backward_find_char(pred: Callable[[...], bool], limit: TextIter | None = None, *user_data: Any) → bool

Same as forward_find_char, but goes backward from iter.

Parameters:

  • pred – function to be called on each character

  • limit – search limit

  • user_data – user data for pred

backward_line() → bool

Moves iter to the start of the previous line.

Returns True if iter could be moved; i.e. if iter was at character offset 0, this function returns False. Therefore, if iter was already on line 0, but not at the start of the line, iter is snapped to the start of the line and the function returns True. (Note that this implies that in a loop calling this function, the line number may not change on every iteration, if your first iteration is on line 0.)

backward_lines(count: int) → bool

Moves count lines backward, if possible.

If count would move past the start or end of the buffer, moves to the start or end of the buffer.

The return value indicates whether the iterator moved onto a dereferenceable position; if the iterator didn’t move, or moved onto the end iterator, then False is returned. If count is 0, the function does nothing and returns False. If count is negative, moves forward by 0 - count lines.

Parameters:

count – number of lines to move backward

Same as forward_search, but moves backward.

match_end will never be set to a GtkTextIter located after iter, even if there is a possible match_start before or at iter.

Parameters:

  • str – search string

  • flags – bitmask of flags affecting the search

  • limit – location of last possible match_start, or None for start of buffer

backward_sentence_start() → bool

Moves backward to the previous sentence start.

If iter is already at the start of a sentence, moves backward to the next one.

Sentence boundaries are determined by Pango and should be correct for nearly any language.

backward_sentence_starts(count: int) → bool

Calls backward_sentence_start up to count times.

If count is negative, moves forward instead of backward.

Parameters:

count – number of sentences to move

backward_to_tag_toggle(tag: TextTag | None = None) → bool

Moves backward to the next toggle (on or off) of the tag, or to the next toggle of any tag if tag is None.

If no matching tag toggles are found, returns False, otherwise True. Does not return toggles located at iter, only toggles before iter. Sets iter to the location of the toggle, or the start of the buffer if no toggle is found.

Parameters:

tag – a GtkTextTag

backward_visible_cursor_position() → bool

Moves iter backward to the previous visible cursor position.

See backward_cursor_position for details.

backward_visible_cursor_positions(count: int) → bool

Moves up to count visible cursor positions.

See backward_cursor_position for details.

Parameters:

count – number of positions to move

backward_visible_line() → bool

Moves iter to the start of the previous visible line.

Returns True if iter could be moved; i.e. if iter was at character offset 0, this function returns False. Therefore if iter was already on line 0, but not at the start of the line, iter is snapped to the start of the line and the function returns True. (Note that this implies that in a loop calling this function, the line number may not change on every iteration, if your first iteration is on line 0.)

backward_visible_lines(count: int) → bool

Moves count visible lines backward, if possible.

If count would move past the start or end of the buffer, moves to the start or end of the buffer.

The return value indicates whether the iterator moved onto a dereferenceable position; if the iterator didn’t move, or moved onto the end iterator, then False is returned. If count is 0, the function does nothing and returns False. If count is negative, moves forward by 0 - count lines.

Parameters:

count – number of lines to move backward

backward_visible_word_start() → bool

Moves backward to the previous visible word start.

If iter is currently on a word start, moves backward to the next one after that.

Word breaks are determined by Pango and should be correct for nearly any language.

backward_visible_word_starts(count: int) → bool

Calls backward_visible_word_start up to count times.

Parameters:

count – number of times to move

backward_word_start() → bool

Moves backward to the previous word start.

If iter is currently on a word start, moves backward to the next one after that.

Word breaks are determined by Pango and should be correct for nearly any language

backward_word_starts(count: int) → bool

Calls backward_word_start up to count times.

Parameters:

count – number of times to move

can_insert(default_editability: bool) → bool

Considering the default editability of the buffer, and tags that affect editability, determines whether text inserted at iter would be editable.

If text inserted at iter would be editable then the user should be allowed to insert text at iter. insert_interactive uses this function to decide whether insertions are allowed at a given position.

Parameters:

default_editability – True if text is editable by default

compare(rhs: TextIter) → int

A qsort()-style function that returns negative if lhs is less than rhs, positive if lhs is greater than rhs, and 0 if they’re equal.

Ordering is in character offset order, i.e. the first character in the buffer is less than the second character in the buffer.

Parameters:

rhs – another GtkTextIter

editable(default_setting: bool) → bool

Returns whether the character at iter is within an editable region of text.

Non-editable text is “locked” and can’t be changed by the user via GtkTextView. If no tags applied to this text affect editability, default_setting will be returned.

You don’t want to use this function to decide whether text can be inserted at iter, because for insertion you don’t want to know whether the char at iter is inside an editable range, you want to know whether a new character inserted at iter would be inside an editable range. Use can_insert to handle this case.

Parameters:

default_setting – True if text is editable by default

ends_line() → bool

Returns True if iter points to the start of the paragraph delimiter characters for a line.

Delimiters will be either a newline, a carriage return, a carriage return followed by a newline, or a Unicode paragraph separator character.

Note that an iterator pointing to the n of a rn pair will not be counted as the end of a line, the line ends before the r. The end iterator is considered to be at the end of a line, even though there are no paragraph delimiter chars there.

ends_sentence() → bool

Determines whether iter ends a sentence.

Sentence boundaries are determined by Pango and should be correct for nearly any language.

ends_tag(tag: TextTag | None = None) → bool

Returns True if tag is toggled off at exactly this point.

If tag is None, returns True if any tag is toggled off at this point.

Note that if this function returns True, it means that iter is at the end of the tagged range, but that the character at iter is outside the tagged range. In other words, unlike starts_tag, if this function returns True, has_tag will return False for the same parameters.

Parameters:

tag – a GtkTextTag

ends_word() → bool

Determines whether iter ends a natural-language word.

Word breaks are determined by Pango and should be correct for nearly any language.

equal(rhs: TextIter) → bool

Tests whether two iterators are equal, using the fastest possible mechanism.

This function is very fast; you can expect it to perform better than e.g. getting the character offset for each iterator and comparing the offsets yourself. Also, it’s a bit faster than compare.

Parameters:

rhs – another GtkTextIter

forward_char() → bool

Moves iter forward by one character offset.

Note that images embedded in the buffer occupy 1 character slot, so this function may actually move onto an image instead of a character, if you have images in your buffer. If iter is the end iterator or one character before it, iter will now point at the end iterator, and this function returns False for convenience when writing loops.

forward_chars(count: int) → bool

Moves count characters if possible.

If count would move past the start or end of the buffer, moves to the start or end of the buffer.

The return value indicates whether the new position of iter is different from its original position, and dereferenceable (the last iterator in the buffer is not dereferenceable). If count is 0, the function does nothing and returns False.

Parameters:

count – number of characters to move, may be negative

forward_cursor_position() → bool

Moves iter forward by a single cursor position.

Cursor positions are (unsurprisingly) positions where the cursor can appear. Perhaps surprisingly, there may not be a cursor position between all characters. The most common example for European languages would be a carriage return/newline sequence.

For some Unicode characters, the equivalent of say the letter “a” with an accent mark will be represented as two characters, first the letter then a “combining mark” that causes the accent to be rendered; so the cursor can’t go between those two characters.

See also the LogAttr struct and the break function.

forward_cursor_positions(count: int) → bool

Moves up to count cursor positions.

See forward_cursor_position for details.

Parameters:

count – number of positions to move

forward_find_char(pred: Callable[[...], bool], limit: TextIter | None = None, *user_data: Any) → bool

Advances iter, calling pred on each character.

If pred returns True, returns True and stops scanning. If pred never returns True, iter is set to limit if limit is non-None, otherwise to the end iterator.

Parameters:

  • pred – a function to be called on each character

  • limit – search limit

  • user_data – user data for pred

forward_line() → bool

Moves iter to the start of the next line.

If the iter is already on the last line of the buffer, moves the iter to the end of the current line. If after the operation, the iter is at the end of the buffer and not dereferenceable, returns False. Otherwise, returns True.

forward_lines(count: int) → bool

Moves count lines forward, if possible.

If count would move past the start or end of the buffer, moves to the start or end of the buffer.

The return value indicates whether the iterator moved onto a dereferenceable position; if the iterator didn’t move, or moved onto the end iterator, then False is returned. If count is 0, the function does nothing and returns False. If count is negative, moves backward by 0 - count lines.

Parameters:

count – number of lines to move forward

Searches forward for str.

Any match is returned by setting match_start to the first character of the match and match_end to the first character after the match. The search will not continue past limit. Note that a search is a linear or O(n) operation, so you may wish to use limit to avoid locking up your UI on large buffers.

match_start will never be set to a GtkTextIter located before iter, even if there is a possible match_end after or at iter.

Parameters:

  • str – a search string

  • flags – flags affecting how the search is done

  • limit – location of last possible match_end, or None for the end of the buffer

forward_sentence_end() → bool

Moves forward to the next sentence end.

If iter is at the end of a sentence, moves to the next end of sentence.

Sentence boundaries are determined by Pango and should be correct for nearly any language.

forward_sentence_ends(count: int) → bool

Calls forward_sentence_end count times.

If count is negative, moves backward instead of forward.

Parameters:

count – number of sentences to move

forward_to_end() → None

Moves iter forward to the “end iterator”, which points one past the last valid character in the buffer.

get_char called on the end iterator returns 0, which is convenient for writing loops.

forward_to_line_end() → bool

Moves the iterator to point to the paragraph delimiter characters.

The possible characters are either a newline, a carriage return, a carriage return/newline in sequence, or the Unicode paragraph separator character.

If the iterator is already at the paragraph delimiter characters, moves to the paragraph delimiter characters for the next line. If iter is on the last line in the buffer, which does not end in paragraph delimiters, moves to the end iterator (end of the last line), and returns False.

forward_to_tag_toggle(tag: TextTag | None = None) → bool

Moves forward to the next toggle (on or off) of the tag, or to the next toggle of any tag if tag is None.

If no matching tag toggles are found, returns False, otherwise True. Does not return toggles located at iter, only toggles after iter. Sets iter to the location of the toggle, or to the end of the buffer if no toggle is found.

Parameters:

tag – a GtkTextTag

forward_visible_cursor_position() → bool

Moves iter forward to the next visible cursor position.

See forward_cursor_position for details.

forward_visible_cursor_positions(count: int) → bool

Moves up to count visible cursor positions.

See forward_cursor_position for details.

Parameters:

count – number of positions to move

forward_visible_line() → bool

Moves iter to the start of the next visible line.

Returns True if there was a next line to move to, and False if iter was simply moved to the end of the buffer and is now not dereferenceable, or if iter was already at the end of the buffer.

forward_visible_lines(count: int) → bool

Moves count visible lines forward, if possible.

If count would move past the start or end of the buffer, moves to the start or end of the buffer.

The return value indicates whether the iterator moved onto a dereferenceable position; if the iterator didn’t move, or moved onto the end iterator, then False is returned. If count is 0, the function does nothing and returns False. If count is negative, moves backward by 0 - count lines.

Parameters:

count – number of lines to move forward

forward_visible_word_end() → bool

Moves forward to the next visible word end.

If iter is currently on a word end, moves forward to the next one after that.

Word breaks are determined by Pango and should be correct for nearly any language

forward_visible_word_ends(count: int) → bool

Calls forward_visible_word_end up to count times.

Parameters:

count – number of times to move

forward_word_end() → bool

Moves forward to the next word end.

If iter is currently on a word end, moves forward to the next one after that.

Word breaks are determined by Pango and should be correct for nearly any language.

forward_word_ends(count: int) → bool

Calls forward_word_end up to count times.

Parameters:

count – number of times to move

free() → None

Free an iterator allocated on the heap.

This function is intended for use in language bindings, and is not especially useful for applications, because iterators can simply be allocated on the stack.

get_buffer() → TextBuffer

Returns the GtkTextBuffer this iterator is associated with.

get_bytes_in_line() → int

Returns the number of bytes in the line containing iter, including the paragraph delimiters.

get_char() → str

The Unicode character at this iterator is returned.

Equivalent to operator* on a C++ iterator. If the element at this iterator is a non-character element, such as an image embedded in the buffer, the Unicode “unknown” character 0xFFFC is returned. If invoked on the end iterator, zero is returned; zero is not a valid Unicode character.

So you can write a loop which ends when this function returns 0.

get_chars_in_line() → int

Returns the number of characters in the line containing iter, including the paragraph delimiters.

get_child_anchor() → TextChildAnchor | None

If the location at iter contains a child anchor, the anchor is returned.

Otherwise, None is returned.

get_language() → Language

Returns the language in effect at iter.

If no tags affecting language apply to iter, the return value is identical to that of get_default_language.

get_line() → int

Returns the line number containing the iterator.

Lines in a GtkTextBuffer are numbered beginning with 0 for the first line in the buffer.

get_line_index() → int

Returns the byte index of the iterator, counting from the start of a newline-terminated line.

Remember that GtkTextBuffer encodes text in UTF-8, and that characters can require a variable number of bytes to represent.

get_line_offset() → int

Returns the character offset of the iterator, counting from the start of a newline-terminated line.

The first character on the line has offset 0.

get_marks() → list[TextMark]

Returns a list of all GtkTextMark at this location.

Because marks are not iterable (they don’t take up any “space” in the buffer, they are just marks in between iterable locations), multiple marks can exist in the same place.

The returned list is not in any meaningful order.

get_offset() → int

Returns the character offset of an iterator.

Each character in a GtkTextBuffer has an offset, starting with 0 for the first character in the buffer. Use get_iter_at_offset to convert an offset back into an iterator.

get_paintable() → Paintable | None

If the element at iter is a paintable, the paintable is returned.

Otherwise, None is returned.

get_slice(end: TextIter) → str

Returns the text in the given range.

A “slice” is an array of characters encoded in UTF-8 format, including the Unicode “unknown” character 0xFFFC for iterable non-character elements in the buffer, such as images. Because images are encoded in the slice, byte and character offsets in the returned array will correspond to byte offsets in the text buffer. Note that 0xFFFC can occur in normal text as well, so it is not a reliable indicator that a paintable or widget is in the buffer.

Parameters:

end – iterator at end of a range

get_tags() → list[TextTag]

Returns a list of tags that apply to iter, in ascending order of priority.

The highest-priority tags are last.

The GtkTextTag’s in the list don’t have a reference added, but you have to free the list itself.

get_text(end: TextIter) → str

Returns text in the given range.

If the range contains non-text elements such as images, the character and byte offsets in the returned string will not correspond to character and byte offsets in the buffer. If you want offsets to correspond, see get_slice.

Parameters:

end – iterator at end of a range

get_toggled_tags(toggled_on: bool) → list[TextTag]

Returns a list of GtkTextTag that are toggled on or off at this point.

If toggled_on is True, the list contains tags that are toggled on. If a tag is toggled on at iter, then some non-empty range of characters following iter has that tag applied to it. If a tag is toggled off, then some non-empty range following iter does not have the tag applied to it.

Parameters:

toggled_on – True to get toggled-on tags

get_visible_line_index() → int

Returns the number of bytes from the start of the line to the given iter, not counting bytes that are invisible due to tags with the “invisible” flag toggled on.

get_visible_line_offset() → int

Returns the offset in characters from the start of the line to the given iter, not counting characters that are invisible due to tags with the “invisible” flag toggled on.

get_visible_slice(end: TextIter) → str

Returns visible text in the given range.

Like get_slice, but invisible text is not included. Invisible text is usually invisible because a GtkTextTag with the “invisible” attribute turned on has been applied to it.

Parameters:

end – iterator at end of range

get_visible_text(end: TextIter) → str

Returns visible text in the given range.

Like get_text, but invisible text is not included. Invisible text is usually invisible because a GtkTextTag with the “invisible” attribute turned on has been applied to it.

Parameters:

end – iterator at end of range

has_tag(tag: TextTag) → bool

Returns True if iter points to a character that is part of a range tagged with tag.

See also starts_tag and ends_tag.

Parameters:

tag – a GtkTextTag

in_range(start: TextIter, end: TextIter) → bool

Checks whether iter falls in the range [start, end).

start and end must be in ascending order.

Parameters:

  • start – start of range

  • end – end of range

inside_sentence() → bool

Determines whether iter is inside a sentence (as opposed to in between two sentences, e.g. after a period and before the first letter of the next sentence).

Sentence boundaries are determined by Pango and should be correct for nearly any language.

inside_word() → bool

Determines whether the character pointed by iter is part of a natural-language word (as opposed to say inside some whitespace).

Word breaks are determined by Pango and should be correct for nearly any language.

Note that if starts_word returns True, then this function returns True too, since iter points to the first character of the word.

is_cursor_position() → bool

Determine if iter is at a cursor position.

See forward_cursor_position or LogAttr or break for details on what a cursor position is.

is_end() → bool

Returns True if iter is the end iterator.

This means it is one past the last dereferenceable iterator in the buffer. is_end is the most efficient way to check whether an iterator is the end iterator.

is_start() → bool

Returns True if iter is the first iterator in the buffer.

order(second: TextIter) → None

Swaps the value of first and second if second comes before first in the buffer.

That is, ensures that first and second are in sequence. Most text buffer functions that take a range call this automatically on your behalf, so there’s no real reason to call it yourself in those cases. There are some exceptions, such as in_range, that expect a pre-sorted range.

Parameters:

second – another GtkTextIter

set_line(line_number: int) → None

Moves iterator iter to the start of the line line_number.

If line_number is negative or larger than or equal to the number of lines in the buffer, moves iter to the start of the last line in the buffer.

Parameters:

line_number – line number (counted from 0)

set_line_index(byte_on_line: int) → None

Same as set_line_offset, but works with a byte index. The given byte index must be at the start of a character, it can’t be in the middle of a UTF-8 encoded character.

Parameters:

byte_on_line – a byte index relative to the start of iter’s current line

set_line_offset(char_on_line: int) → None

Moves iter within a line, to a new character (not byte) offset.

The given character offset must be less than or equal to the number of characters in the line; if equal, iter moves to the start of the next line. See set_line_index if you have a byte index rather than a character offset.

Parameters:

char_on_line – a character offset relative to the start of iter’s current line

set_offset(char_offset: int) → None

Sets iter to point to char_offset.

char_offset counts from the start of the entire text buffer, starting with 0.

Parameters:

char_offset – a character number

set_visible_line_index(byte_on_line: int) → None

Like set_line_index, but the index is in visible bytes, i.e. text with a tag making it invisible is not counted in the index.

Parameters:

byte_on_line – a byte index

set_visible_line_offset(char_on_line: int) → None

Like set_line_offset, but the offset is in visible characters, i.e. text with a tag making it invisible is not counted in the offset.

Parameters:

char_on_line – a character offset

starts_line() → bool

Returns True if iter begins a paragraph.

This is the case if get_line_offset would return 0. However this function is potentially more efficient than get_line_offset, because it doesn’t have to compute the offset, it just has to see whether it’s 0.

starts_sentence() → bool

Determines whether iter begins a sentence.

Sentence boundaries are determined by Pango and should be correct for nearly any language.

starts_tag(tag: TextTag | None = None) → bool

Returns True if tag is toggled on at exactly this point.

If tag is None, returns True if any tag is toggled on at this point.

Note that if this function returns True, it means that iter is at the beginning of the tagged range, and that the character at iter is inside the tagged range. In other words, unlike ends_tag, if this function returns True, has_tag will also return True for the same parameters.

Parameters:

tag – a GtkTextTag

starts_word() → bool

Determines whether iter begins a natural-language word.

Word breaks are determined by Pango and should be correct for nearly any language.

toggles_tag(tag: TextTag | None = None) → bool

Gets whether a range with tag applied to it begins or ends at iter.

This is equivalent to (starts_tag() || ends_tag())

Parameters:

tag – a GtkTextTag

Fields

class TextIter
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