Undo/Redo

A custom GtkSourceUndoManager can be implemented and set with gtk_source_buffer_set_undo_manager(). However the default implementation should be suitable for most uses, so you can use the API provided by GtkSourceBuffer instead of using GtkSourceUndoManager. By default, actions that can be undone or redone are defined as groups of operations between a call to gtk_text_buffer_begin_user_action() and gtk_text_buffer_end_user_action(). In general, this happens whenever the user presses any key which modifies the buffer. But the default undo manager will try to merge similar consecutive actions into one undo/redo level. The merging is done word by word, so after writing a new sentence (character by character), each undo will remove the previous word.

The default undo manager remembers the "modified" state of the buffer, and restores it when an action is undone or redone. It can be useful in a text editor to know whether the file is saved. See gtk_text_buffer_get_modified() and gtk_text_buffer_set_modified().

The default undo manager also restores the selected text (or cursor position), if the selection was related to the action. For example if the user selects some text and deletes it, an undo will restore the selection. On the other hand, if some text is selected but a deletion occurs elsewhere (the deletion was done programmatically), an undo will not restore the selection, it will only moves the cursor (the cursor is moved so that the user sees the undo's effect). Warning: the selection restoring behavior might change in the future.

Context Classes

It is possible to retrieve some information from the syntax highlighting engine. There are currently three default context classes that are applied to regions of a GtkSourceBuffer:

Custom language definition files can create their own context classes, since the functions like gtk_source_buffer_iter_has_context_class() take a string parameter as the context class.

gtk_source_buffer_new ()

GtkSourceBuffer *
gtk_source_buffer_new (GtkTextTagTable *table);

Creates a new source buffer.

gtk_source_buffer_new_with_language ()

GtkSourceBuffer *
gtk_source_buffer_new_with_language (GtkSourceLanguage *language);

Creates a new source buffer using the highlighting patterns in language . This is equivalent to creating a new source buffer with a new tag table and then calling gtk_source_buffer_set_language().

gtk_source_buffer_set_highlight_syntax ()

void
gtk_source_buffer_set_highlight_syntax
                               (GtkSourceBuffer *buffer,
                                gboolean highlight);

Controls whether syntax is highlighted in the buffer. If highlight is TRUE, the text will be highlighted according to the syntax patterns specified in the language set with gtk_source_buffer_set_language(). If highlight is FALSE, syntax highlighting is disabled and all the GtkTextTag objects that have been added by the syntax highlighting engine are removed from the buffer.

gtk_source_buffer_get_highlight_syntax ()

gboolean
gtk_source_buffer_get_highlight_syntax
                               (GtkSourceBuffer *buffer);

Determines whether syntax highlighting is activated in the source buffer.

gtk_source_buffer_set_language ()

void
gtk_source_buffer_set_language (GtkSourceBuffer *buffer,
                                GtkSourceLanguage *language);

Associate a GtkSourceLanguage with the buffer. If language is not-NULL and syntax highlighting is enabled (see gtk_source_buffer_set_highlight_syntax()), the syntax patterns defined in language will be used to highlight the text contained in the buffer. If language is NULL, the text contained in the buffer is not highlighted.

The buffer holds a reference to language .

gtk_source_buffer_get_language ()

GtkSourceLanguage *
gtk_source_buffer_get_language (GtkSourceBuffer *buffer);

Returns the GtkSourceLanguage associated with the buffer, see gtk_source_buffer_set_language(). The returned object should not be unreferenced by the user.

gtk_source_buffer_set_highlight_matching_brackets ()

void
gtk_source_buffer_set_highlight_matching_brackets
                               (GtkSourceBuffer *buffer,
                                gboolean highlight);

Controls the bracket match highlighting function in the buffer. If activated, when you position your cursor over a bracket character (a parenthesis, a square bracket, etc.) the matching opening or closing bracket character will be highlighted.

gtk_source_buffer_get_highlight_matching_brackets ()

gboolean
gtk_source_buffer_get_highlight_matching_brackets
                               (GtkSourceBuffer *buffer);

Determines whether bracket match highlighting is activated for the source buffer.

gtk_source_buffer_set_style_scheme ()

void
gtk_source_buffer_set_style_scheme (GtkSourceBuffer *buffer,
                                    GtkSourceStyleScheme *scheme);

Sets style scheme used by the buffer. If scheme is NULL no style scheme is used.

gtk_source_buffer_get_style_scheme ()

GtkSourceStyleScheme *
gtk_source_buffer_get_style_scheme (GtkSourceBuffer *buffer);

Returns the GtkSourceStyleScheme associated with the buffer, see gtk_source_buffer_set_style_scheme(). The returned object should not be unreferenced by the user.

gtk_source_buffer_ensure_highlight ()

void
gtk_source_buffer_ensure_highlight (GtkSourceBuffer *buffer,
                                    const GtkTextIter *start,
                                    const GtkTextIter *end);

Forces buffer to analyze and highlight the given area synchronously.

gtk_source_buffer_undo ()

void
gtk_source_buffer_undo (GtkSourceBuffer *buffer);

Undoes the last user action which modified the buffer. Use gtk_source_buffer_can_undo() to check whether a call to this function will have any effect.

This function emits the “undo” signal.

gtk_source_buffer_redo ()

void
gtk_source_buffer_redo (GtkSourceBuffer *buffer);

Redoes the last undo operation. Use gtk_source_buffer_can_redo() to check whether a call to this function will have any effect.

This function emits the “redo” signal.

gtk_source_buffer_can_undo ()

gboolean
gtk_source_buffer_can_undo (GtkSourceBuffer *buffer);

Determines whether a source buffer can undo the last action.

gtk_source_buffer_can_redo ()

gboolean
gtk_source_buffer_can_redo (GtkSourceBuffer *buffer);

Determines whether a source buffer can redo the last action (i.e. if the last operation was an undo).

gtk_source_buffer_begin_not_undoable_action ()

void
gtk_source_buffer_begin_not_undoable_action
                               (GtkSourceBuffer *buffer);

Marks the beginning of a not undoable action on the buffer, disabling the undo manager. Typically you would call this function before initially setting the contents of the buffer (e.g. when loading a file in a text editor).

You may nest gtk_source_buffer_begin_not_undoable_action() / gtk_source_buffer_end_not_undoable_action() blocks.

gtk_source_buffer_end_not_undoable_action ()

void
gtk_source_buffer_end_not_undoable_action
                               (GtkSourceBuffer *buffer);

Marks the end of a not undoable action on the buffer. When the last not undoable block is closed through the call to this function, the list of undo actions is cleared and the undo manager is re-enabled.

gtk_source_buffer_get_max_undo_levels ()

gint
gtk_source_buffer_get_max_undo_levels (GtkSourceBuffer *buffer);

Determines the number of undo levels the buffer will track for buffer edits.

gtk_source_buffer_set_max_undo_levels ()

void
gtk_source_buffer_set_max_undo_levels (GtkSourceBuffer *buffer,
                                       gint max_undo_levels);

Sets the number of undo levels for user actions the buffer will track. If the number of user actions exceeds the limit set by this function, older actions will be discarded.

If max_undo_levels is -1, no limit is set.

gtk_source_buffer_get_undo_manager ()

GtkSourceUndoManager *
gtk_source_buffer_get_undo_manager (GtkSourceBuffer *buffer);

Returns the GtkSourceUndoManager associated with the buffer, see gtk_source_buffer_set_undo_manager(). The returned object should not be unreferenced by the user.

gtk_source_buffer_set_undo_manager ()

void
gtk_source_buffer_set_undo_manager (GtkSourceBuffer *buffer,
                                    GtkSourceUndoManager *manager);

Set the buffer undo manager. If manager is NULL the default undo manager will be set.

gtk_source_buffer_iter_has_context_class ()

gboolean
gtk_source_buffer_iter_has_context_class
                               (GtkSourceBuffer *buffer,
                                const GtkTextIter *iter,
                                const gchar *context_class);

Check if the class context_class is set on iter .

See the GtkSourceBuffer description for the list of default context classes.

Since 2.10

gtk_source_buffer_get_context_classes_at_iter ()

gchar **
gtk_source_buffer_get_context_classes_at_iter
                               (GtkSourceBuffer *buffer,
                                const GtkTextIter *iter);

Get all defined context classes at iter .

See the GtkSourceBuffer description for the list of default context classes.

Since 2.10

gtk_source_buffer_iter_forward_to_context_class_toggle ()

gboolean
gtk_source_buffer_iter_forward_to_context_class_toggle
                               (GtkSourceBuffer *buffer,
                                GtkTextIter *iter,
                                const gchar *context_class);

Moves forward to the next toggle (on or off) of the context class. If no matching context class 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.

See the GtkSourceBuffer description for the list of default context classes.

Since 2.10

gtk_source_buffer_iter_backward_to_context_class_toggle ()

gboolean
gtk_source_buffer_iter_backward_to_context_class_toggle
                               (GtkSourceBuffer *buffer,
                                GtkTextIter *iter,
                                const gchar *context_class);

Moves backward to the next toggle (on or off) of the context class. If no matching context class 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.

See the GtkSourceBuffer description for the list of default context classes.

Since 2.10

gtk_source_buffer_create_source_mark ()

GtkSourceMark *
gtk_source_buffer_create_source_mark (GtkSourceBuffer *buffer,
                                      const gchar *name,
                                      const gchar *category,
                                      const GtkTextIter *where);

Creates a source mark in the buffer of category category . A source mark is a GtkTextMark but organised into categories. Depending on the category a pixbuf can be specified that will be displayed along the line of the mark.

Like a GtkTextMark, a GtkSourceMark can be anonymous if the passed name is NULL. Also, the buffer owns the marks so you shouldn't unreference it.

Marks always have left gravity and are moved to the beginning of the line when the user deletes the line they were in.

Typical uses for a source mark are bookmarks, breakpoints, current executing instruction indication in a source file, etc..

Since 2.2

gtk_source_buffer_forward_iter_to_source_mark ()

gboolean
gtk_source_buffer_forward_iter_to_source_mark
                               (GtkSourceBuffer *buffer,
                                GtkTextIter *iter,
                                const gchar *category);

Moves iter to the position of the next GtkSourceMark of the given category . Returns TRUE if iter was moved. If category is NULL, the next source mark can be of any category.

Since 2.2

gtk_source_buffer_backward_iter_to_source_mark ()

gboolean
gtk_source_buffer_backward_iter_to_source_mark
                               (GtkSourceBuffer *buffer,
                                GtkTextIter *iter,
                                const gchar *category);

Moves iter to the position of the previous GtkSourceMark of the given category. Returns TRUE if iter was moved. If category is NULL, the previous source mark can be of any category.

Since 2.2

gtk_source_buffer_get_source_marks_at_line ()

GSList *
gtk_source_buffer_get_source_marks_at_line
                               (GtkSourceBuffer *buffer,
                                gint line,
                                const gchar *category);

Returns the list of marks of the given category at line . If category is NULL, all marks at line are returned.

Since 2.2

gtk_source_buffer_get_source_marks_at_iter ()

GSList *
gtk_source_buffer_get_source_marks_at_iter
                               (GtkSourceBuffer *buffer,
                                GtkTextIter *iter,
                                const gchar *category);

Returns the list of marks of the given category at iter . If category is NULL it returns all marks at iter .

Since 2.2

gtk_source_buffer_remove_source_marks ()

void
gtk_source_buffer_remove_source_marks (GtkSourceBuffer *buffer,
                                       const GtkTextIter *start,
                                       const GtkTextIter *end,
                                       const gchar *category);

Remove all marks of category between start and end from the buffer. If category is NULL, all marks in the range will be removed.

Since 2.2

gtk_source_buffer_change_case ()

void
gtk_source_buffer_change_case (GtkSourceBuffer *buffer,
                               GtkSourceChangeCaseType case_type,
                               GtkTextIter *start,
                               GtkTextIter *end);

Changes the case of the text between the specified iterators.

Since 3.12

gtk_source_buffer_join_lines ()

void
gtk_source_buffer_join_lines (GtkSourceBuffer *buffer,
                              GtkTextIter *start,
                              GtkTextIter *end);

Joins the lines of text between the specified iterators.

Since 3.16

gtk_source_buffer_set_implicit_trailing_newline ()

void
gtk_source_buffer_set_implicit_trailing_newline
                               (GtkSourceBuffer *buffer,
                                gboolean implicit_trailing_newline);

Sets whether the buffer has an implicit trailing newline.

If an explicit trailing newline is present in a GtkTextBuffer, GtkTextView shows it as an empty line. This is generally not what the user expects.

If implicit_trailing_newline is TRUE (the default value):

On the other hand, if implicit_trailing_newline is FALSE, the file's content is not modified when loaded into the buffer , and the buffer 's content is not modified when saved into a file.

Since 3.14

gtk_source_buffer_get_implicit_trailing_newline ()

gboolean
gtk_source_buffer_get_implicit_trailing_newline
                               (GtkSourceBuffer *buffer);

Since 3.14

GtkSourceBuffer

typedef struct _GtkSourceBuffer GtkSourceBuffer;

enum GtkSourceBracketMatchType

enum GtkSourceChangeCaseType

Since 3.12

The “can-redo” property

  “can-redo”                 gboolean

Whether Redo operation is possible.

Flags: Read

Default value: FALSE

The “can-undo” property

  “can-undo”                 gboolean

Whether Undo operation is possible.

Flags: Read

Default value: FALSE

The “highlight-matching-brackets” property

  “highlight-matching-brackets” gboolean

Whether to highlight matching brackets in the buffer.

Flags: Read / Write

Default value: TRUE

The “highlight-syntax” property

  “highlight-syntax”         gboolean

Whether to highlight syntax in the buffer.

Flags: Read / Write

Default value: TRUE

The “implicit-trailing-newline” property

  “implicit-trailing-newline” gboolean

Whether the buffer has an implicit trailing newline. See gtk_source_buffer_set_implicit_trailing_newline().

Flags: Read / Write / Construct

Default value: TRUE

Since 3.14

The “language” property

  “language”                 GtkSourceLanguage *

Language object to get highlighting patterns from.

Flags: Read / Write

The “max-undo-levels” property

  “max-undo-levels”          gint

Number of undo levels for the buffer. -1 means no limit. This property will only affect the default undo manager.

Flags: Read / Write

Allowed values: >= -1

Default value: -1

The “style-scheme” property

  “style-scheme”             GtkSourceStyleScheme *

Style scheme. It contains styles for syntax highlighting, optionally foreground, background, cursor color, current line color, and matching brackets style.

Flags: Read / Write

The “undo-manager” property

  “undo-manager”             GtkSourceUndoManager *

The buffer undo manager.

Flags: Read / Write / Construct

The “bracket-matched” signal

void
user_function (GtkSourceBuffer          *buffer,
               GtkTextIter              *iter,
               GtkSourceBracketMatchType state,
               gpointer                  user_data)

Sets iter to a valid iterator pointing to the matching bracket if state is GTK_SOURCE_BRACKET_MATCH_FOUND. Otherwise iter is meaningless.

Flags: Run Last

Since 2.12

The “highlight-updated” signal

void
user_function (GtkSourceBuffer *buffer,
               GtkTextIter     *start,
               GtkTextIter     *end,
               gpointer         user_data)

The ::highlight-updated signal is emitted when the syntax highlighting is updated in a certain region of the buffer . This signal is useful to be notified when a context class region is updated (e.g. the no-spell-check context class).

Flags: Run Last

The “redo” signal

void
user_function (GtkSourceBuffer *buffer,
               gpointer         user_data)

The ::redo signal is emitted to redo the last undo operation.

Flags: Run Last

The “source-mark-updated” signal

void
user_function (GtkSourceBuffer *buffer,
               GtkTextMark     *mark,
               gpointer         user_data)

The ::source_mark_updated signal is emitted each time a mark is added to, moved or removed from the buffer .

Flags: Run Last

The “undo” signal

void
user_function (GtkSourceBuffer *buffer,
               gpointer         user_data)

The ::undo signal is emitted to undo the last user action which modified the buffer.

Flags: Run Last