Creates a new text buffer.
a tag table, or %NULL to create a new one
The list of targets this buffer supports for clipboard copying and as DND source.
The position of the insert mark (as offset from the beginning of the buffer). It is useful for getting notified when the cursor moves.
Whether the buffer has some text currently selected.
The list of targets this buffer supports for clipboard pasting and as DND destination.
The text content of the buffer. Without child widgets and images, see gtk_text_buffer_get_text() for more information.
Adds the mark at position where. The mark must not be added to
another buffer, and if its name is not %NULL then there must not
be another mark in the buffer with the same name.
Emits the #GtkTextBuffer::mark-set signal as notification of the mark's initial placement.
Emits the “apply-tag” signal on buffer. The default
handler for the signal applies tag to the given range.
start and end do not have to be in order.
a #GtkTextTag
one bound of range to be tagged
other bound of range to be tagged
Performs the appropriate action as if the user hit the delete
key with the cursor at the position specified by iter. In the
normal case a single character will be deleted, but when
combining accents are involved, more than one character can
be deleted, and when precomposed character and accent combinations
are involved, less than one character will be deleted.
Because the buffer is modified, all outstanding iterators become
invalid after calling this function; however, the iter will be
re-initialized to point to the location where text was deleted.
a position in buffer
whether the deletion is caused by user interaction
whether the buffer is editable by default
Called to indicate that the buffer operations between here and a call to gtk_text_buffer_end_user_action() are part of a single user-visible operation. The operations between gtk_text_buffer_begin_user_action() and gtk_text_buffer_end_user_action() can then be grouped when creating an undo stack. #GtkTextBuffer maintains a count of calls to gtk_text_buffer_begin_user_action() that have not been closed with a call to gtk_text_buffer_end_user_action(), and emits the “begin-user-action” and “end-user-action” signals only for the outermost pair of calls. This allows you to build user actions from other user actions.
The “interactive” buffer mutation functions, such as gtk_text_buffer_insert_interactive(), automatically call begin/end user action around the buffer operations they perform, so there's no need to add extra calls if you user action consists solely of a single call to one of those functions.
Creates a binding between source_property on source and target_property
on target.
Whenever the source_property is changed the target_property is
updated using the same value. For instance:
g_object_bind_property (action, "active", widget, "sensitive", 0);
Will result in the "sensitive" property of the widget #GObject instance to be updated with the same value of the "active" property of the action #GObject instance.
If flags contains %G_BINDING_BIDIRECTIONAL then the binding will be mutual:
if target_property on target changes then the source_property on source
will be updated as well.
The binding will automatically be removed when either the source or the
target instances are finalized. To remove the binding without affecting the
source and the target you can just call g_object_unref() on the returned
#GBinding instance.
Removing the binding by calling g_object_unref() on it must only be done if
the binding, source and target are only used from a single thread and it
is clear that both source and target outlive the binding. Especially it
is not safe to rely on this if the binding, source or target can be
finalized from different threads. Keep another reference to the binding and
use g_binding_unbind() instead to be on the safe side.
A #GObject can have multiple bindings.
the property on source to bind
the target #GObject
the property on target to bind
flags to pass to #GBinding
Creates a binding between source_property on source and target_property
on target, allowing you to set the transformation functions to be used by
the binding.
This function is the language bindings friendly version of g_object_bind_property_full(), using #GClosures instead of function pointers.
the property on source to bind
the target #GObject
the property on target to bind
flags to pass to #GBinding
a #GClosure wrapping the transformation function from the source to the target, or %NULL to use the default
a #GClosure wrapping the transformation function from the target to the source, or %NULL to use the default
This is a convenience function which simply creates a child anchor with gtk_text_child_anchor_new() and inserts it into the buffer with gtk_text_buffer_insert_child_anchor(). The new anchor is owned by the buffer; no reference count is returned to the caller of gtk_text_buffer_create_child_anchor().
Creates a mark at position where. If mark_name is %NULL, the mark
is anonymous; otherwise, the mark can be retrieved by name using
gtk_text_buffer_get_mark(). If a mark has left gravity, and text is
inserted at the mark’s current location, the mark will be moved to
the left of the newly-inserted text. If the mark has right gravity
(left_gravity = %FALSE), the mark will end up on the right of
newly-inserted text. The standard left-to-right cursor is a mark
with right gravity (when you type, the cursor stays on the right
side of the text you’re typing).
The caller of this function does not own a reference to the returned #GtkTextMark, so you can ignore the return value if you like. Marks are owned by the buffer and go away when the buffer does.
Emits the #GtkTextBuffer::mark-set signal as notification of the mark's initial placement.
name for mark, or %NULL
location to place mark
whether the mark has left gravity
Deletes text between start and end. The order of start and end
is not actually relevant; gtk_text_buffer_delete() will reorder
them. This function actually emits the “delete-range” signal, and
the default handler of that signal deletes the text. Because the
buffer is modified, all outstanding iterators become invalid after
calling this function; however, the start and end will be
re-initialized to point to the location where text was deleted.
Deletes all editable text in the given range.
Calls gtk_text_buffer_delete() for each editable sub-range of
[start,``end). start and end are revalidated to point to
the location of the last deleted range, or left untouched if
no text was deleted.
start of range to delete
end of range
whether the buffer is editable by default
Deletes mark, so that it’s no longer located anywhere in the
buffer. Removes the reference the buffer holds to the mark, so if
you haven’t called g_object_ref() on the mark, it will be freed. Even
if the mark isn’t freed, most operations on mark become
invalid, until it gets added to a buffer again with
gtk_text_buffer_add_mark(). Use gtk_text_mark_get_deleted() to
find out if a mark has been removed from its buffer.
The #GtkTextBuffer::mark-deleted signal will be emitted as notification after
the mark is deleted.
Deletes the mark named name; the mark must exist. See
gtk_text_buffer_delete_mark() for details.
name of a mark in buffer
Deletes the range between the “insert” and “selection_bound” marks,
that is, the currently-selected text. If interactive is %TRUE,
the editability of the selection will be considered (users can’t delete
uneditable text).
whether the deletion is caused by user interaction
whether the buffer is editable by default
This function deserializes rich text in format format and inserts
it at iter.
formats to be used must be registered using
gtk_text_buffer_register_deserialize_format() or
gtk_text_buffer_register_deserialize_tagset() beforehand.
the #GtkTextBuffer to deserialize into
the rich text format to use for deserializing
insertion point for the deserialized text
data to deserialize
Use this function to allow a rich text deserialization function to create new tags in the receiving buffer. Note that using this function is almost always a bad idea, because the rich text functions you register should know how to map the rich text format they handler to your text buffers set of tags.
The ability of creating new (arbitrary!) tags in the receiving buffer is meant for special rich text formats like the internal one that is registered using gtk_text_buffer_register_deserialize_tagset(), because that format is essentially a dump of the internal structure of the source buffer, including its tag names.
You should allow creation of tags only if you know what you are doing, e.g. if you defined a tagset name for your application suite’s text buffers and you know that it’s fine to receive new tags from these buffers, because you know that your application can handle the newly created tags.
a #GdkAtom representing a registered rich text format
whether deserializing this format may create tags
Should be paired with a call to gtk_text_buffer_begin_user_action(). See that function for a full explanation.
This function is intended for #GObject implementations to re-enforce a [floating][floating-ref] object reference. Doing this is seldom required: all #GInitiallyUnowneds are created with a floating reference which usually just needs to be sunken by calling g_object_ref_sink().
Increases the freeze count on object. If the freeze count is
non-zero, the emission of "notify" signals on object is
stopped. The signals are queued until the freeze count is decreased
to zero. Duplicate notifications are squashed so that at most one
#GObject::notify signal is emitted for each property modified while the
object is frozen.
This is necessary for accessors that modify multiple properties to prevent premature notification while the object is still being modified.
Gets the number of characters in the buffer; note that characters and bytes are not the same, you can’t e.g. expect the contents of the buffer in string form to be this many bytes long. The character count is cached, so this function is very fast.
This function returns the list of targets this text buffer can
provide for copying and as DND source. The targets in the list are
added with info values from the #GtkTextBufferTargetInfo enum,
using gtk_target_list_add_rich_text_targets() and
gtk_target_list_add_text_targets().
Gets a named field from the objects table of associations (see g_object_set_data()).
name of the key for that association
Initializes iter with the “end iterator,” one past the last valid
character in the text buffer. If dereferenced with
gtk_text_iter_get_char(), the end iterator has a character value of 0.
The entire buffer lies in the range from the first position in
the buffer (call gtk_text_buffer_get_start_iter() to get
character position 0) to the end iterator.
Indicates whether the buffer has some text currently selected.
Obtains the location of anchor within buffer.
a child anchor that appears in buffer
Obtains an iterator pointing to byte_index within the given line.
byte_index must be the start of a UTF-8 character. Note bytes, not
characters; UTF-8 may encode one character as multiple bytes.
Before the 3.20 version, it was not allowed to pass an invalid location.
Since the 3.20 version, if line_number is greater than the number of lines
in the buffer, the end iterator is returned. And if byte_index is off the
end of the line, the iterator at the end of the line is returned.
line number counting from 0
byte index from start of line
Obtains an iterator pointing to char_offset within the given line. Note
characters, not bytes; UTF-8 may encode one character as multiple bytes.
Before the 3.20 version, it was not allowed to pass an invalid location.
Since the 3.20 version, if line_number is greater than the number of lines
in the buffer, the end iterator is returned. And if char_offset is off the
end of the line, the iterator at the end of the line is returned.
line number counting from 0
char offset from start of line
Initializes iter to a position char_offset chars from the start
of the entire buffer. If char_offset is -1 or greater than the number
of characters in the buffer, iter is initialized to the end iterator,
the iterator one past the last valid character in the buffer.
char offset from start of buffer, counting from 0, or -1
Obtains the number of lines in the buffer. This value is cached, so the function is very fast.
Indicates whether the buffer has been modified since the last call to gtk_text_buffer_set_modified() set the modification flag to %FALSE. Used for example to enable a “save” function in a text editor.
This function returns the list of targets this text buffer supports
for pasting and as DND destination. The targets in the list are
added with info values from the #GtkTextBufferTargetInfo enum,
using gtk_target_list_add_rich_text_targets() and
gtk_target_list_add_text_targets().
Gets a property of an object.
The value can be:
In general, a copy is made of the property contents and the caller is responsible for freeing the memory by calling g_value_unset().
Note that g_object_get_property() is really intended for language bindings, g_object_get() is much more convenient for C programming.
the name of the property to get
return location for the property value
This function gets back user data pointers stored via g_object_set_qdata().
A #GQuark, naming the user data pointer
Returns the mark that represents the selection bound. Equivalent to calling gtk_text_buffer_get_mark() to get the mark named “selection_bound”, but very slightly more efficient, and involves less typing.
The currently-selected text in buffer is the region between the
“selection_bound” and “insert” marks. If “selection_bound” and
“insert” are in the same place, then there is no current selection.
gtk_text_buffer_get_selection_bounds() is another convenient function
for handling the selection, if you just want to know whether there’s a
selection and what its bounds are.
Returns %TRUE if some text is selected; places the bounds
of the selection in start and end (if the selection has length 0,
then start and end are filled in with the same value).
start and end will be in ascending order. If start and end are
NULL, then they are not filled in, but the return value still indicates
whether text is selected.
Returns the text in the range [start,``end). Excludes undisplayed
text (text marked with tags that set the invisibility attribute) if
include_hidden_chars is %FALSE. The returned string includes a
0xFFFC character whenever the buffer contains
embedded images, so byte and character indexes into
the returned string do correspond to byte
and character indexes into the buffer. Contrast with
gtk_text_buffer_get_text(). Note that 0xFFFC can occur in normal
text as well, so it is not a reliable indicator that a pixbuf or
widget is in the buffer.
start of a range
end of a range
whether to include invisible text
Get the #GtkTextTagTable associated with this buffer.
Returns the text in the range [start,``end). Excludes undisplayed
text (text marked with tags that set the invisibility attribute) if
include_hidden_chars is %FALSE. Does not include characters
representing embedded images, so byte and character indexes into
the returned string do not correspond to byte
and character indexes into the buffer. Contrast with
gtk_text_buffer_get_slice().
start of a range
end of a range
whether to include invisible text
Gets n_properties properties for an object.
Obtained properties will be set to values. All properties must be valid.
Warnings will be emitted and undefined behaviour may result if invalid
properties are passed in.
the names of each property to get
the values of each property to get
Inserts len bytes of text at position iter. If len is -1,
text must be nul-terminated and will be inserted in its
entirety. Emits the “insert-text” signal; insertion actually occurs
in the default handler for the signal. iter is invalidated when
insertion occurs (because the buffer contents change), but the
default signal handler revalidates it to point to the end of the
inserted text.
a position in the buffer
text in UTF-8 format
length of text in bytes, or -1
Simply calls gtk_text_buffer_insert(), using the current cursor position as the insertion point.
text in UTF-8 format
length of text, in bytes
Inserts a child widget anchor into the text buffer at iter. The
anchor will be counted as one character in character counts, and
when obtaining the buffer contents as a string, will be represented
by the Unicode “object replacement character” 0xFFFC. Note that the
“slice” variants for obtaining portions of the buffer as a string
include this character for child anchors, but the “text” variants do
not. E.g. see gtk_text_buffer_get_slice() and
gtk_text_buffer_get_text(). Consider
gtk_text_buffer_create_child_anchor() as a more convenient
alternative to this function. The buffer will add a reference to
the anchor, so you can unref it after insertion.
location to insert the anchor
a #GtkTextChildAnchor
Like gtk_text_buffer_insert(), but the insertion will not occur if
iter is at a non-editable location in the buffer. Usually you
want to prevent insertions at ineditable locations if the insertion
results from a user action (is interactive).
default_editable indicates the editability of text that doesn't
have a tag affecting editability applied to it. Typically the
result of gtk_text_view_get_editable() is appropriate here.
a position in buffer
some UTF-8 text
length of text in bytes, or -1
default editability of buffer
Calls gtk_text_buffer_insert_interactive() at the cursor position.
default_editable indicates the editability of text that doesn't
have a tag affecting editability applied to it. Typically the
result of gtk_text_view_get_editable() is appropriate here.
text in UTF-8 format
length of text in bytes, or -1
default editability of buffer
Inserts the text in markup at position iter. markup will be inserted
in its entirety and must be nul-terminated and valid UTF-8. Emits the
#GtkTextBuffer::insert-text signal, possibly multiple times; insertion
actually occurs in the default handler for the signal. iter will point
to the end of the inserted text on return.
location to insert the markup
a nul-terminated UTF-8 string containing [Pango markup][PangoMarkupFormat]
length of markup in bytes, or -1
Inserts an image into the text buffer at iter. The image will be
counted as one character in character counts, and when obtaining
the buffer contents as a string, will be represented by the Unicode
“object replacement character” 0xFFFC. Note that the “slice”
variants for obtaining portions of the buffer as a string include
this character for pixbufs, but the “text” variants do
not. e.g. see gtk_text_buffer_get_slice() and
gtk_text_buffer_get_text().
Copies text, tags, and pixbufs between start and end (the order
of start and end doesn’t matter) and inserts the copy at iter.
Used instead of simply getting/inserting text because it preserves
images and tags. If start and end are in a different buffer from
buffer, the two buffers must share the same tag table.
Implemented via emissions of the insert_text and apply_tag signals, so expect those.
a position in buffer
a position in a #GtkTextBuffer
another position in the same buffer as start
Same as gtk_text_buffer_insert_range(), but does nothing if the
insertion point isn’t editable. The default_editable parameter
indicates whether the text is editable at iter if no tags
enclosing iter affect editability. Typically the result of
gtk_text_view_get_editable() is appropriate here.
a position in buffer
a position in a #GtkTextBuffer
another position in the same buffer as start
default editability of the buffer
Checks whether object has a [floating][floating-ref] reference.
Emits a "notify" signal for the property property_name on object.
When possible, eg. when signaling a property change from within the class that registered the property, you should use g_object_notify_by_pspec() instead.
Note that emission of the notify signal may be blocked with g_object_freeze_notify(). In this case, the signal emissions are queued and will be emitted (in reverse order) when g_object_thaw_notify() is called.
the name of a property installed on the class of object.
Emits a "notify" signal for the property specified by pspec on object.
This function omits the property name lookup, hence it is faster than g_object_notify().
One way to avoid using g_object_notify() from within the class that registered the properties, and using g_object_notify_by_pspec() instead, is to store the GParamSpec used with g_object_class_install_property() inside a static array, e.g.:
enum
{
PROP_0,
PROP_FOO,
PROP_LAST
};
static GParamSpec *properties[PROP_LAST];
static void
my_object_class_init (MyObjectClass *klass)
{
properties[PROP_FOO] = g_param_spec_int ("foo", "Foo", "The foo",
0, 100,
50,
G_PARAM_READWRITE);
g_object_class_install_property (gobject_class,
PROP_FOO,
properties[PROP_FOO]);
}
and then notify a change on the "foo" property with:
g_object_notify_by_pspec (self, properties[PROP_FOO]);
the #GParamSpec of a property installed on the class of object.
Pastes the contents of a clipboard. If override_location is %NULL, the
pasted text will be inserted at the cursor position, or the buffer selection
will be replaced if the selection is non-empty.
Note: pasting is asynchronous, that is, we’ll ask for the paste data and return, and at some point later after the main loop runs, the paste data will be inserted.
the #GtkClipboard to paste from
location to insert pasted text, or %NULL
whether the buffer is editable by default
This function moves the “insert” and “selection_bound” marks simultaneously. If you move them to the same place in two steps with gtk_text_buffer_move_mark(), you will temporarily select a region in between their old and new locations, which can be pretty inefficient since the temporarily-selected region will force stuff to be recalculated. This function moves them as a unit, which can be optimized.
Increase the reference count of object, and possibly remove the
[floating][floating-ref] reference, if object has a floating reference.
In other words, if the object is floating, then this call "assumes ownership" of the floating reference, converting it to a normal reference by clearing the floating flag while leaving the reference count unchanged. If the object is not floating, then this call adds a new normal reference increasing the reference count by one.
Since GLib 2.56, the type of object will be propagated to the return type
under the same conditions as for g_object_ref().
This function registers a rich text deserialization function along with
its mime_type with the passed buffer.
the format’s mime-type
the deserialize function to register
This function registers a rich text serialization function along with
its mime_type with the passed buffer.
the format’s mime-type
the serialize function to register
This function registers GTK+’s internal rich text serialization
format with the passed buffer. The internal format does not comply
to any standard rich text format and only works between #GtkTextBuffer
instances. It is capable of serializing all of a text buffer’s tags
and embedded pixbufs.
This function is just a wrapper around
gtk_text_buffer_register_serialize_format(). The mime type used
for registering is “application/x-gtk-text-buffer-rich-text”, or
“application/x-gtk-text-buffer-rich-text;format=tagset_name” if a
tagset_name was passed.
The tagset_name can be used to restrict the transfer of rich text
to buffers with compatible sets of tags, in order to avoid unknown
tags from being pasted. It is probably the common case to pass an
identifier != %NULL here, since the %NULL tagset requires the
receiving buffer to deal with with pasting of arbitrary tags.
an optional tagset name, on %NULL
Removes all tags in the range between start and end. Be careful
with this function; it could remove tags added in code unrelated to
the code you’re currently writing. That is, using this function is
probably a bad idea if you have two or more unrelated code sections
that add tags.
one bound of range to be untagged
other bound of range to be untagged
Emits the “remove-tag” signal. The default handler for the signal
removes all occurrences of tag from the given range. start and
end don’t have to be in order.
a #GtkTextTag
one bound of range to be untagged
other bound of range to be untagged
Releases all references to other objects. This can be used to break reference cycles.
This function should only be called from object system implementations.
This function moves the “insert” and “selection_bound” marks simultaneously. If you move them in two steps with gtk_text_buffer_move_mark(), you will temporarily select a region in between their old and new locations, which can be pretty inefficient since the temporarily-selected region will force stuff to be recalculated. This function moves them as a unit, which can be optimized.
where to put the “insert” mark
where to put the “selection_bound” mark
This function serializes the portion of text between start
and end in the rich text format represented by format.
formats to be used must be registered using
gtk_text_buffer_register_serialize_format() or
gtk_text_buffer_register_serialize_tagset() beforehand.
the #GtkTextBuffer to serialize
the rich text format to use for serializing
start of block of text to serialize
end of block of test to serialize
Each object carries around a table of associations from strings to pointers. This function lets you set an association.
If the object already had an association with that name, the old association will be destroyed.
Internally, the key is converted to a #GQuark using g_quark_from_string().
This means a copy of key is kept permanently (even after object has been
finalized) — so it is recommended to only use a small, bounded set of values
for key in your program, to avoid the #GQuark storage growing unbounded.
name of the key
data to associate with that key
Used to keep track of whether the buffer has been modified since the
last time it was saved. Whenever the buffer is saved to disk, call
gtk_text_buffer_set_modified (buffer, FALSE). When the buffer is modified,
it will automatically toggled on the modified bit again. When the modified
bit flips, the buffer emits the #GtkTextBuffer::modified-changed signal.
modification flag setting
Sets a property on an object.
the name of the property to set
the value
Deletes current contents of buffer, and inserts text instead. If
len is -1, text must be nul-terminated. text must be valid UTF-8.
UTF-8 text to insert
length of text in bytes
Remove a specified datum from the object's data associations, without invoking the association's destroy handler.
name of the key
This function gets back user data pointers stored via
g_object_set_qdata() and removes the data from object
without invoking its destroy() function (if any was
set).
Usually, calling this function is only required to update
user data pointers with a destroy notifier, for example:
void
object_add_to_user_list (GObject *object,
const gchar *new_string)
{
// the quark, naming the object data
GQuark quark_string_list = g_quark_from_static_string ("my-string-list");
// retrieve the old string list
GList *list = g_object_steal_qdata (object, quark_string_list);
// prepend new string
list = g_list_prepend (list, g_strdup (new_string));
// this changed 'list', so we need to set it again
g_object_set_qdata_full (object, quark_string_list, list, free_string_list);
}
static void
free_string_list (gpointer data)
{
GList *node, *list = data;
for (node = list; node; node = node->next)
g_free (node->data);
g_list_free (list);
}
Using g_object_get_qdata() in the above example, instead of g_object_steal_qdata() would have left the destroy function set, and thus the partial string list would have been freed upon g_object_set_qdata_full().
A #GQuark, naming the user data pointer
Reverts the effect of a previous call to
g_object_freeze_notify(). The freeze count is decreased on object
and when it reaches zero, queued "notify" signals are emitted.
Duplicate notifications for each property are squashed so that at most one #GObject::notify signal is emitted for each property, in the reverse order in which they have been queued.
It is an error to call this function when the freeze count is zero.
Decreases the reference count of object. When its reference count
drops to 0, the object is finalized (i.e. its memory is freed).
If the pointer to the #GObject may be reused in future (for example, if it is an instance variable of another object), it is recommended to clear the pointer to %NULL rather than retain a dangling pointer to a potentially invalid #GObject instance. Use g_clear_object() for this.
This function essentially limits the life time of the closure to
the life time of the object. That is, when the object is finalized,
the closure is invalidated by calling g_closure_invalidate() on
it, in order to prevent invocations of the closure with a finalized
(nonexisting) object. Also, g_object_ref() and g_object_unref() are
added as marshal guards to the closure, to ensure that an extra
reference count is held on object during invocation of the
closure. Usually, this function will be called on closures that
use this object as closure data.
#GClosure to watch
Find the #GParamSpec with the given name for an
interface. Generally, the interface vtable passed in as g_iface
will be the default vtable from g_type_default_interface_ref(), or,
if you know the interface has already been loaded,
g_type_default_interface_peek().
any interface vtable for the interface, or the default vtable for the interface
name of a property to look up.
Add a property to an interface; this is only useful for interfaces that are added to GObject-derived types. Adding a property to an interface forces all objects classes with that interface to have a compatible property. The compatible property could be a newly created #GParamSpec, but normally g_object_class_override_property() will be used so that the object class only needs to provide an implementation and inherits the property description, default value, bounds, and so forth from the interface property.
This function is meant to be called from the interface's default
vtable initialization function (the class_init member of
#GTypeInfo.) It must not be called after after class_init has
been called for any object types implementing this interface.
If pspec is a floating reference, it will be consumed.
any interface vtable for the interface, or the default vtable for the interface.
the #GParamSpec for the new property
Lists the properties of an interface.Generally, the interface
vtable passed in as g_iface will be the default vtable from
g_type_default_interface_ref(), or, if you know the interface has
already been loaded, g_type_default_interface_peek().
any interface vtable for the interface, or the default vtable for the interface
Creates a new text buffer.
a tag table, or %NULL to create a new one
Creates a new instance of a #GObject subtype and sets its properties.
Construction parameters (see %G_PARAM_CONSTRUCT, %G_PARAM_CONSTRUCT_ONLY) which are not explicitly specified are set to their default values.
the type id of the #GObject subtype to instantiate
an array of #GParameter
You may wish to begin by reading the [text widget conceptual overview][TextWidget] which gives an overview of all the objects and data types related to the text widget and how they work together.