TreeModelFilterProtocol

public protocol TreeModelFilterProtocol : ObjectProtocol, TreeDragSourceProtocol, TreeModelProtocol

A GtkTreeModelFilter is a tree model which wraps another tree model, and can do the following things:

  • Filter specific rows, based on data from a “visible column”, a column storing booleans indicating whether the row should be filtered or not, or based on the return value of a “visible function”, which gets a model, iter and user_data and returns a boolean indicating whether the row should be filtered or not.

  • Modify the “appearance” of the model, using a modify function. This is extremely powerful and allows for just changing some values and also for creating a completely different model based on the given child model.

  • Set a different root node, also known as a “virtual root”. You can pass in a GtkTreePath indicating the root node for the filter at construction time.

The basic API is similar to GtkTreeModelSort. For an example on its usage, see the section on GtkTreeModelSort.

When using GtkTreeModelFilter, it is important to realize that GtkTreeModelFilter maintains an internal cache of all nodes which are visible in its clients. The cache is likely to be a subtree of the tree exposed by the child model. GtkTreeModelFilter will not cache the entire child model when unnecessary to not compromise the caching mechanism that is exposed by the reference counting scheme. If the child model implements reference counting, unnecessary signals may not be emitted because of reference counting rule 3, see the GtkTreeModel documentation. (Note that e.g. GtkTreeStore does not implement reference counting and will always emit all signals, even when the receiving node is not visible).

Because of this, limitations for possible visible functions do apply. In general, visible functions should only use data or properties from the node for which the visibility state must be determined, its siblings or its parents. Usually, having a dependency on the state of any child node is not possible, unless references are taken on these explicitly. When no such reference exists, no signals may be received for these child nodes (see reference couting rule number 3 in the GtkTreeModel section).

Determining the visibility state of a given node based on the state of its child nodes is a frequently occurring use case. Therefore, GtkTreeModelFilter explicitly supports this. For example, when a node does not have any children, you might not want the node to be visible. As soon as the first row is added to the node’s child level (or the last row removed), the node’s visibility should be updated.

This introduces a dependency from the node on its child nodes. In order to accommodate this, GtkTreeModelFilter must make sure the necessary signals are received from the child model. This is achieved by building, for all nodes which are exposed as visible nodes to GtkTreeModelFilter‘s clients, the child level (if any) and take a reference on the first node in this level. Furthermore, for every row-inserted, row-changed or row-deleted signal (also these which were not handled because the node was not cached), GtkTreeModelFilter will check if the visibility state of any parent node has changed.

Beware, however, that this explicit support is limited to these two cases. For example, if you want a node to be visible only if two nodes in a child’s child level (2 levels deeper) are visible, you are on your own. In this case, either rely on GtkTreeStore to emit all signals because it does not implement reference counting, or for models that do implement reference counting, obtain references on these child levels yourself.

The TreeModelFilterProtocol protocol exposes the methods and properties of an underlying GtkTreeModelFilter instance. The default implementation of these can be found in the protocol extension below. For a concrete class that implements these methods and properties, see TreeModelFilter. Alternatively, use TreeModelFilterRef as a lighweight, unowned reference if you already have an instance you just want to use.

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  • ptr

    Untyped pointer to the underlying GtkTreeModelFilter instance.

    Declaration

    Swift

    var ptr: UnsafeMutableRawPointer! { get }
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  • tree_model_filter_ptr Default implementation

    Typed pointer to the underlying GtkTreeModelFilter instance.

    Default Implementation

    Return the stored, untyped pointer as a typed pointer to the GtkTreeModelFilter instance.

    Declaration

    Swift

    var tree_model_filter_ptr: UnsafeMutablePointer<GtkTreeModelFilter>! { get }
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  • Required Initialiser for types conforming to TreeModelFilterProtocol

    Declaration

    Swift

    init(raw: UnsafeMutableRawPointer)
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TreeModelFilter Class

  • Bind a TreeModelFilterPropertyName source property to a given target object.

    Declaration

    Swift

    @discardableResult
@inlinable
func bind<Q, T>(property source_property: TreeModelFilterPropertyName, to target: T, _ target_property: Q, flags f: BindingFlags = .default, transformFrom transform_from: @escaping GLibObject.ValueTransformer = { $0.transform(destValue: $1) }, transformTo transform_to: @escaping GLibObject.ValueTransformer = { $0.transform(destValue: $1) }) -> BindingRef! where Q : PropertyNameProtocol, T : ObjectProtocol

    Parameters

    source_property

    the source property to bind
    target

    the target object to bind to
    target_property

    the target property to bind to
    flags

    the flags to pass to the Binding
    transform_from

    ValueTransformer to use for forward transformation
    transform_to

    ValueTransformer to use for backwards transformation

    Return Value

    binding reference or nil in case of an error

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  • get(property:) Extension method

    Get the value of a TreeModelFilter property

    Declaration

    Swift

    @inlinable
func get(property: TreeModelFilterPropertyName) -> GLibObject.Value

    Parameters

    property

    the property to get the value for

    Return Value

    the value of the named property

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  • set(property:value:) Extension method

    Set the value of a TreeModelFilter property. Note that this will only have an effect on properties that are writable and not construct-only!

    Declaration

    Swift

    @inlinable
func set(property: TreeModelFilterPropertyName, value v: GLibObject.Value)

    Parameters

    property

    the property to get the value for

    Return Value

    the value of the named property

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TreeModelFilter Class: TreeModelFilterProtocol extension (methods and fields)

  • clearCache() Extension method

    This function should almost never be called. It clears the filter of any cached iterators that haven’t been reffed with gtk_tree_model_ref_node(). This might be useful if the child model being filtered is static (and doesn’t change often) and there has been a lot of unreffed access to nodes. As a side effect of this function, all unreffed iters will be invalid.

    Declaration

    Swift

    @inlinable
func clearCache()
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  • Sets filter_iter to point to the row in filter that corresponds to the row pointed at by child_iter. If filter_iter was not set, false is returned.

    Declaration

    Swift

    @inlinable
func convertChildIterToIter<TreeIterT>(filterIter: TreeIterT, childIter: TreeIterT) -> Bool where TreeIterT : TreeIterProtocol
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  • Converts child_path to a path relative to filter. That is, child_path points to a path in the child model. The rerturned path will point to the same row in the filtered model. If child_path isn’t a valid path on the child model or points to a row which is not visible in filter, then nil is returned.

    Declaration

    Swift

    @inlinable
func convertChildPathToPath<TreePathT>(childPath: TreePathT) -> TreePathRef! where TreePathT : TreePathProtocol
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  • Sets child_iter to point to the row pointed to by filter_iter.

    Declaration

    Swift

    @inlinable
func convertIterTo<TreeIterT>(childIter: TreeIterT, filterIter: TreeIterT) where TreeIterT : TreeIterProtocol
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  • Converts filter_path to a path on the child model of filter. That is, filter_path points to a location in filter. The returned path will point to the same location in the model not being filtered. If filter_path does not point to a location in the child model, nil is returned.

    Declaration

    Swift

    @inlinable
func convertPathToChildPath<TreePathT>(filterPath: TreePathT) -> TreePathRef! where TreePathT : TreePathProtocol
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  • getModel() Extension method

    Returns a pointer to the child model of filter.

    Declaration

    Swift

    @inlinable
func getModel() -> TreeModelRef!
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  • refilter() Extension method

    Emits row_changed for each row in the child model, which causes the filter to re-evaluate whether a row is visible or not.

    Declaration

    Swift

    @inlinable
func refilter()
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  • With the n_columns and types parameters, you give an array of column types for this model (which will be exposed to the parent model/view). The func, data and destroy parameters are for specifying the modify function. The modify function will get called for each data access, the goal of the modify function is to return the data which should be displayed at the location specified using the parameters of the modify function.

    Note that gtk_tree_model_filter_set_modify_func() can only be called once for a given filter model.

    Declaration

    Swift

    @inlinable
func setModifyFunc(nColumns: Int, types: UnsafeMutablePointer<GType>!, func: GtkTreeModelFilterModifyFunc?, data: gpointer! = nil, destroy: GDestroyNotify? = nil)
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  • setVisible(column:) Extension method

    Sets column of the child_model to be the column where filter should look for visibility information. columns should be a column of type G_TYPE_BOOLEAN, where true means that a row is visible, and false if not.

    Note that gtk_tree_model_filter_set_visible_func() or gtk_tree_model_filter_set_visible_column() can only be called once for a given filter model.

    Declaration

    Swift

    @inlinable
func setVisible(column: Int)
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  • Sets the visible function used when filtering the filter to be func. The function should return true if the given row should be visible and false otherwise.

    If the condition calculated by the function changes over time (e.g. because it depends on some global parameters), you must call gtk_tree_model_filter_refilter() to keep the visibility information of the model up-to-date.

    Note that func is called whenever a row is inserted, when it may still be empty. The visible function should therefore take special care of empty rows, like in the example below.

    (C Language Example):

    static gboolean
visible_func (GtkTreeModel *model,
              GtkTreeIter  *iter,
              gpointer      data)
{
  // Visible if row is non-empty and first column is “HI”
  gchar *str;
  gboolean visible = FALSE;

  gtk_tree_model_get (model, iter, 0, &str, -1);
  if (str && strcmp (str, "HI") == 0)
    visible = TRUE;
  g_free (str);

  return visible;
}

    Note that gtk_tree_model_filter_set_visible_func() or gtk_tree_model_filter_set_visible_column() can only be called once for a given filter model.

    Declaration

    Swift

    @inlinable
func setVisibleFunc(func: GtkTreeModelFilterVisibleFunc?, data: gpointer! = nil, destroy: GDestroyNotify? = nil)
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  • model Extension method

    Returns a pointer to the child model of filter.

    Declaration

    Swift

    @inlinable
var model: TreeModelRef! { get }
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  • parent Extension method

    Undocumented

    Declaration

    Swift

    @inlinable
var parent: GObject { get }
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