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A PangoContext stores global information used to control the itemization process.

The information stored by PangoContext includes the fontmap used to look up fonts, and default values such as the default language, default gravity, or default font.

To obtain a PangoContext, use [methodPango.FontMap.create_context].

Hierarchy

Index

Constructors

  • Parameters

    Returns Pango.Context

  • Creates a new PangoContext initialized to default values.

    This function is not particularly useful as it should always be followed by a [methodPango.Context.set_font_map] call, and the function [methodPango.FontMap.create_context] does these two steps together and hence users are recommended to use that.

    If you are using Pango as part of a higher-level system, that system may have it's own way of create a PangoContext. For instance, the GTK toolkit has, among others, gtk_widget_get_pango_context(). Use those instead.

    Returns Pango.Context

Properties

gTypeInstance: TypeInstance
name: string

Methods

  • 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.

    Parameters

    • sourceProperty: string

      the property on source to bind

    • target: GObject.Object

      the target #GObject

    • targetProperty: string

      the property on target to bind

    • flags: BindingFlags

      flags to pass to #GBinding

    Returns Binding

  • 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.

    Parameters

    • sourceProperty: string

      the property on source to bind

    • target: GObject.Object

      the target #GObject

    • targetProperty: string

      the property on target to bind

    • flags: BindingFlags

      flags to pass to #GBinding

    • transformTo: TClosure<any, any>

      a #GClosure wrapping the transformation function from the source to the target, or %NULL to use the default

    • transformFrom: TClosure<any, any>

      a #GClosure wrapping the transformation function from the target to the source, or %NULL to use the default

    Returns Binding

  • changed(): void
  • Forces a change in the context, which will cause any PangoLayout using this context to re-layout.

    This function is only useful when implementing a new backend for Pango, something applications won't do. Backends should call this function if they have attached extra data to the context and such data is changed.

    Returns void

  • connect(sigName: string, callback: ((...args: any[]) => void)): number
  • Parameters

    • sigName: string
    • callback: ((...args: any[]) => void)
        • (...args: any[]): void
        • Parameters

          • Rest ...args: any[]

          Returns void

    Returns number

  • emit(sigName: string, ...args: any[]): void
  • forceFloating(): void
  • 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().

    Returns void

  • freezeNotify(): void
  • 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.

    Returns void

  • getData(key?: string): object
  • Gets a named field from the objects table of associations (see g_object_set_data()).

    Parameters

    • Optional key: string

      name of the key for that association

    Returns object

  • Retrieves the gravity for the context.

    This is similar to [methodPango.Context.get_base_gravity], except for when the base gravity is %PANGO_GRAVITY_AUTO for which [funcPango.Gravity.get_for_matrix] is used to return the gravity from the current context matrix.

    Returns Pango.Gravity

  • Retrieves the gravity hint for the context.

    See [methodPango.Context.set_gravity_hint] for details.

    Returns GravityHint

  • Gets the transformation matrix that will be applied when rendering with this context.

    See [methodPango.Context.set_matrix].

    Returns Pango.Matrix

  • Get overall metric information for a particular font description.

    Since the metrics may be substantially different for different scripts, a language tag can be provided to indicate that the metrics should be retrieved that correspond to the script(s) used by that language.

    The PangoFontDescription is interpreted in the same way as by [funcitemize], and the family name may be a comma separated list of names. If characters from multiple of these families would be used to render the string, then the returned fonts would be a composite of the metrics for the fonts loaded for the individual families.

    Parameters

    • desc: FontDescription

      a PangoFontDescription structure. %NULL means that the font description from the context will be used.

    • language: Pango.Language

      language tag used to determine which script to get the metrics for. %NULL means that the language tag from the context will be used. If no language tag is set on the context, metrics for the default language (as determined by [funcPango.Language.get_default] will be returned.

    Returns FontMetrics

  • getProperty(propertyName?: string, value?: any): void
  • Gets a property of an object.

    The value can be:

    • an empty #GValue initialized by %G_VALUE_INIT, which will be automatically initialized with the expected type of the property (since GLib 2.60)
    • a #GValue initialized with the expected type of the property
    • a #GValue initialized with a type to which the expected type of the property can be transformed

    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.

    Parameters

    • Optional propertyName: string

      the name of the property to get

    • Optional value: any

      return location for the property value

    Returns void

  • getQdata(quark: number): object
  • This function gets back user data pointers stored via g_object_set_qdata().

    Parameters

    • quark: number

      A #GQuark, naming the user data pointer

    Returns object

  • getRoundGlyphPositions(): boolean
  • Returns whether font rendering with this context should round glyph positions and widths.

    Returns boolean

  • getSerial(): number
  • Returns the current serial number of context.

    The serial number is initialized to an small number larger than zero when a new context is created and is increased whenever the context is changed using any of the setter functions, or the PangoFontMap it uses to find fonts has changed. The serial may wrap, but will never have the value 0. Since it can wrap, never compare it with "less than", always use "not equals".

    This can be used to automatically detect changes to a PangoContext, and is only useful when implementing objects that need update when their PangoContext changes, like PangoLayout.

    Returns number

  • getv(names: string[], values: any[]): void
  • 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.

    Parameters

    • names: string[]

      the names of each property to get

    • values: any[]

      the values of each property to get

    Returns void

  • isFloating(): boolean
  • Loads the font in one of the fontmaps in the context that is the closest match for desc.

    Parameters

    Returns Pango.Font

  • Load a set of fonts in the context that can be used to render a font matching desc.

    Parameters

    • desc: FontDescription

      a PangoFontDescription describing the fonts to load

    • language: Pango.Language

      a PangoLanguage the fonts will be used for

    Returns Fontset

  • notify(propertyName: string): void
  • 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.

    Parameters

    • propertyName: string

      the name of a property installed on the class of object.

    Returns void

  • 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]);
    

    Parameters

    • pspec: ParamSpec

      the #GParamSpec of a property installed on the class of object.

    Returns void

  • off(sigName: string, callback: ((...args: any[]) => void)): EventEmitter
  • Parameters

    • sigName: string
    • callback: ((...args: any[]) => void)
        • (...args: any[]): void
        • Parameters

          • Rest ...args: any[]

          Returns void

    Returns EventEmitter

  • on(sigName: string, callback: ((...args: any[]) => void), after?: boolean): EventEmitter
  • Parameters

    • sigName: string
    • callback: ((...args: any[]) => void)
        • (...args: any[]): void
        • Parameters

          • Rest ...args: any[]

          Returns void

    • Optional after: boolean

    Returns EventEmitter

  • once(sigName: string, callback: ((...args: any[]) => void), after?: boolean): EventEmitter
  • Parameters

    • sigName: string
    • callback: ((...args: any[]) => void)
        • (...args: any[]): void
        • Parameters

          • Rest ...args: any[]

          Returns void

    • Optional after: boolean

    Returns EventEmitter

  • Increases the reference count of object.

    Since GLib 2.56, if GLIB_VERSION_MAX_ALLOWED is 2.56 or greater, the type of object will be propagated to the return type (using the GCC typeof() extension), so any casting the caller needs to do on the return type must be explicit.

    Returns GObject.Object

  • 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().

    Returns GObject.Object

  • runDispose(): void
  • Releases all references to other objects. This can be used to break reference cycles.

    This function should only be called from object system implementations.

    Returns void

  • Sets the base direction for the context.

    The base direction is used in applying the Unicode bidirectional algorithm; if the direction is %PANGO_DIRECTION_LTR or %PANGO_DIRECTION_RTL, then the value will be used as the paragraph direction in the Unicode bidirectional algorithm. A value of %PANGO_DIRECTION_WEAK_LTR or %PANGO_DIRECTION_WEAK_RTL is used only for paragraphs that do not contain any strong characters themselves.

    Parameters

    Returns void

  • Sets the base gravity for the context.

    The base gravity is used in laying vertical text out.

    Parameters

    Returns void

  • setData(key: string, data?: object): void
  • 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.

    Parameters

    • key: string

      name of the key

    • Optional data: object

      data to associate with that key

    Returns void

  • Sets the font map to be searched when fonts are looked-up in this context.

    This is only for internal use by Pango backends, a PangoContext obtained via one of the recommended methods should already have a suitable font map.

    Parameters

    Returns void

  • Sets the gravity hint for the context.

    The gravity hint is used in laying vertical text out, and is only relevant if gravity of the context as returned by [methodPango.Context.get_gravity] is set to %PANGO_GRAVITY_EAST or %PANGO_GRAVITY_WEST.

    Parameters

    Returns void

  • Sets the global language tag for the context.

    The default language for the locale of the running process can be found using [funcPango.Language.get_default].

    Parameters

    Returns void

  • Sets the transformation matrix that will be applied when rendering with this context.

    Note that reported metrics are in the user space coordinates before the application of the matrix, not device-space coordinates after the application of the matrix. So, they don't scale with the matrix, though they may change slightly for different matrices, depending on how the text is fit to the pixel grid.

    Parameters

    • matrix: Pango.Matrix

      a PangoMatrix, or %NULL to unset any existing matrix. (No matrix set is the same as setting the identity matrix.)

    Returns void

  • setProperty(propertyName: string, value?: any): void
  • Sets a property on an object.

    Parameters

    • propertyName: string

      the name of the property to set

    • Optional value: any

      the value

    Returns void

  • setRoundGlyphPositions(roundPositions: boolean): void
  • Sets whether font rendering with this context should round glyph positions and widths to integral positions, in device units.

    This is useful when the renderer can't handle subpixel positioning of glyphs.

    The default value is to round glyph positions, to remain compatible with previous Pango behavior.

    Parameters

    • roundPositions: boolean

      whether to round glyph positions

    Returns void

  • stealData(key?: string): object
  • Remove a specified datum from the object's data associations, without invoking the association's destroy handler.

    Parameters

    • Optional key: string

      name of the key

    Returns object

  • stealQdata(quark: number): object
  • 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().

    Parameters

    • quark: number

      A #GQuark, naming the user data pointer

    Returns object

  • thawNotify(): void
  • 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.

    Returns void

  • unref(): void
  • 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.

    Returns void

  • watchClosure(closure: TClosure<any, any>): void
  • 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.

    Parameters

    • closure: TClosure<any, any>

      #GClosure to watch

    Returns void

  • compatControl(what: number, data: object): number
  • 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().

    Parameters

    • gIface: TypeInterface

      any interface vtable for the interface, or the default vtable for the interface

    • propertyName: string

      name of a property to look up.

    Returns ParamSpec

  • 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.

    Parameters

    • gIface: TypeInterface

      any interface vtable for the interface, or the default vtable for the interface.

    • pspec: ParamSpec

      the #GParamSpec for the new property

    Returns void

  • 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().

    Parameters

    • gIface: TypeInterface

      any interface vtable for the interface, or the default vtable for the interface

    Returns ParamSpec[]

  • Creates a new PangoContext initialized to default values.

    This function is not particularly useful as it should always be followed by a [methodPango.Context.set_font_map] call, and the function [methodPango.FontMap.create_context] does these two steps together and hence users are recommended to use that.

    If you are using Pango as part of a higher-level system, that system may have it's own way of create a PangoContext. For instance, the GTK toolkit has, among others, gtk_widget_get_pango_context(). Use those instead.

    Returns Pango.Context

  • 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.

    Parameters

    • objectType: GType<unknown>

      the type id of the #GObject subtype to instantiate

    • parameters: GObject.Parameter[]

      an array of #GParameter

    Returns GObject.Object

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