#[repr(transparent)]pub struct Label { /* private fields */ }
Expand description
The Label
widget displays a small amount of text. As the name
implies, most labels are used to label another widget such as a
Button
, a MenuItem
, or a ComboBox
.
CSS nodes
⚠️ The following code is in plain ⚠️
label
├── [selection]
├── [link]
┊
╰── [link]
GtkLabel has a single CSS node with the name label. A wide variety
of style classes may be applied to labels, such as .title, .subtitle,
.dim-label, etc. In the ShortcutsWindow
, labels are used wth the
.keycap style class.
If the label has a selection, it gets a subnode with name selection.
If the label has links, there is one subnode per link. These subnodes carry the link or visited state depending on whether they have been visited.
GtkLabel as GtkBuildable
The GtkLabel implementation of the GtkBuildable interface supports a
custom <attributes>
element, which supports any number of <attribute>
elements. The <attribute>
element has attributes named “name“, “value“,
“start“ and “end“ and allows you to specify PangoAttribute
values for
this label.
An example of a UI definition fragment specifying Pango attributes:
⚠️ The following code is in xml ⚠️
<object class="GtkLabel">
<attributes>
<attribute name="weight" value="PANGO_WEIGHT_BOLD"/>
<attribute name="background" value="red" start="5" end="10"/>
</attributes>
</object>
The start and end attributes specify the range of characters to which the Pango attribute applies. If start and end are not specified, the attribute is applied to the whole text. Note that specifying ranges does not make much sense with translatable attributes. Use markup embedded in the translatable content instead.
Mnemonics
Labels may contain “mnemonics”. Mnemonics are
underlined characters in the label, used for keyboard navigation.
Mnemonics are created by providing a string with an underscore before
the mnemonic character, such as "_File"
, to the
functions with_mnemonic()
or
LabelExt::set_text_with_mnemonic()
.
Mnemonics automatically activate any activatable widget the label is
inside, such as a Button
; if the label is not inside the
mnemonic’s target widget, you have to tell the label about the target
using LabelExt::set_mnemonic_widget()
. Here’s a simple example where
the label is inside a button:
⚠️ The following code is in C ⚠️
// Pressing Alt+H will activate this button
GtkWidget *button = gtk_button_new ();
GtkWidget *label = gtk_label_new_with_mnemonic ("_Hello");
gtk_container_add (GTK_CONTAINER (button), label);
There’s a convenience function to create buttons with a mnemonic label already inside:
⚠️ The following code is in C ⚠️
// Pressing Alt+H will activate this button
GtkWidget *button = gtk_button_new_with_mnemonic ("_Hello");
To create a mnemonic for a widget alongside the label, such as a
Entry
, you have to point the label at the entry with
LabelExt::set_mnemonic_widget()
:
⚠️ The following code is in C ⚠️
// Pressing Alt+H will focus the entry
GtkWidget *entry = gtk_entry_new ();
GtkWidget *label = gtk_label_new_with_mnemonic ("_Hello");
gtk_label_set_mnemonic_widget (GTK_LABEL (label), entry);
Markup (styled text)
To make it easy to format text in a label (changing colors, fonts, etc.), label text can be provided in a simple [markup format][PangoMarkupFormat].
Here’s how to create a label with a small font:
⚠️ The following code is in C ⚠️
GtkWidget *label = gtk_label_new (NULL);
gtk_label_set_markup (GTK_LABEL (label), "<small>Small text</small>");
(See [complete documentation][PangoMarkupFormat] of available tags in the Pango manual.)
The markup passed to LabelExt::set_markup()
must be valid; for example,
literal <, > and & characters must be escaped as <, >, and &.
If you pass text obtained from the user, file, or a network to
LabelExt::set_markup()
, you’ll want to escape it with
g_markup_escape_text()
or g_markup_printf_escaped()
.
Markup strings are just a convenient way to set the pango::AttrList
on
a label; LabelExt::set_attributes()
may be a simpler way to set
attributes in some cases. Be careful though; pango::AttrList
tends to
cause internationalization problems, unless you’re applying attributes
to the entire string (i.e. unless you set the range of each attribute
to [0, G_MAXINT
)). The reason is that specifying the start_index and
end_index for a PangoAttribute
requires knowledge of the exact string
being displayed, so translations will cause problems.
Selectable labels
Labels can be made selectable with LabelExt::set_selectable()
.
Selectable labels allow the user to copy the label contents to
the clipboard. Only labels that contain useful-to-copy information
— such as error messages — should be made selectable.
Text layout # {label
-text-layout}
A label can contain any number of paragraphs, but will have performance problems if it contains more than a small number. Paragraphs are separated by newlines or other paragraph separators understood by Pango.
Labels can automatically wrap text if you call
LabelExt::set_line_wrap()
.
LabelExt::set_justify()
sets how the lines in a label align
with one another. If you want to set how the label as a whole
aligns in its available space, see the property::Widget::halign
and
property::Widget::valign
properties.
The property::Label::width-chars
and property::Label::max-width-chars
properties
can be used to control the size allocation of ellipsized or wrapped
labels. For ellipsizing labels, if either is specified (and less
than the actual text size), it is used as the minimum width, and the actual
text size is used as the natural width of the label. For wrapping labels,
width-chars is used as the minimum width, if specified, and max-width-chars
is used as the natural width. Even if max-width-chars specified, wrapping
labels will be rewrapped to use all of the available width.
Note that the interpretation of property::Label::width-chars
and
property::Label::max-width-chars
has changed a bit with the introduction of
[width-for-height geometry management.][geometry-management]
Links
Since 2.18, GTK+ supports markup for clickable hyperlinks in addition
to regular Pango markup. The markup for links is borrowed from HTML,
using the <a>
with “href“ and “title“ attributes. GTK+ renders links
similar to the way they appear in web browsers, with colored, underlined
text. The “title“ attribute is displayed as a tooltip on the link.
An example looks like this:
⚠️ The following code is in C ⚠️
const gchar *text =
"Go to the"
"<a href=\"http://www.gtk.org title=\"<i>Our</i> website\">"
"GTK+ website</a> for more...";
GtkWidget *label = gtk_label_new (NULL);
gtk_label_set_markup (GTK_LABEL (label), text);
It is possible to implement custom handling for links and their tooltips with
the signal::Label::activate-link
signal and the LabelExt::current_uri()
function.
Implements
LabelExt
, [MiscExt
][trait@crate::prelude::MiscExt], WidgetExt
, glib::ObjectExt
, BuildableExt
, WidgetExtManual
, BuildableExtManual
Implementations
sourceimpl Label
impl Label
pub const NONE: Option<&'static Label> = None
sourcepub fn with_mnemonic(str: &str) -> Label
pub fn with_mnemonic(str: &str) -> Label
Creates a new Label
, containing the text in str
.
If characters in str
are preceded by an underscore, they are
underlined. If you need a literal underscore character in a label, use
‘__’ (two underscores). The first underlined character represents a
keyboard accelerator called a mnemonic. The mnemonic key can be used
to activate another widget, chosen automatically, or explicitly using
LabelExt::set_mnemonic_widget()
.
If LabelExt::set_mnemonic_widget()
is not called, then the first
activatable ancestor of the Label
will be chosen as the mnemonic
widget. For instance, if the label is inside a button or menu item,
the button or menu item will automatically become the mnemonic widget
and be activated by the mnemonic.
str
The text of the label, with an underscore in front of the mnemonic character
Returns
the new Label
sourcepub fn builder() -> LabelBuilder
pub fn builder() -> LabelBuilder
Creates a new builder-pattern struct instance to construct Label
objects.
This method returns an instance of LabelBuilder
which can be used to create Label
objects.
Trait Implementations
sourceimpl Ord for Label
impl Ord for Label
1.21.0 · sourceconst fn max(self, other: Self) -> Self
const fn max(self, other: Self) -> Self
1.21.0 · sourceconst fn min(self, other: Self) -> Self
const fn min(self, other: Self) -> Self
1.50.0 · sourceconst fn clamp(self, min: Self, max: Self) -> Selfwhere
Self: PartialOrd<Self>,
const fn clamp(self, min: Self, max: Self) -> Selfwhere
Self: PartialOrd<Self>,
sourceimpl ParentClassIs for Label
impl ParentClassIs for Label
sourceimpl<OT: ObjectType> PartialOrd<OT> for Label
impl<OT: ObjectType> PartialOrd<OT> for Label
sourcefn partial_cmp(&self, other: &OT) -> Option<Ordering>
fn partial_cmp(&self, other: &OT) -> Option<Ordering>
1.0.0 · sourceconst fn le(&self, other: &Rhs) -> bool
const fn le(&self, other: &Rhs) -> bool
self
and other
) and is used by the <=
operator. Read moresourceimpl StaticType for Label
impl StaticType for Label
sourcefn static_type() -> Type
fn static_type() -> Type
Self
.impl Eq for Label
impl IsA<Buildable> for Label
impl IsA<Label> for AccelLabel
impl IsA<Misc> for Label
impl IsA<Widget> for Label
Auto Trait Implementations
impl RefUnwindSafe for Label
impl !Send for Label
impl !Sync for Label
impl Unpin for Label
impl UnwindSafe for Label
Blanket Implementations
sourceimpl<T> BorrowMut<T> for Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere
T: ?Sized,
const: unstable · sourcefn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
sourceimpl<T> Cast for Twhere
T: ObjectType,
impl<T> Cast for Twhere
T: ObjectType,
sourcefn upcast<T>(self) -> Twhere
T: ObjectType,
Self: IsA<T>,
fn upcast<T>(self) -> Twhere
T: ObjectType,
Self: IsA<T>,
T
. Read moresourcefn upcast_ref<T>(&self) -> &Twhere
T: ObjectType,
Self: IsA<T>,
fn upcast_ref<T>(&self) -> &Twhere
T: ObjectType,
Self: IsA<T>,
T
. Read moresourcefn downcast<T>(self) -> Result<T, Self>where
T: ObjectType,
Self: CanDowncast<T>,
fn downcast<T>(self) -> Result<T, Self>where
T: ObjectType,
Self: CanDowncast<T>,
T
. Read moresourcefn downcast_ref<T>(&self) -> Option<&T>where
T: ObjectType,
Self: CanDowncast<T>,
fn downcast_ref<T>(&self) -> Option<&T>where
T: ObjectType,
Self: CanDowncast<T>,
T
. Read moresourcefn dynamic_cast<T>(self) -> Result<T, Self>where
T: ObjectType,
fn dynamic_cast<T>(self) -> Result<T, Self>where
T: ObjectType,
T
. This handles upcasting, downcasting
and casting between interface and interface implementors. All checks are performed at
runtime, while downcast
and upcast
will do many checks at compile-time already. Read moresourcefn dynamic_cast_ref<T>(&self) -> Option<&T>where
T: ObjectType,
fn dynamic_cast_ref<T>(&self) -> Option<&T>where
T: ObjectType,
T
. This handles upcasting, downcasting
and casting between interface and interface implementors. All checks are performed at
runtime, while downcast
and upcast
will do many checks at compile-time already. Read moresourceunsafe fn unsafe_cast<T>(self) -> Twhere
T: ObjectType,
unsafe fn unsafe_cast<T>(self) -> Twhere
T: ObjectType,
T
unconditionally. Read moresourceunsafe fn unsafe_cast_ref<T>(&self) -> &Twhere
T: ObjectType,
unsafe fn unsafe_cast_ref<T>(&self) -> &Twhere
T: ObjectType,
&T
unconditionally. Read moresourceimpl<U> IsSubclassableExt for Uwhere
U: IsClass + ParentClassIs,
impl<U> IsSubclassableExt for Uwhere
U: IsClass + ParentClassIs,
fn parent_class_init<T>(class: &mut Class<U>)where
T: ObjectSubclass,
<U as ParentClassIs>::Parent: IsSubclassable<T>,
fn parent_instance_init<T>(instance: &mut InitializingObject<T>)where
T: ObjectSubclass,
<U as ParentClassIs>::Parent: IsSubclassable<T>,
sourceimpl<T> ObjectExt for Twhere
T: ObjectType,
impl<T> ObjectExt for Twhere
T: ObjectType,
sourcefn is<U>(&self) -> boolwhere
U: StaticType,
fn is<U>(&self) -> boolwhere
U: StaticType,
true
if the object is an instance of (can be cast to) T
.sourcefn object_class(&self) -> &Class<Object>
fn object_class(&self) -> &Class<Object>
ObjectClass
of the object. Read moresourcefn class_of<U>(&self) -> Option<&Class<U>>where
U: IsClass,
fn class_of<U>(&self) -> Option<&Class<U>>where
U: IsClass,
T
. Read moresourcefn interface<U>(&self) -> Option<InterfaceRef<'_, U>>where
U: IsInterface,
fn interface<U>(&self) -> Option<InterfaceRef<'_, U>>where
U: IsInterface,
T
of the object. Read moresourcefn set_property<V>(&self, property_name: &str, value: V)where
V: ToValue,
fn set_property<V>(&self, property_name: &str, value: V)where
V: ToValue,
sourcefn set_property_from_value(&self, property_name: &str, value: &Value)
fn set_property_from_value(&self, property_name: &str, value: &Value)
sourcefn set_properties(&self, property_values: &[(&str, &dyn ToValue)])
fn set_properties(&self, property_values: &[(&str, &dyn ToValue)])
sourcefn set_properties_from_value(&self, property_values: &[(&str, Value)])
fn set_properties_from_value(&self, property_values: &[(&str, Value)])
sourcefn property<V>(&self, property_name: &str) -> Vwhere
V: 'static + for<'b> FromValue<'b>,
fn property<V>(&self, property_name: &str) -> Vwhere
V: 'static + for<'b> FromValue<'b>,
property_name
of the object and cast it to the type V. Read moresourcefn property_value(&self, property_name: &str) -> Value
fn property_value(&self, property_name: &str) -> Value
property_name
of the object. Read moresourcefn property_type(&self, property_name: &str) -> Option<Type>
fn property_type(&self, property_name: &str) -> Option<Type>
property_name
of this object. Read moresourcefn find_property(&self, property_name: &str) -> Option<ParamSpec>
fn find_property(&self, property_name: &str) -> Option<ParamSpec>
ParamSpec
of the property property_name
of this object.sourcefn list_properties(&self) -> PtrSlice<ParamSpec>
fn list_properties(&self) -> PtrSlice<ParamSpec>
ParamSpec
of the properties of this object.sourcefn freeze_notify(&self) -> PropertyNotificationFreezeGuard
fn freeze_notify(&self) -> PropertyNotificationFreezeGuard
sourceunsafe fn set_qdata<QD>(&self, key: Quark, value: QD)where
QD: 'static,
unsafe fn set_qdata<QD>(&self, key: Quark, value: QD)where
QD: 'static,
key
. Read moresourceunsafe fn qdata<QD>(&self, key: Quark) -> Option<NonNull<QD>>where
QD: 'static,
unsafe fn qdata<QD>(&self, key: Quark) -> Option<NonNull<QD>>where
QD: 'static,
key
. Read moresourceunsafe fn steal_qdata<QD>(&self, key: Quark) -> Option<QD>where
QD: 'static,
unsafe fn steal_qdata<QD>(&self, key: Quark) -> Option<QD>where
QD: 'static,
key
. Read moresourceunsafe fn set_data<QD>(&self, key: &str, value: QD)where
QD: 'static,
unsafe fn set_data<QD>(&self, key: &str, value: QD)where
QD: 'static,
key
. Read moresourceunsafe fn data<QD>(&self, key: &str) -> Option<NonNull<QD>>where
QD: 'static,
unsafe fn data<QD>(&self, key: &str) -> Option<NonNull<QD>>where
QD: 'static,
key
. Read moresourceunsafe fn steal_data<QD>(&self, key: &str) -> Option<QD>where
QD: 'static,
unsafe fn steal_data<QD>(&self, key: &str) -> Option<QD>where
QD: 'static,
key
. Read moresourcefn block_signal(&self, handler_id: &SignalHandlerId)
fn block_signal(&self, handler_id: &SignalHandlerId)
sourcefn unblock_signal(&self, handler_id: &SignalHandlerId)
fn unblock_signal(&self, handler_id: &SignalHandlerId)
sourcefn stop_signal_emission(&self, signal_id: SignalId, detail: Option<Quark>)
fn stop_signal_emission(&self, signal_id: SignalId, detail: Option<Quark>)
sourcefn stop_signal_emission_by_name(&self, signal_name: &str)
fn stop_signal_emission_by_name(&self, signal_name: &str)
sourcefn connect<F>(
&self,
signal_name: &str,
after: bool,
callback: F
) -> SignalHandlerIdwhere
F: 'static + Fn(&[Value]) -> Option<Value> + Send + Sync,
fn connect<F>(
&self,
signal_name: &str,
after: bool,
callback: F
) -> SignalHandlerIdwhere
F: 'static + Fn(&[Value]) -> Option<Value> + Send + Sync,
signal_name
on this object. Read moresourcefn connect_id<F>(
&self,
signal_id: SignalId,
details: Option<Quark>,
after: bool,
callback: F
) -> SignalHandlerIdwhere
F: 'static + Fn(&[Value]) -> Option<Value> + Send + Sync,
fn connect_id<F>(
&self,
signal_id: SignalId,
details: Option<Quark>,
after: bool,
callback: F
) -> SignalHandlerIdwhere
F: 'static + Fn(&[Value]) -> Option<Value> + Send + Sync,
signal_id
on this object. Read moresourcefn connect_local<F>(
&self,
signal_name: &str,
after: bool,
callback: F
) -> SignalHandlerIdwhere
F: 'static + Fn(&[Value]) -> Option<Value>,
fn connect_local<F>(
&self,
signal_name: &str,
after: bool,
callback: F
) -> SignalHandlerIdwhere
F: 'static + Fn(&[Value]) -> Option<Value>,
signal_name
on this object. Read moresourcefn connect_local_id<F>(
&self,
signal_id: SignalId,
details: Option<Quark>,
after: bool,
callback: F
) -> SignalHandlerIdwhere
F: 'static + Fn(&[Value]) -> Option<Value>,
fn connect_local_id<F>(
&self,
signal_id: SignalId,
details: Option<Quark>,
after: bool,
callback: F
) -> SignalHandlerIdwhere
F: 'static + Fn(&[Value]) -> Option<Value>,
signal_id
on this object. Read moresourceunsafe fn connect_unsafe<F>(
&self,
signal_name: &str,
after: bool,
callback: F
) -> SignalHandlerIdwhere
F: Fn(&[Value]) -> Option<Value>,
unsafe fn connect_unsafe<F>(
&self,
signal_name: &str,
after: bool,
callback: F
) -> SignalHandlerIdwhere
F: Fn(&[Value]) -> Option<Value>,
signal_name
on this object. Read moresourceunsafe fn connect_unsafe_id<F>(
&self,
signal_id: SignalId,
details: Option<Quark>,
after: bool,
callback: F
) -> SignalHandlerIdwhere
F: Fn(&[Value]) -> Option<Value>,
unsafe fn connect_unsafe_id<F>(
&self,
signal_id: SignalId,
details: Option<Quark>,
after: bool,
callback: F
) -> SignalHandlerIdwhere
F: Fn(&[Value]) -> Option<Value>,
signal_id
on this object. Read moresourcefn connect_closure(
&self,
signal_name: &str,
after: bool,
closure: RustClosure
) -> SignalHandlerId
fn connect_closure(
&self,
signal_name: &str,
after: bool,
closure: RustClosure
) -> SignalHandlerId
signal_name
on this object. Read moresourcefn connect_closure_id(
&self,
signal_id: SignalId,
details: Option<Quark>,
after: bool,
closure: RustClosure
) -> SignalHandlerId
fn connect_closure_id(
&self,
signal_id: SignalId,
details: Option<Quark>,
after: bool,
closure: RustClosure
) -> SignalHandlerId
signal_id
on this object. Read moresourcefn watch_closure(&self, closure: &impl AsRef<Closure>)
fn watch_closure(&self, closure: &impl AsRef<Closure>)
closure
to the lifetime of the object. When
the object’s reference count drops to zero, the closure will be
invalidated. An invalidated closure will ignore any calls to
invoke_with_values
, or
invoke
when using Rust closures. Read moresourcefn emit<R>(&self, signal_id: SignalId, args: &[&dyn ToValue]) -> Rwhere
R: TryFromClosureReturnValue,
fn emit<R>(&self, signal_id: SignalId, args: &[&dyn ToValue]) -> Rwhere
R: TryFromClosureReturnValue,
sourcefn emit_with_values(&self, signal_id: SignalId, args: &[Value]) -> Option<Value>
fn emit_with_values(&self, signal_id: SignalId, args: &[Value]) -> Option<Value>
Self::emit
but takes Value
for the arguments.sourcefn emit_by_name<R>(&self, signal_name: &str, args: &[&dyn ToValue]) -> Rwhere
R: TryFromClosureReturnValue,
fn emit_by_name<R>(&self, signal_name: &str, args: &[&dyn ToValue]) -> Rwhere
R: TryFromClosureReturnValue,
sourcefn emit_by_name_with_values(
&self,
signal_name: &str,
args: &[Value]
) -> Option<Value>
fn emit_by_name_with_values(
&self,
signal_name: &str,
args: &[Value]
) -> Option<Value>
sourcefn emit_by_name_with_details<R>(
&self,
signal_name: &str,
details: Quark,
args: &[&dyn ToValue]
) -> Rwhere
R: TryFromClosureReturnValue,
fn emit_by_name_with_details<R>(
&self,
signal_name: &str,
details: Quark,
args: &[&dyn ToValue]
) -> Rwhere
R: TryFromClosureReturnValue,
sourcefn emit_by_name_with_details_and_values(
&self,
signal_name: &str,
details: Quark,
args: &[Value]
) -> Option<Value>
fn emit_by_name_with_details_and_values(
&self,
signal_name: &str,
details: Quark,
args: &[Value]
) -> Option<Value>
sourcefn emit_with_details<R>(
&self,
signal_id: SignalId,
details: Quark,
args: &[&dyn ToValue]
) -> Rwhere
R: TryFromClosureReturnValue,
fn emit_with_details<R>(
&self,
signal_id: SignalId,
details: Quark,
args: &[&dyn ToValue]
) -> Rwhere
R: TryFromClosureReturnValue,
sourcefn emit_with_details_and_values(
&self,
signal_id: SignalId,
details: Quark,
args: &[Value]
) -> Option<Value>
fn emit_with_details_and_values(
&self,
signal_id: SignalId,
details: Quark,
args: &[Value]
) -> Option<Value>
sourcefn disconnect(&self, handler_id: SignalHandlerId)
fn disconnect(&self, handler_id: SignalHandlerId)
sourcefn connect_notify<F>(&self, name: Option<&str>, f: F) -> SignalHandlerIdwhere
F: 'static + Fn(&T, &ParamSpec) + Send + Sync,
fn connect_notify<F>(&self, name: Option<&str>, f: F) -> SignalHandlerIdwhere
F: 'static + Fn(&T, &ParamSpec) + Send + Sync,
notify
signal of the object. Read moresourcefn connect_notify_local<F>(&self, name: Option<&str>, f: F) -> SignalHandlerIdwhere
F: 'static + Fn(&T, &ParamSpec),
fn connect_notify_local<F>(&self, name: Option<&str>, f: F) -> SignalHandlerIdwhere
F: 'static + Fn(&T, &ParamSpec),
notify
signal of the object. Read moresourceunsafe fn connect_notify_unsafe<F>(
&self,
name: Option<&str>,
f: F
) -> SignalHandlerIdwhere
F: Fn(&T, &ParamSpec),
unsafe fn connect_notify_unsafe<F>(
&self,
name: Option<&str>,
f: F
) -> SignalHandlerIdwhere
F: Fn(&T, &ParamSpec),
notify
signal of the object. Read more