Label#

class Label(**properties: Any)#

Superclasses: Widget, InitiallyUnowned, Object

Implemented Interfaces: Accessible, AccessibleHypertext, AccessibleText, Buildable, ConstraintTarget

Displays a small amount of text.

Most labels are used to label another widget (such as an Entry).

Shortcuts and Gestures#

GtkLabel supports the following keyboard shortcuts, when the cursor is visible:

Shift+:kbd:F10 or Menu opens the context menu.
Ctrl+:kbd:A or Ctrl+<kbd>wzxhzdk:0</kbd> selects all.
Ctrl+:kbd:Shift+:kbd:A or Ctrl+<kbd>wzxhzdk:1</kbd> unselects all.

Additionally, the following signals have default keybindings:

activate_current_link
copy_clipboard
move_cursor

Actions#

GtkLabel defines a set of built-in actions:

clipboard.copy copies the text to the clipboard.
clipboard.cut doesn’t do anything, since text in labels can’t be deleted.
clipboard.paste doesn’t do anything, since text in labels can’t be edited.
link.open opens the link, when activated on a link inside the label.
link.copy copies the link to the clipboard, when activated on a link inside the label.
menu.popup opens the context menu.
selection.delete doesn’t do anything, since text in labels can’t be deleted.
selection.select-all selects all of the text, if the label allows selection.

CSS nodes#

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 GtkShortcutsWindow, labels are used with 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. In this case, label node also gets a .link style class.

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 Attribute values for this label.

An example of a UI definition fragment specifying Pango attributes:

<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.

Accessibility#

GtkLabel uses the label role.

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 new_with_mnemonic or 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 set_mnemonic_widget.

Here’s a simple example where the label is inside a button:

// Pressing Alt+H will activate this button
GtkWidget *button = gtk_button_new ();
GtkWidget *label = gtk_label_new_with_mnemonic ("_Hello");
gtk_button_set_child (GTK_BUTTON (button), label);

There’s a convenience function to create buttons with a mnemonic label already inside:

// 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 set_mnemonic_widget:

// 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:

Here’s how to create a label with a small font:

GtkWidget *label = gtk_label_new (NULL);
gtk_label_set_markup (GTK_LABEL (label), "<small>Small text</small>");

(See the Pango manual for complete documentation] of available tags, parse_markup)

The markup passed to set_markup must be valid XML; for example, literal <, > and & characters must be escaped as <, >, and &. If you pass text obtained from the user, file, or a network to set_markup, you’ll want to escape it with markup_escape_text or markup_printf_escaped.

Markup strings are just a convenient way to set the AttrList on a label; set_attributes may be a simpler way to set attributes in some cases. Be careful though; 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 Attribute requires knowledge of the exact string being displayed, so translations will cause problems.

Selectable labels#

Labels can be made selectable with 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#

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 set_wrap.

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 halign and valign properties.

The width_chars and 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.

Links#

GTK supports markup for clickable hyperlinks in addition to regular Pango markup. The markup for links is borrowed from HTML, using the <a> tag with “href“, “title“ and “class“ 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. The “class“ attribute is used as style class on the CSS node for the link.

An example of inline links looks like this:

const char *text =
"Go to the "
"<a href=\"https://www.gtk.org\" title=\"&lt;i&gt;Our&lt;/i&gt; 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 activate_link signal and the get_current_uri function.

Constructors#

class Label

classmethod new(str: str | None = None) → Widget#

Creates a new label with the given text inside it.

You can pass NULL to get an empty label widget.

Parameters:: str – the text of the label

classmethod new_with_mnemonic(str: str | None = None) → Widget#

Creates a new label with the given text inside it, and a mnemonic.

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 set_mnemonic_widget.

If 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.

Parameters:: str – the text of the label, with an underscore in front of the mnemonic character

Methods#

class Label

get_attributes() → AttrList | None#

Gets the label’s attribute list.

This is the AttrList that was set on the label using set_attributes, if any. This function does not reflect attributes that come from the label’s markup (see set_markup). If you want to get the effective attributes for the label, use pango_layout_get_attributes (gtk_label_get_layout (self)).

get_current_uri() → str | None#

Returns the URI for the active link in the label.

The active link is the one under the mouse pointer or, in a selectable label, the link in which the text cursor is currently positioned.

This function is intended for use in a activate_link handler or for use in a query_tooltip handler.

get_ellipsize() → EllipsizeMode#

Returns the ellipsization mode of the label.

See set_ellipsize.

get_extra_menu() → MenuModel | None#

Gets the extra menu model of the label.

See set_extra_menu.

get_justify() → Justification#

Returns the justification of the label.

See set_justify.

get_label() → str#

Fetches the text from a label.

The returned text includes any embedded underlines indicating mnemonics and Pango markup. (See get_text).

get_layout() → Layout#

Gets the Pango layout used to display the label.

The layout is useful to e.g. convert text positions to pixel positions, in combination with get_layout_offsets. The returned layout is owned by the label so need not be freed by the caller. The label is free to recreate its layout at any time, so it should be considered read-only.

get_layout_offsets() → tuple[int, int]#

Obtains the coordinates where the label will draw its Pango layout.

The coordinates are useful to convert mouse events into coordinates inside the Layout, e.g. to take some action if some part of the label is clicked. Remember when using the Layout functions you need to convert to and from pixels using PANGO_PIXELS() or SCALE.

get_lines() → int#

Gets the number of lines to which an ellipsized, wrapping label should be limited.

See set_lines.

get_max_width_chars() → int#

Retrieves the maximum width of the label in characters.

See set_width_chars.

get_mnemonic_keyval() → int#

Return the mnemonic accelerator.

If the label has been set so that it has a mnemonic key this function returns the keyval used for the mnemonic accelerator. If there is no mnemonic set up it returns GDK_KEY_VoidSymbol.

get_mnemonic_widget() → Widget | None#

Retrieves the mnemonic target of this label.

See set_mnemonic_widget.

get_natural_wrap_mode() → NaturalWrapMode#

Returns natural line wrap mode used by the label.

See set_natural_wrap_mode.

Added in version 4.6.

get_selectable() → bool#: Returns whether the label is selectable.

get_selection_bounds() → tuple[bool, int, int]#

Gets the selected range of characters in the label.

The returned start and end positions are in characters.

get_single_line_mode() → bool#: Returns whether the label is in single line mode.

get_tabs() → TabArray | None#

Gets the tab stops for the label.

The returned array will be NULL if “standard” (8-space) tabs are used.

Added in version 4.8.

get_text() → str#

Gets the text of the label.

The returned text is as it appears on screen. This does not include any embedded underlines indicating mnemonics or Pango markup. (See get_label)

get_use_markup() → bool#

Returns whether the label’s text is interpreted as Pango markup.

See set_use_markup.

get_use_underline() → bool#

Returns whether underlines in the label indicate mnemonics.

See set_use_underline.

get_width_chars() → int#

Retrieves the desired width of the label in characters.

See set_width_chars.

get_wrap() → bool#

Returns whether lines in the label are automatically wrapped.

See set_wrap.

get_wrap_mode() → WrapMode#

Returns line wrap mode used by the label.

See set_wrap_mode.

get_xalign() → float#

Gets the xalign of the label.

See the xalign property.

get_yalign() → float#

Gets the yalign of the label.

See the yalign property.

select_region(start_offset: int, end_offset: int) → None#

Selects a range of characters in the label, if the label is selectable.

See set_selectable. If the label is not selectable, this function has no effect. If start_offset or end_offset are -1, then the end of the label will be substituted.

Parameters:

start_offset – start offset, in characters
end_offset – end offset, in characters

set_attributes(attrs: AttrList | None = None) → None#

Apply attributes to the label text.

The attributes set with this function will be applied and merged with any other attributes previously effected by way of the use_underline or use_markup properties

While it is not recommended to mix markup strings with manually set attributes, if you must; know that the attributes will be applied to the label after the markup string is parsed.

Parameters:: attrs – a list of style attributes

set_ellipsize(mode: EllipsizeMode) → None#

Sets the mode used to ellipsize the text.

The text will be ellipsized if there is not enough space to render the entire string.

Parameters:: mode – the ellipsization mode

set_extra_menu(model: MenuModel | None = None) → None#

Sets a menu model to add to the context menu of the label.

Parameters:: model – a menu model

set_justify(jtype: Justification) → None#

Sets the alignment of lines in the label relative to each other.

This function has no effect on labels containing only a single line.

left is the default value when the widget is first created with new.

If you instead want to set the alignment of the label as a whole, use set_halign instead.

Parameters:: jtype – the new justification

set_label(str: str) → None#

Sets the text of the label.

The label is interpreted as including embedded underlines and/or Pango markup depending on the values of the use_underline and use_markup properties.

Parameters:: str – the new text to set for the label

set_lines(lines: int) → None#

Sets the number of lines to which an ellipsized, wrapping label should be limited.

This has no effect if the label is not wrapping or ellipsized. Set this to -1 if you don’t want to limit the number of lines.

Parameters:: lines – the desired number of lines, or -1

set_markup(str: str) → None#

Sets the labels text and attributes from markup.

The string must be marked up with Pango markup (see parse_markup).

If str is external data, you may need to escape it with markup_escape_text or markup_printf_escaped:

GtkWidget *self = gtk_label_new (NULL);
const char *str = "...";
const char *format = "<span style=\"italic\">\%s</span>";
char *markup;

markup = g_markup_printf_escaped (format, str);
gtk_label_set_markup (GTK_LABEL (self), markup);
g_free (markup);

This function sets the use_markup property to true.

Also see set_text.

Parameters:: str – the markup string

set_markup_with_mnemonic(str: str) → None#

Sets the labels text, attributes and mnemonic from markup.

Parses str which is marked up with Pango markup (see parse_markup), setting the label’s text and attribute list based on the parse results. If characters in str are preceded by an underscore, they are underlined indicating that they represent a keyboard accelerator called a mnemonic.

The mnemonic key can be used to activate another widget, chosen automatically, or explicitly using set_mnemonic_widget.

Parameters:: str – the markup string

set_max_width_chars(n_chars: int) → None#

Sets the maximum width of the label in characters.

Parameters:: n_chars – the new maximum width, in characters.

set_mnemonic_widget(widget: Widget | None = None) → None#

Associate the label with its mnemonic target.

If the label has been set so that it has a mnemonic key (using i.e. set_markup_with_mnemonic, set_text_with_mnemonic, new_with_mnemonic or the use_underline property) the label can be associated with a widget that is the target of the mnemonic. When the label is inside a widget (like a Button or a Notebook tab) it is automatically associated with the correct widget, but sometimes (i.e. when the target is a Entry next to the label) you need to set it explicitly using this function.

The target widget will be accelerated by emitting the mnemonic_activate signal on it. The default handler for this signal will activate the widget if there are no mnemonic collisions and toggle focus between the colliding widgets otherwise.

Parameters:: widget – the target widget

set_natural_wrap_mode(wrap_mode: NaturalWrapMode) → None#

Selects the line wrapping for the natural size request.

This only affects the natural size requested, for the actual wrapping used, see the wrap_mode property.

Added in version 4.6.

Parameters:: wrap_mode – the line wrapping mode

set_selectable(setting: bool) → None#

Makes text in the label selectable.

Selectable labels allow the user to select text from the label, for copy-and-paste.

Parameters:: setting – true to allow selecting text in the label

set_single_line_mode(single_line_mode: bool) → None#

Sets whether the label is in single line mode.

Parameters:: single_line_mode – true to enable single line mode

set_tabs(tabs: TabArray | None = None) → None#

Sets tab stops for the label.

Added in version 4.8.

Parameters:: tabs – tab stops

set_text(str: str) → None#

Sets the text for the label.

It overwrites any text that was there before and clears any previously set mnemonic accelerators, and sets the use_underline and use_markup properties to false.

Also see set_markup.

Parameters:: str – the text to show in self

set_text_with_mnemonic(str: str) → None#

Sets the text for the label, with mnemonics.

If characters in str are preceded by an underscore, they are underlined indicating that they represent a keyboard accelerator called a mnemonic. The mnemonic key can be used to activate another widget, chosen automatically, or explicitly using set_mnemonic_widget.

Parameters:: str – the text

set_use_markup(setting: bool) → None#

Sets whether the text of the label contains markup.

See set_markup.

Parameters:: setting – true if the label’s text should be parsed for markup.

set_use_underline(setting: bool) → None#

Sets whether underlines in the text indicate mnemonics.

Parameters:: setting – true if underlines in the text indicate mnemonics

set_width_chars(n_chars: int) → None#

Sets the desired width in characters of the label.

Parameters:: n_chars – the new desired width, in characters.

set_wrap(wrap: bool) → None#

Toggles line wrapping within the label.

True makes it break lines if text exceeds the widget’s size. false lets the text get cut off by the edge of the widget if it exceeds the widget size.

Note that setting line wrapping to true does not make the label wrap at its parent widget’s width, because GTK widgets conceptually can’t make their requisition depend on the parent widget’s size. For a label that wraps at a specific position, set the label’s width using set_size_request.

Parameters:: wrap – whether to wrap lines

set_wrap_mode(wrap_mode: WrapMode) → None#

Controls how line wrapping is done.

This only affects the label if line wrapping is on. (See set_wrap)

The default is word, which means wrap on word boundaries.

For sizing behavior, also consider the natural_wrap_mode property.

Parameters:: wrap_mode – the line wrapping mode

set_xalign(xalign: float) → None#

Sets the xalign of the label.

See the xalign property.

Parameters:: xalign – the new xalign value, between 0 and 1

set_yalign(yalign: float) → None#

Sets the yalign of the label.

See the yalign property.

Parameters:: yalign – the new yalign value, between 0 and 1

Properties#

class Label

props.attributes: AttrList#: A list of style attributes to apply to the text of the label.

props.ellipsize: EllipsizeMode#

The preferred place to ellipsize the string, if the label does not have enough room to display the entire string.

Note that setting this property to a value other than [enum.Pango.EllipsizeMode.none] has the side-effect that the label requests only enough space to display the ellipsis “…”. In particular, this means that ellipsizing labels do not work well in notebook tabs, unless the tab_expand child property is set to true.

Other ways to set a label’s width are set_size_request and set_width_chars.

props.extra_menu: MenuModel#: A menu model whose contents will be appended to the context menu.

props.justify: Justification#

The alignment of the lines in the text of the label, relative to each other.

This does not affect the alignment of the label within its allocation. See xalign for that.

props.label: str#

The contents of the label.

If the string contains Pango markup (see parse_markup), you will have to set the use_markup property to true in order for the label to display the markup attributes. See also set_markup for a convenience function that sets both this property and the use_markup property at the same time.

If the string contains underlines acting as mnemonics, you will have to set the use_underline property to true in order for the label to display them.

props.lines: int#

The number of lines to which an ellipsized, wrapping label should display before it gets ellipsized. This both prevents the label from ellipsizing before this many lines are displayed, and limits the height request of the label to this many lines.

::: warning: Setting this property has unintuitive and unfortunate consequences for the minimum width of the label. Specifically, if the height of the label is such that it fits a smaller number of lines than the value of this property, the label can not be ellipsized at all, which means it must be wide enough to fit all the text fully.

This property has no effect if the label is not wrapping or ellipsized.

Set this property to -1 if you don’t want to limit the number of lines.

props.max_width_chars: int#

The desired maximum width of the label, in characters.

If this property is set to -1, the width will be calculated automatically.

See the section on text layout for details of how width_chars and max_width_chars determine the width of ellipsized and wrapped labels.

props.mnemonic_keyval: int#: The mnemonic accelerator key for the label.

props.mnemonic_widget: Widget#: The widget to be activated when the labels mnemonic key is pressed.

props.natural_wrap_mode: NaturalWrapMode#

Select the line wrapping for the natural size request.

This only affects the natural size requested. For the actual wrapping used, see the wrap_mode property.

The default is inherit, which inherits the behavior of the wrap_mode property.

Added in version 4.6.

props.selectable: bool#: Whether the label text can be selected with the mouse.

props.single_line_mode: bool#

Whether the label is in single line mode.

In single line mode, the height of the label does not depend on the actual text, it is always set to ascent + descent of the font. This can be an advantage in situations where resizing the label because of text changes would be distracting, e.g. in a statusbar.

props.tabs: TabArray#: Custom tabs for this label.

Added in version 4.8.

props.use_markup: bool#

True if the text of the label includes Pango markup.

See parse_markup.

props.use_underline: bool#: True if the text of the label indicates a mnemonic with an _ before the mnemonic character.

props.width_chars: int#

The desired width of the label, in characters.

If this property is set to -1, the width will be calculated automatically.

See the section on text layout for details of how width_chars and max_width_chars determine the width of ellipsized and wrapped labels.

props.wrap: bool#: True if the label text will wrap if it gets too wide.

props.wrap_mode: WrapMode#

Controls how the line wrapping is done.

This only affects the formatting if line wrapping is on (see the wrap property). The default is word, which means wrap on word boundaries.

For sizing behavior, also consider the natural_wrap_mode property.

props.xalign: float#

The horizontal alignment of the label text inside its size allocation.

Compare this to halign, which determines how the labels size allocation is positioned in the space available for the label.

props.yalign: float#

The vertical alignment of the label text inside its size allocation.

Compare this to valign, which determines how the labels size allocation is positioned in the space available for the label.

Signals#

class Label.signals

activate_current_link() → None#

Gets emitted when the user activates a link in the label.

The ::activate-current-link is a keybinding signal.

Applications may also emit the signal with signal_emit_by_name() if they need to control activation of URIs programmatically.

The default bindings for this signal are all forms of the Enter key.

activate_link(uri: str) → bool#

Gets emitted to activate a URI.

Applications may connect to it to override the default behaviour, which is to call launch.

Parameters:: uri – the URI that is activated

copy_clipboard() → None#

Gets emitted to copy the selection to the clipboard.

The ::copy-clipboard signal is a keybinding signal.

The default binding for this signal is Ctrl+:kbd:c.

move_cursor(step: MovementStep, count: int, extend_selection: bool) → None#

Gets emitted when the user initiates a cursor movement.

The ::move-cursor signal is a keybinding signal. If the cursor is not visible in entry, this signal causes the viewport to be moved instead.

Applications should not connect to it, but may emit it with signal_emit_by_name if they need to control the cursor programmatically.

The default bindings for this signal come in two variants, the variant with the Shift modifier extends the selection, the variant without the Shift modifier does not. There are too many key combinations to list them all here.

←, →, ↑, ↓ move by individual characters/lines
Ctrl+:kbd:←, etc. move by words/paragraphs
Home and End move to the ends of the buffer

Parameters:

step – the granularity of the move, as a GtkMovementStep
count – the number of step units to move
extend_selection – true if the move should extend the selection