gtk-misc, gtk-widget, g-initially-unowned, gtk-buildable, g-object, common-lisp:standard-object, common-lisp:t
The gtk-label widget displays a small amount of text. As the name implies, most labels are used to label another widget such as a gtk-button, a gtk-menu-item, or a gtk-combo-box.
GtkLabel as GtkBuildableThe gtk-label implementation of the gtk-buildable 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.
Example: 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.
MnemonicsLabels 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 gtk-label-new-with-mnemonic or gtk-label-set-text-with-mnemonic.
Mnemonics automatically activate any activatable widget the label is inside, such as a gtk-button widget; if the label is not inside the mnemonic's target widget, you have to tell the label about the target using gtk-label-set-mnemonic-widget. Here is a simple example where the label is inside a button:
// Pressing Alt+H will activate this button button = gtk_button_new (); label = gtk_label_new_with_mnemonic ("_Hello"); gtk_container_add (GTK_CONTAINER (button), label);There is a convenience function to create buttons with a mnemonic label already inside:
// Pressing Alt+H will activate this button button = gtk_button_new_with_mnemonic ("_Hello");To create a mnemonic for a widget alongside the label, such as a gtk-entry widget, you have to point the label at the entry with gtk-label-set-mnemonic-widget:
// Pressing Alt+H will focus the entry entry = gtk_entry_new (); 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 is how to create a label with a small font:
label = gtk_label_new (NULL); gtk_label_set_markup (GTK_LABEL (label), "<span style="color: red"> <small>Small text</small></span>");(See complete documentation of available tags in the Pango manual.)
The markup passed to gtk-label-set-markup must be valid; for example, literal <, > and & characters must be escaped as <, gt;, and &. If you pass text obtained from the user, file, or a network to gtk-label-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-attr-list on a label; gtk-label-set-attributes may be a simpler way to set attributes in some cases. Be careful though; pango-attr-list tends to cause internationalization problems, unless you are 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 labelsLabels can be made selectable with gtk-label-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 layoutA 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 the function gtk-label-set-line-wrap.
The function gtk-label-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 function gtk-misc-set-alignment.
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.
NoteNote that the interpretation of the properties "width-chars" and "max-width-chars" has changed a bit with the introduction of "width-for-height" geometry management.
LinksSince 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:
gtk_label_set_markup (label, "Go to the <span style="color: red"> <a>GTK+ website</a></span> for more...");It is possible to implement custom handling for links and their tooltips with the "activate-link" signal and gtk-label-get-current-uri function.
The "activate-current-link" signal
lambda (label) : ActionA keybinding signal which gets emitted when the user activates a link in the label. Applications may also emit the signal with g-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.
The "activate-link" signal
lambda (label uri) : Run LastThe signal which gets emitted to activate a URI. Applications may connect to it to override the default behaviour, which is to call the function gtk-show-uri.
The "copy-clipboard" signal
lambda (label) : ActionThe "copy-clipboard" signal is a keybinding signal which gets emitted to copy the selection to the clipboard. The default binding for this signal is Ctrl-c.
The "move-cursor" signal
lambda (entry step count extended-selection) : ActionThe "move-cursor" signal is a keybinding signal which gets emitted when the user initiates a cursor movement. 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 g-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 modifer does not. There are too many key combinations to list them all here.
The "populate-popup" signal
lambda (label menu) : Run LastThe "populate-popup" signal gets emitted before showing the context menu of the label. Note that only selectable labels have context menus. If you need to add items to the context menu, connect to this signal and append your menuitems to the menu.
Slot Access Functions
Inherited Slot Access Functions