GtkLabel {RGtk2} | R Documentation

## GtkLabel

### Description

A widget that displays a small to medium amount of text

### Methods and Functions

`gtkLabelNew(str = NULL, show = TRUE)`
`gtkLabelSetText(object, str)`
`gtkLabelSetAttributes(object, attrs)`
`gtkLabelSetMarkup(object, str)`
`gtkLabelSetMarkupWithMnemonic(object, str)`
`gtkLabelSetPattern(object, pattern)`
`gtkLabelSetJustify(object, jtype)`
`gtkLabelSetEllipsize(object, mode)`
`gtkLabelSetWidthChars(object, n.chars)`
`gtkLabelSetMaxWidthChars(object, n.chars)`
`gtkLabelGet(object)`
`gtkLabelParseUline(object, string)`
`gtkLabelSetLineWrap(object, wrap)`
`gtkLabelSetLineWrapMode(object, wrap.mode)`
`gtkLabelGetLayoutOffsets(object)`
`gtkLabelGetMnemonicKeyval(object)`
`gtkLabelGetSelectable(object)`
`gtkLabelGetText(object)`
`gtkLabelNewWithMnemonic(str = NULL, show = TRUE)`
`gtkLabelSelectRegion(object, start.offset, end.offset)`
`gtkLabelSetMnemonicWidget(object, widget)`
`gtkLabelSetSelectable(object, setting)`
`gtkLabelSetTextWithMnemonic(object, str)`
`gtkLabelGetAttributes(object)`
`gtkLabelGetJustify(object)`
`gtkLabelGetEllipsize(object)`
`gtkLabelGetWidthChars(object)`
`gtkLabelGetMaxWidthChars(object)`
`gtkLabelGetLabel(object)`
`gtkLabelGetLayout(object)`
`gtkLabelGetLineWrap(object)`
`gtkLabelGetLineWrapMode(object)`
`gtkLabelGetMnemonicWidget(object)`
`gtkLabelGetSelectionBounds(object)`
`gtkLabelGetUseMarkup(object)`
`gtkLabelGetUseUnderline(object)`
`gtkLabelGetSingleLineMode(object)`
`gtkLabelGetAngle(object)`
`gtkLabelSetLabel(object, str)`
`gtkLabelSetUseMarkup(object, setting)`
`gtkLabelSetUseUnderline(object, setting)`
`gtkLabelSetSingleLineMode(object, single.line.mode)`
`gtkLabelSetAngle(object, angle)`
`gtkLabelGetCurrentUri(object)`
`gtkLabelSetTrackVisitedLinks(object, track.links)`
`gtkLabelGetTrackVisitedLinks(object)`
`gtkLabel(str = NULL, show = TRUE)`

### Hierarchy

    GObject
       +----GInitiallyUnowned
             +----GtkObject
                   +----GtkWidget
                         +----GtkMisc
                               +----GtkLabel
                                     +----GtkAccelLabel
                                     +----GtkTipsQuery

### Interfaces

GtkLabel implements AtkImplementorIface and `GtkBuildable`.

### Detailed Description

The `GtkLabel` widget displays a small amount of text. As the name implies, most labels are used to label another widget such as a `GtkButton`, a `GtkMenuItem`, or a `GtkOptionMenu`.

### 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.

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.

### 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 `gtkLabelNewWithMnemonic` or `gtkLabelSetTextWithMnemonic`.

Mnemonics automatically activate any activatable widget the label is inside, such as a `GtkButton`; if the label is not inside the mnemonic's target widget, you have to tell the label about the target using `gtkLabelSetMnemonicWidget`. Here's a simple example where the label is inside a button:

    ## Pressing Alt-H will activate this button
    button <- gtkButton()
    label <- gtkLabelNewWithMnemonic("_Hello")
    button$add(label)

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

    ## Pressing Alt+H will activate this button
    button <- gtkButtonNewWithMnemonic("_Hello")

To create a mnemonic for a widget alongside the label, such as a `GtkEntry`, you have to point the label at the entry with `gtkLabelSetMnemonicWidget`:

    ## Pressing Alt+H will focus the entry
    entry <- gtkEntry()
    label <- gtkLabelNewWithMnemonic("_Hello")
    label$setMnemonicWidget(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:

    label <- gtkLabelNew()
    label$setMarkup("<small>Small text</small>")

(See complete documentation of available tags in the Pango manual.)

The markup passed to `gtkLabelSetMarkup` must be valid; for example, literal </>/& characters must be escaped as &lt;, &gt;, and &amp;. If you pass text obtained from the user, file, or a network to `gtkLabelSetMarkup`, you'll want to escape it with `gMarkupEscapeText()` or `gMarkupPrintfEscaped()`.

Markup strings are just a convenient way to set the `PangoAttrList` on a label; `gtkLabelSetAttributes` may be a simpler way to set attributes in some cases. Be careful though; `PangoAttrList` 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 `gtkLabelSetSelectable`. 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 `gtkLabelSetLineWrap`. `gtkLabelSetJustify` 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 `gtkMiscSetAlignment`.

### 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:

    label$setMarkup("Go to the &lt;a href=\"http://www.gtk.org\" title=\"&amp;lt;i&amp;gt;Our&amp;/i&amp;gt; website\"&gt;GTK+ website&lt;/a&gt; for more...")

It is possible to implement custom handling for links and their tooltips with the `"activate-link"` signal and the `gtkLabelGetCurrentUri` function.

### Structures

`GtkLabel`

  This should not be accessed directly. Use the accessor functions as described below.

### Convenient Construction

`gtkLabel` is the result of collapsing the constructors of `GtkLabel` (`gtkLabelNew`, `gtkLabelNewWithMnemonic`) and accepts a subset of its arguments matching the required arguments of one of its delegate constructors.

### Signals

`activate-current-link(label, user.data)`

  A keybinding signal which gets emitted when the user activates a link in the label.

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

  The default bindings for this signal are all forms of the Enter key. Since 2.18

  `label`

    The label on which the signal was emitted

  `user.data`

    user data set when the signal handler was connected.

`activate-link(label, uri, user.data)`

  The signal which gets emitted to activate a URI. Applications may connect to it to override the default behaviour, which is to call `gtkShowUri`. Since 2.18

  `label`

    The label on which the signal was emitted

  `uri`

    the URI that is activated

  `user.data`

    user data set when the signal handler was connected.

  Returns: [logical] `TRUE` if the link has been activated

`copy-clipboard(label, user.data)`

  The ::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.

  `label`

    the object which received the signal

  `user.data`

    user data set when the signal handler was connected.

`move-cursor(entry, step, count, extend.selection, user.data)`

  The ::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 `gSignalEmitByName()` 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.

  `entry`

    the object which received the signal

  `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

  `user.data`

    user data set when the signal handler was connected.

`populate-popup(label, menu, user.data)`

  The ::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`.

  `label`

    The label on which the signal is emitted

  `menu`

    the menu that is being populated

  `user.data`

    user data set when the signal handler was connected.

### Properties

`angle` [numeric : Read / Write]

  The angle that the baseline of the label makes with the horizontal, in degrees, measured counterclockwise. An angle of 90 reads from from bottom to top, an angle of 270, from top to bottom. Ignored if the label is selectable, wrapped, or ellipsized. Allowed values: [0,360] Default value: 0 Since 2.6

`attributes` [`PangoAttrList` : * : Read / Write]

  A list of style attributes to apply to the text of the label.

`cursor-position` [integer : Read]

  The current position of the insertion cursor in chars. Allowed values: >= 0 Default value: 0

`ellipsize` [`PangoEllipsizeMode` : Read / Write]

  The preferred place to ellipsize the string, if the label does not have enough room to display the entire string, specified as a `PangoEllisizeMode`.

  Note that setting this property to a value other than `PANGO_ELLIPSIZE_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's `"tab-expand"` property is set to `TRUE`. Other ways to set a label's width are `gtkWidgetSetSizeRequest` and `gtkLabelSetWidthChars`. Default value: PANGO_ELLIPSIZE_NONE Since 2.6

`justify` [`GtkJustification` : Read / Write]

  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 GtkMisc::xalign for that. Default value: GTK_JUSTIFY_LEFT

`label` [character : * : Read / Write]

  The text of the label. Default value: ""

`max-width-chars` [integer : Read / Write]

  The desired maximum width of the label, in characters. If this property is set to -1, the width will be calculated automatically, otherwise the label will request space for no more than the requested number of characters. If the `"width-chars"` property is set to a positive value, then the "max-width-chars" property is ignored. Allowed values: >= -1 Default value: -1 Since 2.6

`mnemonic-keyval` [numeric : Read]

  The mnemonic accelerator key for this label. Default value: 16777215

`mnemonic-widget` [`GtkWidget` : * : Read / Write]

  The widget to be activated when the label's mnemonic key is pressed.

`pattern` [character : * : Write]

  A string with _ characters in positions correspond to characters in the text to underline. Default value: NULL

`selectable` [logical : Read / Write]

  Whether the label text can be selected with the mouse. Default value: FALSE

`selection-bound` [integer : Read]

  The position of the opposite end of the selection from the cursor in chars. Allowed values: >= 0 Default value: 0

`single-line-mode` [logical : Read / Write]

  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. Default value: FALSE Since 2.6

`track-visited-links` [logical : Read / Write]

  Set this property to `TRUE` to make the label track which links have been clicked. It will then apply the ::visited-link-color color, instead of ::link-color. Default value: TRUE Since 2.18

`use-markup` [logical : Read / Write]

  The text of the label includes XML markup. See pango_parse_markup(). Default value: FALSE

`use-underline` [logical : Read / Write]

  If set, an underline in the text indicates the next character should be used for the mnemonic accelerator key. Default value: FALSE

`width-chars` [integer : Read / Write]

  The desired width of the label, in characters. If this property is set to -1, the width will be calculated automatically, otherwise the label will request either 3 characters or the property value, whichever is greater. If the "width-chars" property is set to a positive value, then the `"max-width-chars"` property is ignored. Allowed values: >= -1 Default value: -1 Since 2.6

`wrap` [logical : Read / Write]

  If set, wrap lines if the text becomes too wide. Default value: FALSE

`wrap-mode` [`PangoWrapMode` : Read / Write]

  If line wrapping is on (see the `"wrap"` property) this controls how the line wrapping is done. The default is `PANGO_WRAP_WORD`, which means wrap on word boundaries. Default value: PANGO_WRAP_WORD Since 2.10

### Author(s)

Derived by RGtkGen from GTK+ documentation

### References

https://developer.gnome.org/gtk2/stable/GtkLabel.html

[Package RGtk2 version 2.20.36.3 Index]