Commit c1e8577a authored by Javier Jardón's avatar Javier Jardón

Move documentation to inline comments: GtkLabel

parent c5a760ad
......@@ -61,6 +61,7 @@ gtkimcontextsimple.sgml
gtkimmulticontext.sgml
gtkinvisible.sgml
gtkitemfactory.sgml
gtklabel.sgml
gtklayout.sgml
gtklinkbutton.sgml
gtkliststore.sgml
......
<!-- ##### SECTION Title ##### -->
GtkLabel
<!-- ##### SECTION Short_Description ##### -->
A widget that displays a small to medium amount of text
<!-- ##### SECTION Long_Description ##### -->
<para>
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.
</para>
<refsect2 id="GtkLabel-BUILDER-UI">
<title>GtkLabel as GtkBuildable</title>
<para>
The GtkLabel implementation of the GtkBuildable interface supports a
custom &lt;attributes&gt; element, which supports any number of &lt;attribute&gt;
elements. the &lt;attribute&gt; element has attributes named name, value,
start and end and allows you to specify #PangoAttribute values for this label.
</para>
<example>
<title>A UI definition fragment specifying Pango attributes</title>
<programlisting><![CDATA[
<object class="GtkLabel">
<attributes>
<attribute name="weight" value="PANGO_WEIGHT_BOLD"/>
<attribute name="background" value="red" start="5" end="10"/>"
</attributes>
</object>
]]></programlisting>
</example>
<para>
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.
</para>
</refsect2>
<refsect2>
<title>Mnemonics</title>
<para>
Labels may contain <firstterm>mnemonics</firstterm>. 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 <literal>"_File"</literal>, to the
functions gtk_label_new_with_mnemonic() or
gtk_label_set_text_with_mnemonic().
</para>
<para>
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 gtk_label_set_mnemonic_widget(). Here's a simple example where
the label is inside a button:
<informalexample>
<programlisting>
/* 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);
</programlisting>
</informalexample>
There's a convenience function to create buttons with a mnemonic label
already inside:
<informalexample>
<programlisting>
/* Pressing Alt+H will activate this button */
button = gtk_button_new_with_mnemonic ("_Hello");
</programlisting>
</informalexample>
To create a mnemonic for a widget alongside the label, such as a
#GtkEntry, you have to point the label at the entry with
gtk_label_set_mnemonic_widget():
<informalexample>
<programlisting>
/* 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);
</programlisting>
</informalexample>
</para>
</refsect2>
<refsect2>
<title>Markup (styled text)</title>
<para>
To make it easy to format text in a label (changing colors, fonts,
etc.), label text can be provided in a simple <link
linkend="PangoMarkupFormat">markup format</link>.
Here's how to create a label with a small font:
<informalexample>
<programlisting>
label = gtk_label_new (NULL);
gtk_label_set_markup (GTK_LABEL (label), "&lt;small&gt;Small text&lt;/small&gt;");
</programlisting>
</informalexample>
(See <link
linkend="PangoMarkupFormat">complete documentation</link> of available
tags in the Pango manual.)
</para>
<para>
The markup passed to gtk_label_set_markup() must be valid; for example,
literal &lt;/&gt;/&amp; characters must be escaped as &amp;lt;,
&amp;gt;, and &amp;amp;. 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().
</para>
<para>
Markup strings are just a convenient way to set the #PangoAttrList on
a label; gtk_label_set_attributes() 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.
</para>
</refsect2>
<refsect2>
<title>Selectable labels</title>
<para>
Labels 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
&mdash; such as error messages &mdash; should be made selectable.
</para>
</refsect2>
<refsect2 id="label-text-layout">
<title>Text layout</title>
<para>
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.
</para>
<para>
Labels can automatically wrap text if you call
gtk_label_set_line_wrap().
</para>
<para>
gtk_label_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 gtk_misc_set_alignment().
</para>
<para>
The #GtkLabel:width-chars and #GtkLabel: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.
</para>
<note><para>Note that the interpretation of #GtkLabel:width-chars and
#GtkLabel:max-width-chars has changed a bit with the introduction of
width-for-height geometry management and #GtkExtendedLayout.</para></note>
</refsect2>
<refsect2>
<title>Links</title>
<para>
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
<tag>a</tag> 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:
<informalexample><programlisting>
gtk_label_set_markup (label, "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...");
</programlisting></informalexample>
It is possible to implement custom handling for links and their tooltips with
the #GtkLabel::activate-link signal and the gtk_label_get_current_uri() function.
</para>
</refsect2>
<!-- ##### SECTION See_Also ##### -->
<para>
</para>
<!-- ##### SECTION Stability_Level ##### -->
<!-- ##### SECTION Image ##### -->
<!-- ##### STRUCT GtkLabel ##### -->
<para>
This should not be accessed directly. Use the accessor functions as
described below.
</para>
<!-- ##### SIGNAL GtkLabel::activate-current-link ##### -->
<para>
</para>
@label: the object which received the signal.
<!-- ##### SIGNAL GtkLabel::activate-link ##### -->
<para>
</para>
@label: the object which received the signal.
@arg1:
@Returns:
<!-- ##### SIGNAL GtkLabel::copy-clipboard ##### -->
<para>
</para>
@label: the object which received the signal.
<!-- ##### SIGNAL GtkLabel::move-cursor ##### -->
<para>
</para>
@label: the object which received the signal.
@arg1:
@arg2:
@arg3:
<!-- ##### SIGNAL GtkLabel::populate-popup ##### -->
<para>
</para>
@label: the object which received the signal.
@arg1:
<!-- ##### ARG GtkLabel:angle ##### -->
<para>
</para>
<!-- ##### ARG GtkLabel:attributes ##### -->
<para>
</para>
<!-- ##### ARG GtkLabel:cursor-position ##### -->
<para>
</para>
<!-- ##### ARG GtkLabel:ellipsize ##### -->
<para>
</para>
<!-- ##### ARG GtkLabel:justify ##### -->
<para>
</para>
<!-- ##### ARG GtkLabel:label ##### -->
<para>
</para>
<!-- ##### ARG GtkLabel:max-width-chars ##### -->
<para>
</para>
<!-- ##### ARG GtkLabel:mnemonic-keyval ##### -->
<para>
</para>
<!-- ##### ARG GtkLabel:mnemonic-widget ##### -->
<para>
</para>
<!-- ##### ARG GtkLabel:pattern ##### -->
<para>
</para>
<!-- ##### ARG GtkLabel:selectable ##### -->
<para>
</para>
<!-- ##### ARG GtkLabel:selection-bound ##### -->
<para>
</para>
<!-- ##### ARG GtkLabel:single-line-mode ##### -->
<para>
</para>
<!-- ##### ARG GtkLabel:track-visited-links ##### -->
<para>
</para>
<!-- ##### ARG GtkLabel:use-markup ##### -->
<para>
</para>
<!-- ##### ARG GtkLabel:use-underline ##### -->
<para>
</para>
<!-- ##### ARG GtkLabel:width-chars ##### -->
<para>
</para>
<!-- ##### ARG GtkLabel:wrap ##### -->
<para>
</para>
<!-- ##### ARG GtkLabel:wrap-mode ##### -->
<para>
</para>
<!-- ##### FUNCTION gtk_label_new ##### -->
<para>
</para>
@str:
@Returns:
<!-- ##### FUNCTION gtk_label_set_text ##### -->
<para>
</para>
@label:
@str:
<!-- ##### FUNCTION gtk_label_set_attributes ##### -->
<para>
</para>
@label:
@attrs:
<!-- ##### FUNCTION gtk_label_set_markup ##### -->
<para>
</para>
@label:
@str:
<!-- ##### FUNCTION gtk_label_set_markup_with_mnemonic ##### -->
<para>
</para>
@label:
@str:
<!-- ##### FUNCTION gtk_label_set_pattern ##### -->
<para>
The pattern of underlines you want under the existing text within the
#GtkLabel widget. For example if the current text of the label says
&quot;FooBarBaz&quot; passing a pattern of &quot;___ ___&quot; will underline
&quot;Foo&quot; and &quot;Baz&quot; but not &quot;Bar&quot;.
</para>
@label: The #GtkLabel you want to set the pattern to.
@pattern: The pattern as described above.
<!-- ##### FUNCTION gtk_label_set_justify ##### -->
<para>
</para>
@label:
@jtype:
<!-- ##### FUNCTION gtk_label_set_ellipsize ##### -->
<para>
</para>
@label:
@mode:
<!-- ##### FUNCTION gtk_label_set_width_chars ##### -->
<para>
</para>
@label:
@n_chars:
<!-- ##### FUNCTION gtk_label_set_max_width_chars ##### -->
<para>
</para>
@label:
@n_chars:
<!-- ##### FUNCTION gtk_label_set_line_wrap ##### -->
<para>
</para>
@label:
@wrap:
<!-- ##### FUNCTION gtk_label_set_line_wrap_mode ##### -->
<para>
</para>
@label:
@wrap_mode:
<!-- ##### FUNCTION gtk_label_get_layout_offsets ##### -->
<para>
</para>
@label:
@x:
@y:
<!-- ##### FUNCTION gtk_label_get_mnemonic_keyval ##### -->
<para>
</para>
@label:
@Returns:
<!-- ##### FUNCTION gtk_label_get_selectable ##### -->
<para>
</para>
@label:
@Returns:
<!-- ##### FUNCTION gtk_label_get_text ##### -->
<para>
</para>
@label:
@Returns:
<!-- ##### FUNCTION gtk_label_new_with_mnemonic ##### -->
<para>
</para>
@str:
@Returns:
<!-- ##### FUNCTION gtk_label_select_region ##### -->
<para>
</para>
@label:
@start_offset:
@end_offset:
<!-- ##### FUNCTION gtk_label_set_mnemonic_widget ##### -->
<para>
</para>
@label:
@widget:
<!-- ##### FUNCTION gtk_label_set_selectable ##### -->
<para>
</para>
@label:
@setting:
<!-- ##### FUNCTION gtk_label_set_text_with_mnemonic ##### -->
<para>
</para>
@label:
@str:
<!-- ##### FUNCTION gtk_label_get_attributes ##### -->
<para>
</para>
@label:
@Returns:
<!-- ##### FUNCTION gtk_label_get_justify ##### -->
<para>
</para>
@label:
@Returns:
<!-- ##### FUNCTION gtk_label_get_ellipsize ##### -->
<para>
</para>
@label:
@Returns:
<!-- ##### FUNCTION gtk_label_get_width_chars ##### -->
<para>
</para>
@label:
@Returns:
<!-- ##### FUNCTION gtk_label_get_max_width_chars ##### -->
<para>
</para>
@label:
@Returns:
<!-- ##### FUNCTION gtk_label_get_label ##### -->
<para>
</para>
@label:
@Returns:
<!-- ##### FUNCTION gtk_label_get_layout ##### -->
<para>
</para>
@label:
@Returns:
<!-- ##### FUNCTION gtk_label_get_line_wrap ##### -->
<para>
</para>
@label:
@Returns:
<!-- ##### FUNCTION gtk_label_get_line_wrap_mode ##### -->
<para>
</para>
@label:
@Returns:
<!-- ##### FUNCTION gtk_label_get_mnemonic_widget ##### -->
<para>
</para>
@label:
@Returns:
<!-- ##### FUNCTION gtk_label_get_selection_bounds ##### -->
<para>
</para>
@label:
@start:
@end:
@Returns:
<!-- ##### FUNCTION gtk_label_get_use_markup ##### -->
<para>
</para>
@label:
@Returns:
<!-- ##### FUNCTION gtk_label_get_use_underline ##### -->
<para>
</para>
@label:
@Returns:
<!-- ##### FUNCTION gtk_label_get_single_line_mode ##### -->
<para>
</para>
@label:
@Returns: