Supported HTML Subset

Describes the support for HTML markup in text widgets.

Qt’s text widgets are able to display rich text, specified using a subset of HTML 4 markup. Widgets that use QTextDocument , such as QLabel and QTextEdit , are able to display rich text specified in this way.

Using HTML Markup in Text Widgets

Widgets automatically detect HTML markup and display rich text accordingly. For example, setting a label’s text property with the string "<b>Hello</b> <i>Qt!</i>" will result in the label displaying text like this: Hello Qt!

When HTML markup is used for text, Qt follows the rules defined by the HTML 4 specification. This includes default properties for text layout, such as the direction of the text flow (left-to-right) which can be changed by applying the dir :ref:` <Supported-HTML-Subset>` attribute to blocks of text.

Supported Tags

The following table lists the HTML tags supported by Qt’s rich text engine:

Tag	Description	Comment
a	Anchor or link	Supports the href and name attributes.
address	Address
b	Bold
big	Larger font
blockquote	Indented paragraph
body	Document body	Supports the bgcolor attribute, which can be a Qt color name or a #RRGGBB color specification.
br	Line break
center	Centered paragraph
cite	Inline citation	Same as i.
code	Code	Same as tt.
dd	Definition data
dfn	Definition	Same as i.
div	Document division	Supports the standard block attributes .
dl	Definition list	Supports the standard block attributes .
dt	Definition term	Supports the standard block attributes .
em	Emphasized	Same as i.
font	Font size, family, and/or color	Supports the following attributes: size, face, and color (Qt color names or #RRGGBB).
h1	Level 1 heading	Supports the standard block attributes .
h2	Level 2 heading	Supports the standard block attributes .
h3	Level 3 heading	Supports the standard block attributes .
h4	Level 4 heading	Supports the standard block attributes .
h5	Level 5 heading	Supports the standard block attributes .
h6	Level 6 heading	Supports the standard block attributes .
head	Document header
hr	Horizontal line	Supports the width attribute, which can be specified as an absolute or relative (%) value.
html	HTML document
i	Italic
img	Image	Supports the src, source (for Qt 3 compatibility), width, and height attributes.
kbd	User-entered text
meta	Meta-information	If a text encoding is specified using the meta tag, it is picked up by Qt::codecForHtml(). Likewise, if an encoding is specified to toHtml() , the encoding is stored using a meta tag, for example: <meta http-equiv="Content-Type" content="text/html; charset=EUC-JP" />
li	List item
nobr	Non-breakable text
ol	Ordered list	Supports the standard list attributes .
p	Paragraph	Left-aligned by default. Supports the standard block attributes .
pre	Preformated text
qt	Qt rich-text document	Synonym for html. Provided for compatibility with earlier versions of Qt.
s	Strikethrough
samp	Sample code	Same as tt.
small	Small font
span	Grouped elements
strong	Strong	Same as b.
sub	Subscript
sup	Superscript
table	Table	Supports the following attributes: border, bgcolor (Qt color names or #RRGGBB), cellspacing, cellpadding, width (absolute or relative), and height.
tbody	Table body	Does nothing.
td	Table data cell	Supports the standard table cell attributes .
tfoot	Table footer	Does nothing.
th	Table header cell	Supports the standard table cell attributes .
thead	Table header	If the thead tag is specified, it is used when printing tables that span multiple pages.
title	Document title	The value specified using the title tag is available through metaInformation() .
tr	Table row	Supports the bgcolor attribute, which can be a Qt color name or a #RRGGBB color specification.
tt	Typewrite font
u	Underlined
ul	Unordered list	Supports the standard list attributes .
var	Variable	Same as i.

Block Attributes

The following attributes are supported by the div, dl, dt, h1, h2, h3, h4, h5, h6, p tags:

• align (left, right, center, justify)

• dir (ltr, rtl)

List Attributes

The following attribute is supported by the ol and ul tags:

• type (1, a, A, square, disc, circle)

Table Cell Attributes

The following attributes are supported by the td and th tags:

• width (absolute, relative, or no-value)

• bgcolor (Qt color names or #RRGGBB)

• colspan

• rowspan

• align (left, right, center, justify)

• valign (top, middle, bottom)

CSS Properties

The following table lists the CSS properties supported by Qt’s rich text engine:

Qt-specific CSS properties

Besides the standard CSS properties listed earlier, the following Qt-specific properties can also be used to style a text block:

Property	Values	Description
-qt-block-indent	<number>	Indents the text block by the specified no. spaces.
-qt-list-indent	<number>	Indents the list items by the specified no. of spaces.
-qt-list-number-prefix	<string>	Prefixes the given string to list number in an HTML ordered list.
-qt-list-number-suffix	<string>	Suffixes the given string to list number in an HTML ordered list.
-qt-paragraph-type	empty	Hides the text block.
-qt-table-type	root | frame	root renders the text blocks inline without borders and indentation, whereas frame renders them on a new line with a frame around.
-qt-user-state	<number>	Adds it as user data for the text block.

Supported CSS Selectors

All CSS 2.1 selector classes are supported except pseudo-class selectors such as :first-child, :visited and :hover.