QLabel(3qt)QLabel(3qt)NAME
QLabel - Text or image display
SYNOPSIS
#include <qlabel.h>
Inherits QFrame.
Public Members
QLabel ( QWidget * parent, const char * name = 0, WFlags f = 0 )
QLabel ( const QString & text, QWidget * parent, const char * name = 0,
WFlags f = 0 )
QLabel ( QWidget * buddy, const QString & text, QWidget * parent, const
char * name = 0, WFlags f = 0 )
~QLabel ()
QString text () const
QPixmap * pixmap () const
QPicture * picture () const
QMovie * movie () const
TextFormat textFormat () const
void setTextFormat ( TextFormat )
int alignment () const
virtual void setAlignment ( int )
int indent () const
void setIndent ( int )
bool autoResize () const (obsolete)
virtual void setAutoResize ( bool enable ) (obsolete)
bool hasScaledContents () const
void setScaledContents ( bool )
virtual void setBuddy ( QWidget * buddy )
QWidget * buddy () const
virtual void setFont ( const QFont & f )
Public Slots
virtual void setText ( const QString & )
virtual void setPixmap ( const QPixmap & )
virtual void setPicture ( const QPicture & picture )
virtual void setMovie ( const QMovie & movie )
virtual void setNum ( int num )
virtual void setNum ( double num )
void clear ()
Properties
Alignment alignment - the alignment of the label's contents
BackgroundMode backgroundMode - the label's background mode (read
only)
int indent - the label's text indent in pixels
QPixmap pixmap - the label's pixmap
bool scaledContents - whether the label will scale its contents to fill
all available space
QString text - the label's text
TextFormat textFormat - the label's text format
Protected Members
virtual void drawContents ( QPainter * p )
DESCRIPTION
The QLabel widget provides a text or image display.
QLabel is used for displaying text or an image. No user interaction
functionality is provided. The visual appearance of the label can be
configured in various ways, and it can be used for specifying a focus
accelerator key for another widget.
A QLabel can contain any of the following content types: <center>.nf
</center>
When the content is changed using any of these functions, any previous
content is cleared.
The look of a QLabel can be tuned in several ways. All the settings of
QFrame are available for specifying a widget frame. The positioning of
the content within the QLabel widget area can be tuned with
setAlignment() and setIndent(). For example, this code sets up a sunken
panel with a two-line text in the bottom right corner (both lines being
flush with the right side of the label):
QLabel *label = new QLabel( this );
label->setFrameStyle( QFrame::Panel | QFrame::Sunken );
label->setText( "first line\nsecond line" );
label->setAlignment( AlignBottom | AlignRight );
A QLabel is often used as a label for an interactive widget. For this
use QLabel provides a useful mechanism for adding an accelerator key
(see QAccel) that will set the keyboard focus to the other widget
(called the QLabel's "buddy"). For example:
QLineEdit* phoneEdit = new QLineEdit( this, "phoneEdit" );
QLabel* phoneLabel = new QLabel( phoneEdit, "&Phone:", this, "phoneLabel" );
In this example, keyboard focus is transferred to the label's buddy
(the QLineEdit) when the user presses Alt+P. You can also use the
setBuddy() function to accomplish the same thing.
[Image Omitted]
[Image Omitted]
See also QLineEdit, QTextEdit, QPixmap, QMovie, GUI Design Handbook:
Label, Basic Widgets, and Text Related Classes.
MEMBER FUNCTION DOCUMENTATIONQLabel::QLabel ( QWidget * parent, const char * name = 0, WFlags f = 0 )
Constructs an empty label.
The parent, name and widget flag f, arguments are passed to the QFrame
constructor.
See also alignment, setFrameStyle(), and indent.
QLabel::QLabel ( const QString & text, QWidget * parent, const char * name =
0, WFlags f = 0 )
Constructs a label that displays the text, text.
The parent, name and widget flag f, arguments are passed to the QFrame
constructor.
See also text, alignment, setFrameStyle(), and indent.
QLabel::QLabel ( QWidget * buddy, const QString & text, QWidget * parent,
const char * name = 0, WFlags f = 0 )
Constructs a label that displays the text text. The label has a buddy
widget, buddy.
If the text contains an underlined letter (a letter preceded by an
ampersand, &), and the text is in plain text format, when the user
presses Alt+ the underlined letter, focus is passed to the buddy
widget.
The parent, name and widget flag, f, arguments are passed to the QFrame
constructor.
See also text, setBuddy(), alignment, setFrameStyle(), and indent.
QLabel::~QLabel ()
Destroys the label.
int QLabel::alignment () const
Returns the alignment of the label's contents. See the "alignment"
property for details.
bool QLabel::autoResize () const
This function is obsolete. It is provided to keep old source working.
We strongly advise against using it in new code.
Returns TRUE if auto-resizing is enabled, or FALSE if auto-resizing is
disabled.
Auto-resizing is disabled by default.
See also setAutoResize().
QWidget * QLabel::buddy () const
Returns this label's buddy, or 0 if no buddy is currently set.
See also setBuddy().
void QLabel::clear () [slot]
Clears any label contents. Equivalent to setText( "" ).
void QLabel::drawContents ( QPainter * p ) [virtual protected]
Draws the label contents using the painter p.
Reimplemented from QFrame.
bool QLabel::hasScaledContents () const
Returns TRUE if the label will scale its contents to fill all available
space; otherwise returns FALSE. See the "scaledContents" property for
details.
int QLabel::indent () const
Returns the label's text indent in pixels. See the "indent" property
for details.
QMovie * QLabel::movie () const
Returns a pointer to the label's movie, or 0 if no movie has been set.
See also setMovie().
QPicture * QLabel::picture () const
Returns the label's picture or 0 if the label doesn't have a picture.
QPixmap * QLabel::pixmap () const
Returns the label's pixmap. See the "pixmap" property for details.
void QLabel::setAlignment ( int ) [virtual]
Sets the alignment of the label's contents. See the "alignment"
property for details.
void QLabel::setAutoResize ( bool enable ) [virtual]
This function is obsolete. It is provided to keep old source working.
We strongly advise against using it in new code.
Enables auto-resizing if enable is TRUE, or disables it if enable is
FALSE.
When auto-resizing is enabled the label will resize itself to fit the
contents whenever the contents change. The top-left corner is not
moved. This is useful for QLabel widgets that are not managed by a
QLayout (e.g., top-level widgets).
Auto-resizing is disabled by default.
See also autoResize(), adjustSize(), and sizeHint.
void QLabel::setBuddy ( QWidget * buddy ) [virtual]
Sets this label's buddy to buddy.
When the user presses the accelerator key indicated by this label, the
keyboard focus is transferred to the label's buddy widget.
The buddy mechanism is only available for QLabels that contain plain
text in which one letter is prefixed with an ampersand, &. This letter
is set as the accelerator key. The letter is displayed underlined, and
the '&' is not displayed (i.e. the ShowPrefix alignment flag is turned
on; see setAlignment()).
In a dialog, you might create two data entry widgets and a label for
each, and set up the geometry layout so each label is just to the left
of its data entry widget (its "buddy"), for example:
QLineEdit *nameEd = new QLineEdit( this );
QLabel *nameLb = new QLabel( "&Name:", this );
nameLb->setBuddy( nameEd );
QLineEdit *phoneEd = new QLineEdit( this );
QLabel *phoneLb = new QLabel( "&Phone:", this );
phoneLb->setBuddy( phoneEd );
// ( layout setup not shown )
With the code above, the focus jumps to the Name field when the user
presses Alt+N, and to the Phone field when the user presses Alt+P.
To unset a previously set buddy, call this function with buddy set to
0.
See also buddy(), text, QAccel, and alignment.
Examples:
void QLabel::setFont ( const QFont & f ) [virtual]
Sets the font used on the QLabel to font f.
Example: menu/menu.cpp.
Reimplemented from QWidget.
void QLabel::setIndent ( int )
Sets the label's text indent in pixels. See the "indent" property for
details.
void QLabel::setMovie ( const QMovie & movie ) [virtual slot]
Sets the label contents to movie. Any previous content is cleared.
The buddy accelerator, if any, is disabled.
The label resizes itself if auto-resizing is enabled.
See also movie() and setBuddy().
void QLabel::setNum ( int num ) [virtual slot]
Sets the label contents to plain text containing the textual
representation of integer num. Any previous content is cleared. Does
nothing if the integer's string representation is the same as the
current contents of the label.
The buddy accelerator, if any, is disabled.
The label resizes itself if auto-resizing is enabled.
See also text, QString::setNum(), and setBuddy().
void QLabel::setNum ( double num ) [virtual slot]
This is an overloaded member function, provided for convenience. It
behaves essentially like the above function.
Sets the label contents to plain text containing the textual
representation of double num. Any previous content is cleared. Does
nothing if the double's string representation is the same as the
current contents of the label.
The buddy accelerator, if any, is disabled.
The label resizes itself if auto-resizing is enabled.
See also text, QString::setNum(), and setBuddy().
void QLabel::setPicture ( const QPicture & picture ) [virtual slot]
Sets the label contents to picture. Any previous content is cleared.
The buddy accelerator, if any, is disabled.
See also picture() and setBuddy().
void QLabel::setPixmap ( const QPixmap & ) [virtual slot]
Sets the label's pixmap. See the "pixmap" property for details.
void QLabel::setScaledContents ( bool )
Sets whether the label will scale its contents to fill all available
space. See the "scaledContents" property for details.
void QLabel::setText ( const QString & ) [virtual slot]
Sets the label's text. See the "text" property for details.
void QLabel::setTextFormat ( TextFormat )
Sets the label's text format. See the "textFormat" property for
details.
QString QLabel::text () const
Returns the label's text. See the "text" property for details.
TextFormat QLabel::textFormat () const
Returns the label's text format. See the "textFormat" property for
details.
Property Documentation
Alignment alignment
This property holds the alignment of the label's contents.
The alignment is a bitwise OR of Qt::AlignmentFlags and Qt::TextFlags
values. The ExpandTabs, SingleLine and ShowPrefix flags apply only if
the label contains plain text; otherwise they are ignored. The DontClip
flag is always ignored. WordBreak applies to both rich text and plain
text labels. The BreakAnywhere flag is not supported in QLabel.
If the label has a buddy, the ShowPrefix flag is forced to TRUE.
The default alignment is AlignAuto | AlignVCenter | ExpandTabs if the
label doesn't have a buddy and AlignAuto | AlignVCenter | ExpandTabs |
ShowPrefix if the label has a buddy. If the label contains rich text,
additionally WordBreak is turned on.
See also Qt::AlignmentFlags, setBuddy(), and text.
Set this property's value with setAlignment() and get this property's
value with alignment().
BackgroundMode backgroundMode
This property holds the label's background mode.
Get this property with backgroundMode().
See also QWidget::backgroundMode.
int indent
This property holds the label's text indent in pixels.
If a label displays text, the indent applies to the left edge if
alignment() is AlignLeft, to the right edge if alignment() is
AlignRight, to the top edge if alignment() is AlignTop, and to to the
bottom edge if alignment() is AlignBottom.
If indent is negative, or if no indent has been set, the label computes
the effective indent as follows: If frameWidth() is 0, the effective
indent becomes 0. If frameWidth() is greater than 0, the effective
indent becomes half the width of the "x" character of the widget's
current font().
See also alignment, frameWidth, and font.
Set this property's value with setIndent() and get this property's
value with indent().
QPixmap pixmap
This property holds the label's pixmap.
If no pixmap has been set this will return an invalid pixmap.
Setting the pixmap clears any previous content, and resizes the label
if QLabel::autoResize() is TRUE. The buddy accelerator, if any, is
disabled.
Set this property's value with setPixmap() and get this property's
value with pixmap().
bool scaledContents
This property holds whether the label will scale its contents to fill
all available space.
When enabled and the label shows a pixmap, it will scale the pixmap to
fill the available space.
This property's default is FALSE.
See also scaledContents.
Set this property's value with setScaledContents() and get this
property's value with hasScaledContents().
QString text
This property holds the label's text.
If no text has been set this will return an empty string. Setting the
text clears any previous content, unless they are the same.
The text will be interpreted either as a plain text or as a rich text,
depending on the text format setting; see setTextFormat(). The default
setting is AutoText, i.e. QLabel will try to auto-detect the format of
the text set.
If the text is interpreted as a plain text and a buddy has been set,
the buddy accelerator key is updated from the new text.
The label resizes itself if auto-resizing is enabled.
Note that Qlabel is well-suited to display small rich text documents,
i.e. those small documents that get their document specific settings
(font, text color, link color) from the label's palette and font
properties. For large documents, use QTextEdit in read-only mode
instead. QTextEdit will flicker less on resize and can also provide a
scrollbar when necessary.
See also textFormat, setBuddy(), and alignment.
Set this property's value with setText() and get this property's value
with text().
TextFormat textFormat
This property holds the label's text format.
See the Qt::TextFormat enum for an explanation of the possible options.
The default format is AutoText.
See also text.
Set this property's value with setTextFormat() and get this property's
value with textFormat().
SEE ALSO
http://doc.trolltech.com/qlabel.html
http://www.trolltech.com/faq/tech.html
COPYRIGHT
Copyright 1992-2007 Trolltech ASA, http://www.trolltech.com. See the
license file included in the distribution for a complete license
statement.
AUTHOR
Generated automatically from the source code.
BUGS
If you find a bug in Qt, please report it as described in
http://doc.trolltech.com/bughowto.html. Good bug reports help us to
help you. Thank you.
The definitive Qt documentation is provided in HTML format; it is
located at $QTDIR/doc/html and can be read using Qt Assistant or with a
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by Trolltech.
If you find errors in this manual page, please report them to qt-
bugs@trolltech.com. Please include the name of the manual page
(qlabel.3qt) and the Qt version (3.3.8).
Trolltech AS 2 February 2007 QLabel(3qt)
