QLabel(3qt)QLabel(3qt)NAME
QLabel - Static information display
#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 &, QWidget *
parent, const char * name=0, WFlags f=0 )
~QLabel ()
QString text () const
QPixmap* pixmap () 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 ) (obsolete)
bool hasScaledContents () const
void setScaledContents ( bool )
virtual void setBuddy ( QWidget * )
QWidget* buddy () const
Public Slots
virtual void setText ( const QString & )
virtual void setPixmap ( const QPixmap & )
virtual void setMovie ( const QMovie & )
virtual void setNum ( int )
virtual void setNum ( double )
void clear ()
Protected Members
virtual void drawContents ( QPainter * )
virtual void drawContentsMask ( QPainter * )
Properties
Type Name READ WRITE Options
------------------------------------------------------------------------------
QString text text setText
TextFormat textFormat textFormat setTextFormat
QPixmap pixmap pixmap setPixmap
bool scaledContents hasScaledContents setScaledContents
Alignment alignment alignment setAlignment
int indent indent setIndent
Trolltech AS 13 June 2001 1
QLabel(3qt)QLabel(3qt)DESCRIPTION
The QLabel widget provides a static information display
QLabel is used for displaying information in the form of
text or image to the user. 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:
A plain text: set by passing a QString to setText().
A rich text: set by passing a QString that contains a rich
text to setText().
A pixmap: set by passing a QPixmap to setPixmap().
A movie: set by passing a QMovie to setMovie().
A number: set by passing an int or a double to setNum(),
which converts the number to plain text.
Nothing: The same as an empty plain text. This is the
default. Set by clear().
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;
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 another, interactive
widget. For this use, QLabel provides a handy mechanism
for adding an accelerator key (see QAccel) that will set
the keyboard focus to the other widget (called the
QLabel's "buddy"). 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.
Trolltech AS 13 June 2001 2
QLabel(3qt)QLabel(3qt)
You can also use the setBuddy() function to accomplish the
same.
[Image Omitted]
[Image Omitted]
See also QLineEdit, QTextView, QPixmap, QMovie and GUI
Design Handbook: Label
Examples: cursor/cursor.cpp layout/layout.cpp
popup/popup.cpp menu/menu.cpp progress/progress.cpp
qmag/qmag.cpp xml/tagreader movies/main.cpp
customlayout/main.cpp
MEMBER FUNCTION DOCUMENTATIONQLabel::QLabel ( QWidget * buddy, const QString & text, QWidget *
parent, const char * name=0, WFlags f=0 )
Constructs a label with a text and a buddy.
The text is set with setText(). The buddy is set with
setBuddy().
The parent, name and f arguments are passed to the QFrame
constructor.
See also setText(), setBuddy(), setAlignment(),
setFrameStyle() and setIndent().
QLabel::QLabel ( QWidget * parent, const char * name=0, WFlags
f=0 )
Constructs an empty label.
The parent, name and f arguments are passed to the QFrame
constructor.
See also setAlignment(), setFrameStyle() and setIndent().
QLabel::QLabel ( const QString & text, QWidget * parent, const
char * name=0, WFlags f=0 )
Constructs a label with a text. The text is set with
setText().
The parent, name and f arguments are passed to the QFrame
constructor.
See also setText(), setAlignment(), setFrameStyle() and
setIndent().
QLabel::~QLabel ()
Destructs the label.
Trolltech AS 13 June 2001 3
QLabel(3qt)QLabel(3qt)int QLabel::alignment () const
Returns the alignment setting.
See also setAlignment().
bool QLabel::autoResize () const
This function is obsolete. It is provided to keep old
source working, and will probably be removed in a future
version of Qt. 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 the buddy of this label, or 0 if no buddy is
currently set.
See also setBuddy().
void QLabel::clear () [slot]
Clears any label contents. Equivalent with setText( "" ).
void QLabel::drawContents ( QPainter * p ) [virtual protected]
Draws the label contents using the painter p.
Reimplemented from QFrame.
void QLabel::drawContentsMask ( QPainter * p ) [virtual
protected]
Draws the label contents mask using the painter p. Used
only in transparent mode.
See also QWidget::setAutoMask();.
Reimplemented from QFrame.
void QLabel::fontChange ( const QFont & ) [virtual protected]
Reimplemented for internal reasons; the API is not
affected.
Reimplemented from QWidget.
bool QLabel::hasScaledContents () const
Returns whether the label will scale its contents to fill
all available space.
See also setScaledContents().
Trolltech AS 13 June 2001 4
QLabel(3qt)QLabel(3qt)int QLabel::heightForWidth ( int w ) const [virtual]
Reimplemented for internal reasons; the API is not
affected.
Reimplemented from QWidget.
int QLabel::indent () const
Returns the indent of the label.
See also setIndent().
QSize QLabel::minimumSizeHint () const [virtual]
Reimplemented for internal reasons; the API is not
affected.
Reimplemented from QWidget.
QMovie* QLabel::movie () const
If the label contains a movie, returns a pointer to it.
Otherwise, returns 0.
See also setMovie().
QPixmap * QLabel::pixmap () const
If the label contains a pixmap, returns a pointer to it.
Otherwise, returns 0.
See also setPixmap().
void QLabel::resizeEvent ( QResizeEvent * e ) [virtual protected]
Reimplemented for internal reasons; the API is not
affected.
Reimplemented from QWidget.
void QLabel::setAlignment ( int alignment ) [virtual]
Sets the alignment of the label contents.
The alignment must be a bitwise OR of Qt::AlignmentFlags
values. The WordBreak, ExpandTabs, SingleLine and
ShowPrefix flags apply only if the label contains a plain
text, and are otherwise ignored. The DontClip flag is
always ignored.
If the label has a buddy, the ShowPrefix flag is forced to
TRUE.
The default alignment is AlignLeft | AlignVCenter |
ExpandTabs if the label doesn't have a buddy and AlignLeft
| AlignVCenter | ExpandTabs | ShowPrefix if the label has
a buddy.
See also Qt::AlignmentFlags, alignment(), setBuddy() and
setText().
Trolltech AS 13 June 2001 5
QLabel(3qt)QLabel(3qt)
Examples: cursor/cursor.cpp layout/layout.cpp
popup/popup.cpp qmag/qmag.cpp customlayout/main.cpp
void QLabel::setAutoMask ( bool b ) [virtual]
Reimplemented for internal reasons; the API is not
affected.
Reimplemented from QWidget.
void QLabel::setAutoResize ( bool enable ) [virtual]
This function is obsolete. It is provided to keep old
source working, and will probably be removed in a future
version of Qt. 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 the buddy of this label 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 a plain text in which one letter is prefixed with
'&'. It is this letter that 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"), somewhat like this:
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 )
Trolltech AS 13 June 2001 6
QLabel(3qt)QLabel(3qt)
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(), setText(), QAccel and setAlignment().
void QLabel::setIndent ( int indent )
Sets the indent of the label to indent pixels.
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().
If indent is non-negative, the effective indent is indent
pixels.
See also indent(), setAlignment(), frameWidth() and
font().
Examples: movies/main.cpp
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 ( double num ) [virtual slot]
Sets the label contents to a plain text containing the
printed value of num. Does nothing if this is equal to the
current contents of the label. Any previous content is
cleared.
The buddy accelerator, if any, is disabled.
The label resizes itself if auto-resizing is enabled.
See also setText(), QString::setNum() and setBuddy().
Trolltech AS 13 June 2001 7
QLabel(3qt)QLabel(3qt)void QLabel::setNum ( int num ) [virtual slot]
Sets the label contents to a plain text containing the
printed value of num. Does nothing if this is equal to the
current contents of the label. Any previous content is
cleared.
The buddy accelerator, if any, is disabled.
The label resizes itself if auto-resizing is enabled.
See also setText(), QString::setNum() and setBuddy().
void QLabel::setPixmap ( const QPixmap & pixmap ) [virtual slot]
Sets the label contents to pixmap. Any previous content is
cleared.
The buddy accelerator, if any, is disabled.
The label resizes itself if auto-resizing is enabled.
See also pixmap() and setBuddy().
void QLabel::setScaledContents ( bool enable )
When called with enable == TRUE, and the label shows a
pixmap, it will scale the pixmap to fill available space.
See also hasScaledContents().
void QLabel::setText ( const QString & text ) [virtual slot]
Sets the label contents to text, or does nothing if text
is equal to the current contents of the label. Any
previous content is cleared.
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 text.
If 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 only. For large documents, use QTextView
instead. It will flicker less on resize and can also
provide a scrollbar if necessary.
See also text(), setTextFormat(), setBuddy() and
setAlignment().
Examples: cursor/cursor.cpp layout/layout.cpp
popup/popup.cpp qmag/qmag.cpp customlayout/main.cpp
Trolltech AS 13 June 2001 8
QLabel(3qt)QLabel(3qt)void QLabel::setTextFormat ( Qt::TextFormat format )
Sets the text format to format. See the Qt::TextFormat
enum for an explanation of the possible options.
The default format is AutoText.
See also textFormat() and setText().
QSize QLabel::sizeHint () const [virtual]
Reimplemented for internal reasons; the API is not
affected.
Examples: layout/layout.cpp
Reimplemented from QWidget.
QSizePolicy QLabel::sizePolicy () const [virtual]
Reimplemented for internal reasons; the API is not
affected.
Reimplemented from QWidget.
QString QLabel::text () const
Returns the label text. If the content is a plain or a
rich text, this is the string that was passed to
setText(). Otherwise, it is an empty/null string.
See also setText(), setNum() and clear().
Qt::TextFormat QLabel::textFormat() const
Returns the current text format.
See also setTextFormat().
SEE ALSO
http://doc.trolltech.com/qlabel.html
http://www.trolltech.com/faq/tech.html
COPYRIGHT
Copyright 1992-2001 Trolltech AS,
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
make our job much simpler. Thank you.
In case of content or formattting problems with this
manual page, please report them to qt-bugs@trolltech.com.
Please include the name of the manual page (qlabel.3qt)
Trolltech AS 13 June 2001 9
QLabel(3qt)QLabel(3qt)
and the Qt version (2.3.1).
Trolltech AS 13 June 2001 10
