TQt Toolkit - TQLabel Class

# TQLabel Class Reference

The TQLabel widget provides a static information display More...

`#include <ntqlabel.h>`

Inherits TQFrame.

List of all member functions.

## Public Members

- TQLabel ( TQWidget * parent, const char * name=0, WFlags f=0 )
- TQLabel ( const TQString & text, TQWidget * parent, const char * name=0, WFlags f=0 )
- TQLabel ( TQWidget * buddy, const TQString &, TQWidget * parent, const char * name=0, WFlags f=0 )
- ~TQLabel ()
- TQString text () const
- TQPixmap* pixmap () const
- TQMovie* 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 ( TQWidget * )
- TQWidget* buddy () const

## Public Slots

- virtual void setText ( const TQString & )
- 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
--- | --- | --- | --- | ---
TQString | text | text | setText |
TextFormat | textFormat | textFormat | setTextFormat |
TQPixmap | pixmap | pixmap | setPixmap |
bool | scaledContents | hasScaledContents | setScaledContents |
Alignment | alignment | alignment | setAlignment |
int | indent | indent | setIndent |

## Detailed Description

The TQLabel widget provides a static information display

TQLabel 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 TQLabel can contain any of the following content types:

- A plain text: set by passing a TQString to setText().
- A rich text: set by passing a TQString that contains a rich text to setText().
- A pixmap: set by passing a TQPixmap to setPixmap().
- A movie: set by passing a TQMovie 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 TQLabel can be tuned in several ways. All the settings of TQFrame are available for specifying a widget frame. The positioning of the content within the TQLabel 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):

        TQLabel *label = new TQLabel;
        label->setFrameStyle( TQFrame::Panel | TQFrame::Sunken );
        label->setText( "first line\nsecond line" );
        label->setAlignment( AlignBottom | AlignRight );

A TQLabel is often used as a label for another, interactive widget. For this use, TQLabel provides a handy mechanism for adding an accelerator key (see TQAccel) that will set the keyboard focus to the other widget (called the TQLabel's "buddy"). Example:

         TQLineEdit* phoneEdit = new TQLineEdit( this, "phoneEdit" );
         TQLabel* phoneLabel = new TQLabel( phoneEdit, "&Phone:", this, "phoneLabel" );

In this example, keyboard focus is transferred to the label's buddy (the TQLineEdit) when the user presses Alt-P. You can also use the setBuddy() function to accomplish the same.

See also TQLineEdit, TQTextView, TQPixmap, TQMovie and GUI Design Handbook: Label

Examples: cursor/cursor.cpp layout/layout.cpp popup/popup.cpp menu/menu.cpp progress/progress.cpp qmag/qmag.cpp movies/main.cpp customlayout/main.cpp

## Member Function Documentation

### TQLabel::TQLabel ( TQWidget * buddy, const TQString & text, TQWidget * 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 TQFrame constructor.

See also setText(), setBuddy(), setAlignment(), setFrameStyle() and setIndent().

### TQLabel::TQLabel ( TQWidget * parent, const char * name=0, WFlags f=0 )

Constructs an empty label.

The parent, name and f arguments are passed to the TQFrame constructor.

See also setAlignment(), setFrameStyle() and setIndent().

### TQLabel::TQLabel ( const TQString & text, TQWidget * 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 TQFrame constructor.

See also setText(), setAlignment(), setFrameStyle() and setIndent().

### TQLabel::~TQLabel ()

Destructs the label.

### int TQLabel::alignment () const

Returns the alignment setting.

See also setAlignment().

### bool TQLabel::autoResize () const

This function is obsolete. It is provided to keep old source working, and will probably be removed in a future version of TQt. 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().

### TQWidget * TQLabel::buddy () const

Returns the buddy of this label, or 0 if no buddy is currently set.

See also setBuddy().

### void TQLabel::clear () `[slot]`

Clears any label contents. Equivalent with setText( "" ).

### void TQLabel::drawContents ( TQPainter * p ) `[virtual protected]`

Draws the label contents using the painter p.

Reimplemented from TQFrame.

### void TQLabel::drawContentsMask ( TQPainter * p ) `[virtual protected]`

Draws the label contents mask using the painter p. Used only in transparent mode.

See also TQWidget::setAutoMask();.

Reimplemented from TQFrame.

### void TQLabel::fontChange ( const TQFont & ) `[virtual protected]`

Reimplemented for internal reasons; the API is not affected.

Reimplemented from TQWidget.

### bool TQLabel::hasScaledContents () const

Returns whether the label will scale its contents to fill all available space.

See also setScaledContents().

### int TQLabel::heightForWidth ( int w ) const `[virtual]`

Reimplemented for internal reasons; the API is not affected.

Reimplemented from TQWidget.

### int TQLabel::indent () const

Returns the indent of the label.

See also setIndent().

### TQSize TQLabel::minimumSizeHint () const `[virtual]`

Reimplemented for internal reasons; the API is not affected.

Reimplemented from TQWidget.

### TQMovie* TQLabel::movie () const

If the label contains a movie, returns a pointer to it. Otherwise, returns 0.

See also setMovie().

### TQPixmap * TQLabel::pixmap () const

If the label contains a pixmap, returns a pointer to it. Otherwise, returns 0.

See also setPixmap().

### void TQLabel::resizeEvent ( TQResizeEvent * e ) `[virtual protected]`

Reimplemented for internal reasons; the API is not affected.

Reimplemented from TQWidget.

### void TQLabel::setAlignment ( int alignment ) `[virtual]`

Sets the alignment of the label contents.

The alignment must be a bitwise OR of TQt::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 TQt::AlignmentFlags, alignment(), setBuddy() and setText().

Examples: cursor/cursor.cpp layout/layout.cpp popup/popup.cpp qmag/qmag.cpp customlayout/main.cpp

### void TQLabel::setAutoMask ( bool b ) `[virtual]`

Reimplemented for internal reasons; the API is not affected.

Reimplemented from TQWidget.

### void TQLabel::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 TQt. 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 TQLabel widgets that are not managed by a TQLayout (e.g. top-level widgets).

Auto-resizing is disabled by default.

See also autoResize(), adjustSize() and sizeHint().

### void TQLabel::setBuddy ( TQWidget * 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 TQLabels 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:

        TQLineEdit *nameEd  = new TQLineEdit( this );
        TQLabel    *nameLb  = new TQLabel( "&Name:", this );
        nameLb->setBuddy( nameEd );
        TQLineEdit *phoneEd = new TQLineEdit( this );
        TQLabel    *phoneLb = new TQLabel( "&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(), setText(), TQAccel and setAlignment().

Examples: layout/layout.cpp

### void TQLabel::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 TQLabel::setMovie ( const TQMovie & 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 TQLabel::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(), TQString::setNum() and setBuddy().

### void TQLabel::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(), TQString::setNum() and setBuddy().

### void TQLabel::setPixmap ( const TQPixmap & 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 TQLabel::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 TQLabel::setText ( const TQString & 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. TQLabel 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 TQTextView 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

### void TQLabel::setTextFormat ( TQt::TextFormat format )

Sets the text format to format. See the TQt::TextFormat enum for an explanation of the possible options.

The default format is `AutoText.`

See also textFormat() and setText().

### TQSize TQLabel::sizeHint () const `[virtual]`

Reimplemented for internal reasons; the API is not affected.

Examples: layout/layout.cpp

Reimplemented from TQWidget.

### TQSizePolicy TQLabel::sizePolicy () const `[virtual]`

Reimplemented for internal reasons; the API is not affected.

Reimplemented from TQWidget.

### TQString TQLabel::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().

### TQt::TextFormat TQLabel::textFormat() const

Returns the current text format.

See also setTextFormat().

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