QLCDNumber

Section: Misc. Reference Manual Pages (3qt)
Updated: 2 February 2007
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NAME

QLCDNumber - Displays a number with LCD-like digits

SYNOPSIS

Inherits QFrame.

Public Members

QLCDNumber ( QWidget * parent = 0, const char * name = 0 )

QLCDNumber ( uint numDigits, QWidget * parent = 0, const char * name = 0 )

~QLCDNumber ()

enum Mode { Hex, Dec, Oct, Bin, HEX = Hex, DEC = Dec, OCT = Oct, BIN = Bin }

enum SegmentStyle { Outline, Filled, Flat }

bool smallDecimalPoint () const

int numDigits () const

virtual void setNumDigits ( int nDigits )

bool checkOverflow ( double num ) const

bool checkOverflow ( int num ) const

Mode mode () const

virtual void setMode ( Mode )

SegmentStyle segmentStyle () const

virtual void setSegmentStyle ( SegmentStyle )

double value () const

int intValue () const

Public Slots

void display ( const QString & s )

void display ( int num )

void display ( double num )

virtual void setHexMode ()

virtual void setDecMode ()

virtual void setOctMode ()

virtual void setBinMode ()

virtual void setSmallDecimalPoint ( bool )

Signals

void overflow ()

Properties

int intValue - the displayed value rounded to the nearest integer

Mode mode - the current display mode (number base)

int numDigits - the current number of digits displayed

SegmentStyle segmentStyle - the style of the LCDNumber

bool smallDecimalPoint - the style of the decimal point

double value - the displayed value

Protected Members

virtual void drawContents ( QPainter * p )

DESCRIPTION

The QLCDNumber widget displays a number with LCD-like digits.

It can display a number in just about any size. It can display decimal, hexadecimal, octal or binary numbers. It is easy to connect to data sources using the display() slot, which is overloaded to take any of five argument types.

There are also slots to change the base with setMode() and the decimal point with setSmallDecimalPoint().

QLCDNumber emits the overflow() signal when it is asked to display something beyond its range. The range is set by setNumDigits(), but setSmallDecimalPoint() also influences it. If the display is set to hexadecimal, octal or binary, the integer equivalent of the value is displayed.

These digits and other symbols can be shown: 0/O, 1, 2, 3, 4, 5/S, 6, 7, 8, 9/g, minus, decimal point, A, B, C, D, E, F, h, H, L, o, P, r, u, U, Y, colon, degree sign (which is specified as single quote in the string) and space. QLCDNumber substitutes spaces for illegal characters.

It is not possible to retrieve the contents of a QLCDNumber object, although you can retrieve the numeric value with value(). If you really need the text, we recommend that you connect the signals that feed the display() slot to another slot as well and store the value there.

Incidentally, QLCDNumber is the very oldest part of Qt, tracing back to a BASIC program on the Sinclair Spectrum.

[Image Omitted]

See also QLabel, QFrame, and Basic Widgets.

Member Type Documentation

QLCDNumber::Mode

This type determines how numbers are shown.

QLCDNumber::Hex - Hexadecimal
QLCDNumber::Dec - Decimal
QLCDNumber::Oct - Octal
QLCDNumber::Bin - Binary

If the display is set to hexadecimal, octal or binary, the integer equivalent of the value is displayed.

QLCDNumber::SegmentStyle

This type determines the visual appearance of the QLCDNumber widget.

QLCDNumber::Outline - gives raised segments filled with the background brush.
QLCDNumber::Filled - gives raised segments filled with the foreground brush.
QLCDNumber::Flat - gives flat segments filled with the foreground brush.

MEMBER FUNCTION DOCUMENTATION

QLCDNumber::QLCDNumber ( QWidget * parent = 0, const char * name = 0 )

Constructs an LCD number, sets the number of digits to 5, the base to decimal, the decimal point mode to 'small' and the frame style to a raised box. The segmentStyle() is set to Outline.

The parent and name arguments are passed to the QFrame constructor.

See also numDigits and smallDecimalPoint.

QLCDNumber::QLCDNumber ( uint numDigits, QWidget * parent = 0, const char * name = 0 )

Constructs an LCD number, sets the number of digits to numDigits, the base to decimal, the decimal point mode to 'small' and the frame style to a raised box. The segmentStyle() is set to Outline.

The parent and name arguments are passed to the QFrame constructor.

See also numDigits and smallDecimalPoint.

QLCDNumber::~QLCDNumber ()

Destroys the LCD number.

bool QLCDNumber::checkOverflow ( double num ) const

Returns TRUE if num is too big to be displayed in its entirety; otherwise returns FALSE.

See also display(), numDigits, and smallDecimalPoint.

bool QLCDNumber::checkOverflow ( int num ) const

This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

Returns TRUE if num is too big to be displayed in its entirety; otherwise returns FALSE.

See also display(), numDigits, and smallDecimalPoint.

void QLCDNumber::display ( const QString & s ) [slot]

Displays the number represented by the string s.

This version of the function disregards mode() and smallDecimalPoint().

Examples:

void QLCDNumber::display ( int num ) [slot]

Sets the displayed value rounded to the nearest integer to num. See the "intValue" property for details.

void QLCDNumber::display ( double num ) [slot]

This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

Displays the number num.

void QLCDNumber::drawContents ( QPainter * p ) [virtual protected]

Draws the LCD number using painter p. This function is called from QFrame::paintEvent().

Reimplemented from QFrame.

int QLCDNumber::intValue () const

Returns the displayed value rounded to the nearest integer. See the "intValue" property for details.

Mode QLCDNumber::mode () const

Returns the current display mode (number base). See the "mode" property for details.

int QLCDNumber::numDigits () const

Returns the current number of digits displayed. See the "numDigits" property for details.

void QLCDNumber::overflow () [signal]

This signal is emitted whenever the QLCDNumber is asked to display a too-large number or a too-long string.

It is never emitted by setNumDigits().

SegmentStyle QLCDNumber::segmentStyle () const

Returns the style of the LCDNumber. See the "segmentStyle" property for details.

void QLCDNumber::setBinMode () [virtual slot]

Calls setMode( BIN ). Provided for convenience (e.g. for connecting buttons to it).

See also mode, setHexMode(), setDecMode(), setOctMode(), and mode.

void QLCDNumber::setDecMode () [virtual slot]

Calls setMode( DEC ). Provided for convenience (e.g. for connecting buttons to it).

See also mode, setHexMode(), setOctMode(), setBinMode(), and mode.

void QLCDNumber::setHexMode () [virtual slot]

Calls setMode( HEX ). Provided for convenience (e.g. for connecting buttons to it).

See also mode, setDecMode(), setOctMode(), setBinMode(), and mode.

void QLCDNumber::setMode ( Mode ) [virtual]

Sets the current display mode (number base). See the "mode" property for details.

void QLCDNumber::setNumDigits ( int nDigits ) [virtual]

Sets the current number of digits displayed to nDigits. See the "numDigits" property for details.

void QLCDNumber::setOctMode () [virtual slot]

Calls setMode( OCT ). Provided for convenience (e.g. for connecting buttons to it).

See also mode, setHexMode(), setDecMode(), setBinMode(), and mode.

void QLCDNumber::setSegmentStyle ( SegmentStyle ) [virtual]

Sets the style of the LCDNumber. See the "segmentStyle" property for details.

void QLCDNumber::setSmallDecimalPoint ( bool ) [virtual slot]

Sets the style of the decimal point. See the "smallDecimalPoint" property for details.

bool QLCDNumber::smallDecimalPoint () const

Returns the style of the decimal point. See the "smallDecimalPoint" property for details.

double QLCDNumber::value () const

Returns the displayed value. See the "value" property for details.

Property Documentation

int intValue

This property holds the displayed value rounded to the nearest integer.

This property corresponds to the nearest integer to the current value displayed by the LCDNumber. This is the value used for hexadecimal, octal and binary modes.

If the displayed value is not a number, the property has a value of 0.

Set this property's value with display() and get this property's value with intValue().

Mode mode

This property holds the current display mode (number base).

Corresponds to the current display mode, which is one of BIN, OCT, DEC (the default) and HEX. DEC mode can display floating point values, the other modes display the integer equivalent.

See also smallDecimalPoint, setHexMode(), setDecMode(), setOctMode(), and setBinMode().

Set this property's value with setMode() and get this property's value with mode().

int numDigits

This property holds the current number of digits displayed.

Corresponds to the current number of digits. If QLCDNumber::smallDecimalPoint is FALSE, the decimal point occupies one digit position.

SegmentStyle segmentStyle

This