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<QtMath> - Generic Math Functions

The <QtMath> header file provides various math functions.

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<QtMath> - Generic Math Functions

  • Header: QtMath

  • Group: <QtMath> is part of funclists

Detailed Description

These functions are partly convenience definitions for basic math operations not available in the C or Standard Template Libraries.

The header also ensures some constants specified in POSIX, but not present in C++ standards (so absent from <math.h> on some platforms), are defined:

Constant

Description

M_E

The base of the natural logarithms, e = exp(1)

M_LOG2E

The base-two logarithm of e

M_LOG10E

The base-ten logarithm of e

M_LN2

The natural logarithm of two

M_LN10

The natural logarithm of ten

M_PI

The ratio of a circle's circumference to diameter, π

M_PI_2

Half M_PI, π / 2

M_PI_4

Quarter M_PI, π / 4

M_1_PI

The inverse of M_PI, 1 / π

M_2_PI

Twice the inverse of M_PI, 2 / π

M_2_SQRTPI

Two divided by the square root of pi, 2 / √π

M_SQRT2

The square root of two, √2

M_SQRT1_2

The square roof of half, 1 / √2

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Function Documentation

 

qreal qAcos(qreal v)

Returns the arccosine of v as an angle in radians. Arccosine is the inverse operation of cosine.

See Also

See also qAtan(), qAsin(), qCos()

qreal qAsin(qreal v)

Returns the arcsine of v as an angle in radians. Arcsine is the inverse operation of sine.

See Also

See also qSin(), qAtan(), qAcos()

qreal qAtan2(qreal y, qreal x)

Returns the arctangent of a point specified by the coordinates y and x. This function will return the angle (argument) of that point.

See Also

See also qAtan()

qreal qAtan(qreal v)

Returns the arctangent of v as an angle in radians. Arctangent is the inverse operation of tangent.

See Also

See also qTan(), qAcos(), qAsin()

int qCeil(qreal v)

Return the ceiling of the value v.

The ceiling is the smallest integer that is not less than v. For example, if v is 41.2, then the ceiling is 42.

See Also

See also qFloor()

qreal qCos(qreal v)

Returns the cosine of an angle v in radians.

See Also

See also qSin(), qTan()

[since 5.1] int qDegreesToRadians(float degrees)

This function converts the degrees in float to radians.

Example:

 
Sélectionnez
float degrees = 180.0f
float radians = qDegreesToRadians(degrees)

This function was introduced in Qt 5.1.

See Also

See also qRadiansToDegrees()

[since 5.1] int qDegreesToRadians(double degrees)

This function converts the degrees in double to radians.

Example:

 
Sélectionnez
double degrees = 180.0
double radians = qDegreesToRadians(degrees)

This function was introduced in Qt 5.1.

See Also

See also qRadiansToDegrees()

qreal qExp(qreal v)

Returns the exponential function of e to the power of v.

See Also

See also qLn()

qreal qFabs(qreal v)

Returns the absolute value of v as a qreal.

int qFloor(qreal v)

Return the floor of the value v.

The floor is the largest integer that is not greater than v. For example, if v is 41.2, then the floor is 41.

See Also

See also qCeil()

qreal qLn(qreal v)

Returns the natural logarithm of v. Natural logarithm uses base e.

See Also

See also qExp()

qreal qPow(qreal x, qreal y)

Returns the value of x raised to the power of y. That is, x is the base and y is the exponent.

See Also

See also qSqrt()

[since 5.1] int qRadiansToDegrees(float radians)

This function converts the radians in float to degrees.

Example:

 
Sélectionnez
float radians = float(M_PI)
float degrees = qRadiansToDegrees(radians)

This function was introduced in Qt 5.1.

See Also

See also qDegreesToRadians()

[since 5.1] int qRadiansToDegrees(double radians)

This function converts the radians in double to degrees.

Example:

 
Sélectionnez
double radians = M_PI
double degrees = qRadiansToDegrees(radians)

This function was introduced in Qt 5.1.

See Also

See also qDegreesToRadians()

qreal qSin(qreal v)

Returns the sine of the angle v in radians.

See Also

See also qCos(), qTan()

qreal qSqrt(qreal v)

Returns the square root of v. This function returns a NaN if v is a negative number.

See Also

See also qPow()

qreal qTan(qreal v)

Returns the tangent of an angle v in radians.

See Also

See also qSin(), qCos()

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