QGradient Class

The QGradient class is the base of the gradients that brushes fill with. More…

Header	`#include <QGradient>`
CMake	`target_link_libraries(app PRIVATE Nt::Gui)`
Module	Nt GUI C++ Classes
Inherited by	QConicalGradient, QLinearGradient, QRadialGradient

List of all members, including inherited members

Public Types

enum	Type
enum	Spread
enum	CoordinateMode

Public Functions

	QGradient()
Type	type() const
void	setSpread(Spread spread)
Spread	spread() const
void	setColorAt(qreal position, const QColor &color)
void	setStops(const QGradientStops &stops)
QGradientStops	stops() const
CoordinateMode	coordinateMode() const
void	setCoordinateMode(CoordinateMode mode)
bool	operator==(const QGradient &other) const
bool	operator!=(const QGradient &other) const

Detailed Description

A gradient goes through colors at stops from 0.0 to 1.0. setSpread() decides what lies beyond them. QLinearGradient, QRadialGradient and QConicalGradient, from left to right:

A linear, a radial and a conical gradient

const qreal w = size.width() / 3, h = size.height();
QLinearGradient linear(0, 0, w, h);
linear.setColorAt(0, QColor(40, 90, 200));
linear.setColorAt(1, QColor(230, 240, 255));
painter.fillRect(QRectF(0, 0, w, h), linear);

QRadialGradient radial(QPointF(w * 1.5, h / 2), w / 2, QPointF(w * 1.35, h * 0.35));
radial.setColorAt(0, Qt::white);
radial.setColorAt(1, QColor(200, 40, 60));
painter.fillRect(QRectF(w, 0, w, h), radial);

QConicalGradient conical(QPointF(w * 2.5, h / 2), phase);
for (int i = 0; i <= 6; ++i)
    conical.setColorAt(i / 6.0, QColor::fromHsv((i * 60) % 360, 220, 240));
painter.fillRect(QRectF(2 * w, 0, w, h), conical);

A shorter example:

QLinearGradient sky(0, 0, 0, 200);
sky.setColorAt(0.0, QColor(30, 60, 140));
sky.setColorAt(1.0, QColor(200, 220, 255));
painter.fillRect(QRectF(0, 0, 300, 200), sky);

See also QLinearGradient, QRadialGradient, QConicalGradient and QBrush.

Differences from Qt

The coordinate modes are kept, but gradients are always in the logical coordinates of the painter, as with LogicalMode. There are no presets and no interpolation modes.

Member Type Documentation

enum QGradient::CoordinateMode

Constant	Description
`QGradient::LogicalMode`	The points of the gradient are in the logical coordinates of the painter.
`QGradient::StretchToDeviceMode`	Relative to the paint device; drawn as LogicalMode in Nt.
`QGradient::ObjectBoundingMode`	Relative to the shape filled; drawn as LogicalMode in Nt.
`QGradient::ObjectMode`	Relative to the shape filled; drawn as LogicalMode in Nt.

enum QGradient::Spread

What lies beyond the first and last stops.

Constant	Description
`QGradient::PadSpread`	The colors of the first and last stops.
`QGradient::ReflectSpread`	The gradient again, mirrored.
`QGradient::RepeatSpread`	The gradient again.

enum QGradient::Type

Constant	Description
`QGradient::LinearGradient`	A QLinearGradient.
`QGradient::RadialGradient`	A QRadialGradient.
`QGradient::ConicalGradient`	A QConicalGradient.
`QGradient::NoGradient`	No gradient.

Member Function Documentation

QGradient::QGradient()

Constructs an empty gradient of no type.

CoordinateMode QGradient::coordinateMode() const

Returns the coordinate mode; LogicalMode by default.

bool QGradient::operator!=(const QGradient &other) const

Returns true if other differs from this gradient.

bool QGradient::operator==(const QGradient &other) const

Returns true if other has the same type, stops, spread, mode and points; otherwise returns false.

void QGradient::setColorAt(qreal position, const QColor &color)

Puts color at position, from 0.0 to 1.0, replacing a stop at the same position.

void QGradient::setCoordinateMode(CoordinateMode mode)

Sets the coordinate mode to mode.

void QGradient::setSpread(Spread spread)

Sets what lies beyond the stops to spread.

void QGradient::setStops(const QGradientStops &stops)

Replaces the stops with stops; positions outside 0.0 to 1.0 are skipped.

Spread QGradient::spread() const

Returns what lies beyond the stops; PadSpread by default.

QGradientStops QGradient::stops() const

Returns the stops, in order. A gradient without stops goes from black to white.

Type QGradient::type() const

Returns the type of the gradient.