QGradient Class

The QGradient class is used in combination with QBrush to specify gradient fills. More...

Header:	#include <QGradient>
CMake:	find_package(Qt6 COMPONENTS Gui REQUIRED) target_link_libraries(mytarget PRIVATE Qt6::Gui)
qmake:	QT += gui
Inherited By:	QConicalGradient, QLinearGradient, and QRadialGradient

• List of all members, including inherited members

Public Types

enum	CoordinateMode { LogicalMode, ObjectMode, StretchToDeviceMode, ObjectBoundingMode }
enum	Preset { WarmFlame, NightFade, SpringWarmth, JuicyPeach, YoungPassion, …, PerfectBlue }
enum	Spread { PadSpread, RepeatSpread, ReflectSpread }
enum	Type { LinearGradient, RadialGradient, ConicalGradient, NoGradient }

Public Functions

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

Related Non-Members

	QGradientStop
	QGradientStops

Detailed Description

Qt currently supports three types of gradient fills:

• Linear gradients interpolate colors between start and end points.
• Simple radial gradients interpolate colors between a focal point and end points on a circle surrounding it.
• Extended radial gradients interpolate colors between a center and a focal circle.
• Conical gradients interpolate colors around a center point.

A gradient's type can be retrieved using the type() function. Each of the types is represented by a subclass of QGradient:

QLinearGradient	QRadialGradient	QConicalGradient

The colors in a gradient are defined using stop points of the QGradientStop type; i.e., a position and a color. Use the setColorAt() function to define a single stop point. Alternatively, use the setStops() function to define several stop points in one go. Note that the latter function replaces the current set of stop points.

It is the gradient's complete set of stop points (accessible through the stops() function) that describes how the gradient area should be filled. If no stop points have been specified, a gradient of black at 0 to white at 1 is used.

A diagonal linear gradient from black at (100, 100) to white at (200, 200) could be specified like this:

QLinearGradient linearGrad(QPointF(100, 100), QPointF(200, 200));
linearGrad.setColorAt(0, Qt::black);
linearGrad.setColorAt(1, Qt::white);

A gradient can have an arbitrary number of stop points. The following would create a radial gradient starting with red in the center, blue and then green on the edges:

QRadialGradient radialGrad(QPointF(100, 100), 100);
radialGrad.setColorAt(0, Qt::red);
radialGrad.setColorAt(0.5, Qt::blue);
radialGrad.setColorAt(1, Qt::green);

It is possible to repeat or reflect the gradient outside its area by specifiying the spread method using the setSpread() function. The default is to pad the outside area with the color at the closest stop point. The currently set spread method can be retrieved using the spread() function. The QGradient::Spread enum defines three different methods:

PadSpread	RepeatSpread	ReflectSpread

Note that the setSpread() function only has effect for linear and radial gradients. The reason is that the conical gradient is closed by definition, i.e. the conical gradient fills the entire circle from 0 - 360 degrees, while the boundary of a radial or a linear gradient can be specified through its radius or final stop points, respectively.

The gradient coordinates can be specified in logical coordinates, relative to device coordinates, or relative to object bounding box coordinates. The coordinate mode can be set using the setCoordinateMode() function. The default is LogicalMode, where the gradient coordinates are specified in the same way as the object coordinates. To retrieve the currently set coordinate mode use coordinateMode().

See also The Gradients Example and QBrush.

Member Type Documentation

enum QGradient::CoordinateMode

This enum specifies how gradient coordinates map to the paint device on which the gradient is used.

Constant	Value	Description
QGradient::LogicalMode	0	This is the default mode. The gradient coordinates are specified logical space just like the object coordinates.
QGradient::ObjectMode	3	In this mode the gradient coordinates are relative to the bounding rectangle of the object being drawn, with (0,0) in the top left corner, and (1,1) in the bottom right corner of the object's bounding rectangle. This value was added in Qt 5.12.
QGradient::StretchToDeviceMode	1	In this mode the gradient coordinates are relative to the bounding rectangle of the paint device, with (0,0) in the top left corner, and (1,1) in the bottom right corner of the paint device.
QGradient::ObjectBoundingMode	2	This mode is the same as ObjectMode, except that the {QBrush::transform()} {brush transform}, if any, is applied relative to the logical space instead of the object space. This enum value is deprecated and should not be used in new code.

[since 5.12] enum QGradient::Preset

This enum specifies a set of predefined presets for QGradient, based on the gradients from https://webgradients.com/.

Constant	Value
QGradient::WarmFlame	1
QGradient::NightFade	2
QGradient::SpringWarmth	3
QGradient::JuicyPeach	4
QGradient::YoungPassion	5
QGradient::LadyLips	6
QGradient::SunnyMorning	7
QGradient::RainyAshville	8
QGradient::FrozenDreams	9
QGradient::WinterNeva	10
QGradient::DustyGrass	11
QGradient::TemptingAzure	12
QGradient::HeavyRain	13
QGradient::AmyCrisp	14
QGradient::MeanFruit	15
QGradient::DeepBlue	16
QGradient::RipeMalinka	17
QGradient::CloudyKnoxville	18
QGradient::MalibuBeach	19
QGradient::NewLife	20
QGradient::TrueSunset	21
QGradient::MorpheusDen	22
QGradient::RareWind	23
QGradient::NearMoon	24
QGradient::WildApple	25
QGradient::SaintPetersburg	26
QGradient::PlumPlate	28
QGradient::EverlastingSky	29
QGradient::HappyFisher	30
QGradient::Blessing	31
QGradient::SharpeyeEagle	32
QGradient::LadogaBottom	33
QGradient::LemonGate	34
QGradient::ItmeoBranding	35
QGradient::ZeusMiracle	36
QGradient::OldHat	37
QGradient::StarWine	38
QGradient::HappyAcid	41
QGradient::AwesomePine	42
QGradient::NewYork	43
QGradient::ShyRainbow	44
QGradient::MixedHopes	46
QGradient::FlyHigh	47
QGradient::StrongBliss	48
QGradient::FreshMilk	49
QGradient::SnowAgain	50
QGradient::FebruaryInk	51
QGradient::KindSteel	52
QGradient::SoftGrass	53
QGradient::GrownEarly	54
QGradient::SharpBlues	55
QGradient::ShadyWater	56
QGradient::DirtyBeauty	57
QGradient::GreatWhale	58
QGradient::TeenNotebook	59
QGradient::PoliteRumors	60
QGradient::SweetPeriod	61
QGradient::WideMatrix	62
QGradient::SoftCherish	63
QGradient::RedSalvation	64
QGradient::BurningSpring	65
QGradient::NightParty	66
QGradient::SkyGlider	67
QGradient::HeavenPeach	68
QGradient::PurpleDivision	69
QGradient::AquaSplash	70
QGradient::SpikyNaga	72
QGradient::LoveKiss	73
QGradient::CleanMirror	75
QGradient::PremiumDark	76
QGradient::ColdEvening	77
QGradient::CochitiLake	78
QGradient::SummerGames	79
QGradient::PassionateBed	80
QGradient::MountainRock	81
QGradient::DesertHump	82
QGradient::JungleDay	83
QGradient::PhoenixStart	84
QGradient::OctoberSilence	85
QGradient::FarawayRiver	86
QGradient::AlchemistLab	87
QGradient::OverSun	88
QGradient::PremiumWhite	89
QGradient::MarsParty	90
QGradient::EternalConstance	91
QGradient::JapanBlush	92
QGradient::SmilingRain	93
QGradient::CloudyApple	94
QGradient::BigMango	95
QGradient::HealthyWater	96
QGradient::AmourAmour	97
QGradient::RiskyConcrete	98
QGradient::StrongStick	99
QGradient::ViciousStance	100
QGradient::PaloAlto	101
QGradient::HappyMemories	102
QGradient::MidnightBloom	103
QGradient::Crystalline	104
QGradient::PartyBliss	106
QGradient::ConfidentCloud	107
QGradient::LeCocktail	108
QGradient::RiverCity	109
QGradient::FrozenBerry	110
QGradient::ChildCare	112
QGradient::FlyingLemon	113
QGradient::NewRetrowave	114
QGradient::HiddenJaguar	115
QGradient::AboveTheSky	116
QGradient::Nega	117
QGradient::DenseWater	118
QGradient::Seashore	120
QGradient::MarbleWall	121
QGradient::CheerfulCaramel	122
QGradient::NightSky	123
QGradient::MagicLake	124
QGradient::YoungGrass	125
QGradient::ColorfulPeach	126
QGradient::GentleCare	127
QGradient::PlumBath	128
QGradient::HappyUnicorn	129
QGradient::AfricanField	131
QGradient::SolidStone	132
QGradient::OrangeJuice	133
QGradient::GlassWater	134
QGradient::NorthMiracle	136
QGradient::FruitBlend	137
QGradient::MillenniumPine	138
QGradient::HighFlight	139
QGradient::MoleHall	140
QGradient::SpaceShift	142
QGradient::ForestInei	143
QGradient::RoyalGarden	144
QGradient::RichMetal	145
QGradient::JuicyCake	146
QGradient::SmartIndigo	147
QGradient::SandStrike	148
QGradient::NorseBeauty	149
QGradient::AquaGuidance	150
QGradient::SunVeggie	151
QGradient::SeaLord	152
QGradient::BlackSea	153
QGradient::GrassShampoo	154
QGradient::LandingAircraft	155
QGradient::WitchDance	156
QGradient::SleeplessNight	157
QGradient::AngelCare	158
QGradient::CrystalRiver	159
QGradient::SoftLipstick	160
QGradient::SaltMountain	161
QGradient::PerfectWhite	162
QGradient::FreshOasis	163
QGradient::StrictNovember	164
QGradient::MorningSalad	165
QGradient::DeepRelief	166
QGradient::SeaStrike	167
QGradient::NightCall	168
QGradient::SupremeSky	169
QGradient::LightBlue	170
QGradient::MindCrawl	171
QGradient::LilyMeadow	172
QGradient::SugarLollipop	173
QGradient::SweetDessert	174
QGradient::MagicRay	175
QGradient::TeenParty	176
QGradient::FrozenHeat	177
QGradient::GagarinView	178
QGradient::FabledSunset	179
QGradient::PerfectBlue	180

This enum was introduced or modified in Qt 5.12.

enum QGradient::Spread

Specifies how the area outside the gradient area should be filled.

Constant	Value	Description
QGradient::PadSpread	0	The area is filled with the closest stop color. This is the default.
QGradient::RepeatSpread	2	The gradient is repeated outside the gradient area.
QGradient::ReflectSpread	1	The gradient is reflected outside the gradient area.

See also spread() and setSpread().

enum QGradient::Type

Specifies the type of gradient.

Constant	Value	Description
QGradient::LinearGradient	0	Interpolates colors between start and end points (QLinearGradient).
QGradient::RadialGradient	1	Interpolate colors between a focal point and end points on a circle surrounding it (QRadialGradient).
QGradient::ConicalGradient	2	Interpolate colors around a center point (QConicalGradient).
QGradient::NoGradient	3	No gradient is used.

See also type().

Member Function Documentation

[since 5.12] QGradient::QGradient(QGradient::Preset preset)

Constructs a gradient based on a predefined preset.

The coordinate mode of the resulting gradient is QGradient::ObjectMode, allowing the preset to be applied to arbitrary object sizes.

This function was introduced in Qt 5.12.

QGradient::CoordinateMode QGradient::coordinateMode() const

Returns the coordinate mode of this gradient. The default mode is LogicalMode.

See also setCoordinateMode().

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

Creates a stop point at the given position with the given color. The given position must be in the range 0 to 1.

See also setStops() and stops().

void QGradient::setCoordinateMode(QGradient::CoordinateMode mode)

Sets the coordinate mode of this gradient to mode. The default mode is LogicalMode.

See also coordinateMode().

void QGradient::setSpread(QGradient::Spread method)

Specifies the spread method that should be used for this gradient.

Note that this function only has effect for linear and radial gradients.

See also spread().

void QGradient::setStops(const QGradientStops &stopPoints)

Replaces the current set of stop points with the given stopPoints. The positions of the points must be in the range 0 to 1, and must be sorted with the lowest point first.

See also setColorAt() and stops().

QGradient::Spread QGradient::spread() const

Returns the spread method use by this gradient. The default is PadSpread.

See also setSpread().

QGradientStops QGradient::stops() const

Returns the stop points for this gradient.

If no stop points have been specified, a gradient of black at 0 to white at 1 is used.

See also setStops() and setColorAt().

QGradient::Type QGradient::type() const

Returns the type of gradient.

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

Returns true if the gradient is the same as the other gradient specified; otherwise returns false.

See also operator==().

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

Returns true if the gradient is the same as the other gradient specified; otherwise returns false.

See also operator!=().