QGradient Class

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

Header: #include <QGradient>
qmake: QT += gui
Inherited By:

QConicalGradient, QLinearGradient, and QRadialGradient

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
typedef QGradientStop
typedef 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:

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:

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.

ConstantValueDescription
QGradient::LogicalMode0This is the default mode. The gradient coordinates are specified logical space just like the object coordinates.
QGradient::ObjectMode3In 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::StretchToDeviceMode1In 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::ObjectBoundingMode2This 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.

This enum was introduced or modified in Qt 4.4.

enum QGradient::Preset

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

ConstantValue
QGradient::WarmFlame1
QGradient::NightFade2
QGradient::SpringWarmth3
QGradient::JuicyPeach4
QGradient::YoungPassion5
QGradient::LadyLips6
QGradient::SunnyMorning7
QGradient::RainyAshville8
QGradient::FrozenDreams9
QGradient::WinterNeva10
QGradient::DustyGrass11
QGradient::TemptingAzure12
QGradient::HeavyRain13
QGradient::AmyCrisp14
QGradient::MeanFruit15
QGradient::DeepBlue16
QGradient::RipeMalinka17
QGradient::CloudyKnoxville18
QGradient::MalibuBeach19
QGradient::NewLife20
QGradient::TrueSunset21
QGradient::MorpheusDen22
QGradient::RareWind23
QGradient::NearMoon24
QGradient::WildApple25
QGradient::SaintPetersburg26
QGradient::PlumPlate28
QGradient::EverlastingSky29
QGradient::HappyFisher30
QGradient::Blessing31
QGradient::SharpeyeEagle32
QGradient::LadogaBottom33
QGradient::LemonGate34
QGradient::ItmeoBranding35
QGradient::ZeusMiracle36
QGradient::OldHat37
QGradient::StarWine38
QGradient::HappyAcid41
QGradient::AwesomePine42
QGradient::NewYork43
QGradient::ShyRainbow44
QGradient::MixedHopes46
QGradient::FlyHigh47
QGradient::StrongBliss48
QGradient::FreshMilk49
QGradient::SnowAgain50
QGradient::FebruaryInk51
QGradient::KindSteel52
QGradient::SoftGrass53
QGradient::GrownEarly54
QGradient::SharpBlues55
QGradient::ShadyWater56
QGradient::DirtyBeauty57
QGradient::GreatWhale58
QGradient::TeenNotebook59
QGradient::PoliteRumors60
QGradient::SweetPeriod61
QGradient::WideMatrix62
QGradient::SoftCherish63
QGradient::RedSalvation64
QGradient::BurningSpring65
QGradient::NightParty66
QGradient::SkyGlider67
QGradient::HeavenPeach68
QGradient::PurpleDivision69
QGradient::AquaSplash70
QGradient::SpikyNaga72
QGradient::LoveKiss73
QGradient::CleanMirror75
QGradient::PremiumDark76
QGradient::ColdEvening77
QGradient::CochitiLake78
QGradient::SummerGames79
QGradient::PassionateBed80
QGradient::MountainRock81
QGradient::DesertHump82
QGradient::JungleDay83
QGradient::PhoenixStart84
QGradient::OctoberSilence85
QGradient::FarawayRiver86
QGradient::AlchemistLab87
QGradient::OverSun88
QGradient::PremiumWhite89
QGradient::MarsParty90
QGradient::EternalConstance91
QGradient::JapanBlush92
QGradient::SmilingRain93
QGradient::CloudyApple94
QGradient::BigMango95
QGradient::HealthyWater96
QGradient::AmourAmour97
QGradient::RiskyConcrete98
QGradient::StrongStick99
QGradient::ViciousStance100
QGradient::PaloAlto101
QGradient::HappyMemories102
QGradient::MidnightBloom103
QGradient::Crystalline104
QGradient::PartyBliss106
QGradient::ConfidentCloud107
QGradient::LeCocktail108
QGradient::RiverCity109
QGradient::FrozenBerry110
QGradient::ChildCare112
QGradient::FlyingLemon113
QGradient::NewRetrowave114
QGradient::HiddenJaguar115
QGradient::AboveTheSky116
QGradient::Nega117
QGradient::DenseWater118
QGradient::Seashore120
QGradient::MarbleWall121
QGradient::CheerfulCaramel122
QGradient::NightSky123
QGradient::MagicLake124
QGradient::YoungGrass125
QGradient::ColorfulPeach126
QGradient::GentleCare127
QGradient::PlumBath128
QGradient::HappyUnicorn129
QGradient::AfricanField131
QGradient::SolidStone132
QGradient::OrangeJuice133
QGradient::GlassWater134
QGradient::NorthMiracle136
QGradient::FruitBlend137
QGradient::MillenniumPine138
QGradient::HighFlight139
QGradient::MoleHall140
QGradient::SpaceShift142
QGradient::ForestInei143
QGradient::RoyalGarden144
QGradient::RichMetal145
QGradient::JuicyCake146
QGradient::SmartIndigo147
QGradient::SandStrike148
QGradient::NorseBeauty149
QGradient::AquaGuidance150
QGradient::SunVeggie151
QGradient::SeaLord152
QGradient::BlackSea153
QGradient::GrassShampoo154
QGradient::LandingAircraft155
QGradient::WitchDance156
QGradient::SleeplessNight157
QGradient::AngelCare158
QGradient::CrystalRiver159
QGradient::SoftLipstick160
QGradient::SaltMountain161
QGradient::PerfectWhite162
QGradient::FreshOasis163
QGradient::StrictNovember164
QGradient::MorningSalad165
QGradient::DeepRelief166
QGradient::SeaStrike167
QGradient::NightCall168
QGradient::SupremeSky169
QGradient::LightBlue170
QGradient::MindCrawl171
QGradient::LilyMeadow172
QGradient::SugarLollipop173
QGradient::SweetDessert174
QGradient::MagicRay175
QGradient::TeenParty176
QGradient::FrozenHeat177
QGradient::GagarinView178
QGradient::FabledSunset179
QGradient::PerfectBlue180

This enum was introduced or modified in Qt 5.12.

enum QGradient::Spread

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

ConstantValueDescription
QGradient::PadSpread0The area is filled with the closest stop color. This is the default.
QGradient::RepeatSpread2The gradient is repeated outside the gradient area.
QGradient::ReflectSpread1The gradient is reflected outside the gradient area.

See also spread() and setSpread().

enum QGradient::Type

Specifies the type of gradient.

ConstantValueDescription
QGradient::LinearGradient0Interpolates colors between start and end points (QLinearGradient).
QGradient::RadialGradient1Interpolate colors between a focal point and end points on a circle surrounding it (QRadialGradient).
QGradient::ConicalGradient2Interpolate colors around a center point (QConicalGradient).
QGradient::NoGradient3No gradient is used.

See also type().

Member Function Documentation

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.

This function was introduced in Qt 4.4.

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.

This function was introduced in Qt 4.4.

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.

This function was introduced in Qt 4.2.

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!=().

Related Non-Members

typedef QGradientStop

Typedef for QPair<qreal, QColor>.

typedef QGradientStops

Typedef for QVector<QGradientStop>.

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