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QGradient 类

QGradient 类用于组合 QBrush 以指定渐变填充。 更多...

头： #include <QGradient>
CMake: find_package(Qt6 COMPONENTS Gui REQUIRED)
target_link_libraries(mytarget PRIVATE Qt6::Gui)
qmake: QT += gui
继承者： QConicalGradient , QLinearGradient ，和 QRadialGradient

公共类型

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 }

公共函数

  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
  QGradientStop
  QGradientStops

详细描述

Qt currently supports three types of gradient fills:

  • Linear gradients interpolate colors between start and end points.
  • 简单 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 替换 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 specifying the spread method 使用 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 () 函数。 QGradient::Spread enum defines three different methods:

PadSpread RepeatSpread ReflectSpread

注意， 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 使用 coordinateMode ().

另请参阅 The Gradients Example and QBrush .

成员类型文档编制

enum QGradient:: CoordinateMode

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

常量 值 描述
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/ .

常量 值
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

该枚举在 Qt 5.12 引入或被修改。

enum QGradient:: Spread

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

常量 值 描述
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.

另请参阅 spread () 和 setSpread ().

enum QGradient:: Type

Specifies the type of gradient.

常量 值 描述
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.

另请参阅 type ().

成员函数文档编制

[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.

该函数在 Qt 5.12 引入。

QGradient::CoordinateMode QGradient:: coordinateMode () const

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

另请参阅 setCoordinateMode ().

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

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

另请参阅 setStops () 和 stops ().

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

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

另请参阅 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.

另请参阅 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.

另请参阅 setColorAt () 和 stops ().

QGradient::Spread QGradient:: spread () const

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

另请参阅 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.

另请参阅 setStops () 和 setColorAt ().

QGradient::Type QGradient:: type () const

Returns the type of gradient.

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

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

另请参阅 operator== ().

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

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

另请参阅 operator!= ().

相关非成员

QGradientStop

Typedef for QPair< qreal , QColor >.

QGradientStops

typedef 对于 QList < QGradientStop >.