QGradient ¶

概要 ¶

详细描述 ¶

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 方法 使用 setSpread() function. The default is to pad the outside area with the color at the closest stop point. The currently set spread 方法 can be retrieved using the spread() function. The 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 use coordinateMode() .

另请参阅

The Gradients Example QBrush

class QGradient ¶

QGradient(arg__1)

QGradient(QGradient)

param arg__1

Preset

param QGradient

QGradient

Constructs a gradient based on a predefined preset .

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

PySide2.QtGui.QGradient. Type ¶

Specifies the type of gradient.

常量	描述
QGradient.LinearGradient	Interpolates colors between start and end points ( QLinearGradient ).
QGradient.RadialGradient	Interpolate colors between a focal point and end points on a circle surrounding it ( QRadialGradient ).
QGradient.ConicalGradient	Interpolate colors around a center point ( QConicalGradient ).
QGradient.NoGradient	No gradient is used.

另请参阅

type()

PySide2.QtGui.QGradient. Spread ¶

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

常量	描述
QGradient.PadSpread	The area is filled with the closest stop color. This is the default.
QGradient.RepeatSpread	The gradient is repeated outside the gradient area.
QGradient.ReflectSpread	The gradient is reflected outside the gradient area.

另请参阅

spread() setSpread()

PySide2.QtGui.QGradient. CoordinateMode ¶

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

常量	描述
QGradient.LogicalMode	This is the default mode. The gradient coordinates are specified logical space just like the object coordinates.
QGradient.ObjectMode	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	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	This mode is the same as , except that the { 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.

PySide2.QtGui.QGradient. InterpolationMode ¶

常量	描述
QGradient.ComponentInterpolation	The color components and the alpha component are independently linearly interpolated.
QGradient.ColorInterpolation	The colors are linearly interpolated in premultiplied color space.

PySide2.QtGui.QGradient. Preset ¶

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

PySide2.QtGui.QGradient. coordinateMode ( ) ¶

返回类型

CoordinateMode

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

另请参阅

setCoordinateMode()

PySide2.QtGui.QGradient. interpolationMode ( ) ¶

返回类型

InterpolationMode

Returns the interpolation mode of this gradient. The default mode is .

PySide2.QtGui.QGradient. __ne__ ( other ) ¶

参数

other – QGradient

返回类型

bool

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

另请参阅

operator==()

PySide2.QtGui.QGradient. __eq__ ( gradient ) ¶

参数

gradient – QGradient

返回类型

bool

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

另请参阅

operator!=()

PySide2.QtGui.QGradient. setColorAt ( pos , color ) ¶

参数

• pos – qreal

• color – QColor

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() stops()

PySide2.QtGui.QGradient. setCoordinateMode ( mode ) ¶

参数

mode – CoordinateMode

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

另请参阅

coordinateMode()

PySide2.QtGui.QGradient. setInterpolationMode ( mode ) ¶

参数

mode – InterpolationMode

Sets the interpolation mode of this gradient to mode . The default mode is .

PySide2.QtGui.QGradient. setSpread ( spread ) ¶

参数

spread – Spread

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

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

另请参阅

spread()

PySide2.QtGui.QGradient. setStops ( stops ) ¶

参数

stops –

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() stops()

PySide2.QtGui.QGradient. spread ( ) ¶

返回类型

Spread

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

另请参阅

setSpread()

PySide2.QtGui.QGradient. stops ( ) ¶

返回类型

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() setColorAt()

PySide2.QtGui.QGradient. type ( ) ¶

返回类型

Type

Returns the type of gradient.