QtGui.QGradient Class Reference

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

Inheritance diagram for QtGui.QGradient:

Collaboration diagram for QtGui.QGradient:

Public Types
enum	CoordinateMode { LogicalMode = 0, ObjectBoundingMode = 2, StretchToDeviceMode = 1 }
	More...
enum	InterpolationMode { ColorInterpolation = 0, ComponentInterpolation = 1 }
enum	Spread { PadSpread = 0, ReflectSpread = 1, RepeatSpread = 2 }
	More...
enum	Type { ConicalGradient = 2, LinearGradient = 0, NoGradient = 3, RadialGradient = 1 }
	More...

Public Member Functions
override bool	Equals (object o)
override int	GetHashCode ()
	QGradient ()
	QGradient (QGradient copy)
virtual void	CreateProxy ()
new void	SetColorAt (double pos, QColor color)
new QGradient.Type	type ()
new void	Dispose ()

Static Public Member Functions
static bool	operator!= (QGradient arg1, QGradient arg2)
static bool	operator== (QGradient arg1, QGradient arg2)

Protected Member Functions
	QGradient (System.Type dummy)

Protected Attributes
SmokeInvocation	interceptor

Properties
new QGradient.CoordinateMode	coordinateMode [get, set]
new QGradient.InterpolationMode	interpolationMode [get, set]
new QGradient.Spread	spread [get, set]
virtual System.IntPtr	SmokeObject [get, set]
static new QMetaObject	StaticMetaObject [get]

Detailed Description

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

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:

QLinearGradientQRadialGradientQConicalGradient

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 Demo and QBrush.

Member Enumeration Documentation

enum QtGui.QGradient.CoordinateMode

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

This enum was introduced or modified in Qt 4.4.

Enumerator:

LogicalMode	This is the default mode. The gradient coordinates are specified logical space just like the object coordinates.
ObjectBoundingMode	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.
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.

enum QtGui.QGradient.InterpolationMode

Enumerator:

ColorInterpolation
ComponentInterpolation

enum QtGui.QGradient.Spread

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

See also spread() and setSpread().

Enumerator:

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

enum QtGui.QGradient.Type

Specifies the type of gradient.

See also type().

Enumerator:

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

Constructor & Destructor Documentation

QtGui.QGradient.QGradient ( System.Type  dummy )

protected

QtGui.QGradient.QGradient

(

)

QtGui.QGradient.QGradient

(

QGradient

copy

)

Member Function Documentation

virtual void QtGui.QGradient.CreateProxy ( )

virtual

Reimplemented in QtGui.QRadialGradient, QtGui.QLinearGradient, and QtGui.QConicalGradient.

new void QtGui.QGradient.Dispose

(

)

override bool QtGui.QGradient.Equals

(

object

o

)

override int QtGui.QGradient.GetHashCode

(

)

static bool QtGui.QGradient.operator!= ( QGradient  arg1, QGradient  arg2  )

static

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==().

static bool QtGui.QGradient.operator== ( QGradient  arg1, QGradient  arg2  )

static

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

See also operator!=().

new void QtGui.QGradient.SetColorAt	(	double	pos,
		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().

new QGradient.Type QtGui.QGradient.type

(

)

Returns the type of gradient.

Member Data Documentation

SmokeInvocation QtGui.QGradient.interceptor

protected

Property Documentation

new QGradient.CoordinateMode QtGui.QGradient.coordinateMode

getset

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

This function was introduced in Qt 4.4.

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

This function was introduced in Qt 4.4.

new QGradient.InterpolationMode QtGui.QGradient.interpolationMode

getset

virtual System.IntPtr QtGui.QGradient.SmokeObject

getset

new QGradient.Spread QtGui.QGradient.spread

getset

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

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

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

new QMetaObject QtGui.QGradient.StaticMetaObject

staticget