QtGui.QPen Class Reference

The QPen class defines how a QPainter should draw lines and outlines of shapes. More...

Inheritance diagram for QtGui.QPen:

Collaboration diagram for QtGui.QPen:

Public Member Functions
override bool	Equals (object o)
override int	GetHashCode ()
	QPen ()
	QPen (QColor color)
	QPen (QPen pen)
	QPen (QBrush brush, double width, Qt.PenStyle s=Qt.PenStyle.SolidLine, Qt.PenCapStyle c=Qt.PenCapStyle.SquareCap, Qt.PenJoinStyle j=Qt.PenJoinStyle.BevelJoin)
	QPen (Qt.PenStyle arg1)
virtual void	CreateProxy ()
new bool	IsCosmetic ()
new bool	IsDetached ()
new bool	IsSolid ()
new void	SetCosmetic (bool cosmetic)
new void	Swap (QPen other)
new void	Dispose ()

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

Protected Member Functions
	QPen (System.Type dummy)

Protected Attributes
SmokeInvocation	interceptor

Properties
new QBrush	Brush [get, set]
new Qt.PenCapStyle	CapStyle [get, set]
new QColor	Color [get, set]
new double	DashOffset [get, set]
new System.Collections.Generic.List < System.Double >	DashPattern [get, set]
new Qt.PenJoinStyle	JoinStyle [get, set]
new double	MiterLimit [get, set]
new Qt.PenStyle	Style [get, set]
new int	Width [get, set]
new double	WidthF [get, set]
virtual System.IntPtr	SmokeObject [get, set]

Detailed Description

The QPen class defines how a QPainter should draw lines and outlines of shapes.

A pen has a style(), width(), brush(), capStyle() and joinStyle().

The pen style defines the line type. The brush is used to fill strokes generated with the pen. Use the QBrush class to specify fill styles. The cap style determines the line end caps that can be drawn using QPainter, while the join style describes how joins between two lines are drawn. The pen width can be specified in both integer (width()) and floating point (widthF()) precision. A line width of zero indicates a cosmetic pen. This means that the pen width is always drawn one pixel wide, independent of the transformation set on the painter.

The various settings can easily be modified using the corresponding setStyle(), setWidth(), setBrush(), setCapStyle() and setJoinStyle() functions (note that the painter's pen must be reset when altering the pen's properties).

For example:

QPainter painter(this);

QPen pen(Qt::green, 3, Qt::DashDotLine, Qt::RoundCap, Qt::RoundJoin);

painter.setPen(pen);

which is equivalent to

QPainter painter(this);

QPen pen; // creates a default pen

pen.setStyle(Qt::DashDotLine);

pen.setWidth(3);

pen.setBrush(Qt::green);

pen.setCapStyle(Qt::RoundCap);

pen.setJoinStyle(Qt::RoundJoin);

painter.setPen(pen);

The default pen is a solid black brush with 0 width, square cap style (Qt::SquareCap), and bevel join style (Qt::BevelJoin).

In addition QPen provides the color() and setColor() convenience functions to extract and set the color of the pen's brush, respectively. Pens may also be compared and streamed.

For more information about painting in general, see the Paint System documentation.

Pen Style

Qt provides several built-in styles represented by the Qt::PenStyle enum:

Qt::SolidLine Qt::DashLine Qt::DotLine

Qt::DashDotLine Qt::DashDotDotLine Qt::CustomDashLine

Simply use the setStyle() function to convert the pen style to either of the built-in styles, except the Qt::CustomDashLine style which we will come back to shortly. Setting the style to Qt::NoPen tells the painter to not draw lines or outlines. The default pen style is Qt::SolidLine.

Since Qt 4.1 it is also possible to specify a custom dash pattern using the setDashPattern() function which implicitly converts the style of the pen to Qt::CustomDashLine. The pattern argument, a QVector, must be specified as an even number of qreal entries where the entries 1, 3, 5... are the dashes and 2, 4, 6... are the spaces. For example, the custom pattern shown above is created using the following code:

QPen pen;

QVector<qreal> dashes;

qreal space = 4;

dashes << 1 << space << 3 << space << 9 << space

<< 27 << space << 9 << space;

pen.setDashPattern(dashes);

Note that the dash pattern is specified in units of the pens width, e.g. a dash of length 5 in width 10 is 50 pixels long.

The currently set dash pattern can be retrieved using the dashPattern() function. Use the isSolid() function to determine whether the pen has a solid fill, or not.

Cap Style

The cap style defines how the end points of lines are drawn using QPainter. The cap style only apply to wide lines, i.e. when the width is 1 or greater. The Qt::PenCapStyle enum provides the following styles:

Qt::SquareCap Qt::FlatCap Qt::RoundCap

The Qt::SquareCap style is a square line end that covers the end point and extends beyond it by half the line width. The Qt::FlatCap style is a square line end that does not cover the end point of the line. And the Qt::RoundCap style is a rounded line end covering the end point.

The default is Qt::SquareCap.

Whether or not end points are drawn when the pen width is 0 or 1 depends on the cap style. Using Qt::SquareCap or Qt::RoundCap they are drawn, using Qt::FlatCap they are not drawn.

Join Style

The join style defines how joins between two connected lines can be drawn using QPainter. The join style only apply to wide lines, i.e. when the width is 1 or greater. The Qt::PenJoinStyle enum provides the following styles:

Qt::BevelJoin Qt::MiterJoin Qt::RoundJoin

The Qt::BevelJoin style fills the triangular notch between the two lines. The Qt::MiterJoin style extends the lines to meet at an angle. And the Qt::RoundJoin style fills a circular arc between the two lines.

The default is Qt::BevelJoin.

When the Qt::MiterJoin style is applied, it is possible to use the setMiterLimit() function to specify how far the miter join can extend from the join point. The miterLimit() is used to reduce artifacts between line joins where the lines are close to parallel.

The miterLimit() must be specified in units of the pens width, e.g. a miter limit of 5 in width 10 is 50 pixels long. The default miter limit is 2, i.e. twice the pen width in pixels.

The Path Stroking DemoThe Path Stroking demo shows Qt's built-in dash patterns and shows how custom patterns can be used to extend the range of available patterns.

See also QPainter, QBrush, Path Stroking Demo, and Scribble Example.

Constructor & Destructor Documentation

QtGui.QPen.QPen ( System.Type  dummy )

protected

QtGui.QPen.QPen

(

)

Constructs a default black solid line pen with 0 width.

QtGui.QPen.QPen

(

QColor

color

)

Constructs a solid line pen with 0 width and the given color.

See also setBrush() and setColor().

QtGui.QPen.QPen

(

QPen

pen

)

Constructs a pen that is a copy of the given pen.

QtGui.QPen.QPen	(	QBrush	brush,
		double	width,
		Qt.PenStyle	s = Qt.PenStyle.SolidLine,
		Qt.PenCapStyle	c = Qt.PenCapStyle.SquareCap,
		Qt.PenJoinStyle	j = Qt.PenJoinStyle.BevelJoin
	)

Constructs a default black solid line pen with 0 width.

QtGui.QPen.QPen

(

Qt.PenStyle

arg1

)

Constructs a black pen with 0 width and the given style.

See also setStyle().

Member Function Documentation

virtual void QtGui.QPen.CreateProxy ( )

virtual

new void QtGui.QPen.Dispose

(

)

override bool QtGui.QPen.Equals

(

object

o

)

override int QtGui.QPen.GetHashCode

(

)

new bool QtGui.QPen.IsCosmetic

(

)

Returns true if the pen is cosmetic; otherwise returns false.

Cosmetic pens are used to draw strokes that have a constant width regardless of any transformations applied to the QPainter they are used with. Drawing a shape with a cosmetic pen ensures that its outline will have the same thickness at different scale factors.

A zero width pen is cosmetic by default; pens with a non-zero width are non-cosmetic.

See also setCosmetic() and widthF().

new bool QtGui.QPen.IsDetached

(

)

new bool QtGui.QPen.IsSolid

(

)

Returns true if the pen has a solid fill, otherwise false.

See also style() and dashPattern().

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

static

Returns true if the pen is different from the given pen; otherwise false. Two pens are different if they have different styles, widths or colors.

See also operator==().

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

static

Returns true if the pen is equal to the given pen; otherwise false. Two pens are equal if they have equal styles, widths and colors.

See also operator!=().

new void QtGui.QPen.SetCosmetic

(

bool

cosmetic

)

Sets this pen to cosmetic or non-cosmetic, depending on the value of cosmetic.

See also isCosmetic().

new void QtGui.QPen.Swap

(

QPen

other

)

Swaps pen other with this pen. This operation is very fast and never fails.

This function was introduced in Qt 4.8.

Member Data Documentation

SmokeInvocation QtGui.QPen.interceptor

protected

Property Documentation

new QBrush QtGui.QPen.Brush

getset

Returns the brush used to fill strokes generated with this pen.

Sets the brush used to fill strokes generated with this pen to the given brush.

new Qt.PenCapStyle QtGui.QPen.CapStyle

getset

Returns the pen's cap style.

Sets the pen's cap style to the given style. The default value is Qt::SquareCap.

new QColor QtGui.QPen.Color

getset

Returns the color of this pen's brush.

Sets the color of this pen's brush to the given color.

new double QtGui.QPen.DashOffset

getset

Returns the dash offset for the pen.

Sets the dash offset (the starting point on the dash pattern) for this pen to the offset specified. The offset is measured in terms of the units used to specify the dash pattern.

For example, a pattern where each stroke is four units long, followed by a gap of two units, will begin with the stroke when drawn as a line.However, if the dash offset is set to 4.0, any line drawn will begin with the gap. Values of the offset up to 4.0 will cause part of the stroke to be drawn first, and values of the offset between 4.0 and 6.0 will cause the line to begin with part of the gap.

new System.Collections.Generic.List<System.Double> QtGui.QPen.DashPattern

getset

Returns the dash pattern of this pen.

Sets the dash pattern for this pen to the given pattern. This implicitly converts the style of the pen to Qt::CustomDashLine.

The pattern must be specified as an even number of positive entries where the entries 1, 3, 5... are the dashes and 2, 4, 6... are the spaces. For example:

QPen pen;

QVector<qreal> dashes;

qreal space = 4;

dashes << 1 << space << 3 << space << 9 << space

<< 27 << space << 9 << space;

pen.setDashPattern(dashes);

new Qt.PenJoinStyle QtGui.QPen.JoinStyle

getset

Returns the pen's join style.

Sets the pen's join style to the given style. The default value is Qt::BevelJoin.

new double QtGui.QPen.MiterLimit

getset

Returns the miter limit of the pen. The miter limit is only relevant when the join style is set to Qt::MiterJoin.

Sets the miter limit of this pen to the given limit.

The miter limit describes how far a miter join can extend from the join point. This is used to reduce artifacts between line joins where the lines are close to parallel.

This value does only have effect when the pen style is set to Qt::MiterJoin. The value is specified in units of the pen's width, e.g. a miter limit of 5 in width 10 is 50 pixels long. The default miter limit is 2, i.e. twice the pen width in pixels.

virtual System.IntPtr QtGui.QPen.SmokeObject

getset

new Qt.PenStyle QtGui.QPen.Style

getset

Returns the pen style.

Sets the pen style to the given style.

See the Qt::PenStyle documentation for a list of the available styles. Since Qt 4.1 it is also possible to specify a custom dash pattern using the setDashPattern() function which implicitly converts the style of the pen to Qt::CustomDashLine.

Note: This function resets the dash offset to zero.

new int QtGui.QPen.Width

getset

Returns the pen width with integer precision.

Sets the pen width to the given width in pixels with integer precision.

A line width of zero indicates a cosmetic pen. This means that the pen width is always drawn one pixel wide, independent of the transformation set on the painter.

Setting a pen width with a negative value is not supported.

new double QtGui.QPen.WidthF

getset

Returns the pen width with floating point precision.

Sets the pen width to the given width in pixels with floating point precision.

A line width of zero indicates a cosmetic pen. This means that the pen width is always drawn one pixel wide, independent of the transformation on the painter.

Setting a pen width with a negative value is not supported.