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QPen

Inheritance diagram of QPen

Synopsis

Functions

Detailed Description

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

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

The pen style defines the line type. The brush is used to fill strokes generated with the pen. Use the PySide.QtGui.QBrush class to specify fill styles. The cap style determines the line end caps that can be drawn using PySide.QtGui.QPainter , while the join style describes how joins between two lines are drawn. The pen width can be specified in both integer ( PySide.QtGui.QPen.width() ) and floating point ( PySide.QtGui.QPen.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 PySide.QtGui.QPen.setStyle() , PySide.QtGui.QPen.setWidth() , PySide.QtGui.QPen.setBrush() , PySide.QtGui.QPen.setCapStyle() and PySide.QtGui.QPen.setJoinStyle() functions (note that the painter’s pen must be reset when altering the pen’s properties).

For example:

painter = QPainter(self)
pen = QPen(Qt.green, 3, Qt.DashDotLine, Qt.RoundCap, Qt.RoundJoin)
painter.setPen(pen)

which is equivalent to

painter = QPainter(self)
pen = QPen()  # 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 PySide.QtGui.QPen provides the PySide.QtGui.QPen.color() and PySide.QtGui.QPen.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:

../../_images/qpen-solid1.png ../../_images/qpen-dash1.png ../../_images/qpen-dot1.png
Qt.SolidLine Qt.DashLine Qt.DotLine
../../_images/qpen-dashdot1.png ../../_images/qpen-dashdotdot1.png ../../_images/qpen-custom1.png
Qt.DashDotLine Qt.DashDotDotLine Qt.CustomDashLine

Simply use the PySide.QtGui.QPen.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 PySide.QtGui.QPen.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 PySide.QtCore.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:

pen = QPen()
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 PySide.QtGui.QPen.dashPattern() function. Use the PySide.QtGui.QPen.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 PySide.QtGui.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:

../../_images/qpen-square1.png ../../_images/qpen-flat1.png ../../_images/qpen-roundcap1.png
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 PySide.QtGui.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:

../../_images/qpen-bevel1.png ../../_images/qpen-miter1.png ../../_images/qpen-roundjoin1.png
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 .

../../_images/qpen-miterlimit.png

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

The PySide.QtGui.QPen.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.

../../_images/qpen-demo.png

** The Path Stroking Demo ****

The 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

PySide.QtGui.QPainter PySide.QtGui.QBrush Path Stroking Demo Scribble Example

class PySide.QtGui.QPen
class PySide.QtGui.QPen(arg__1)
class PySide.QtGui.QPen(brush, width[, s=Qt.SolidLine[, c=Qt.SquareCap[, j=Qt.BevelJoin]]])
class PySide.QtGui.QPen(color)
class PySide.QtGui.QPen(pen)
Parameters:

Constructs a default black solid line pen with 0 width.

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

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

PySide.QtGui.QPen.brush()
Return type:PySide.QtGui.QBrush

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

PySide.QtGui.QPen.capStyle()
Return type:PySide.QtCore.Qt.PenCapStyle

Returns the pen’s cap style.

See also

PySide.QtGui.QPen.setCapStyle() Cap Style

PySide.QtGui.QPen.color()
Return type:PySide.QtGui.QColor

Returns the color of this pen’s brush.

PySide.QtGui.QPen.dashOffset()
Return type:PySide.QtCore.qreal

Returns the dash offset for the pen.

PySide.QtGui.QPen.dashPattern()
Return type:

Returns the dash pattern of this pen.

PySide.QtGui.QPen.isCosmetic()
Return type:PySide.QtCore.bool

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 PySide.QtGui.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.

PySide.QtGui.QPen.isSolid()
Return type:PySide.QtCore.bool

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

PySide.QtGui.QPen.joinStyle()
Return type:PySide.QtCore.Qt.PenJoinStyle

Returns the pen’s join style.

See also

PySide.QtGui.QPen.setJoinStyle() Join Style

PySide.QtGui.QPen.miterLimit()
Return type:PySide.QtCore.qreal

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

See also

PySide.QtGui.QPen.setMiterLimit() Join Style

PySide.QtGui.QPen.__ne__(p)
Parameters:pPySide.QtGui.QPen
Return type:PySide.QtCore.bool

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

PySide.QtGui.QPen.operator==()

PySide.QtGui.QPen.__eq__(p)
Parameters:pPySide.QtGui.QPen
Return type:PySide.QtCore.bool

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

PySide.QtGui.QPen.operator!=()

PySide.QtGui.QPen.setBrush(brush)
Parameters:brushPySide.QtGui.QBrush

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

PySide.QtGui.QPen.setCapStyle(pcs)
Parameters:pcsPySide.QtCore.Qt.PenCapStyle
PySide.QtGui.QPen.setColor(color)
Parameters:colorPySide.QtGui.QColor

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

PySide.QtGui.QPen.setCosmetic(cosmetic)
Parameters:cosmeticPySide.QtCore.bool

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

PySide.QtGui.QPen.setDashOffset(doffset)
Parameters:doffsetPySide.QtCore.qreal

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.

../../_images/qpen-dashpattern.png

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.

Note

This implicitly converts the style of the pen to Qt.CustomDashLine .

PySide.QtGui.QPen.setDashPattern(pattern)
Parameters:pattern
PySide.QtGui.QPen.setJoinStyle(pcs)
Parameters:pcsPySide.QtCore.Qt.PenJoinStyle
PySide.QtGui.QPen.setMiterLimit(limit)
Parameters:limitPySide.QtCore.qreal

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

../../_images/qpen-miterlimit.png

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.

PySide.QtGui.QPen.setStyle(arg__1)
Parameters:arg__1PySide.QtCore.Qt.PenStyle
PySide.QtGui.QPen.setWidth(width)
Parameters:widthPySide.QtCore.int

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.

PySide.QtGui.QPen.setWidthF(width)
Parameters:widthPySide.QtCore.qreal

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.

PySide.QtGui.QPen.style()
Return type:PySide.QtCore.Qt.PenStyle

Returns the pen style.

See also

PySide.QtGui.QPen.setStyle() Pen Style

PySide.QtGui.QPen.width()
Return type:PySide.QtCore.int

Returns the pen width with integer precision.

PySide.QtGui.QPen.widthF()
Return type:PySide.QtCore.qreal

Returns the pen width with floating point precision.