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java.lang.Objectcom.trolltech.qt.QSignalEmitter
com.trolltech.qt.QtJambiObject
com.trolltech.qt.gui.QPen
public class QPen
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.
Qt provides several built-in styles represented by the Qt::PenStyle enum:
![]() | ![]() | ![]() |
Qt::SolidLine | Qt::DashLine | Qt::DotLine |
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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; 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.
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.
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 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. |
Stroking Demo
,
Example
Nested Class Summary |
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Nested classes/interfaces inherited from class com.trolltech.qt.QSignalEmitter |
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QSignalEmitter.Signal0, QSignalEmitter.Signal1<A>, QSignalEmitter.Signal2<A,B>, QSignalEmitter.Signal3<A,B,C>, QSignalEmitter.Signal4<A,B,C,D>, QSignalEmitter.Signal5<A,B,C,D,E>, QSignalEmitter.Signal6<A,B,C,D,E,F>, QSignalEmitter.Signal7<A,B,C,D,E,F,G>, QSignalEmitter.Signal8<A,B,C,D,E,F,G,H>, QSignalEmitter.Signal9<A,B,C,D,E,F,G,H,I> |
Field Summary | |
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static QPen |
NoPen
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Constructor Summary | |
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QPen()
Constructs a default black solid line pen with 0 width. |
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QPen(QBrush brush,
double width)
Equivalent to QPen(brush, width, Qt::SolidLine, Qt::SquareCap, Qt::BevelJoin). |
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QPen(QBrush brush,
double width,
Qt.PenStyle s)
Equivalent to QPen(brush, width, s, Qt::SquareCap, Qt::BevelJoin). |
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QPen(QBrush brush,
double width,
Qt.PenStyle s,
Qt.PenCapStyle c)
Equivalent to QPen(brush, width, s, c, Qt::BevelJoin). |
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QPen(QBrush brush,
double width,
Qt.PenStyle s,
Qt.PenCapStyle c,
Qt.PenJoinStyle j)
Constructs a pen with the specified brush, width, pen s, c style and j style. |
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QPen(QColor color)
Constructs a solid line pen with 0 width and the given color. |
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QPen(QColor color,
double width)
This is an overloaded constructor provided for convenience. |
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QPen(QColor color,
double width,
Qt.PenStyle s)
This is an overloaded constructor provided for convenience. |
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QPen(QColor color,
double width,
Qt.PenStyle s,
Qt.PenCapStyle c)
Constructs a pen with the specified color, width, pen style s, and c cap style. |
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QPen(QColor color,
double width,
Qt.PenStyle s,
Qt.PenCapStyle c,
Qt.PenJoinStyle j)
Constructs a pen with the specified color, width, pen style s, pen cap style c, and pen join style j |
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QPen(QPen pen)
Constructs a pen that is a copy of the given pen. |
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QPen(Qt.PenStyle arg__1)
Constructs a black pen with 0 width and the given arg__1. |
Method Summary | |
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QBrush |
brush()
Returns the brush used to fill strokes generated with this pen. |
Qt.PenCapStyle |
capStyle()
Returns the pen's cap style. |
QColor |
color()
Returns the color of this pen's brush. |
double |
dashOffset()
Returns the dash offset for the pen. |
java.util.List<java.lang.Double> |
dashPattern()
Returns the dash pattern of this pen. |
boolean |
equals(java.lang.Object other)
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static QPen |
fromNativePointer(QNativePointer nativePointer)
This function returns the QPen instance pointed to by nativePointer |
boolean |
isCosmetic()
Returns true if the pen is cosmetic; otherwise returns false. |
boolean |
isSolid()
Returns true if the pen has a solid fill, otherwise false. |
Qt.PenJoinStyle |
joinStyle()
Returns the pen's join style. |
double |
miterLimit()
Returns the miter limit of the pen. |
static QNativePointer |
nativePointerArray(QPen[] array)
This function returns a QNativePointer that is pointing to the specified QPen array. |
void |
readFrom(QDataStream arg__1)
Reads a QPen from arg__1. |
void |
setBrush(QBrush brush)
Sets the brush used to fill strokes generated with this pen to the given brush. |
void |
setCapStyle(Qt.PenCapStyle pcs)
Sets the pen's cap style to the given pcs. |
void |
setColor(QColor color)
Sets the color of this pen's brush to the given color. |
void |
setCosmetic(boolean cosmetic)
Sets this pen to cosmetic or non-cosmetic, depending on the value of cosmetic. |
void |
setDashOffset(double doffset)
Sets the dash offset for this pen to the given doffset. |
void |
setDashPattern(java.util.List<java.lang.Double> pattern)
Sets the dash pattern for this pen to the given pattern. |
void |
setJoinStyle(Qt.PenJoinStyle pcs)
Sets the pen's join style to the given pcs. |
void |
setMiterLimit(double limit)
Sets the miter limit of this pen to the given limit. |
void |
setStyle(Qt.PenStyle arg__1)
Sets the pen style to the given arg__1. |
void |
setWidth(int width)
Sets the pen width to the given width in pixels with integer precision. |
void |
setWidthF(double width)
Sets the pen width to the given width in pixels with floating point precision. |
Qt.PenStyle |
style()
Returns the pen style. |
int |
width()
Returns the pen width with integer precision. |
double |
widthF()
Returns the pen width with floating point precision. |
void |
writeTo(QDataStream arg__1)
Writes thisQPen to arg__1. |
Methods inherited from class com.trolltech.qt.QtJambiObject |
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dispose, disposed, finalize, reassignNativeResources, tr, tr, tr |
Methods inherited from class com.trolltech.qt.QSignalEmitter |
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blockSignals, disconnect, disconnect, signalsBlocked, signalSender, thread |
Methods inherited from class java.lang.Object |
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clone, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Methods inherited from interface com.trolltech.qt.QtJambiInterface |
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disableGarbageCollection, nativeId, nativePointer, reenableGarbageCollection, setJavaOwnership |
Field Detail |
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public static final QPen NoPen
Constructor Detail |
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public QPen(QPen pen)
Constructs a pen that is a copy of the given pen.
public QPen()
Constructs a default black solid line pen with 0 width.
public QPen(Qt.PenStyle arg__1)
Constructs a black pen with 0 width and the given arg__1.
public QPen(QColor color)
Constructs a solid line pen with 0 width and the given color.
public QPen(QBrush brush, double width, Qt.PenStyle s, Qt.PenCapStyle c)
Equivalent to QPen(brush, width, s, c, Qt::BevelJoin).
public QPen(QBrush brush, double width, Qt.PenStyle s)
Equivalent to QPen(brush, width, s, Qt::SquareCap, Qt::BevelJoin).
public QPen(QBrush brush, double width)
Equivalent to QPen(brush, width, Qt::SolidLine, Qt::SquareCap, Qt::BevelJoin).
public QPen(QBrush brush, double width, Qt.PenStyle s, Qt.PenCapStyle c, Qt.PenJoinStyle j)
Constructs a pen with the specified brush, width, pen s, c style and j style.
public QPen(QColor color, double width, Qt.PenStyle s, Qt.PenCapStyle c, Qt.PenJoinStyle j)
public QPen(QColor color, double width, Qt.PenStyle s, Qt.PenCapStyle c)
public QPen(QColor color, double width, Qt.PenStyle s)
public QPen(QColor color, double width)
Method Detail |
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public final QBrush brush()
Returns the brush used to fill strokes generated with this pen.
public final Qt.PenCapStyle capStyle()
Returns the pen's cap style.
Style
public final QColor color()
Returns the color of this pen's brush.
public final double dashOffset()
Returns the dash offset for the pen.
public final java.util.List<java.lang.Double> dashPattern()
Returns the dash pattern of this pen.
public final boolean 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.
public final boolean isSolid()
Returns true if the pen has a solid fill, otherwise false.
public final Qt.PenJoinStyle joinStyle()
Returns the pen's join style.
Style
public final double miterLimit()
Returns the miter limit of the pen. The miter limit is only relevant when the join style is set to Qt::MiterJoin.
Style
public final void writeTo(QDataStream arg__1)
public final void readFrom(QDataStream arg__1)
public final void setBrush(QBrush brush)
Sets the brush used to fill strokes generated with this pen to the given brush.
public final void setCapStyle(Qt.PenCapStyle pcs)
Sets the pen's cap style to the given pcs. The default value is Qt::SquareCap.
Style
public final void setColor(QColor color)
Sets the color of this pen's brush to the given color.
public final void setCosmetic(boolean cosmetic)
Sets this pen to cosmetic or non-cosmetic, depending on the value of cosmetic.
public final void setDashOffset(double doffset)
Sets the dash offset for this pen to the given doffset. This implicitly converts the style of the pen to Qt::CustomDashLine.
public final void setDashPattern(java.util.List<java.lang.Double> pattern)
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 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; pen.setDashPattern(dashes); |
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. Each dash is also subject to cap styles so a dash of 1 with square cap set will extend 0.5 pixels out in each direction resulting in a total width of 2.
Note that the default cap style is Qt::SquareCap, meaning that a square line end covers the end point and extends beyond it by half the line width.
public final void setJoinStyle(Qt.PenJoinStyle pcs)
Sets the pen's join style to the given pcs. The default value is Qt::BevelJoin.
Style
public final void setMiterLimit(double limit)
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.
Style
public final void setStyle(Qt.PenStyle arg__1)
Sets the pen style to the given arg__1.
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.
Style
public final void setWidth(int width)
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.
public final void setWidthF(double width)
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.
public final Qt.PenStyle style()
Returns the pen style.
Style
public final int width()
Returns the pen width with integer precision.
public final double widthF()
Returns the pen width with floating point precision.
public static QPen fromNativePointer(QNativePointer nativePointer)
nativePointer
- the QNativePointer of which object should be returned.public static QNativePointer nativePointerArray(QPen[] array)
array
- the array that the returned pointer will point to.
public boolean equals(java.lang.Object other)
equals
in class java.lang.Object
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