QStyleOptionGraphicsItem Class Reference

The QStyleOptionGraphicsItem class is used to describe the parameters needed to draw a QGraphicsItem. More...

#include <qstyleoption.h>

Inheritance diagram for QStyleOptionGraphicsItem:

Public Types
enum	StyleOptionType { Type = SO_GraphicsItem }
	This enum is used to hold information about the type of the style option, and is defined for each QStyleOption subclass. More...
enum	StyleOptionVersion { Version = 1 }
	This enum is used to hold information about the version of the style option, and is defined for each QStyleOption subclass. More...
Public Types inherited from QStyleOption
enum	OptionType {   SO_Default, SO_FocusRect, SO_Button, SO_Tab,   SO_MenuItem, SO_Frame, SO_ProgressBar, SO_ToolBox,   SO_Header, SO_Q3DockWindow, SO_DockWidget, SO_Q3ListViewItem,   SO_ViewItem, SO_TabWidgetFrame, SO_TabBarBase, SO_RubberBand,   SO_ToolBar, SO_GraphicsItem, SO_Complex = 0xf0000, SO_Slider,   SO_SpinBox, SO_ToolButton, SO_ComboBox, SO_Q3ListView,   SO_TitleBar, SO_GroupBox, SO_SizeGrip, SO_CustomBase = 0xf00,   SO_ComplexCustomBase = 0xf000000 }
	This enum is used internally by QStyleOption, its subclasses, and qstyleoption_cast() to determine the type of style option. More...
enum	StyleOptionType { Type = SO_Default }
	This enum is used to hold information about the type of the style option, and is defined for each QStyleOption subclass. More...
enum	StyleOptionVersion { Version = 1 }
	This enum is used to hold information about the version of the style option, and is defined for each QStyleOption subclass. More...

Public Functions
	QStyleOptionGraphicsItem ()
	Constructs a QStyleOptionGraphicsItem. More...
	QStyleOptionGraphicsItem (const QStyleOptionGraphicsItem &other)
	Constructs a copy of other. More...
Public Functions inherited from QStyleOption
void	init (const QWidget *w)
	Use initFrom(widget) instead. More...
void	initFrom (const QWidget *w)
QStyleOption &	operator= (const QStyleOption &other)
	Assign other to this QStyleOption. More...
	QStyleOption (int version=QStyleOption::Version, int type=SO_Default)
	Constructs a QStyleOption with the specified version and type. More...
	QStyleOption (const QStyleOption &other)
	Constructs a copy of other. More...
	~QStyleOption ()
	Destroys this style option object. More...

Static Public Functions
static qreal	levelOfDetailFromTransform (const QTransform &worldTransform)
	Returns the level of detail from the worldTransform. More...

Public Variables
QRectF	exposedRect
	the exposed rectangle, in item coordinates More...
qreal	levelOfDetail
	Use QStyleOptionGraphicsItem::levelOfDetailFromTransform() together with QPainter::worldTransform() instead. More...
QMatrix	matrix
	the complete transformation matrix for the item More...
Public Variables inherited from QStyleOption
Qt::LayoutDirection	direction
	the text layout direction that should be used when drawing text in the control More...
QFontMetrics	fontMetrics
	the font metrics that should be used when drawing text in the control More...
QPalette	palette
	the palette that should be used when painting the control More...
QRect	rect
	the area that should be used for various calculations and painting More...
QStyle::State	state
	the style flags that are used when drawing the control More...
int	type
	the option type of the style option More...
int	version
	the version of the style option More...

Protected Functions
	QStyleOptionGraphicsItem (int version)

Additional Inherited Members
Related Functions inherited from QStyleOption
T	qstyleoption_cast (const QStyleOption *option)
T	qstyleoption_cast (QStyleOption *option)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts. More...

Detailed Description

The QStyleOptionGraphicsItem class is used to describe the parameters needed to draw a QGraphicsItem.

Since

4.2

For performance reasons, the access to the member variables is direct (i.e., using the . or -> operator). This low-level feel makes the structures straightforward to use and emphasizes that these are simply parameters.

For an example demonstrating how style options can be used, see the widgets/styles{Styles} example.

See also

QStyleOption, QGraphicsItem::paint()

Definition at line 867 of file qstyleoption.h.

Enumerations

StyleOptionType

enum QStyleOptionGraphicsItem::StyleOptionType

This enum is used to hold information about the type of the style option, and is defined for each QStyleOption subclass.

• Type The type of style option provided (SO_GraphicsItem for this class).

The type is used internally by QStyleOption, its subclasses, and qstyleoption_cast() to determine the type of style option. In general you do not need to worry about this unless you want to create your own QStyleOption subclass and your own styles.

See also

StyleOptionVersion

Enumerator
Type

Definition at line 870 of file qstyleoption.h.

{ Type = SO_GraphicsItem };

StyleOptionVersion

enum QStyleOptionGraphicsItem::StyleOptionVersion

This enum is used to hold information about the version of the style option, and is defined for each QStyleOption subclass.

• Version 1

The version is used by QStyleOption subclasses to implement extensions without breaking compatibility. If you use qstyleoption_cast(), you normally do not need to check it.

See also

StyleOptionType

Enumerator
Version

Definition at line 871 of file qstyleoption.h.

{ Version = 1 };

Constructors and Destructors

QStyleOptionGraphicsItem() [1/3]

QStyleOptionGraphicsItem::QStyleOptionGraphicsItem

(

)

Constructs a QStyleOptionGraphicsItem.

Definition at line 6027 of file qstyleoption.cpp.

    : QStyleOption(Version, Type), levelOfDetail(1)
{
}

QStyleOptionGraphicsItem() [2/3]

QStyleOptionGraphicsItem::QStyleOptionGraphicsItem ( const QStyleOptionGraphicsItem &  other )

inline

Constructs a copy of other.

Definition at line 878 of file qstyleoption.h.

: QStyleOption(Version, Type) { *this = other; }

QStyleOptionGraphicsItem() [3/3]

QStyleOptionGraphicsItem::QStyleOptionGraphicsItem ( int  version )

protected

Warning

This function is not part of the public interface.

Definition at line 6035 of file qstyleoption.cpp.

    : QStyleOption(version, Type), levelOfDetail(1)
{
}

Functions

levelOfDetailFromTransform()

qreal QStyleOptionGraphicsItem::levelOfDetailFromTransform ( const QTransform &  worldTransform )

static

Returns the level of detail from the worldTransform.

Since

4.6

Its value represents the maximum value of the height and width of a unity rectangle, mapped using the worldTransform of the painter used to draw the item. By default, if no transformations are applied, its value is 1. If zoomed out 1:2, the level of detail will be 0.5, and if zoomed in 2:1, its value is 2.

Definition at line 6054 of file qstyleoption.cpp.

{
    if (worldTransform.type() <= QTransform::TxTranslate)
        return 1; // Translation only? The LOD is 1.

    // Two unit vectors.
    QLineF v1(0, 0, 1, 0);
    QLineF v2(0, 0, 0, 1);
    // LOD is the transformed area of a 1x1 rectangle.
    return qSqrt(worldTransform.map(v1).length() * worldTransform.map(v2).length());
}

Properties

exposedRect

QStyleOptionGraphicsItem::exposedRect

the exposed rectangle, in item coordinates

Make use of this rectangle to speed up item drawing when only parts of the item are exposed. If the whole item is exposed, this rectangle will be the same as QGraphicsItem::boundingRect().

This member is only initialized for items that have the QGraphicsItem::ItemUsesExtendedStyleOption flag set.

Definition at line 873 of file qstyleoption.h.

Referenced by _q_paintItem(), QGraphicsScenePrivate::drawItemHelper(), QGraphicsItemPrivate::initStyleOption(), QGraphicsProxyWidget::paint(), QGraphicsTextItem::paint(), and QGraphicsWidget::paintWindowFrame().

levelOfDetail

QStyleOptionGraphicsItem::levelOfDetail

Use QStyleOptionGraphicsItem::levelOfDetailFromTransform() together with QPainter::worldTransform() instead.

Definition at line 875 of file qstyleoption.h.

Referenced by QGraphicsItemPrivate::initStyleOption().

matrix

QStyleOptionGraphicsItem::matrix

the complete transformation matrix for the item

The QMatrix provided through this member does include information about
any perspective transformations applied to the view or item. To get the
correct transformation matrix, use QPainter::transform() on the painter
passed into the QGraphicsItem::paint() implementation.

This matrix is the combination of the item's scene matrix and the matrix
of the painter used for drawing the item. It is provided for convenience,
allowing anvanced level-of-detail metrics that can be used to speed up
item drawing.

To find the dimensions of an item in screen coordinates (i.e., pixels),
you can use the mapping functions of QMatrix, such as QMatrix::map().

This member is only initialized for items that have the
QGraphicsItem::ItemUsesExtendedStyleOption flag set.

\sa QStyleOptionGraphicsItem::levelOfDetailFromTransform()

Definition at line 874 of file qstyleoption.h.

Referenced by QGraphicsItemPrivate::initStyleOption().

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The documentation for this class was generated from the following files:

• /src/gui/styles/qstyleoption.h
• /src/gui/styles/qstyleoption.cpp