com.trolltech.qt.gui
Class QStyleOption

java.lang.Object
  extended by com.trolltech.qt.internal.QSignalEmitterInternal
      extended by com.trolltech.qt.QSignalEmitter
          extended by com.trolltech.qt.QtJambiObject
              extended by com.trolltech.qt.gui.QStyleOption
All Implemented Interfaces:
QtJambiInterface, java.lang.Cloneable
Direct Known Subclasses:
QStyleOptionButton, QStyleOptionComplex, QStyleOptionDockWidget, QStyleOptionFocusRect, QStyleOptionFrame, QStyleOptionGraphicsItem, QStyleOptionHeader, QStyleOptionMenuItem, QStyleOptionProgressBar, QStyleOptionRubberBand, QStyleOptionTab, QStyleOptionTabBarBase, QStyleOptionTabWidgetFrame, QStyleOptionToolBar, QStyleOptionToolBox, QStyleOptionViewItem

public class QStyleOption
extends QtJambiObject
implements java.lang.Cloneable

The QStyleOption class stores the parameters used by QStyle functions. QStyleOption and its subclasses contain all the information that QStyle functions need to draw a graphical element.

For performance reasons, there are few member functions and 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 used by the style functions.

The caller of a QStyle function usually creates QStyleOption objects on the stack. This combined with Qt's extensive use of implicit sharing for types such as QString, QPalette, and QColor ensures that no memory allocation needlessly takes place.

The following code snippet shows how to use a specific QStyleOption subclass to paint a push button:

    public void paintEvent(QPaintEvent event)
    {
        QStyleOptionButton optioni = new QStyleOptionButton();
        option.initFrom(this);
        option.state() = isDown() ? QStyle.State.State_Sunken :
                                    QStyle.State.State_Raised;
        if (isDefault())
            option.features().setFlag(QStyleOptionButton.ButtonFeature.DefaultButton);
        option.setText(text());
        option.setIcon(icon());

        QPainter painter = new QPainter(this);
        style().drawControl(QStyle.ControlElement.CE_PushButton, option, painter, this);
    }
In our example, the control is a QStyle::CE_PushButton , and according to the QStyle::drawControl() documentation the corresponding class is QStyleOptionButton.

When reimplementing QStyle functions that take a QStyleOption parameter, you often need to cast the QStyleOption to a subclass. For safety, you can use qstyleoption_cast() to ensure that the pointer type is correct. For example:

    void drawPrimitive(QStyle.PrimitiveElement element,
                       QStyleOption option,
                       QPainter painter,
                       QWidget widget)
    {
        if (element.equals(PrimitiveElement.PE_FrameFocusRect)) {
            QStyleOptionFocusRect focusRectOption =
                    (QStyleOptionFocusRect) option;
            if (focusRectOption != null) {
                // ...
            }
        }
        // ...
    }
    
The qstyleoption_cast() function will return 0 if the object to which option points is not of the correct type.

For an example demonstrating how style options can be used, see the Styles example.

See also:
QStyle, and QStylePainter.


Nested Class Summary
static class QStyleOption.OptionType
          This enum is used internally by QStyleOption, its subclasses, and qstyleoption_cast() to determine the type of style option.
static class QStyleOption.StyleOptionType
          This enum is used to hold information about the type of the style option, and is defined for each QStyleOption subclass.
static class QStyleOption.StyleOptionVersion
          This enum is used to hold information about the version of the style option, and is defined for each QStyleOption subclass.
 
Nested classes/interfaces inherited from class com.trolltech.qt.QSignalEmitter
QSignalEmitter.AbstractSignal, QSignalEmitter.PrivateSignal0, QSignalEmitter.PrivateSignal1, QSignalEmitter.PrivateSignal2, QSignalEmitter.PrivateSignal3, QSignalEmitter.PrivateSignal4, QSignalEmitter.PrivateSignal5, QSignalEmitter.PrivateSignal6, QSignalEmitter.PrivateSignal7, QSignalEmitter.PrivateSignal8, QSignalEmitter.PrivateSignal9, QSignalEmitter.Signal0, QSignalEmitter.Signal1, QSignalEmitter.Signal2, QSignalEmitter.Signal3, QSignalEmitter.Signal4, QSignalEmitter.Signal5, QSignalEmitter.Signal6, QSignalEmitter.Signal7, QSignalEmitter.Signal8, QSignalEmitter.Signal9
 
Nested classes/interfaces inherited from class com.trolltech.qt.internal.QSignalEmitterInternal
com.trolltech.qt.internal.QSignalEmitterInternal.AbstractSignalInternal
 
Field Summary
 
Fields inherited from class com.trolltech.qt.internal.QSignalEmitterInternal
currentSender
 
Constructor Summary
QStyleOption()
          Constructs a QStyleOption with the specified version and type.
QStyleOption(int version)
          Constructs a QStyleOption with the specified version and type.
QStyleOption(int version, int type)
          Constructs a QStyleOption with the specified version and type.
QStyleOption(QStyleOption other)
          Constructs a copy of other.
 
Method Summary
 QStyleOption clone()
          This method is reimplemented for internal reasons
 Qt.LayoutDirection direction()
          This variable holds the text layout direction that should be used when drawing text in the control.
 QFontMetrics fontMetrics()
          This variable holds the font metrics that should be used when drawing text in the control.
 void initFrom(QWidget w)
          Initializes the state, direction, rect, palette, and fontMetrics member variables based on the specified widget.
 QPalette palette()
          This variable holds the palette that should be used when painting the control.
 QRect rect()
          This variable holds the area that should be used for various calculations and painting.
 void setDirection(Qt.LayoutDirection direction)
          This variable holds the text layout direction that should be used when drawing text in the control.
 void setFontMetrics(QFontMetrics fontMetrics)
          This variable holds the font metrics that should be used when drawing text in the control.
 void setPalette(QPalette palette)
          This variable holds the palette that should be used when painting the control.
 void setRect(QRect rect)
          This variable holds the area that should be used for various calculations and painting.
 void setState(QStyle.State state)
          This variable holds the style flags that are used when drawing the control.
 void setState(QStyle.StateFlag[] state)
           
 void setType(int type)
          This variable holds the option type of the style option.
 void setVersion(int version)
          This variable holds the version of the style option.
 QStyle.State state()
          This variable holds the style flags that are used when drawing the control.
 int type()
          This variable holds the option type of the style option.
 int version()
          This variable holds the version of the style option.
 
Methods inherited from class com.trolltech.qt.QtJambiObject
dispose, disposed, equals, finalize, reassignNativeResources, tr, tr, tr
 
Methods inherited from class com.trolltech.qt.QSignalEmitter
blockSignals, disconnect, disconnect, signalsBlocked, signalSender, thread
 
Methods inherited from class com.trolltech.qt.internal.QSignalEmitterInternal
__qt_signalInitialization
 
Methods inherited from class java.lang.Object
getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 
Methods inherited from interface com.trolltech.qt.QtJambiInterface
disableGarbageCollection, nativeId, nativePointer, reenableGarbageCollection, setJavaOwnership
 

Constructor Detail

QStyleOption

public QStyleOption(QStyleOption other)
Constructs a copy of other.


QStyleOption

public QStyleOption(int version)
Constructs a QStyleOption with the specified version and type.

The version has no special meaning for QStyleOption; it can be used by subclasses to distinguish between different version of the same option type.

The state member variable is initialized to QStyle::State_None .

See also:
version, and type.


QStyleOption

public QStyleOption()
Constructs a QStyleOption with the specified version and type.

The version has no special meaning for QStyleOption; it can be used by subclasses to distinguish between different version of the same option type.

The state member variable is initialized to QStyle::State_None .

See also:
version, and type.


QStyleOption

public QStyleOption(int version,
                    int type)
Constructs a QStyleOption with the specified version and type.

The version has no special meaning for QStyleOption; it can be used by subclasses to distinguish between different version of the same option type.

The state member variable is initialized to QStyle::State_None .

See also:
version, and type.

Method Detail

initFrom

public final void initFrom(QWidget w)
Initializes the state, direction, rect, palette, and fontMetrics member variables based on the specified widget.

This is a convenience function; the member variables can also be initialized manually.

See also:
QWidget::layoutDirection(), QWidget::rect(), QWidget::palette(), and QWidget::fontMetrics().


setPalette

public final void setPalette(QPalette palette)
This variable holds the palette that should be used when painting the control. By default, the application's default palette is used.

See also:
initFrom().


palette

public final QPalette palette()
This variable holds the palette that should be used when painting the control. By default, the application's default palette is used.

See also:
initFrom().


setVersion

public final void setVersion(int version)
This variable holds the version of the style option. This value can be used by subclasses to implement extensions without breaking compatibility. If you use the qstyleoption_cast() function, you normally do not need to check it.

The default value is 1.


version

public final int version()
This variable holds the version of the style option. This value can be used by subclasses to implement extensions without breaking compatibility. If you use the qstyleoption_cast() function, you normally do not need to check it.

The default value is 1.


setDirection

public final void setDirection(Qt.LayoutDirection direction)
This variable holds the text layout direction that should be used when drawing text in the control. By default, the layout direction is Qt::LeftToRight .

See also:
initFrom().


direction

public final Qt.LayoutDirection direction()
This variable holds the text layout direction that should be used when drawing text in the control. By default, the layout direction is Qt::LeftToRight .

See also:
initFrom().


setRect

public final void setRect(QRect rect)
This variable holds the area that should be used for various calculations and painting. This can have different meanings for different types of elements. For example, for a QStyle::CE_PushButton element it would be the rectangle for the entire button, while for a QStyle::CE_PushButtonLabel element it would be just the area for the push button label.

The default value is a null rectangle, i.e. a rectangle with both the width and the height set to 0.

See also:
initFrom().


rect

public final QRect rect()
This variable holds the area that should be used for various calculations and painting. This can have different meanings for different types of elements. For example, for a QStyle::CE_PushButton element it would be the rectangle for the entire button, while for a QStyle::CE_PushButtonLabel element it would be just the area for the push button label.

The default value is a null rectangle, i.e. a rectangle with both the width and the height set to 0.

See also:
initFrom().


setType

public final void setType(int type)
This variable holds the option type of the style option. The default value is SO_Default .

See also:
OptionType .


type

public final int type()
This variable holds the option type of the style option. The default value is SO_Default .

See also:
OptionType .


setState

public final void setState(QStyle.StateFlag[] state)

setState

public final void setState(QStyle.State state)
This variable holds the style flags that are used when drawing the control. The default value is QStyle::State_None .

See also:
initFrom(), QStyle::drawPrimitive(), QStyle::drawControl(), QStyle::drawComplexControl(), and QStyle::State.


state

public final QStyle.State state()
This variable holds the style flags that are used when drawing the control. The default value is QStyle::State_None .

See also:
initFrom(), QStyle::drawPrimitive(), QStyle::drawControl(), QStyle::drawComplexControl(), and QStyle::State.


setFontMetrics

public final void setFontMetrics(QFontMetrics fontMetrics)
This variable holds the font metrics that should be used when drawing text in the control. By default, the application's default font is used.

See also:
initFrom().


fontMetrics

public final QFontMetrics fontMetrics()
This variable holds the font metrics that should be used when drawing text in the control. By default, the application's default font is used.

See also:
initFrom().


clone

public QStyleOption clone()
This method is reimplemented for internal reasons

Overrides:
clone in class java.lang.Object