com.trolltech.qt.gui
Class QGraphicsScene

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.core.QObject
                  extended by com.trolltech.qt.gui.QGraphicsScene
All Implemented Interfaces:
QtJambiInterface

public class QGraphicsScene
extends QObject

The QGraphicsScene class provides a surface for managing a large number of 2D graphical items. The class serves as a container for QGraphicsItems. It is used together with QGraphicsView for visualizing graphical items, such as lines, rectangles, text, or even custom items, on a 2D surface. QGraphicsScene is part of The Graphics View Framework.

QGraphicsScene also provides functionality that lets you efficiently determine both the location of items, and for determining what items are visible within an arbitrary area on the scene. With the QGraphicsView widget, you can either visualize the whole scene, or zoom in and view only parts of the scene.

Example:

        QGraphicsScene scene = new QGraphicsScene();
        scene.addText("Hello, world!");

        QGraphicsView view = new QGraphicsView(scene);
        view.show();
Note that QGraphicsScene has no visual appearance of its own; it only manages the items. You need to create a QGraphicsView widget to visualize the scene.

To add items to a scene, you start off by constructing a QGraphicsScene object. Then, you have two options: either add your existing QGraphicsItem objects by calling addItem(), or you can call one of the convenience functions addEllipse(), addLine(), addPath(), addPixmap(), addPolygon(), addRect(), or addText(), which all return a pointer to the newly added item. The dimensions of the items added with these functions are relative to the item's coordinate system, and the items position is initialized to (0, 0) in the scene.

You can then visualize the scene using QGraphicsView. When the scene changes, (e.g., when an item moves or is transformed) QGraphicsScene emits the changed() signal. To remove an item, call removeItem().

QGraphicsScene uses an indexing algorithm to manage the location of items efficiently. By default, a BSP (Binary Space Partitioning) tree is used; an algorithm suitable for large scenes where most items remain static (i.e., do not move around). You can choose to disable this index by calling setItemIndexMethod(). For more information about the available indexing algorithms, see the itemIndexMethod property.

The scene's bounding rect is set by calling setSceneRect(). Items can be placed at any position on the scene, and the size of the scene is by default unlimited. The scene rect is used only for internal bookkeeping, maintaining the scene's item index. If the scene rect is unset, QGraphicsScene will use the bounding area of all items, as returned by itemsBoundingRect(), as the scene rect. However, itemsBoundingRect() is a relatively time consuming function, as it operates by collecting positional information for every item on the scene. Because of this, you should always set the scene rect when operating on large scenes.

One of QGraphicsScene's greatest strengths is its ability to efficiently determine the location of items. Even with millions of items on the scene, the items() functions can determine the location of an item within few milliseconds. There are several overloads to items(): one that finds items at a certain position, one that finds items inside or intersecting with a polygon or a rectangle, and more. The list of returned items is sorted by stacking order, with the topmost item being the first item in the list. For convenience, there is also an itemAt() function that returns the topmost item at a given position.

QGraphicsScene maintains selection information for the scene. To select items, call setSelectionArea(), and to clear the current selection, call clearSelection(). Call selectedItems() to get the list of all selected items.

Event Handling and Propagation

Another responsibility that QGraphicsScene has, is to propagate events from QGraphicsView. To send an event to a scene, you construct an event that inherits QEvent, and then send it using, for example, QApplication::sendEvent(). event() is responsible for dispatching the event to the individual items. Some common events are handled by convenience event handlers. For example, key press events are handled by keyPressEvent(), and mouse press events are handled by mousePressEvent().

Key events are delivered to the focus item. To set the focus item, you can either call setFocusItem(), passing an item that accepts focus, or the item itself can call QGraphicsItem::setFocus(). Call focusItem() to get the current focus item. For compatibility with widgets, the scene also maintains its own focus information. By default, the scene does not have focus, and all key events are discarded. If setFocus() is called, or if an item on the scene gains focus, the scene automatically gains focus. If the scene has focus, hasFocus() will return true, and key events will be forwarded to the focus item, if any. If the scene loses focus, (i.e., someone calls clearFocus(),) while an item has focus, the scene will maintain its item focus information, and once the scene regains focus, it will make sure the last focus item regains focus.

For mouse-over effects, QGraphicsScene dispatches hover events. If an item accepts hover events (see QGraphicsItem::acceptHoverEvents()), it will receive a GraphicsSceneHoverEnter event when the mouse enters its area. As the mouse continues moving inside the item's area, QGraphicsScene will send it GraphicsSceneHoverMove events. When the mouse leaves the item's area, the item will receive a GraphicsSceneHoverLeave event.

All mouse events are delivered to the current mouse grabber item. An item becomes the scene's mouse grabber if it accepts mouse events (see QGraphicsItem::acceptedMouseButtons()) and it receives a mouse press. It stays the mouse grabber until it receives a mouse release when no other mouse buttons are pressed. You can call mouseGrabberItem() to determine what item is currently grabbing the mouse.

See also:
QGraphicsItem, and QGraphicsView.


Nested Class Summary
static class QGraphicsScene.ItemIndexMethod
          This enum describes the indexing algorithms QGraphicsScene provides for managing positional information about items on the scene.
static class QGraphicsScene.SceneLayer
          This enum describes the rendering layers in a QGraphicsScene.
static class QGraphicsScene.SceneLayers
           
 
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
 QSignalEmitter.Signal1 changed
          This signal takes 1 generic argument(s).
 QSignalEmitter.Signal1 sceneRectChanged
          This signal takes 1 generic argument(s).
 QSignalEmitter.Signal0 selectionChanged
          This signal is emitted by QGraphicsScene whenever the selection changes.
 
Fields inherited from class com.trolltech.qt.internal.QSignalEmitterInternal
currentSender
 
Constructor Summary
QGraphicsScene()
          Constructs a QGraphicsScene object.
QGraphicsScene(double x, double y, double width, double height)
          Constructs a QGraphicsScene object, using the rectangle specified by (x, y), and the given width and height for its scene rectangle.
QGraphicsScene(double x, double y, double width, double height, QObject parent)
          Constructs a QGraphicsScene object, using the rectangle specified by (x, y), and the given width and height for its scene rectangle.
QGraphicsScene(QObject parent)
          Constructs a QGraphicsScene object.
QGraphicsScene(QRectF sceneRect)
          Constructs a QGraphicsScene object, using sceneRect for its scene rectangle.
QGraphicsScene(QRectF sceneRect, QObject parent)
          Constructs a QGraphicsScene object, using sceneRect for its scene rectangle.
 
Method Summary
 QGraphicsWidget activeWindow()
          Returns the current active window, or 0 if there is no window is currently active.
 QGraphicsEllipseItem addEllipse(double x, double y, double w, double h)
          Equivalent to addEllipse(x, y, w, h, null, null)
 QGraphicsEllipseItem addEllipse(double x, double y, double w, double h, QPen pen)
          Equivalent to addEllipse(x, y, w, h, pen, null)
 QGraphicsEllipseItem addEllipse(double x, double y, double w, double h, QPen pen, QBrush brush)
          Creates and adds an ellipse item to the scene, and returns the item reference.
 QGraphicsEllipseItem addEllipse(QRectF rect)
          Equivalent to addEllipse(rect, null, null)
 QGraphicsEllipseItem addEllipse(QRectF rect, QPen pen)
          Equivalent to addEllipse(rect, pen, null)
 QGraphicsEllipseItem addEllipse(QRectF rect, QPen pen, QBrush brush)
          Creates and adds an ellipse item to the scene, and returns the item reference.
 void addItem(QGraphicsItemInterface item)
          Adds or moves the item item and all its childen to the scene.
 QGraphicsLineItem addLine(double x1, double y1, double x2, double y2)
          Equivalent to addLine(x1, y1, x2, y2, null)
 QGraphicsLineItem addLine(double x1, double y1, double x2, double y2, QPen pen)
          Creates and adds a line item to the scene, and returns the item reference.
 QGraphicsLineItem addLine(QLineF line)
          Equivalent to addLine(line, null)
 QGraphicsLineItem addLine(QLineF line, QPen pen)
          Creates and adds a line item to the scene, and returns the item reference.
 QGraphicsPathItem addPath(QPainterPath path)
          Equivalent to addPath(path, null, null)
 QGraphicsPathItem addPath(QPainterPath path, QPen pen)
          Equivalent to addPath(path, pen, null)
 QGraphicsPathItem addPath(QPainterPath path, QPen pen, QBrush brush)
          Creates and adds a path item to the scene, and returns the item reference.
 QGraphicsPixmapItem addPixmap(QPixmap pixmap)
          Creates and adds a pixmap item to the scene, and returns the item reference.
 QGraphicsPolygonItem addPolygon(QPolygonF polygon)
          Equivalent to addPolygon(polygon, null, null)
 QGraphicsPolygonItem addPolygon(QPolygonF polygon, QPen pen)
          Equivalent to addPolygon(polygon, pen, null)
 QGraphicsPolygonItem addPolygon(QPolygonF polygon, QPen pen, QBrush brush)
          Creates and adds a polygon item to the scene, and returns the item reference.
 QGraphicsRectItem addRect(double x, double y, double w, double h)
          Equivalent to addRect(x, y, w, h, null, null)
 QGraphicsRectItem addRect(double x, double y, double w, double h, QPen pen)
          Equivalent to addRect(x, y, w, h, pen, null)
 QGraphicsRectItem addRect(double x, double y, double w, double h, QPen pen, QBrush brush)
          Creates and adds a rectangle item to the scene, and returns the item reference.
 QGraphicsRectItem addRect(QRectF rect)
          Equivalent to addRect(rect, null, null)
 QGraphicsRectItem addRect(QRectF rect, QPen pen)
          Equivalent to addRect(rect, pen, null)
 QGraphicsRectItem addRect(QRectF rect, QPen pen, QBrush brush)
          Creates and adds a rectangle item to the scene, and returns the item reference.
 QGraphicsSimpleTextItem addSimpleText(java.lang.String text)
          Equivalent to addSimpleText(text, null)
 QGraphicsSimpleTextItem addSimpleText(java.lang.String text, QFont font)
          Creates and adds a QGraphicsSimpleTextItem to the scene, and returns the item reference.
 QGraphicsTextItem addText(java.lang.String text)
          Equivalent to addText(text, null)
 QGraphicsTextItem addText(java.lang.String text, QFont font)
          Creates and adds a text item to the scene, and returns the item reference.
 QGraphicsProxyWidget addWidget(QWidget widget)
          Creates a new QGraphicsProxyWidget for widget, adds it to the scene, and returns a pointer to the proxy.
 QGraphicsProxyWidget addWidget(QWidget widget, Qt.WindowFlags wFlags)
          Creates a new QGraphicsProxyWidget for widget, adds it to the scene, and returns a pointer to the proxy.
 QGraphicsProxyWidget addWidget(QWidget widget, Qt.WindowType[] wFlags)
           
 void advance()
          This slot advances the scene by one step, by calling QGraphicsItem::advance() for all items on the scene.
 QBrush backgroundBrush()
          This property holds the background brush of the scene.
 int bspTreeDepth()
          This property holds the depth of QGraphicsScene's BSP index tree.
 void clear()
          Removes and deletes all items from the scene, but otherwise leaves the state of the scene unchanged.
 void clearFocus()
          Clears focus from the scene.
 void clearSelection()
          Clears the current selection.
 java.util.List collidingItems(QGraphicsItemInterface item)
          Returns a list of all items that collide with item.
 java.util.List collidingItems(QGraphicsItemInterface item, Qt.ItemSelectionMode mode)
          Returns a list of all items that collide with item.
protected  void contextMenuEvent(QGraphicsSceneContextMenuEvent event)
          This event handler, for event contextMenuEvent, can be reimplemented in a subclass to receive context menu events.
 QGraphicsItemGroup createItemGroup(java.util.List items)
          Groups all items in items into a new QGraphicsItemGroup, and returns a pointer to the group.
 void destroyItemGroup(QGraphicsItemGroup group)
          Reparents all items in group to group's parent item, then removes group from the scene, and finally deletes it.
protected  void dragEnterEvent(QGraphicsSceneDragDropEvent event)
          This event handler, for event event, can be reimplemented in a subclass to receive drag enter events for the scene.
protected  void dragLeaveEvent(QGraphicsSceneDragDropEvent event)
          This event handler, for event event, can be reimplemented in a subclass to receive drag leave events for the scene.
protected  void dragMoveEvent(QGraphicsSceneDragDropEvent event)
          This event handler, for event event, can be reimplemented in a subclass to receive drag move events for the scene.
protected  void drawBackground(QPainter painter, QRectF rect)
          Draws the background of the scene using painter, before any items and the foreground are drawn.
protected  void drawForeground(QPainter painter, QRectF rect)
          Draws the foreground of the scene using painter, after the background and all items have been drawn.
protected  void drawItems(QPainter painter, QGraphicsItemInterface[] items, QStyleOptionGraphicsItem[] options)
           
protected  void drawItems(QPainter painter, QGraphicsItemInterface[] items, QStyleOptionGraphicsItem[] options, QWidget widget)
           
protected  void dropEvent(QGraphicsSceneDragDropEvent event)
          This event handler, for event event, can be reimplemented in a subclass to receive drop events for the scene.
protected  void focusInEvent(QFocusEvent event)
          This event handler, for event focusEvent, can be reimplemented in a subclass to receive focus in events.
 QGraphicsItemInterface focusItem()
          Returns the scene's current focus item, or 0 if no item currently has focus.
protected  boolean focusNextPrevChild(boolean next)
          Finds a new widget to give the keyboard focus to, as appropriate for Tab and Shift+Tab, and returns true if it can find a new widget, or false if it cannot.
protected  void focusOutEvent(QFocusEvent event)
          This event handler, for event focusEvent, can be reimplemented in a subclass to receive focus out events.
 QFont font()
          This property holds the scene's default font.
 QBrush foregroundBrush()
          This property holds the foreground brush of the scene.
 boolean hasFocus()
          Returns true if the scene has focus; otherwise returns false.
 double height()
          This convenience function is equivalent to calling sceneRect().
protected  void helpEvent(QGraphicsSceneHelpEvent event)
          This event handler, for event helpEvent, can be reimplemented in a subclass to receive help events.
protected  void inputMethodEvent(QInputMethodEvent event)
          This event handler, for event event, can be reimplemented in a subclass to receive input method events for the scene.
 java.lang.Object inputMethodQuery(Qt.InputMethodQuery query)
          This method is used by input methods to query a set of properties of the scene to be able to support complex input method operations as support for surrounding text and reconversions.
 void invalidate()
          Invalidates and schedules a redraw of the layers in rect on the scene.
 void invalidate(double x, double y, double w, double h)
          This is an overloaded member function, provided for convenience.
 void invalidate(double x, double y, double w, double h, QGraphicsScene.SceneLayer[] layers)
           
 void invalidate(double x, double y, double w, double h, QGraphicsScene.SceneLayers layers)
          This is an overloaded member function, provided for convenience.
 void invalidate(QRectF rect)
          Invalidates and schedules a redraw of the layers in rect on the scene.
 void invalidate(QRectF rect, QGraphicsScene.SceneLayer[] layers)
           
 void invalidate(QRectF rect, QGraphicsScene.SceneLayers layers)
          Invalidates and schedules a redraw of the layers in rect on the scene.
 boolean isSortCacheEnabled()
          This property holds whether sort caching is enabled.
 QGraphicsItemInterface itemAt(double x, double y)
          This is an overloaded member function, provided for convenience.
 QGraphicsItemInterface itemAt(QPointF pos)
          Returns the topmost visible item at the specified position, or 0 if there are no items at this position.
 QGraphicsScene.ItemIndexMethod itemIndexMethod()
          This property holds the item indexing method.
 java.util.List items()
          Returns a list of all items on the scene, in no particular order.
 java.util.List items(double x, double y, double w, double h)
          This convenience function is equivalent to calling items(QRectF(x, y, w, h).
 java.util.List items(double x, double y, double w, double h, Qt.ItemSelectionMode mode)
          This convenience function is equivalent to calling items(QRectF(x, y, w, h), mode).
 java.util.List items(QPainterPath path)
          Returns all visible items that are either inside or intersect with the path path.
 java.util.List items(QPainterPath path, Qt.ItemSelectionMode mode)
          This is an overloaded member function, provided for convenience.
 java.util.List items(QPointF pos)
          Returns all visible items at position pos in the scene.
 java.util.List items(QPolygonF polygon)
          Returns all visible items that are either inside or intersect with the polygon polygon.
 java.util.List items(QPolygonF polygon, Qt.ItemSelectionMode mode)
          This is an overloaded member function, provided for convenience.
 java.util.List items(QRectF rect)
          Returns all visible items that are either inside or intersect with the specified rectangle.
 java.util.List items(QRectF rect, Qt.ItemSelectionMode mode)
          This is an overloaded member function, provided for convenience.
 QRectF itemsBoundingRect()
          Calculates and returns the bounding rect of all items on the scene.
protected  void keyPressEvent(QKeyEvent event)
          This event handler, for event keyEvent, can be reimplemented in a subclass to receive keypress events.
protected  void keyReleaseEvent(QKeyEvent event)
          This event handler, for event keyEvent, can be reimplemented in a subclass to receive key release events.
protected  void mouseDoubleClickEvent(QGraphicsSceneMouseEvent event)
          This event handler, for event mouseEvent, can be reimplemented in a subclass to receive mouse doubleclick events for the scene.
 QGraphicsItemInterface mouseGrabberItem()
          Returns the current mouse grabber item, or 0 if no item is currently grabbing the mouse.
protected  void mouseMoveEvent(QGraphicsSceneMouseEvent event)
          This event handler, for event mouseEvent, can be reimplemented in a subclass to receive mouse move events for the scene.
protected  void mousePressEvent(QGraphicsSceneMouseEvent event)
          This event handler, for event mouseEvent, can be reimplemented in a subclass to receive mouse press events for the scene.
protected  void mouseReleaseEvent(QGraphicsSceneMouseEvent event)
          This event handler, for event mouseEvent, can be reimplemented in a subclass to receive mouse release events for the scene.
 QPalette palette()
          This property holds the scene's default palette.
 void removeItem(QGraphicsItemInterface item)
          Removes the item item and all its children from the scene.
 void render(QPainter painter)
          Renders the source rect from scene into target, using painter.
 void render(QPainter painter, QRectF target)
          Renders the source rect from scene into target, using painter.
 void render(QPainter painter, QRectF target, QRectF source)
          Renders the source rect from scene into target, using painter.
 void render(QPainter painter, QRectF target, QRectF source, Qt.AspectRatioMode aspectRatioMode)
          Renders the source rect from scene into target, using painter.
 QRectF sceneRect()
          This property holds the scene rectangle; the bounding rectangle of the scene.
 java.util.List selectedItems()
          Returns a list of all currently selected items.
 QPainterPath selectionArea()
          Returns the selection area that was previously set with setSelectionArea(), or an empty QPainterPath if no selection area has been set.
 void setActiveWindow(QGraphicsWidget widget)
          Activates widget, which must be a widget in this scene.
 void setBackgroundBrush(QBrush brush)
          This property holds the background brush of the scene.
 void setBspTreeDepth(int depth)
          This property holds the depth of QGraphicsScene's BSP index tree.
 void setFocus()
          Sets focus on the scene by sending a QFocusEvent to the scene, passing focusReason as the reason.
 void setFocus(Qt.FocusReason focusReason)
          Sets focus on the scene by sending a QFocusEvent to the scene, passing focusReason as the reason.
 void setFocusItem(QGraphicsItemInterface item)
          Sets the scene's focus item to item, with the focus reason focusReason, after removing focus from any previous item that may have had focus.
 void setFocusItem(QGraphicsItemInterface item, Qt.FocusReason focusReason)
          Sets the scene's focus item to item, with the focus reason focusReason, after removing focus from any previous item that may have had focus.
 void setFont(QFont font)
          This property holds the scene's default font.
 void setForegroundBrush(QBrush brush)
          This property holds the foreground brush of the scene.
 void setItemIndexMethod(QGraphicsScene.ItemIndexMethod method)
          This property holds the item indexing method.
 void setPalette(QPalette palette)
          This property holds the scene's default palette.
 void setSceneRect(double x, double y, double w, double h)
          This property holds the scene rectangle; the bounding rectangle of the scene.
 void setSceneRect(QRectF rect)
          This property holds the scene rectangle; the bounding rectangle of the scene.
 void setSelectionArea(QPainterPath path)
          Sets the selection area to path.
 void setSelectionArea(QPainterPath path, Qt.ItemSelectionMode arg__2)
          This is an overloaded member function, provided for convenience.
 void setSortCacheEnabled(boolean enabled)
          This property holds whether sort caching is enabled.
 void setStyle(QStyle style)
          Sets or replaces the style of the scene to style, and reparents the style to this scene.
 QStyle style()
          Returns the scene's style, or the same as QApplication::style() if the scene has not been explicitly assigned a style.
 void update()
          Schedules a redraw of the area rect on the scene.
 void update(double x, double y, double w, double h)
          This is an overloaded member function, provided for convenience.
 void update(QRectF rect)
          Schedules a redraw of the area rect on the scene.
 java.util.List views()
          Returns a list of all the views that display this scene.
protected  void wheelEvent(QGraphicsSceneWheelEvent event)
          This event handler, for event wheelEvent, can be reimplemented in a subclass to receive mouse wheel events for the scene.
 double width()
          This convenience function is equivalent to calling sceneRect().width().
 
Methods inherited from class com.trolltech.qt.core.QObject
childEvent, children, connectSlotsByName, customEvent, disposeLater, dumpObjectInfo, dumpObjectTree, dynamicPropertyNames, event, eventFilter, findChild, findChild, findChild, findChildren, findChildren, findChildren, findChildren, indexOfProperty, installEventFilter, isWidgetType, killTimer, moveToThread, objectName, parent, properties, property, removeEventFilter, setObjectName, setParent, setProperty, startTimer, timerEvent, toString, userProperty
 
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
clone, getClass, hashCode, notify, notifyAll, wait, wait, wait
 
Methods inherited from interface com.trolltech.qt.QtJambiInterface
disableGarbageCollection, nativeId, nativePointer, reenableGarbageCollection, setJavaOwnership
 

Field Detail

changed

public final QSignalEmitter.Signal1 changed

This signal takes 1 generic argument(s). We list their type and the name they go by in the description of this signal. <java.util.List(named: region)>:

This signal is emitted by QGraphicsScene when control reaches the event loop, if the scene content changes. The region parameter contains a list of scene rectangles that indicate the area that has been changed.

See also:
QGraphicsView::updateScene().


sceneRectChanged

public final QSignalEmitter.Signal1 sceneRectChanged

This signal takes 1 generic argument(s). We list their type and the name they go by in the description of this signal. <com.trolltech.qt.core.QRectF(named: rect)>:

This signal is emitted by QGraphicsScene whenever the scene rect changes. The rect parameter is the new scene rectangle.

See also:
QGraphicsView::updateSceneRect().


selectionChanged

public final QSignalEmitter.Signal0 selectionChanged
This signal is emitted by QGraphicsScene whenever the selection changes. You can call selectedItems() to get the new list of selected items.

The selection changes whenever an item is selected or unselected, a selection area is set, cleared or otherwise changed, if a preselected item is added to the scene, or if a selected item is removed from the scene.

QGraphicsScene emits this signal only once for group selection operations. For example, if you set a selection area, select or unselect a QGraphicsItemGroup, or if you add or remove from the scene a parent item that contains several selected items, selectionChanged() is emitted only once after the operation has completed (instead of once for each item).

See also:
setSelectionArea(), selectedItems(), and QGraphicsItem::setSelected().

Constructor Detail

QGraphicsScene

public QGraphicsScene()
Constructs a QGraphicsScene object. The parent parameter is passed to QObject's constructor.


QGraphicsScene

public QGraphicsScene(QObject parent)
Constructs a QGraphicsScene object. The parent parameter is passed to QObject's constructor.


QGraphicsScene

public QGraphicsScene(QRectF sceneRect)
Constructs a QGraphicsScene object, using sceneRect for its scene rectangle. The parent parameter is passed to QObject's constructor.

See also:
sceneRect.


QGraphicsScene

public QGraphicsScene(QRectF sceneRect,
                      QObject parent)
Constructs a QGraphicsScene object, using sceneRect for its scene rectangle. The parent parameter is passed to QObject's constructor.

See also:
sceneRect.


QGraphicsScene

public QGraphicsScene(double x,
                      double y,
                      double width,
                      double height)
Constructs a QGraphicsScene object, using the rectangle specified by (x, y), and the given width and height for its scene rectangle. The parent parameter is passed to QObject's constructor.

See also:
sceneRect.


QGraphicsScene

public QGraphicsScene(double x,
                      double y,
                      double width,
                      double height,
                      QObject parent)
Constructs a QGraphicsScene object, using the rectangle specified by (x, y), and the given width and height for its scene rectangle. The parent parameter is passed to QObject's constructor.

See also:
sceneRect.

Method Detail

activeWindow

public final QGraphicsWidget activeWindow()
Returns the current active window, or 0 if there is no window is currently active.

See also:
QGraphicsScene::setActiveWindow().


addItem

public final void addItem(QGraphicsItemInterface item)
Adds or moves the item item and all its childen to the scene.

If the item is visible (i.e., QGraphicsItem::isVisible() returns true), QGraphicsScene will emit changed() once control goes back to the event loop.

If the item is already in a different scene, it will first be removed from its old scene, and then added to this scene as a top-level.

QGraphicsScene will send ItemSceneChange notifications to item while it is added to the scene. If item does not currently belong to a scene, only one notification is sent. If it does belong to scene already (i.e., it is moved to this scene), QGraphicsScene will send an addition notification as the item is removed from its previous scene.

See also:
removeItem(), addEllipse(), addLine(), addPath(), addPixmap(), addRect(), addText(), and addWidget().


addWidget

public final QGraphicsProxyWidget addWidget(QWidget widget,
                                            Qt.WindowType[] wFlags)

addWidget

public final QGraphicsProxyWidget addWidget(QWidget widget)
Creates a new QGraphicsProxyWidget for widget, adds it to the scene, and returns a pointer to the proxy. wFlags set the default window flags for the embedding proxy widget.

The item's position is initialized to (0, 0).

If the item is visible (i.e., QGraphicsItem::isVisible() returns true), QGraphicsScene will emit changed() once control goes back to the event loop.

Note that widgets with the Qt::WA_PaintOnScreen widget attribute set and widgets that wrap an external application or controller are not supported. Examples are QGLWidget and QAxWidget.

See also:
addEllipse(), addLine(), addPixmap(), addPixmap(), addRect(), addText(), addSimpleText(), and addItem().


addWidget

public final QGraphicsProxyWidget addWidget(QWidget widget,
                                            Qt.WindowFlags wFlags)
Creates a new QGraphicsProxyWidget for widget, adds it to the scene, and returns a pointer to the proxy. wFlags set the default window flags for the embedding proxy widget.

The item's position is initialized to (0, 0).

If the item is visible (i.e., QGraphicsItem::isVisible() returns true), QGraphicsScene will emit changed() once control goes back to the event loop.

Note that widgets with the Qt::WA_PaintOnScreen widget attribute set and widgets that wrap an external application or controller are not supported. Examples are QGLWidget and QAxWidget.

See also:
addEllipse(), addLine(), addPixmap(), addPixmap(), addRect(), addText(), addSimpleText(), and addItem().


advance

public final void advance()
This slot advances the scene by one step, by calling QGraphicsItem::advance() for all items on the scene. This is done in two phases: in the first phase, all items are notified that the scene is about to change, and in the second phase all items are notified that they can move. In the first phase, QGraphicsItem::advance() is called passing a value of 0 as an argument, and 1 is passed in the second phase.

See also:
QGraphicsItem::advance(), QGraphicsItemAnimation, and QTimeLine.


backgroundBrush

public final QBrush backgroundBrush()
This property holds the background brush of the scene. Set this property to changes the scene's background to a different color, gradient or texture. The default background brush is Qt::NoBrush . The background is drawn before (behind) the items.

Example:

        QGraphicsScene scene = new QGraphicsScene();
        QGraphicsView view = new QGraphicsView(scene);
        view.show();

        // a blue background
        scene.setBackgroundBrush(new QBrush(QColor.blue));

        // a gradient background
        QRadialGradient gradient = new QRadialGradient(0, 0, 10);
        gradient.setSpread(QGradient.Spread.RepeatSpread);
        scene.setBackgroundBrush(new QBrush(gradient));
QGraphicsScene::render() calls drawBackground() to draw the scene background. For more detailed control over how the background is drawn, you can reimplement drawBackground() in a subclass of QGraphicsScene.


bspTreeDepth

public final int bspTreeDepth()
This property holds the depth of QGraphicsScene's BSP index tree. This property has no effect when NoIndex is used.

This value determines the depth of QGraphicsScene's BSP tree. The depth directly affects QGraphicsScene's performance and memory usage; the latter growing exponentially with the depth of the tree. With an optimal tree depth, QGraphicsScene can instantly determine the locality of items, even for scenes with thousands or millions of items. This also greatly improves rendering performance.

By default, the value is 0, in which case Qt will guess a reasonable default depth based on the size, location and number of items in the scene. If these parameters change frequently, however, you may experience slowdowns as QGraphicsScene retunes the depth internally. You can avoid potential slowdowns by fixating the tree depth through setting this property.

The depth of the tree and the size of the scene rectangle decide the granularity of the scene's partitioning. The size of each scene segment is determined by the following algorithm:

        QSizeF segmentSize = sceneRect().size().divide(java.lang.Math.pow(2, depth - 1));
The BSP tree has an optimal size when each segment contains between 0 and 10 items.

See also:
itemIndexMethod.


clear

public final void clear()
Removes and deletes all items from the scene, but otherwise leaves the state of the scene unchanged.

See also:
addItem().


clearFocus

public final void clearFocus()
Clears focus from the scene. If any item has focus when this function is called, it will lose focus, and regain focus again once the scene regains focus.

A scene that does not have focus ignores key events.

See also:
hasFocus(), setFocus(), and setFocusItem().


clearSelection

public final void clearSelection()
Clears the current selection.

See also:
setSelectionArea(), and selectedItems().


collidingItems

public final java.util.List collidingItems(QGraphicsItemInterface item)
Returns a list of all items that collide with item. Collisions are determined by calling QGraphicsItem.collidesWithItem(); the collision detection is determined by \a mode. By default, all items whose shape intersects \a item or is contained inside \a item's shape are returned.

The items are returned in descending Z order (i.e., the first item in the list is the top-most item, and the last item is the bottom-most item).


collidingItems

public final java.util.List collidingItems(QGraphicsItemInterface item,
                                           Qt.ItemSelectionMode mode)
Returns a list of all items that collide with item. Collisions are determined by calling QGraphicsItem::collidesWithItem(); the collision detection is determined by mode. By default, all items whose shape intersects item or is contained inside item's shape are returned.

The items are returned in descending Z order (i.e., the first item in the list is the top-most item, and the last item is the bottom-most item).

See also:
items(), itemAt(), and QGraphicsItem::collidesWithItem().


createItemGroup

public final QGraphicsItemGroup createItemGroup(java.util.List items)
Groups all items in items into a new QGraphicsItemGroup, and returns a pointer to the group. The group is created with the common ancestor of items as its parent, and with position (0, 0). The items are all reparented to the group, and their positions and transformations are mapped to the group. If items is empty, this function will return an empty top-level QGraphicsItemGroup.

QGraphicsScene has ownership of the group item; you do not need to delete it. To dismantle (ungroup) a group, call destroyItemGroup().

See also:
destroyItemGroup(), and QGraphicsItemGroup::addToGroup().


destroyItemGroup

public final void destroyItemGroup(QGraphicsItemGroup group)
Reparents all items in group to group's parent item, then removes group from the scene, and finally deletes it. The items' positions and transformations are mapped from the group to the group's parent.

See also:
createItemGroup(), and QGraphicsItemGroup::removeFromGroup().


focusItem

public final QGraphicsItemInterface focusItem()
Returns the scene's current focus item, or 0 if no item currently has focus.

The focus item receives keyboard input when the scene receives a key event.

See also:
setFocusItem(), and QGraphicsItem::hasFocus().


focusNextPrevChild

protected final boolean focusNextPrevChild(boolean next)
Finds a new widget to give the keyboard focus to, as appropriate for Tab and Shift+Tab, and returns true if it can find a new widget, or false if it cannot. If next is true, this function searches forward; if next is false, it searches backward.

You can reimplement this function in a subclass of QGraphicsScene to provide fine-grained control over how tab focus passes inside your scene. The default implementation is based on the tab focus chain defined by QGraphicsWidget::setTabOrder().


font

public final QFont font()
This property holds the scene's default font. This property provides the scene's font. The scene font defaults to, and resolves all its entries from, QApplication::font.

If the scene's font changes, either directly through setFont() or indirectly when the application font changes, QGraphicsScene first sends itself a FontChange event, and it then sends FontChange events to all top-level widget items in the scene. These items respond by resolving their own fonts to the scene, and they then notify their children, who again notify their children, and so on, until all widget items have updated their fonts.

Changing the scene font, (directly or indirectly through QApplication::setFont(),) automatically schedules a redraw the entire scene.

See also:
QWidget::font, QApplication::setFont(), palette, and style().


foregroundBrush

public final QBrush foregroundBrush()
This property holds the foreground brush of the scene. Change this property to set the scene's foreground to a different color, gradient or texture.

The foreground is drawn after (on top of) the items. The default foreground brush is Qt::NoBrush ( i.e. the foreground is not drawn).

Example:

        QGraphicsScene scene = new QGraphicsScene();
        QGraphicsView view = new QGraphicsView(scene);
        view.show();

        // a white semi-transparent foreground
        scene.setForegroundBrush(new QBrush(new QColor(255, 255, 255, 127)));

        // a grid foreground
        scene.setForegroundBrush(new QBrush(QColor.lightGray, Qt.BrushStyle.CrossPattern));
QGraphicsScene::render() calls drawForeground() to draw the scene foreground. For more detailed control over how the foreground is drawn, you can reimplement the drawForeground() function in a QGraphicsScene subclass.


hasFocus

public final boolean hasFocus()
Returns true if the scene has focus; otherwise returns false. If the scene has focus, it will will forward key events from QKeyEvent to any item that has focus.

See also:
setFocus(), and setFocusItem().


height

public final double height()
This convenience function is equivalent to calling sceneRect(). eight().

See also:
width().


invalidate

public final void invalidate(QRectF rect,
                             QGraphicsScene.SceneLayer[] layers)

invalidate

public final void invalidate(QRectF rect)
Invalidates and schedules a redraw of the layers in rect on the scene. Any cached content in layers is unconditionally invalidated and redrawn.

You can use this function overload to notify QGraphicsScene of changes to the background or the foreground of the scene. This function is commonly used for scenes with tile-based backgrounds to notify changes when QGraphicsView has enabled CacheBackground .

Example:

    class TileScene extends QGraphicsScene {

    private final int tileWidth = 10;
    private final int tileHeight = 10;
    private final int numTilesH = 10;
    private final int numTilesV = 10;
    private QPixmap[][] tiles;

    TileScene() {
        tiles = new QPixmap[numTilesH][numTilesV];
    }

      public QRectF rectForTile(int x, int y)
      {
          // Return the rectangle for the tile at position (x, y).
          return new QRectF(x * tileWidth,y * tileHeight,tileWidth,tileHeight);
      }

      public void setTile(int x, int y, QPixmap pixmap)
      {
          // Sets or replaces the tile at position (x, y) with pixmap.
          if (x >= 0 && x < numTilesH && y >= 0 && y < numTilesV) {
              tiles[y][x] = pixmap;
              invalidate(rectForTile(x, y), QGraphicsScene.SceneLayer.BackgroundLayer);
          }
      }

      protected void drawBackground(QPainter painter, QRectF exposed)
      {
          // Draws all tiles that intersect the exposed area.
          for (int y = 0; y < numTilesV; ++y) {
              for (int x = 0; x < numTilesH; ++x) {
                  QRectF rect = rectForTile(x, y);
                  if (exposed.intersects(rect))
                      painter.drawPixmap(rect.topLeft(), tiles[y][x]);
              }
          }
      }

    }

Note that QGraphicsView currently supports background caching only (see QGraphicsView::CacheBackground ). This function is equivalent to calling update() if any layer but BackgroundLayer is passed.

See also:
QGraphicsView::resetCachedContent().


invalidate

public final void invalidate()
Invalidates and schedules a redraw of the layers in rect on the scene. Any cached content in layers is unconditionally invalidated and redrawn.

You can use this function overload to notify QGraphicsScene of changes to the background or the foreground of the scene. This function is commonly used for scenes with tile-based backgrounds to notify changes when QGraphicsView has enabled CacheBackground .

Example:

    class TileScene extends QGraphicsScene {

    private final int tileWidth = 10;
    private final int tileHeight = 10;
    private final int numTilesH = 10;
    private final int numTilesV = 10;
    private QPixmap[][] tiles;

    TileScene() {
        tiles = new QPixmap[numTilesH][numTilesV];
    }

      public QRectF rectForTile(int x, int y)
      {
          // Return the rectangle for the tile at position (x, y).
          return new QRectF(x * tileWidth,y * tileHeight,tileWidth,tileHeight);
      }

      public void setTile(int x, int y, QPixmap pixmap)
      {
          // Sets or replaces the tile at position (x, y) with pixmap.
          if (x >= 0 && x < numTilesH && y >= 0 && y < numTilesV) {
              tiles[y][x] = pixmap;
              invalidate(rectForTile(x, y), QGraphicsScene.SceneLayer.BackgroundLayer);
          }
      }

      protected void drawBackground(QPainter painter, QRectF exposed)
      {
          // Draws all tiles that intersect the exposed area.
          for (int y = 0; y < numTilesV; ++y) {
              for (int x = 0; x < numTilesH; ++x) {
                  QRectF rect = rectForTile(x, y);
                  if (exposed.intersects(rect))
                      painter.drawPixmap(rect.topLeft(), tiles[y][x]);
              }
          }
      }

    }

Note that QGraphicsView currently supports background caching only (see QGraphicsView::CacheBackground ). This function is equivalent to calling update() if any layer but BackgroundLayer is passed.

See also:
QGraphicsView::resetCachedContent().


invalidate

public final void invalidate(QRectF rect,
                             QGraphicsScene.SceneLayers layers)
Invalidates and schedules a redraw of the layers in rect on the scene. Any cached content in layers is unconditionally invalidated and redrawn.

You can use this function overload to notify QGraphicsScene of changes to the background or the foreground of the scene. This function is commonly used for scenes with tile-based backgrounds to notify changes when QGraphicsView has enabled CacheBackground .

Example:

    class TileScene extends QGraphicsScene {

    private final int tileWidth = 10;
    private final int tileHeight = 10;
    private final int numTilesH = 10;
    private final int numTilesV = 10;
    private QPixmap[][] tiles;

    TileScene() {
        tiles = new QPixmap[numTilesH][numTilesV];
    }

      public QRectF rectForTile(int x, int y)
      {
          // Return the rectangle for the tile at position (x, y).
          return new QRectF(x * tileWidth,y * tileHeight,tileWidth,tileHeight);
      }

      public void setTile(int x, int y, QPixmap pixmap)
      {
          // Sets or replaces the tile at position (x, y) with pixmap.
          if (x >= 0 && x < numTilesH && y >= 0 && y < numTilesV) {
              tiles[y][x] = pixmap;
              invalidate(rectForTile(x, y), QGraphicsScene.SceneLayer.BackgroundLayer);
          }
      }

      protected void drawBackground(QPainter painter, QRectF exposed)
      {
          // Draws all tiles that intersect the exposed area.
          for (int y = 0; y < numTilesV; ++y) {
              for (int x = 0; x < numTilesH; ++x) {
                  QRectF rect = rectForTile(x, y);
                  if (exposed.intersects(rect))
                      painter.drawPixmap(rect.topLeft(), tiles[y][x]);
              }
          }
      }

    }

Note that QGraphicsView currently supports background caching only (see QGraphicsView::CacheBackground ). This function is equivalent to calling update() if any layer but BackgroundLayer is passed.

See also:
QGraphicsView::resetCachedContent().


invalidate

public final void invalidate(double x,
                             double y,
                             double w,
                             double h,
                             QGraphicsScene.SceneLayer[] layers)

invalidate

public final void invalidate(double x,
                             double y,
                             double w,
                             double h)
This is an overloaded member function, provided for convenience.

This convenience function is equivalent to calling invalidate(QRectF(x, y, w, h), layers);


invalidate

public final void invalidate(double x,
                             double y,
                             double w,
                             double h,
                             QGraphicsScene.SceneLayers layers)
This is an overloaded member function, provided for convenience.

This convenience function is equivalent to calling invalidate(QRectF(x, y, w, h), layers);


isSortCacheEnabled

public final boolean isSortCacheEnabled()
This property holds whether sort caching is enabled. When enabled, this property adds a cache that speeds up sorting and transformations for scenes with deep hierarchies (i.e., items with many levels of descendents), at the cost of using more memory (approx. 100 more bytes of memory per item).

Items that are not part of a deep hierarchy suffer no penalty from this cache.


itemAt

public final QGraphicsItemInterface itemAt(QPointF pos)
Returns the topmost visible item at the specified position, or 0 if there are no items at this position.

Note: The topmost item is the one with the highest Z-value.

See also:
items(), collidingItems(), and QGraphicsItem::setZValue().


itemAt

public final QGraphicsItemInterface itemAt(double x,
                                           double y)
This is an overloaded member function, provided for convenience.

Returns the topmost item at the position specified by (x, y), or 0 if there are no items at this position.

This convenience function is equivalent to calling itemAt(QPointF(x, y)).

Note: The topmost item is the one with the highest Z-value.


itemIndexMethod

public final QGraphicsScene.ItemIndexMethod itemIndexMethod()
This property holds the item indexing method. QGraphicsScene applies an indexing algorithm to the scene, to speed up item discovery functions like items() and itemAt(). Indexing is most efficient for static scenes (i.e., where items don't move around). For dynamic scenes, or scenes with many animated items, the index bookkeeping can outweight the fast lookup speeds.

For the common case, the default index method BspTreeIndex works fine. If your scene uses many animations and you are experiencing slowness, you can disable indexing by calling setItemIndexMethod(NoIndex).

See also:
bspTreeDepth.


items

public final java.util.List items()
Returns a list of all items on the scene, in no particular order.

See also:
addItem(), and removeItem().


items

public final java.util.List items(QPainterPath path)
Returns all visible items that are either inside or intersect with the path path.


items

public final java.util.List items(QPainterPath path,
                                  Qt.ItemSelectionMode mode)
This is an overloaded member function, provided for convenience.

Returns all visible items that, depending on path, are either inside or intersect with the path path.

The default value for mode is Qt::IntersectsItemShape ; all items whose exact shape intersects with or is contained by path are returned.

See also:
itemAt().


items

public final java.util.List items(QPointF pos)
Returns all visible items at position pos in the scene. The items are listed in descending Z order (i.e., the first item in the list is the top-most item, and the last item is the bottom-most item).

See also:
itemAt().


items

public final java.util.List items(QPolygonF polygon)
Returns all visible items that are either inside or intersect with the polygon polygon.


items

public final java.util.List items(QPolygonF polygon,
                                  Qt.ItemSelectionMode mode)
This is an overloaded member function, provided for convenience.

Returns all visible items that, depending on mode, are either inside or intersect with the polygon polygon.

The default value for mode is Qt::IntersectsItemShape ; all items whose exact shape intersects with or is contained by polygon are returned.

See also:
itemAt().


items

public final java.util.List items(QRectF rect)
Returns all visible items that are either inside or intersect with the specified rectangle.


items

public final java.util.List items(QRectF rect,
                                  Qt.ItemSelectionMode mode)
This is an overloaded member function, provided for convenience.

Returns all visible items that, depending on mode, are either inside or intersect with the specified rectangle.

The default value for mode is Qt::IntersectsItemShape ; all items whose exact shape intersects with or is contained by rectangle are returned.

See also:
itemAt().


items

public final java.util.List items(double x,
                                  double y,
                                  double w,
                                  double h)
This convenience function is equivalent to calling items(QRectF(x, y, w, h).


items

public final java.util.List items(double x,
                                  double y,
                                  double w,
                                  double h,
                                  Qt.ItemSelectionMode mode)
This convenience function is equivalent to calling items(QRectF(x, y, w, h), mode).


itemsBoundingRect

public final QRectF itemsBoundingRect()
Calculates and returns the bounding rect of all items on the scene. This function works by iterating over all items, and because if this, it can be slow for large scenes.

See also:
sceneRect().


mouseGrabberItem

public final QGraphicsItemInterface mouseGrabberItem()
Returns the current mouse grabber item, or 0 if no item is currently grabbing the mouse. The mouse grabber item is the item that receives all mouse events sent to the scene.

An item becomes a mouse grabber when it receives and accepts a mouse press event, and it stays the mouse grabber until either of the following events occur:

If the item loses its mouse grab, the scene will ignore all mouse events until a new item grabs the mouse (i.e., until a new item receives a mouse press event).


palette

public final QPalette palette()
This property holds the scene's default palette. This property provides the scene's palette. The scene palette defaults to, and resolves all its entries from, QApplication::palette.

If the scene's palette changes, either directly through setPalette() or indirectly when the application palette changes, QGraphicsScene first sends itself a PaletteChange event, and it then sends PaletteChange events to all top-level widget items in the scene. These items respond by resolving their own palettes to the scene, and they then notify their children, who again notify their children, and so on, until all widget items have updated their palettes.

Changing the scene palette, (directly or indirectly through QApplication::setPalette(),) automatically schedules a redraw the entire scene.

See also:
QWidget::palette, QApplication::setPalette(), font, and style().


removeItem

public final void removeItem(QGraphicsItemInterface item)
Removes the item item and all its children from the scene. The ownership of item is passed on to the caller (i.e., QGraphicsScene will no longer delete item when destroyed).

See also:
addItem().


render

public final void render(QPainter painter,
                         QRectF target,
                         QRectF source)
Renders the source rect from scene into target, using painter. This function is useful for capturing the contents of the scene onto a paint device, such as a QImage (e.g., to take a screenshot), or for printing with QPrinter. For example:
        QGraphicsScene scene = new QGraphicsScene();
        scene.addRect(0d,0d,50d,50d);
        QPrinter printer = new QPrinter(QPrinter.PrinterMode.HighResolution);
        printer.setPageSize(QPrinter.PageSize.A4);

        QPainter painter = new QPainter(printer);
        scene.render(painter);
If source is a null rect, this function will use sceneRect() to determine what to render. If target is a null rect, the dimensions of painter's paint device will be used.

The source rect contents will be transformed according to aspectRatioMode to fit into the target rect. By default, the aspect ratio is kept, and source is scaled to fit in target.

See also:
QGraphicsView::render().


render

public final void render(QPainter painter,
                         QRectF target)
Renders the source rect from scene into target, using painter. This function is useful for capturing the contents of the scene onto a paint device, such as a QImage (e.g., to take a screenshot), or for printing with QPrinter. For example:
        QGraphicsScene scene = new QGraphicsScene();
        scene.addRect(0d,0d,50d,50d);
        QPrinter printer = new QPrinter(QPrinter.PrinterMode.HighResolution);
        printer.setPageSize(QPrinter.PageSize.A4);

        QPainter painter = new QPainter(printer);
        scene.render(painter);
If source is a null rect, this function will use sceneRect() to determine what to render. If target is a null rect, the dimensions of painter's paint device will be used.

The source rect contents will be transformed according to aspectRatioMode to fit into the target rect. By default, the aspect ratio is kept, and source is scaled to fit in target.

See also:
QGraphicsView::render().


render

public final void render(QPainter painter)
Renders the source rect from scene into target, using painter. This function is useful for capturing the contents of the scene onto a paint device, such as a QImage (e.g., to take a screenshot), or for printing with QPrinter. For example:
        QGraphicsScene scene = new QGraphicsScene();
        scene.addRect(0d,0d,50d,50d);
        QPrinter printer = new QPrinter(QPrinter.PrinterMode.HighResolution);
        printer.setPageSize(QPrinter.PageSize.A4);

        QPainter painter = new QPainter(printer);
        scene.render(painter);
If source is a null rect, this function will use sceneRect() to determine what to render. If target is a null rect, the dimensions of painter's paint device will be used.

The source rect contents will be transformed according to aspectRatioMode to fit into the target rect. By default, the aspect ratio is kept, and source is scaled to fit in target.

See also:
QGraphicsView::render().


render

public final void render(QPainter painter,
                         QRectF target,
                         QRectF source,
                         Qt.AspectRatioMode aspectRatioMode)
Renders the source rect from scene into target, using painter. This function is useful for capturing the contents of the scene onto a paint device, such as a QImage (e.g., to take a screenshot), or for printing with QPrinter. For example:
        QGraphicsScene scene = new QGraphicsScene();
        scene.addRect(0d,0d,50d,50d);
        QPrinter printer = new QPrinter(QPrinter.PrinterMode.HighResolution);
        printer.setPageSize(QPrinter.PageSize.A4);

        QPainter painter = new QPainter(printer);
        scene.render(painter);
If source is a null rect, this function will use sceneRect() to determine what to render. If target is a null rect, the dimensions of painter's paint device will be used.

The source rect contents will be transformed according to aspectRatioMode to fit into the target rect. By default, the aspect ratio is kept, and source is scaled to fit in target.

See also:
QGraphicsView::render().


sceneRect

public final QRectF sceneRect()
This property holds the scene rectangle; the bounding rectangle of the scene. The scene rectangle defines the extent of the scene. It is primarily used by QGraphicsView to determine the view's default scrollable area, and by QGraphicsScene to manage item indexing.

If unset, or if set to a null QRectF, sceneRect() will return the largest bounding rect of all items on the scene since the scene was created (i.e., a rectangle that grows when items are added to or moved in the scene, but never shrinks).

See also:
width(), height(), and QGraphicsView::sceneRect.


selectedItems

public final java.util.List selectedItems()
Returns a list of all currently selected items. The items are returned in no particular order.

See also:
setSelectionArea().


selectionArea

public final QPainterPath selectionArea()
Returns the selection area that was previously set with setSelectionArea(), or an empty QPainterPath if no selection area has been set.

See also:
setSelectionArea().


setActiveWindow

public final void setActiveWindow(QGraphicsWidget widget)
Activates widget, which must be a widget in this scene. You can also pass 0 for widget, in which case QGraphicsScene will deactivate any currently active window.

See also:
activeWindow(), and QGraphicsWidget::isActiveWindow().


setBackgroundBrush

public final void setBackgroundBrush(QBrush brush)
This property holds the background brush of the scene. Set this property to changes the scene's background to a different color, gradient or texture. The default background brush is Qt::NoBrush . The background is drawn before (behind) the items.

Example:

        QGraphicsScene scene = new QGraphicsScene();
        QGraphicsView view = new QGraphicsView(scene);
        view.show();

        // a blue background
        scene.setBackgroundBrush(new QBrush(QColor.blue));

        // a gradient background
        QRadialGradient gradient = new QRadialGradient(0, 0, 10);
        gradient.setSpread(QGradient.Spread.RepeatSpread);
        scene.setBackgroundBrush(new QBrush(gradient));
QGraphicsScene::render() calls drawBackground() to draw the scene background. For more detailed control over how the background is drawn, you can reimplement drawBackground() in a subclass of QGraphicsScene.


setBspTreeDepth

public final void setBspTreeDepth(int depth)
This property holds the depth of QGraphicsScene's BSP index tree. This property has no effect when NoIndex is used.

This value determines the depth of QGraphicsScene's BSP tree. The depth directly affects QGraphicsScene's performance and memory usage; the latter growing exponentially with the depth of the tree. With an optimal tree depth, QGraphicsScene can instantly determine the locality of items, even for scenes with thousands or millions of items. This also greatly improves rendering performance.

By default, the value is 0, in which case Qt will guess a reasonable default depth based on the size, location and number of items in the scene. If these parameters change frequently, however, you may experience slowdowns as QGraphicsScene retunes the depth internally. You can avoid potential slowdowns by fixating the tree depth through setting this property.

The depth of the tree and the size of the scene rectangle decide the granularity of the scene's partitioning. The size of each scene segment is determined by the following algorithm:

        QSizeF segmentSize = sceneRect().size().divide(java.lang.Math.pow(2, depth - 1));
The BSP tree has an optimal size when each segment contains between 0 and 10 items.

See also:
itemIndexMethod.


setFocus

public final void setFocus()
Sets focus on the scene by sending a QFocusEvent to the scene, passing focusReason as the reason. If the scene regains focus after having previously lost it while an item had focus, the last focus item will receive focus with focusReason as the reason.

If the scene already has focus, this function does nothing.

See also:
hasFocus(), clearFocus(), and setFocusItem().


setFocus

public final void setFocus(Qt.FocusReason focusReason)
Sets focus on the scene by sending a QFocusEvent to the scene, passing focusReason as the reason. If the scene regains focus after having previously lost it while an item had focus, the last focus item will receive focus with focusReason as the reason.

If the scene already has focus, this function does nothing.

See also:
hasFocus(), clearFocus(), and setFocusItem().


setFocusItem

public final void setFocusItem(QGraphicsItemInterface item)
Sets the scene's focus item to item, with the focus reason focusReason, after removing focus from any previous item that may have had focus.

If item is 0, or if it either does not accept focus (i.e., it does not have the QGraphicsItem::ItemIsFocusable flag enabled), or is not visible or not enabled, this function only removes focus from any previous focusitem.

If item is not 0, and the scene does not currently have focus (i.e., hasFocus() returns false), this function will call setFocus() automatically.

See also:
focusItem(), hasFocus(), and setFocus().


setFocusItem

public final void setFocusItem(QGraphicsItemInterface item,
                               Qt.FocusReason focusReason)
Sets the scene's focus item to item, with the focus reason focusReason, after removing focus from any previous item that may have had focus.

If item is 0, or if it either does not accept focus (i.e., it does not have the QGraphicsItem::ItemIsFocusable flag enabled), or is not visible or not enabled, this function only removes focus from any previous focusitem.

If item is not 0, and the scene does not currently have focus (i.e., hasFocus() returns false), this function will call setFocus() automatically.

See also:
focusItem(), hasFocus(), and setFocus().


setFont

public final void setFont(QFont font)
This property holds the scene's default font. This property provides the scene's font. The scene font defaults to, and resolves all its entries from, QApplication::font.

If the scene's font changes, either directly through setFont() or indirectly when the application font changes, QGraphicsScene first sends itself a FontChange event, and it then sends FontChange events to all top-level widget items in the scene. These items respond by resolving their own fonts to the scene, and they then notify their children, who again notify their children, and so on, until all widget items have updated their fonts.

Changing the scene font, (directly or indirectly through QApplication::setFont(),) automatically schedules a redraw the entire scene.

See also:
QWidget::font, QApplication::setFont(), palette, and style().


setForegroundBrush

public final void setForegroundBrush(QBrush brush)
This property holds the foreground brush of the scene. Change this property to set the scene's foreground to a different color, gradient or texture.

The foreground is drawn after (on top of) the items. The default foreground brush is Qt::NoBrush ( i.e. the foreground is not drawn).

Example:

        QGraphicsScene scene = new QGraphicsScene();
        QGraphicsView view = new QGraphicsView(scene);
        view.show();

        // a white semi-transparent foreground
        scene.setForegroundBrush(new QBrush(new QColor(255, 255, 255, 127)));

        // a grid foreground
        scene.setForegroundBrush(new QBrush(QColor.lightGray, Qt.BrushStyle.CrossPattern));
QGraphicsScene::render() calls drawForeground() to draw the scene foreground. For more detailed control over how the foreground is drawn, you can reimplement the drawForeground() function in a QGraphicsScene subclass.


setItemIndexMethod

public final void setItemIndexMethod(QGraphicsScene.ItemIndexMethod method)
This property holds the item indexing method. QGraphicsScene applies an indexing algorithm to the scene, to speed up item discovery functions like items() and itemAt(). Indexing is most efficient for static scenes (i.e., where items don't move around). For dynamic scenes, or scenes with many animated items, the index bookkeeping can outweight the fast lookup speeds.

For the common case, the default index method BspTreeIndex works fine. If your scene uses many animations and you are experiencing slowness, you can disable indexing by calling setItemIndexMethod(NoIndex).

See also:
bspTreeDepth.


setPalette

public final void setPalette(QPalette palette)
This property holds the scene's default palette. This property provides the scene's palette. The scene palette defaults to, and resolves all its entries from, QApplication::palette.

If the scene's palette changes, either directly through setPalette() or indirectly when the application palette changes, QGraphicsScene first sends itself a PaletteChange event, and it then sends PaletteChange events to all top-level widget items in the scene. These items respond by resolving their own palettes to the scene, and they then notify their children, who again notify their children, and so on, until all widget items have updated their palettes.

Changing the scene palette, (directly or indirectly through QApplication::setPalette(),) automatically schedules a redraw the entire scene.

See also:
QWidget::palette, QApplication::setPalette(), font, and style().


setSceneRect

public final void setSceneRect(QRectF rect)
This property holds the scene rectangle; the bounding rectangle of the scene. The scene rectangle defines the extent of the scene. It is primarily used by QGraphicsView to determine the view's default scrollable area, and by QGraphicsScene to manage item indexing.

If unset, or if set to a null QRectF, sceneRect() will return the largest bounding rect of all items on the scene since the scene was created (i.e., a rectangle that grows when items are added to or moved in the scene, but never shrinks).

See also:
width(), height(), and QGraphicsView::sceneRect.


setSceneRect

public final void setSceneRect(double x,
                               double y,
                               double w,
                               double h)
This property holds the scene rectangle; the bounding rectangle of the scene. The scene rectangle defines the extent of the scene. It is primarily used by QGraphicsView to determine the view's default scrollable area, and by QGraphicsScene to manage item indexing.

If unset, or if set to a null QRectF, sceneRect() will return the largest bounding rect of all items on the scene since the scene was created (i.e., a rectangle that grows when items are added to or moved in the scene, but never shrinks).

See also:
width(), height(), and QGraphicsView::sceneRect.


setSelectionArea

public final void setSelectionArea(QPainterPath path)
Sets the selection area to path. All items within this area are immediately selected, and all items outside are unselected. You can get the list of all selected items by calling selectedItems().

For an item to be selected, it must be marked as selectable (QGraphicsItem::ItemIsSelectable ).

See also:
clearSelection(), and selectionArea().


setSelectionArea

public final void setSelectionArea(QPainterPath path,
                                   Qt.ItemSelectionMode arg__2)
This is an overloaded member function, provided for convenience.

Sets the selection area to path using mode to determine if items are included in the selection area.

See also:
clearSelection(), and selectionArea().


setSortCacheEnabled

public final void setSortCacheEnabled(boolean enabled)
This property holds whether sort caching is enabled. When enabled, this property adds a cache that speeds up sorting and transformations for scenes with deep hierarchies (i.e., items with many levels of descendents), at the cost of using more memory (approx. 100 more bytes of memory per item).

Items that are not part of a deep hierarchy suffer no penalty from this cache.


setStyle

public final void setStyle(QStyle style)
Sets or replaces the style of the scene to style, and reparents the style to this scene. Any previously assigned style is deleted. The scene's style defaults to QApplication::style(), and serves as the default for all QGraphicsWidget items in the scene.

Changing the style, either directly by calling this function, or indirectly by calling QApplication::setStyle(), will automatically update the style for all widgets in the scene that do not have a style explicitly assigned to them.

If style is 0, QGraphicsScene will revert to QApplication::style().

See also:
style().


style

public final QStyle style()
Returns the scene's style, or the same as QApplication::style() if the scene has not been explicitly assigned a style.

See also:
setStyle().


update

public final void update()
Schedules a redraw of the area rect on the scene.

See also:
sceneRect(), and changed() .


update

public final void update(QRectF rect)
Schedules a redraw of the area rect on the scene.

See also:
sceneRect(), and changed() .


update

public final void update(double x,
                         double y,
                         double w,
                         double h)
This is an overloaded member function, provided for convenience.

This function is equivalent to calling update(QRectF(x, y, w, h));


views

public final java.util.List views()
Returns a list of all the views that display this scene.

See also:
QGraphicsView::scene().


width

public final double width()
This convenience function is equivalent to calling sceneRect().width().

See also:
height().


contextMenuEvent

protected void contextMenuEvent(QGraphicsSceneContextMenuEvent event)
This event handler, for event contextMenuEvent, can be reimplemented in a subclass to receive context menu events. The default implementation forwards the event to the topmost item that accepts context menu events at the position of the event. If no items accept context menu events at this position, the event is ignored.

See also:
QGraphicsItem::contextMenuEvent().


dragEnterEvent

protected void dragEnterEvent(QGraphicsSceneDragDropEvent event)
This event handler, for event event, can be reimplemented in a subclass to receive drag enter events for the scene.

The default implementation accepts the event and prepares the scene to accept drag move events.

See also:
QGraphicsItem::dragEnterEvent(), dragMoveEvent(), dragLeaveEvent(), and dropEvent().


dragLeaveEvent

protected void dragLeaveEvent(QGraphicsSceneDragDropEvent event)
This event handler, for event event, can be reimplemented in a subclass to receive drag leave events for the scene.

See also:
QGraphicsItem::dragLeaveEvent(), dragEnterEvent(), dragMoveEvent(), and dropEvent().


dragMoveEvent

protected void dragMoveEvent(QGraphicsSceneDragDropEvent event)
This event handler, for event event, can be reimplemented in a subclass to receive drag move events for the scene.

See also:
QGraphicsItem::dragMoveEvent(), dragEnterEvent(), dragLeaveEvent(), and dropEvent().


drawBackground

protected void drawBackground(QPainter painter,
                              QRectF rect)
Draws the background of the scene using painter, before any items and the foreground are drawn. Reimplement this function to provide a custom background for the scene.

All painting is done in scene coordinates. The rect parameter is the exposed rectangle.

If all you want is to define a color, texture, or gradient for the background, you can call setBackgroundBrush() instead.

See also:
drawForeground(), and drawItems().


drawForeground

protected void drawForeground(QPainter painter,
                              QRectF rect)
Draws the foreground of the scene using painter, after the background and all items have been drawn. Reimplement this function to provide a custom foreground for the scene.

All painting is done in scene coordinates. The rect parameter is the exposed rectangle.

If all you want is to define a color, texture or gradient for the foreground, you can call setForegroundBrush() instead.

See also:
drawBackground(), and drawItems().


drawItems

protected final void drawItems(QPainter painter,
                               QGraphicsItemInterface[] items,
                               QStyleOptionGraphicsItem[] options)

drawItems

protected void drawItems(QPainter painter,
                         QGraphicsItemInterface[] items,
                         QStyleOptionGraphicsItem[] options,
                         QWidget widget)

dropEvent

protected void dropEvent(QGraphicsSceneDragDropEvent event)
This event handler, for event event, can be reimplemented in a subclass to receive drop events for the scene.

See also:
QGraphicsItem::dropEvent(), dragEnterEvent(), dragMoveEvent(), and dragLeaveEvent().


focusInEvent

protected void focusInEvent(QFocusEvent event)
This event handler, for event focusEvent, can be reimplemented in a subclass to receive focus in events.

The default implementation sets focus on the scene, and then on the last focus item.

See also:
QGraphicsItem::focusOutEvent().


focusOutEvent

protected void focusOutEvent(QFocusEvent event)
This event handler, for event focusEvent, can be reimplemented in a subclass to receive focus out events.

The default implementation removes focus from any focus item, then removes focus from the scene.

See also:
QGraphicsItem::focusInEvent().


helpEvent

protected void helpEvent(QGraphicsSceneHelpEvent event)
This event handler, for event helpEvent, can be reimplemented in a subclass to receive help events. The events are of type QEvent::ToolTip , which are created when a tooltip is requested.

The default implementation shows the tooltip of the topmost item, i.e., the item with the highest z-value, at the mouse cursor position. If no item has a tooltip set, this function does nothing.

See also:
QGraphicsItem::toolTip(), and QGraphicsSceneHelpEvent.


inputMethodEvent

protected void inputMethodEvent(QInputMethodEvent event)
This event handler, for event event, can be reimplemented in a subclass to receive input method events for the scene.

The default implementation forwards the event to the focusItem(). If no item currently has focus, this function does nothing.

See also:
QGraphicsItem::inputMethodEvent().


inputMethodQuery

public java.lang.Object inputMethodQuery(Qt.InputMethodQuery query)
This method is used by input methods to query a set of properties of the scene to be able to support complex input method operations as support for surrounding text and reconversions.

The query parameter specifies which property is queried.

See also:
QWidget::inputMethodQuery().


keyPressEvent

protected void keyPressEvent(QKeyEvent event)
This event handler, for event keyEvent, can be reimplemented in a subclass to receive keypress events. The default implementation forwards the event to current focus item.

See also:
QGraphicsItem::keyPressEvent(), and focusItem().


keyReleaseEvent

protected void keyReleaseEvent(QKeyEvent event)
This event handler, for event keyEvent, can be reimplemented in a subclass to receive key release events. The default implementation forwards the event to current focus item.

See also:
QGraphicsItem::keyReleaseEvent(), and focusItem().


mouseDoubleClickEvent

protected void mouseDoubleClickEvent(QGraphicsSceneMouseEvent event)
This event handler, for event mouseEvent, can be reimplemented in a subclass to receive mouse doubleclick events for the scene.

If someone doubleclicks on the scene, the scene will first receive a mouse press event, followed by a release event (i.e., a click), then a doubleclick event, and finally a release event. If the doubleclick event is delivered to a different item than the one that received the first press and release, it will be delivered as a press event. However, tripleclick events are not delivered as doubleclick events in this case.

The default implementation is similar to mousePressEvent().

See also:
QGraphicsItem::mousePressEvent(), QGraphicsItem::mouseMoveEvent(), QGraphicsItem::mouseReleaseEvent(), and QGraphicsItem::setAcceptedMouseButtons().


mouseMoveEvent

protected void mouseMoveEvent(QGraphicsSceneMouseEvent event)
This event handler, for event mouseEvent, can be reimplemented in a subclass to receive mouse move events for the scene.

The default implementation depends on the mouse grabber state. If there is a mouse grabber item, the event is sent to the mouse grabber. If there are any items that accept hover events at the current position, the event is translated into a hover event and accepted; otherwise it's ignored.

See also:
QGraphicsItem::mousePressEvent(), QGraphicsItem::mouseReleaseEvent(), QGraphicsItem::mouseDoubleClickEvent(), and QGraphicsItem::setAcceptedMouseButtons().


mousePressEvent

protected void mousePressEvent(QGraphicsSceneMouseEvent event)
This event handler, for event mouseEvent, can be reimplemented in a subclass to receive mouse press events for the scene.

The default implementation depends on the state of the scene. If there is a mouse grabber item, then the event is sent to the mouse grabber. Otherwise, it is forwarded to the topmost item that accepts mouse events at the scene position from the event, and that item promptly becomes the mouse grabber item.

If there is no item at the given position on the scene, the selection area is reset, any focus item loses its input focus, and the event is then ignored.

See also:
QGraphicsItem::mousePressEvent(), and QGraphicsItem::setAcceptedMouseButtons().


mouseReleaseEvent

protected void mouseReleaseEvent(QGraphicsSceneMouseEvent event)
This event handler, for event mouseEvent, can be reimplemented in a subclass to receive mouse release events for the scene.

The default implementation depends on the mouse grabber state. If there is no mouse grabber, the event is ignored. Otherwise, if there is a mouse grabber item, the event is sent to the mouse grabber. If this mouse release represents the last pressed button on the mouse, the mouse grabber item then loses the mouse grab.

See also:
QGraphicsItem::mousePressEvent(), QGraphicsItem::mouseMoveEvent(), QGraphicsItem::mouseDoubleClickEvent(), and QGraphicsItem::setAcceptedMouseButtons().


wheelEvent

protected void wheelEvent(QGraphicsSceneWheelEvent event)
This event handler, for event wheelEvent, can be reimplemented in a subclass to receive mouse wheel events for the scene.

By default, the event is delivered to the topmost visible item under the cursor. If ignored, the event propagates to the item beneath, and again until the event is accepted, or it reaches the scene. If no items accept the event, it is ignored.

See also:
QGraphicsItem::wheelEvent().


addEllipse

public final QGraphicsEllipseItem addEllipse(QRectF rect)
Equivalent to addEllipse(rect, null, null)


addEllipse

public final QGraphicsEllipseItem addEllipse(QRectF rect,
                                             QPen pen)
Equivalent to addEllipse(rect, pen, null)


addEllipse

public final QGraphicsEllipseItem addEllipse(QRectF rect,
                                             QPen pen,
                                             QBrush brush)
Creates and adds an ellipse item to the scene, and returns the item reference. The geometry of the ellipse is defined by rect, and its pen and brush are initialized to pen and brush. Note that the item's geometry is provided in item coordinates, and its position is initialized to (0, 0). If the item is visible (i.e., QGraphicsItem::isVisible() returns true), QGraphicsScene will emit changed() once control goes back to the event loop.

Parameters:
rect - The bounding rectangle of the ellipse.
pen - The pen for the resulting QGraphicsEllipseItem.
brush - The brush for the resulting QGraphicsEllipseItem.
Returns:
The resulting item.

addEllipse

public final QGraphicsEllipseItem addEllipse(double x,
                                             double y,
                                             double w,
                                             double h)
Equivalent to addEllipse(x, y, w, h, null, null)


addEllipse

public final QGraphicsEllipseItem addEllipse(double x,
                                             double y,
                                             double w,
                                             double h,
                                             QPen pen)
Equivalent to addEllipse(x, y, w, h, pen, null)


addEllipse

public final QGraphicsEllipseItem addEllipse(double x,
                                             double y,
                                             double w,
                                             double h,
                                             QPen pen,
                                             QBrush brush)
Creates and adds an ellipse item to the scene, and returns the item reference. The geometry of the ellipse is defined by x, y, w, h, and its pen and brush are initialized to pen and brush. Note that the item's geometry is provided in item coordinates, and its position is initialized to (0, 0). If the item is visible (i.e., QGraphicsItem.isVisible() returns true), QGraphicsScene will emit changed once control goes back to the event loop.

Parameters:
x - The left horizontal coordinate of the ellipse's bounding rectangle.
y - The top vertical coordinate of the ellipse's bounding rectangle.
w - The width of the ellipse's bounding rectangle.
h - The height of the ellipse's bounding rectangle.
pen - The pen for the resulting QGraphicsEllipseItem.
brush - The brush for the resulting QGraphicsEllipseItem.
Returns:
The resulting item.

addLine

public final QGraphicsLineItem addLine(QLineF line)
Equivalent to addLine(line, null)


addLine

public final QGraphicsLineItem addLine(QLineF line,
                                       QPen pen)
Creates and adds a line item to the scene, and returns the item reference. The geometry of the line is defined by line, and its pen is initialized to pen. Note that the item's geometry is provided in item coordinates, and its position is initialized to (0, 0). If the item is visible (i.e., QGraphicsItem.isVisible() returns true), QGraphicsScene will emit changed once control goes back to the event loop.

Parameters:
line - The definition of the line.
pen - The pen with which to draw the line.
Returns:
The resulting item.

addLine

public final QGraphicsLineItem addLine(double x1,
                                       double y1,
                                       double x2,
                                       double y2)
Equivalent to addLine(x1, y1, x2, y2, null)


addLine

public final QGraphicsLineItem addLine(double x1,
                                       double y1,
                                       double x2,
                                       double y2,
                                       QPen pen)
Creates and adds a line item to the scene, and returns the item reference. The geometry of the line is defined by x1, y1, x2, y2, and its pen is initialized to pen. Note that the item's geometry is provided in item coordinates, and its position is initialized to (0, 0). If the item is visible (i.e., QGraphicsItem.isVisible() returns true), QGraphicsScene will emit changed once control goes back to the event loop.

Parameters:
x1 - The first horizontal coordinate of the line.
y1 - The first vertical coordinate of the line.
x2 - The second horizontal coordinate of the line.
y2 - The second vertical coordinate of the line.
pen - The pen with which to draw the line.
Returns:
The resulting item.

addPath

public final QGraphicsPathItem addPath(QPainterPath path)
Equivalent to addPath(path, null, null)


addPath

public final QGraphicsPathItem addPath(QPainterPath path,
                                       QPen pen)
Equivalent to addPath(path, pen, null)


addPath

public final QGraphicsPathItem addPath(QPainterPath path,
                                       QPen pen,
                                       QBrush brush)
Creates and adds a path item to the scene, and returns the item reference. The geometry of the path is defined by path, and its pen and brush are initialized to pen and brush. Note that the item's geometry is provided in item coordinates, and its position is initialized to (0, 0). If the item is visible (i.e., QGraphicsItem.isVisible() returns true), QGraphicsScene will emit changed once control goes back to the event loop.

Parameters:
path - The definition of the path.
pen - The pen for drawing the path.
brush - The brush for drawing the path.
Returns:
The resulting item.

addPixmap

public final QGraphicsPixmapItem addPixmap(QPixmap pixmap)
Creates and adds a pixmap item to the scene, and returns the item reference. The pixmap is defined by pixmap. Note that the item's geometry is provided in item coordinates, and its position is initialized to (0, 0). If the item is visible (i.e., QGraphicsItem.isVisible() returns true), QGraphicsScene will emit changed once control goes back to the event loop.

Parameters:
pixmap - The pixmap for which to create a graphics item.
Returns:
The resulting item.

addPolygon

public final QGraphicsPolygonItem addPolygon(QPolygonF polygon)
Equivalent to addPolygon(polygon, null, null)


addPolygon

public final QGraphicsPolygonItem addPolygon(QPolygonF polygon,
                                             QPen pen)
Equivalent to addPolygon(polygon, pen, null)


addPolygon

public final QGraphicsPolygonItem addPolygon(QPolygonF polygon,
                                             QPen pen,
                                             QBrush brush)
Creates and adds a polygon item to the scene, and returns the item reference. The polygon is defined by polygon, and its pen and brush are initialized to pen and brush. Note that the item's geometry is provided in item coordinates, and its position is initialized to (0, 0). If the item is visible (i.e., QGraphicsItem.isVisible() returns true), QGraphicsScene will emit changed once control goes back to the event loop.

Parameters:
polygon - The definition of the polygon.
pen - The pen with which to draw the polygon.
brush - The brush with which to draw the polygon.
Returns:
The resulting item.

addRect

public final QGraphicsRectItem addRect(QRectF rect)
Equivalent to addRect(rect, null, null)


addRect

public final QGraphicsRectItem addRect(QRectF rect,
                                       QPen pen)
Equivalent to addRect(rect, pen, null)


addRect

public final QGraphicsRectItem addRect(QRectF rect,
                                       QPen pen,
                                       QBrush brush)
Creates and adds a rectangle item to the scene, and returns the item reference. The geometry of the rectangle is defined by rect, and its pen and brush are initialized to pen and brush. Note that the item's geometry is provided in item coordinates, and its position is initialized to (0, 0). For example, if a QRect(50, 50, 100, 100) is added, its top-left corner will be at (50, 50) relative to the origin in the item's coordinate system. If the item is visible (i.e., QGraphicsItem.isVisible() returns true), QGraphicsScene will emit changed once control goes back to the event loop.

Parameters:
rect - The definition of the rectangle.
pen - The pen with which to draw the rectangle.
brush - The brush with which to draw the rectangle.
Returns:
The resulting item.

addRect

public final QGraphicsRectItem addRect(double x,
                                       double y,
                                       double w,
                                       double h)
Equivalent to addRect(x, y, w, h, null, null)


addRect

public final QGraphicsRectItem addRect(double x,
                                       double y,
                                       double w,
                                       double h,
                                       QPen pen)
Equivalent to addRect(x, y, w, h, pen, null)


addRect

public final QGraphicsRectItem addRect(double x,
                                       double y,
                                       double w,
                                       double h,
                                       QPen pen,
                                       QBrush brush)
Creates and adds a rectangle item to the scene, and returns the item reference. The geometry of the rectangle is defined by x, y, w, h, and its pen and brush are initialized to pen and brush. Note that the item's geometry is provided in item coordinates, and its position is initialized to (0, 0). If the item is visible (i.e., QGraphicsItem.isVisible() returns true), QGraphicsScene will emit changed once control goes back to the event loop.

Parameters:
x - The left horizontal coordinate of the rectangle.
y - The top vertical coordinate of the rectangle.
w - The width of the rectangle.
h - The height of the rectangle.
pen - The pen with which to draw the rectangle.
brush - The brush with which to draw the rectangle.
Returns:
The resulting item.

addSimpleText

public final QGraphicsSimpleTextItem addSimpleText(java.lang.String text)
Equivalent to addSimpleText(text, null)


addSimpleText

public final QGraphicsSimpleTextItem addSimpleText(java.lang.String text,
                                                   QFont font)
Creates and adds a QGraphicsSimpleTextItem to the scene, and returns the item reference. The text string is initialized to text, and its font is initialized to font. The item's position is initialized to (0, 0). If the item is visible (i.e., QGraphicsItem.isVisible() returns true), QGraphicsScene will emit changed once control goes back to the event loop.

Parameters:
text - The text to add to the scene.
font - The font to use for displaying the text.
Returns:
The resulting item.

addText

public final QGraphicsTextItem addText(java.lang.String text)
Equivalent to addText(text, null)


addText

public final QGraphicsTextItem addText(java.lang.String text,
                                       QFont font)
Creates and adds a text item to the scene, and returns the item reference. The text string is initialized to text, and its font is initialized to font. The item's position is initialized to (0, 0). If the item is visible (i.e., QGraphicsItem.isVisible() returns true), QGraphicsScene will emit changed once control goes back to the event loop.

Parameters:
text - The text to add to the scene.
font - The font to use for displaying the text.
Returns:
The resulting item.