QGraphicsWidget

The QGraphicsWidget class is the base class for all widget items in a QGraphicsScene . More

Inheritance diagram of PySide2.QtWidgets.QGraphicsWidget

Inherited by: QtCharts.QChart, QtCharts.QLegend, QtCharts.QPolarChart, QGraphicsProxyWidget

Synopsis

Functions

Virtual functions

Slots

Signals

Static functions

Detailed Description

QGraphicsWidget is an extended base item that provides extra functionality over QGraphicsItem . It is similar to QWidget in many ways:

Unlike QGraphicsItem , QGraphicsWidget is not an abstract class; you can create instances of a QGraphicsWidget without having to subclass it. This approach is useful for widgets that only serve the purpose of organizing child widgets into a layout.

QGraphicsWidget can be used as a base item for your own custom item if you require advanced input focus handling, e.g., tab focus and activation, or layouts.

Since QGraphicsWidget resembles QWidget and has similar API, it is easier to port a widget from QWidget to QGraphicsWidget , instead of QGraphicsItem .

Note

QWidget -based widgets can be directly embedded into a QGraphicsScene using QGraphicsProxyWidget .

Noticeable differences between QGraphicsWidget and QWidget are:

QGraphicsWidget

QWidget

Coordinates and geometry are defined with qreals (doubles or floats, depending on the platform).

QWidget uses integer geometry ( QPoint , QRect ).

The widget is already visible by default; you do not have to call show() to display the widget.

QWidget is hidden by default until you call show() .

A subset of widget attributes are supported.

All widget attributes are supported.

A top-level item’s style defaults to style

A top-level widget’s style defaults to style

Graphics View provides a custom drag and drop framework, different from QWidget .

Standard drag and drop framework.

Widget items do not support modality.

Full modality support.

QGraphicsWidget supports a subset of Qt’s widget attributes, ( WidgetAttribute ), as shown in the table below. Any attributes not listed in this table are unsupported, or otherwise unused.

Widget Attribute

Usage

WA_SetLayoutDirection

Set by setLayoutDirection() , cleared by unsetLayoutDirection() . You can test this attribute to check if the widget has been explicitly assigned a layoutDirection . If the attribute is not set, the layoutDirection() is inherited.

WA_RightToLeft

Toggled by setLayoutDirection() . Inherited from the parent/scene. If set, the widget’s layout will order horizontally arranged widgets from right to left.

WA_SetStyle

Set and cleared by setStyle() . If this attribute is set, the widget has been explicitly assigned a style. If it is unset, the widget will use the scene’s or the application’s style.

WA_Resized

Set by setGeometry() and resize() .

WA_SetPalette

Set by setPalette() .

WA_SetFont

Set by setFont() .

WA_WindowPropagation

Enables propagation to window widgets.

Although QGraphicsWidget inherits from both QObject and QGraphicsItem , you should use the functions provided by QGraphicsItem , not QObject , to manage the relationships between parent and child items. These functions control the stacking order of items as well as their ownership.

Note

The parent() should always return None for QGraphicsWidgets, but this policy is not strictly defined.

class QGraphicsWidget([parent=None[, wFlags=Qt.WindowFlags()]])
param parent

QGraphicsItem

param wFlags

WindowFlags

Constructs a QGraphicsWidget instance. The optional parent argument is passed to QGraphicsItem ‘s constructor. The optional wFlags argument specifies the widget’s window flags (e.g., whether the widget should be a window, a tool, a popup, etc).

PySide2.QtWidgets.QGraphicsWidget.actions()
Return type

Returns the (possibly empty) list of this widget’s actions.

See also

insertAction() removeAction() actions() associatedWidgets() associatedGraphicsWidgets()

PySide2.QtWidgets.QGraphicsWidget.addAction(action)
Parameters

actionQAction

Appends the action action to this widget’s list of actions.

All QGraphicsWidgets have a list of QAction s, however they can be represented graphically in many different ways. The default use of the QAction list (as returned by actions() ) is to create a context QMenu .

A QGraphicsWidget should only have one of each action and adding an action it already has will not cause the same action to be in the widget twice.

PySide2.QtWidgets.QGraphicsWidget.addActions(actions)
Parameters

actions

Appends the actions actions to this widget’s list of actions.

PySide2.QtWidgets.QGraphicsWidget.adjustSize()

Adjusts the size of the widget to its effective preferred size hint.

This function is called implicitly when the item is shown for the first time.

See also

effectiveSizeHint() MinimumSize

PySide2.QtWidgets.QGraphicsWidget.autoFillBackground()
Return type

bool

PySide2.QtWidgets.QGraphicsWidget.changeEvent(event)
Parameters

eventQEvent

This event handler can be reimplemented to handle state changes.

The state being changed in this event can be retrieved through event .

Change events include: ActivationChange , EnabledChange , FontChange , StyleChange , PaletteChange , ParentChange , LayoutDirectionChange , and ContentsRectChange .

PySide2.QtWidgets.QGraphicsWidget.close()
Return type

bool

Call this function to close the widget.

Returns true if the widget was closed; otherwise returns false . This slot will first send a QCloseEvent to the widget, which may or may not accept the event. If the event was ignored, nothing happens. If the event was accepted, it will hide() the widget.

If the widget has the WA_DeleteOnClose attribute set it will be deleted.

PySide2.QtWidgets.QGraphicsWidget.closeEvent(event)
Parameters

eventQCloseEvent

This event handler, for event , can be reimplemented in a subclass to receive widget close events. The default implementation accepts the event.

See also

close() QCloseEvent

PySide2.QtWidgets.QGraphicsWidget.focusNextPrevChild(next)
Parameters

nextbool

Return type

bool

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; returns false otherwise. If next is true, this function searches forward; if next is false, it searches backward.

Sometimes, you will want to reimplement this function to provide special focus handling for your widget and its subwidgets. For example, a web browser might reimplement it to move its current active link forward or backward, and call the base implementation only when it reaches the last or first link on the page.

Child widgets call on their parent widgets, but only the window that contains the child widgets decides where to redirect focus. By reimplementing this function for an object, you gain control of focus traversal for all child widgets.

See also

focusPolicy()

PySide2.QtWidgets.QGraphicsWidget.focusPolicy()
Return type

FocusPolicy

See also

setFocusPolicy()

PySide2.QtWidgets.QGraphicsWidget.focusWidget()
Return type

QGraphicsWidget

If this widget, a child or descendant of this widget currently has input focus, this function will return a pointer to that widget. If no descendant widget has input focus, None is returned.

PySide2.QtWidgets.QGraphicsWidget.font()
Return type

QFont

See also

setFont()

PySide2.QtWidgets.QGraphicsWidget.geometryChanged()
PySide2.QtWidgets.QGraphicsWidget.getWindowFrameMargins()

Gets the widget’s window frame margins. The margins are stored in left , top , right and bottom as pointers to qreals. Each argument can be omitted by passing None .

PySide2.QtWidgets.QGraphicsWidget.grabKeyboardEvent(event)
Parameters

eventQEvent

This event handler, for event , can be reimplemented in a subclass to receive notifications for GrabKeyboard events.

PySide2.QtWidgets.QGraphicsWidget.grabMouseEvent(event)
Parameters

eventQEvent

This event handler, for event , can be reimplemented in a subclass to receive notifications for GrabMouse events.

PySide2.QtWidgets.QGraphicsWidget.grabShortcut(sequence[, context=Qt.WindowShortcut])
Parameters
  • sequenceQKeySequence

  • contextShortcutContext

Return type

int

Adds a shortcut to Qt’s shortcut system that watches for the given key sequence in the given context . If the context is ApplicationShortcut , the shortcut applies to the application as a whole. Otherwise, it is either local to this widget, WidgetShortcut , or to the window itself, WindowShortcut . For widgets that are not part of a window (i.e., top-level widgets and their children), WindowShortcut shortcuts apply to the scene.

If the same key sequence has been grabbed by several widgets, when the key sequence occurs a Shortcut event is sent to all the widgets to which it applies in a non-deterministic order, but with the ``ambiguous’’ flag set to true.

Warning

You should not normally need to use this function; instead create QAction s with the shortcut key sequences you require (if you also want equivalent menu options and toolbar buttons), or create QShortcut s if you just need key sequences. Both QAction and QShortcut handle all the event filtering for you, and provide signals which are triggered when the user triggers the key sequence, so are much easier to use than this low-level function.

PySide2.QtWidgets.QGraphicsWidget.hideEvent(event)
Parameters

eventQHideEvent

This event handler, for Hide events, is delivered after the widget has been hidden, for example, setVisible (false) has been called for the widget or one of its ancestors when the widget was previously shown.

You can reimplement this event handler to detect when your widget is hidden. Calling accept() or ignore() on event has no effect.

See also

showEvent() hideEvent() ItemVisibleChange

PySide2.QtWidgets.QGraphicsWidget.initStyleOption(option)
Parameters

optionQStyleOption

Populates a style option object for this widget based on its current state, and stores the output in option . The default implementation populates option with the following properties.

Style Option Property

Value

state & State_Enabled

Corresponds to isEnabled() .

state & State_HasFocus

Corresponds to hasFocus() .

state & State_MouseOver

Corresponds to isUnderMouse() .

direction

Corresponds to layoutDirection() .

rect

Corresponds to rect() .toRect().

palette

Corresponds to palette() .

fontMetrics

Corresponds to QFontMetrics ( font() ).

Subclasses of QGraphicsWidget should call the base implementation, and then test the type of option using qstyleoption_cast <>() or test Type before storing widget-specific options.

For example:

class MyGroupBoxWidget (QStyleOptionGroupBox):
    # ...
    def initStyleOption(option):
        QGraphicsWidget.initStyleOption(self, option)
        if isinstance(option, QStyleOptionGroupBox):
            # Add group box specific state.
            box.flat = isFlat()
            # ...

See also

initFrom()

PySide2.QtWidgets.QGraphicsWidget.insertAction(before, action)
Parameters

Inserts the action action to this widget’s list of actions, before the action before . It appends the action if before is None or before is not a valid action for this widget.

A QGraphicsWidget should only have one of each action.

PySide2.QtWidgets.QGraphicsWidget.insertActions(before, actions)
Parameters

Inserts the actions actions to this widget’s list of actions, before the action before . It appends the action if before is None or before is not a valid action for this widget.

A QGraphicsWidget can have at most one of each action.

PySide2.QtWidgets.QGraphicsWidget.isActiveWindow()
Return type

bool

Returns true if this widget’s window is in the active window, or if the widget does not have a window but is in an active scene (i.e., a scene that currently has focus).

The active window is the window that either contains a child widget that currently has input focus, or that itself has input focus.

PySide2.QtWidgets.QGraphicsWidget.layout()
Return type

QGraphicsLayout

Returns this widget’s layout, or None if no layout is currently managing this widget.

See also

setLayout()

PySide2.QtWidgets.QGraphicsWidget.layoutChanged()
PySide2.QtWidgets.QGraphicsWidget.layoutDirection()
Return type

LayoutDirection

PySide2.QtWidgets.QGraphicsWidget.moveEvent(event)
Parameters

eventQGraphicsSceneMoveEvent

This event handler, for GraphicsSceneMove events, is delivered after the widget has moved (e.g., its local position has changed).

This event is only delivered when the item is moved locally. Calling setTransform() or moving any of the item’s ancestors does not affect the item’s local position.

You can reimplement this event handler to detect when your widget has moved. Calling accept() or ignore() on event has no effect.

See also

ItemPositionChange ItemPositionHasChanged

PySide2.QtWidgets.QGraphicsWidget.paintWindowFrame(painter, option[, widget=None])
Parameters

This virtual function is called by QGraphicsScene to draw the window frame for windows using painter , option , and widget , in local coordinates. The base implementation uses the current style to render the frame and title bar.

You can reimplement this function in a subclass of QGraphicsWidget to provide custom rendering of the widget’s window frame.

See also

paint()

PySide2.QtWidgets.QGraphicsWidget.palette()
Return type

QPalette

See also

setPalette()

PySide2.QtWidgets.QGraphicsWidget.polishEvent()

This event is delivered to the item by the scene at some point after it has been constructed, but before it is shown or otherwise accessed through the scene. You can use this event handler to do last-minute initializations of the widget which require the item to be fully constructed.

The base implementation does nothing.

PySide2.QtWidgets.QGraphicsWidget.propertyChange(propertyName, value)
Parameters
  • propertyName – unicode

  • value – object

Return type

object

This virtual function is used to notify changes to any property (both dynamic properties, and registered with Q_PROPERTY ) in the widget. Depending on the property itself, the notification can be delivered before or after the value has changed.

propertyName is the name of the property (e.g., “size” or “font”), and value is the (proposed) new value of the property. The function returns the new value, which may be different from value if the notification supports adjusting the property value. The base implementation simply returns value for any propertyName .

QGraphicsWidget delivers notifications for the following properties:

propertyName

Property

layoutDirection

layoutDirection

size

size

font

font

palette

palette

See also

itemChange()

PySide2.QtWidgets.QGraphicsWidget.rect()
Return type

QRectF

Returns the item’s local rect as a QRectF . This function is equivalent to QRectF (QPointF(), size() ).

PySide2.QtWidgets.QGraphicsWidget.releaseShortcut(id)
Parameters

idint

Removes the shortcut with the given id from Qt’s shortcut system. The widget will no longer receive Shortcut events for the shortcut’s key sequence (unless it has other shortcuts with the same key sequence).

Warning

You should not normally need to use this function since Qt’s shortcut system removes shortcuts automatically when their parent widget is destroyed. It is best to use QAction or QShortcut to handle shortcuts, since they are easier to use than this low-level function. Note also that this is an expensive operation.

PySide2.QtWidgets.QGraphicsWidget.removeAction(action)
Parameters

actionQAction

Removes the action action from this widget’s list of actions.

PySide2.QtWidgets.QGraphicsWidget.resize(size)
Parameters

sizeQSizeF

PySide2.QtWidgets.QGraphicsWidget.resize(w, h)
Parameters
  • wqreal

  • hqreal

This is an overloaded function.

Constructs a resize with the given width (w ) and height (h ). This convenience function is equivalent to calling resize( QSizeF (w, h)).

PySide2.QtWidgets.QGraphicsWidget.resizeEvent(event)
Parameters

eventQGraphicsSceneResizeEvent

This event handler, for GraphicsSceneResize events, is delivered after the widget has been resized (i.e., its local size has changed). event contains both the old and the new size.

This event is only delivered when the widget is resized locally; calling setTransform() on the widget or any of its ancestors or view, does not affect the widget’s local size.

You can reimplement this event handler to detect when your widget has been resized. Calling accept() or ignore() on event has no effect.

PySide2.QtWidgets.QGraphicsWidget.setAttribute(attribute[, on=true])
Parameters
  • attributeWidgetAttribute

  • onbool

If on is true, this function enables attribute ; otherwise attribute is disabled.

See the class documentation for QGraphicsWidget for a complete list of which attributes are supported, and what they are for.

PySide2.QtWidgets.QGraphicsWidget.setAutoFillBackground(enabled)
Parameters

enabledbool

PySide2.QtWidgets.QGraphicsWidget.setContentsMargins(left, top, right, bottom)
Parameters
  • leftqreal

  • topqreal

  • rightqreal

  • bottomqreal

Sets the widget’s contents margins to left , top , right and bottom .

Contents margins are used by the assigned layout to define the placement of subwidgets and layouts. Margins are particularly useful for widgets that constrain subwidgets to only a section of its own geometry. For example, a group box with a layout will place subwidgets inside its frame, but below the title.

Changing a widget’s contents margins will always trigger an update() , and any assigned layout will be activated automatically. The widget will then receive a ContentsRectChange event.

See also

getContentsMargins() setGeometry()

PySide2.QtWidgets.QGraphicsWidget.setFocusPolicy(policy)
Parameters

policyFocusPolicy

See also

focusPolicy()

PySide2.QtWidgets.QGraphicsWidget.setFont(font)
Parameters

fontQFont

See also

font()

PySide2.QtWidgets.QGraphicsWidget.setGeometry(x, y, w, h)
Parameters
  • xqreal

  • yqreal

  • wqreal

  • hqreal

This convenience function is equivalent to calling setGeometry ( QRectF ( x , y , w , h )).

See also

geometry() resize()

PySide2.QtWidgets.QGraphicsWidget.setLayout(layout)
Parameters

layoutQGraphicsLayout

Sets the layout for this widget to layout . Any existing layout manager is deleted before the new layout is assigned. If layout is None , the widget is left without a layout. Existing subwidgets’ geometries will remain unaffected.

All widgets that are currently managed by layout or all of its sublayouts, are automatically reparented to this item. The layout is then invalidated, and the child widget geometries are adjusted according to this item’s geometry() and contentsMargins(). Children who are not explicitly managed by layout remain unaffected by the layout after it has been assigned to this widget.

QGraphicsWidget takes ownership of layout .

PySide2.QtWidgets.QGraphicsWidget.setLayoutDirection(direction)
Parameters

directionLayoutDirection

PySide2.QtWidgets.QGraphicsWidget.setPalette(palette)
Parameters

paletteQPalette

See also

palette()

PySide2.QtWidgets.QGraphicsWidget.setShortcutAutoRepeat(id[, enabled=true])
Parameters
  • idint

  • enabledbool

If enabled is true, auto repeat of the shortcut with the given id is enabled; otherwise it is disabled.

PySide2.QtWidgets.QGraphicsWidget.setShortcutEnabled(id[, enabled=true])
Parameters
  • idint

  • enabledbool

If enabled is true, the shortcut with the given id is enabled; otherwise the shortcut is disabled.

Warning

You should not normally need to use this function since Qt’s shortcut system enables/disables shortcuts automatically as widgets become hidden/visible and gain or lose focus. It is best to use QAction or QShortcut to handle shortcuts, since they are easier to use than this low-level function.

PySide2.QtWidgets.QGraphicsWidget.setStyle(style)
Parameters

styleQStyle

Sets the widget’s style to style . QGraphicsWidget does not take ownership of style .

If no style is assigned, or style is None , the widget will use style() (if this has been set). Otherwise the widget will use style() .

This function sets the WA_SetStyle attribute if style is not None ; otherwise it clears the attribute.

See also

style()

static PySide2.QtWidgets.QGraphicsWidget.setTabOrder(first, second)
Parameters

Moves the second widget around the ring of focus widgets so that keyboard focus moves from the first widget to the second widget when the Tab key is pressed.

Note that since the tab order of the second widget is changed, you should order a chain like this:

setTabOrder(a, b) # a to b
setTabOrder(b, c) # a to b to c
setTabOrder(c, d) # a to b to c to d

not like this:

# WRONG
setTabOrder(c, d) # c to d
setTabOrder(a, b) # a to b AND c to d
setTabOrder(b, c) # a to b to c, but not c to d

If first is None , this indicates that second should be the first widget to receive input focus should the scene gain Tab focus (i.e., the user hits Tab so that focus passes into the scene). If second is None , this indicates that first should be the first widget to gain focus if the scene gained BackTab focus.

By default, tab order is defined implicitly using widget creation order.

PySide2.QtWidgets.QGraphicsWidget.setWindowFlags(wFlags)
Parameters

wFlagsWindowFlags

See also

windowFlags()

PySide2.QtWidgets.QGraphicsWidget.setWindowFrameMargins(left, top, right, bottom)
Parameters
  • leftqreal

  • topqreal

  • rightqreal

  • bottomqreal

Sets the widget’s window frame margins to left , top , right and bottom . The default frame margins are provided by the style, and they depend on the current window flags.

If you would like to draw your own window decoration, you can set your own frame margins to override the default margins.

PySide2.QtWidgets.QGraphicsWidget.setWindowTitle(title)
Parameters

title – unicode

See also

windowTitle()

PySide2.QtWidgets.QGraphicsWidget.showEvent(event)
Parameters

eventQShowEvent

This event handler, for Show events, is delivered before the widget has been shown, for example, setVisible (true) has been called for the widget or one of its ancestors when the widget was previously hidden.

You can reimplement this event handler to detect when your widget is shown. Calling accept() or ignore() on event has no effect.

See also

hideEvent() showEvent() ItemVisibleChange

PySide2.QtWidgets.QGraphicsWidget.size()
Return type

QSizeF

PySide2.QtWidgets.QGraphicsWidget.style()
Return type

QStyle

Returns a pointer to the widget’s style. If this widget does not have any explicitly assigned style, the scene’s style is returned instead. In turn, if the scene does not have any assigned style, this function returns style() .

See also

setStyle()

PySide2.QtWidgets.QGraphicsWidget.testAttribute(attribute)
Parameters

attributeWidgetAttribute

Return type

bool

Returns true if attribute is enabled for this widget; otherwise, returns false .

See also

setAttribute()

PySide2.QtWidgets.QGraphicsWidget.ungrabKeyboardEvent(event)
Parameters

eventQEvent

This event handler, for event , can be reimplemented in a subclass to receive notifications for UngrabKeyboard events.

PySide2.QtWidgets.QGraphicsWidget.ungrabMouseEvent(event)
Parameters

eventQEvent

This event handler, for event , can be reimplemented in a subclass to receive notifications for UngrabMouse events.

PySide2.QtWidgets.QGraphicsWidget.unsetLayoutDirection()
PySide2.QtWidgets.QGraphicsWidget.unsetWindowFrameMargins()

Resets the window frame margins to the default value, provided by the style.

PySide2.QtWidgets.QGraphicsWidget.windowFlags()
Return type

WindowFlags

See also

setWindowFlags()

PySide2.QtWidgets.QGraphicsWidget.windowFrameEvent(e)
Parameters

eQEvent

Return type

bool

This event handler, for event , receives events for the window frame if this widget is a window. Its base implementation provides support for default window frame interaction such as moving, resizing, etc.

You can reimplement this handler in a subclass of QGraphicsWidget to provide your own custom window frame interaction support.

Returns true if event has been recognized and processed; otherwise, returns false .

See also

event()

PySide2.QtWidgets.QGraphicsWidget.windowFrameGeometry()
Return type

QRectF

Returns the widget’s geometry in parent coordinates including any window frame.

PySide2.QtWidgets.QGraphicsWidget.windowFrameRect()
Return type

QRectF

Returns the widget’s local rect including any window frame.

PySide2.QtWidgets.QGraphicsWidget.windowFrameSectionAt(pos)
Parameters

posQPointF

Return type

WindowFrameSection

Returns the window frame section at position pos , or NoSection if there is no window frame section at this position.

This function is used in QGraphicsWidget ‘s base implementation for window frame interaction.

You can reimplement this function if you want to customize how a window can be interactively moved or resized. For instance, if you only want to allow a window to be resized by the bottom right corner, you can reimplement this function to return NoSection for all sections except BottomRightSection .

PySide2.QtWidgets.QGraphicsWidget.windowTitle()
Return type

unicode

See also

setWindowTitle()

PySide2.QtWidgets.QGraphicsWidget.windowType()
Return type

WindowType

Returns the widgets window type.