QWidget Class | Qt Widgets | Qt 6.10.0

This property holds the widget's name as seen by assistive technologies

accessibleName : QString

This is the primary name by which assistive technology such as screen readers announce this widget. For most widgets setting this property is not required. For example for QPushButton the button's text will be used.

It is important to set this property when the widget does not provide any text. For example a button that only contains an icon needs to set this property to work with screen readers. The name should be short and equivalent to the visual information conveyed by the widget.

This property has to be localized .

By default, this property contains an empty string.

Access functions:

autoFillBackground : bool

This property holds whether the widget background is filled automatically

If enabled, this property will cause Qt to fill the background of the widget before invoking the paint event. The color used is defined by the QPalette::Window color role from the widget's palette .

In addition, Windows are always filled with QPalette::Window , unless the WA_OpaquePaintEvent or WA_NoSystemBackground attributes are set.

This property cannot be turned off (i.e., set to false) if a widget's parent has a static gradient for its background.

Warning: Use this property with caution in conjunction with Qt Style Sheets . When a widget has a style sheet with a valid background or a border-image, this property is automatically disabled.

By default, this property is false .

Access functions:

baseSize : QSize

This property holds the base size of the widget

The base size is used to calculate a proper widget size if the widget defines sizeIncrement ().

By default, for a newly-created widget, this property contains a size with zero width and height.

Access functions:

See also setSizeIncrement ().

Access functions:

See also contextMenuEvent (), customContextMenuRequested (), and actions ().

cursor : QCursor

This property holds the cursor shape for this widget

The mouse cursor will assume this shape when it's over this widget. See the list of predefined cursor objects for a range of useful shapes.

An editor widget might use an I-beam cursor:

setCursor(Qt::IBeamCursor);

If no cursor has been set, or after a call to unsetCursor(), the parent's cursor is used.

By default, this property contains a cursor with the Qt::ArrowCursor shape.

Some underlying window implementations will reset the cursor if it leaves a widget even if the mouse is grabbed. If you want to have a cursor set for all widgets, even when outside the window, consider QGuiApplication::setOverrideCursor ().

Access functions:

See also QGuiApplication::setOverrideCursor ().

enabled : bool

This property holds whether the widget is enabled

In general an enabled widget handles keyboard and mouse events; a disabled widget does not. An exception is made with QAbstractButton .

Some widgets display themselves differently when they are disabled. For example a button might draw its label grayed out. If your widget needs to know when it becomes enabled or disabled, you can use the changeEvent () with type QEvent::EnabledChange .

Disabling a widget implicitly disables all its children. Enabling respectively enables all child widgets unless they have been explicitly disabled. It it not possible to explicitly enable a child widget which is not a window while its parent widget remains disabled.

By default, this property is true .

Access functions:

See also isEnabledTo (), QKeyEvent , QMouseEvent , and changeEvent ().

`[read-only]` focus : const bool

This property holds whether this widget (or its focus proxy) has the keyboard input focus

This property holds the way the widget accepts keyboard focus

Note: Obtaining the value of this property for a widget is effectively equivalent to checking whether QApplication::focusWidget () refers to the widget.

Access functions:

See also setFocus (), clearFocus (), setFocusPolicy (), and QApplication::focusWidget ().

focusPolicy : Qt::FocusPolicy

The policy is Qt::TabFocus if the widget accepts keyboard focus by tabbing, Qt::ClickFocus if the widget accepts focus by clicking, Qt::StrongFocus if it accepts both, and Qt::NoFocus (the default) if it does not accept focus at all.

You must enable keyboard focus for a widget if it processes keyboard events. This is normally done from the widget's constructor. For instance, the QLineEdit constructor calls setFocusPolicy( Qt::StrongFocus ).

If the widget has a focus proxy, then the focus policy will be propagated to it.

Access functions:

See also focusInEvent (), focusOutEvent (), keyPressEvent (), keyReleaseEvent (), and enabled .

font : QFont

This property holds the font currently set for the widget

This property describes the widget's requested font. The font is used by the widget's style when rendering standard components, and is available as a means to ensure that custom widgets can maintain consistency with the native platform's look and feel. It's common that different platforms, or different styles, define different fonts for an application.

When you assign a new font to a widget, the properties from this font are combined with the widget's default font to form the widget's final font. You can call fontInfo () to get a copy of the widget's final font. The final font is also used to initialize QPainter 's font.

The default depends on the system environment. QApplication maintains a system/theme font which serves as a default for all widgets. There may also be special font defaults for certain types of widgets. You can also define default fonts for widgets yourself by passing a custom font and the name of a widget to QApplication::setFont (). Finally, the font is matched against Qt's font database to find the best match.

QWidget propagates explicit font properties from parent to child. If you change a specific property on a font and assign that font to a widget, that property will propagate to all the widget's children, overriding any system defaults for that property. Note that fonts by default don't propagate to windows (see isWindow ()) unless the Qt::WA_WindowPropagation attribute is enabled.

QWidget 's font propagation is similar to its palette propagation.

The current style, which is used to render the content of all standard Qt widgets, is free to choose to use the widget font, or in some cases, to ignore it (partially, or completely). In particular, certain styles like GTK style, Mac style, and Windows Vista style, apply special modifications to the widget font to match the platform's native look and feel. Because of this, assigning properties to a widget's font is not guaranteed to change the appearance of the widget. Instead, you may choose to apply a styleSheet .

Note: If Qt Style Sheets are used on the same widget as setFont(), style sheets will take precedence if the settings conflict.

Access functions:

See also fontInfo () and fontMetrics ().

`[read-only]` frameGeometry : const QRect

geometry of the widget relative to its parent including any window frame

See the Window Geometry documentation for an overview of geometry issues with windows.

By default, this property contains a value that depends on the user's platform and screen geometry.

Access functions:

See also geometry (), x (), y (), and pos ().

`[read-only]` frameSize : const QSize

This property holds the size of the widget including any window frame

By default, this property contains a value that depends on the user's platform and screen geometry.

This property holds whether the widget is shown in full screen mode

`[read-only]` fullScreen : const bool

A widget in full screen mode occupies the whole screen area and does not display window decorations, such as a title bar.

This property holds the geometry of the widget relative to its parent and excluding the window frame

geometry : QRect

When changing the geometry, the widget, if visible, receives a move event ( moveEvent ()) and/or a resize event ( resizeEvent ()) immediately. If the widget is not currently visible, it is guaranteed to receive appropriate events before it is shown.

The size component is adjusted if it lies outside the range defined by minimumSize () and maximumSize ().

Warning: Calling setGeometry() inside resizeEvent () or moveEvent () can lead to infinite recursion.

See the Window Geometry documentation for an overview of geometry issues with windows.

By default, this property contains a value that depends on the user's platform and screen geometry.

Access functions:

See also frameGeometry (), rect (), move (), resize (), moveEvent (), resizeEvent (), minimumSize (), and maximumSize ().

`[read-only]` height : const int

This property holds the height of the widget excluding any window frame

See the Window Geometry documentation for an overview of geometry issues with windows.

By default, this property contains a value that depends on the user's platform and screen geometry .

Access functions:

See also geometry , width , and size .

inputMethodHints : Qt::InputMethodHints

What input method specific hints the widget has.

This is only relevant for input widgets. It is used by the input method to retrieve hints as to how the input method should operate. For example, if the Qt::ImhFormattedNumbersOnly flag is set, the input method may change its visual components to reflect that only numbers can be entered.

Warning: Some widgets require certain flags to work as intended. To set a flag, do w->setInputMethodHints(w->inputMethodHints()|f) instead of w->setInputMethodHints(f) .

Note: The flags are only hints, so the particular input method implementation is free to ignore them. If you want to be sure that a certain type of characters are entered, you should also set a QValidator on the widget.

The default value is Qt::ImhNone .

Access functions:

See also inputMethodQuery ().

`[read-only]` isActiveWindow : const bool

This property holds whether this widget's window is the active window

The active window is the window that contains the widget that has keyboard focus (The window may still have focus if it has no widgets or none of its widgets accepts keyboard focus).

When popup windows are visible, this property is true for both the active window and for the popup.

This property holds the layout direction for this widget.

layoutDirection : Qt::LayoutDirection

Note: This method no longer affects text layout direction since Qt 4.7.

By default, this property is set to Qt::LeftToRight .

When the layout direction is set on a widget, it will propagate to the widget's children, but not to a child that is a window and not to a child for which setLayoutDirection() has been explicitly called. Also, child widgets added after setLayoutDirection() has been called for the parent do not inherit the parent's layout direction.

Access functions:

See also QApplication::layoutDirection .

locale : QLocale

This property holds the widget's locale

As long as no special locale has been set, this is either the parent's locale or (if this widget is a top level widget), the default locale.

If the widget displays dates or numbers, these should be formatted using the widget's locale.

This property holds whether this widget is maximized

`[read-only]` maximized : const bool

This property is only relevant for windows.

Note: Due to limitations on some window systems, this does not always report the expected results (e.g., if the user on X11 maximizes the window via the window manager, Qt has no way of distinguishing this from any other resize). This is expected to improve as window manager protocols evolve.

This property holds the widget's maximum height in pixels

See also windowState (), showMaximized (), visible , show (), hide (), showNormal (), and minimized .

maximumHeight : int

This property corresponds to the height held by the maximumSize property.

By default, this property contains a value of 16777215.

Note: The definition of the QWIDGETSIZE_MAX macro limits the maximum size of widgets.

Access functions:

See also maximumSize and maximumWidth .

maximumSize : QSize

This property holds the widget's maximum size in pixels

The widget cannot be resized to a larger size than the maximum widget size.

By default, this property contains a size in which both width and height have values of 16777215.

Note: The definition of the QWIDGETSIZE_MAX macro limits the maximum size of widgets.

This property holds the widget's maximum width in pixels

maximumWidth : int

This property corresponds to the width held by the maximumSize property.

By default, this property contains a value of 16777215.

Note: The definition of the QWIDGETSIZE_MAX macro limits the maximum size of widgets.

Access functions:

See also maximumSize and maximumHeight .

`[read-only]` minimized : const bool

This property holds whether this widget is minimized (iconified)

This property is only relevant for windows.

This property holds the widget's minimum height in pixels

See also showMinimized (), visible , show (), hide (), showNormal (), and maximized .

minimumHeight : int

This property corresponds to the height held by the minimumSize property.

By default, this property has a value of 0.

Access functions:

See also minimumSize and minimumWidth .

minimumSize : QSize

This property holds the widget's minimum size

The widget cannot be resized to a smaller size than the minimum widget size. The widget's size is forced to the minimum size if the current size is smaller.

The minimum size set by this function will override the minimum size defined by QLayout . To unset the minimum size, use a value of QSize(0, 0) .

By default, this property contains a size with zero width and height.

Access functions:

See also minimumWidth , minimumHeight , maximumSize , and sizeIncrement .

`[read-only]` minimumSizeHint : const QSize

This property holds the recommended minimum size for the widget

If the value of this property is an invalid size, no minimum size is recommended.

The default implementation of minimumSizeHint() returns an invalid size if there is no layout for this widget, and returns the layout's minimum size otherwise. Most built-in widgets reimplement minimumSizeHint().

QLayout will never resize a widget to a size smaller than the minimum size hint unless minimumSize () is set or the size policy is set to QSizePolicy::Ignore. If minimumSize () is set, the minimum size hint will be ignored.

Access functions:

See also QSize::isValid (), resize (), setMinimumSize (), and sizePolicy ().

minimumWidth : int

This property holds the widget's minimum width in pixels

This property corresponds to the width held by the minimumSize property.

By default, this property has a value of 0.

Access functions:

See also minimumSize and minimumHeight .

`[read-only]` modal : const bool

This property holds whether the widget is a modal widget

This property only makes sense for windows. A modal widget prevents widgets in all other windows from getting any input.

This property holds whether mouse tracking is enabled for the widget

mouseTracking : bool

If mouse tracking is disabled (the default), the widget only receives mouse move events when at least one mouse button is pressed while the mouse is being moved.

If mouse tracking is enabled, the widget receives mouse move events even if no buttons are pressed.

This property holds the geometry of the widget as it will appear when shown as a normal (not maximized or full screen) top-level widget

See also mouseMoveEvent ().

`[read-only]` normalGeometry : const QRect

If the widget is already in this state the normal geometry will reflect the widget's current geometry ().

For child widgets this property always holds an empty rectangle.

By default, this property contains an empty rectangle.

Access functions:

See also QWidget::windowState () and QWidget::geometry .

palette : QPalette

This property holds the widget's palette

This property describes the widget's palette. The palette is used by the widget's style when rendering standard components, and is available as a means to ensure that custom widgets can maintain consistency with the native platform's look and feel. It's common that different platforms, or different styles, have different palettes.

When you assign a new palette to a widget, the color roles from this palette are combined with the widget's default palette to form the widget's final palette. The palette entry for the widget's background role is used to fill the widget's background (see QWidget::autoFillBackground ), and the foreground role initializes QPainter 's pen.

The default depends on the system environment. QApplication maintains a system/theme palette which serves as a default for all widgets. There may also be special palette defaults for certain types of widgets (e.g., on Windows Vista, all classes that derive from QMenuBar have a special default palette). You can also define default palettes for widgets yourself by passing a custom palette and the name of a widget to QApplication::setPalette (). Finally, the style always has the option of polishing the palette as it's assigned (see QStyle::polish ()).

QWidget propagates explicit palette roles from parent to child. If you assign a brush or color to a specific role on a palette and assign that palette to a widget, that role will propagate to all the widget's children, overriding any system defaults for that role. Note that palettes by default don't propagate to windows (see isWindow ()) unless the Qt::WA_WindowPropagation attribute is enabled.

QWidget 's palette propagation is similar to its font propagation.

The current style, which is used to render the content of all standard Qt widgets, is free to choose colors and brushes from the widget palette, or, in some cases, to ignore the palette (partially, or completely). In particular, certain styles like GTK style, Mac style, and Windows Vista style, depend on third party APIs to render the content of widgets, and these styles typically do not follow the palette. Because of this, assigning roles to a widget's palette is not guaranteed to change the appearance of the widget. Instead, you may choose to apply a styleSheet .

Warning: Do not use this function in conjunction with Qt Style Sheets . When using style sheets, the palette of a widget can be customized using the "color", "background-color", "selection-color", "selection-background-color" and "alternate-background-color".

Access functions:

See also QGuiApplication::palette (), QWidget::font (), and Qt Style Sheets .

pos : QPoint

This property holds the position of the widget within its parent widget

If the widget is a window, the position is that of the widget on the desktop, including its frame.

When changing the position, the widget, if visible, receives a move event ( moveEvent ()) immediately. If the widget is not currently visible, it is guaranteed to receive an event before it is shown.

By default, this property contains a position that refers to the origin.

Warning: Calling move() or setGeometry () inside moveEvent () can lead to infinite recursion.

See the Window Geometry documentation for an overview of geometry issues with windows.

Note: Not all windowing systems support setting or querying top level window positions. On such a system, programmatically moving windows may not have any effect, and artificial values may be returned for the current positions, such as QPoint(0, 0) .

Access functions:

See also frameGeometry , size , x (), and y ().

`[read-only]` rect : const QRect

This property holds the internal geometry of the widget excluding any window frame

The rect property equals QRect (0, 0, width (), height ()).

See the Window Geometry documentation for an overview of geometry issues with windows.

By default, this property contains a value that depends on the user's platform and screen geometry.

Access functions:

See also size .

size : QSize

This property holds the size of the widget excluding any window frame

If the widget is visible when it is being resized, it receives a resize event ( resizeEvent ()) immediately. If the widget is not currently visible, it is guaranteed to receive an event before it is shown.

The size is adjusted if it lies outside the range defined by minimumSize () and maximumSize ().

By default, this property contains a value that depends on the user's platform and screen geometry.

Warning: Calling resize() or setGeometry () inside resizeEvent () can lead to infinite recursion.

Note: Setting the size to QSize(0, 0) will cause the widget to not appear on screen. This also applies to windows.

Access functions:

See also pos , geometry , minimumSize , maximumSize , resizeEvent (), and adjustSize ().

`[read-only]` sizeHint : const QSize

This property holds the recommended size for the widget

If the value of this property is an invalid size, no size is recommended.

The default implementation of sizeHint() returns an invalid size if there is no layout for this widget, and returns the layout's preferred size otherwise.

This property holds the size increment of the widget

sizeIncrement : QSize

When the user resizes the window, the size will move in steps of sizeIncrement(). width () pixels horizontally and sizeIncrement. height () pixels vertically, with baseSize () as the basis. Preferred widget sizes are for non-negative integers i and j :

width = baseSize().width() + i * sizeIncrement().width();
height = baseSize().height() + j * sizeIncrement().height();

Note that while you can set the size increment for all widgets, it only affects windows.

By default, this property contains a size with zero width and height.

Warning: The size increment has no effect under Windows, and may be disregarded by the window manager on X11.

Access functions:

See also size , minimumSize , and maximumSize .

sizePolicy : QSizePolicy

This property holds the default layout behavior of the widget

If there is a QLayout that manages this widget's children, the size policy specified by that layout is used. If there is no such QLayout , the result of this function is used.

The default policy is Preferred/Preferred, which means that the widget can be freely resized, but prefers to be the size sizeHint () returns. Button-like widgets set the size policy to specify that they may stretch horizontally, but are fixed vertically. The same applies to lineedit controls (such as QLineEdit , QSpinBox or an editable QComboBox ) and other horizontally orientated widgets (such as QProgressBar ). QToolButton 's are normally square, so they allow growth in both directions. Widgets that support different directions (such as QSlider , QScrollBar or QHeader) specify stretching in the respective direction only. Widgets that can provide scroll bars (usually subclasses of QScrollArea ) tend to specify that they can use additional space, and that they can make do with less than sizeHint ().

Access functions:

See also sizeHint (), QLayout , QSizePolicy , and updateGeometry ().

statusTip : QString

This property holds the widget's status tip

By default, this property contains an empty string.

This property holds the widget's style sheet

See also toolTip and whatsThis .

styleSheet : QString

The style sheet contains a textual description of customizations to the widget's style, as described in the Qt Style Sheets document.

Since Qt 4.5, Qt style sheets fully supports macOS.

Warning: Qt style sheets are currently not supported for custom QStyle subclasses. We plan to address this in some future release.

Access functions:

See also setStyle (), QApplication::styleSheet , and Qt Style Sheets .

tabletTracking : bool

This property holds whether tablet tracking is enabled for the widget

If tablet tracking is disabled (the default), the widget only receives tablet move events when the stylus is in contact with the tablet, or at least one stylus button is pressed, while the stylus is being moved.

If tablet tracking is enabled, the widget receives tablet move events even while hovering in proximity. This is useful for monitoring position as well as the auxiliary properties such as rotation and tilt, and providing feedback in the UI.

This property holds the widget's tooltip

See also tabletEvent ().

Note that by default tooltips are only shown for widgets that are children of the active window. You can change this behavior by setting the attribute Qt::WA_AlwaysShowToolTips on the window , not on the widget with the tooltip.

If you want to control a tooltip's behavior, you can intercept the event () function and catch the QEvent::ToolTip event (e.g., if you want to customize the area for which the tooltip should be shown).

By default, this property contains an empty string.

Access functions:

See also QToolTip , statusTip , and whatsThis .

toolTipDuration : int

This property holds the widget's tooltip duration

Specifies how long time the tooltip will be displayed, in milliseconds. If the value is -1 (default) the duration is calculated depending on the length of the tooltip.

This property holds whether updates are enabled

See also toolTip .

updatesEnabled : bool

An updates enabled widget receives paint events and has a system background; a disabled widget does not. This also implies that calling update () and repaint () has no effect if updates are disabled.

By default, this property is true .

setUpdatesEnabled() is normally used to disable updates for a short period of time, for instance to avoid screen flicker during large changes. In Qt, widgets normally do not generate screen flicker, but on X11 the server might erase regions on the screen when widgets get hidden before they can be replaced by other widgets. Disabling updates solves this.

Example:

setUpdatesEnabled(false);
bigVisualChanges();
setUpdatesEnabled(true);

Disabling a widget implicitly disables all its children. Enabling a widget enables all child widgets except top-level widgets or those that have been explicitly disabled. Re-enabling updates implicitly calls update () on the widget.

Access functions:

See also paintEvent ().

visible : bool

This property holds whether the widget is visible

Calling setVisible(true) or show () sets the widget to visible status if all its parent widgets up to the window are visible. If an ancestor is not visible, the widget won't become visible until all its ancestors are shown. If its size or position has changed, Qt guarantees that a widget gets move and resize events just before it is shown. If the widget has not been resized yet, Qt will adjust the widget's size to a useful default using adjustSize ().

Calling setVisible(false) or hide () hides a widget explicitly. An explicitly hidden widget will never become visible, even if all its ancestors become visible, unless you show it.

A widget receives show and hide events when its visibility status changes. Between a hide and a show event, there is no need to waste CPU cycles preparing or displaying information to the user. A video application, for example, might simply stop generating new frames.

A widget that happens to be obscured by other windows on the screen is considered to be visible. The same applies to iconified windows and windows that exist on another virtual desktop (on platforms that support this concept). A widget receives spontaneous show and hide events when its mapping status is changed by the window system, e.g. a spontaneous hide event when the user minimizes the window, and a spontaneous show event when the window is restored again.

You seldom have to reimplement the setVisible() function. If you need to change some settings before a widget is shown, use showEvent () instead. If you need to do some delayed initialization use the Polish event delivered to the event () function.

Access functions:

See also show (), hide (), isHidden (), isVisibleTo (), isMinimized (), showEvent (), and hideEvent ().

whatsThis : QString

This property holds the widget's What's This help text.

By default, this property contains an empty string.

This property holds the width of the widget excluding any window frame

`[read-only]` width : const int

See the Window Geometry documentation for an overview of geometry issues with windows.

Note: Do not use this function to find the width of a screen on a multi-screen desktop. See QScreen for details.

By default, this property contains a value that depends on the user's platform and screen geometry.

Access functions:

See also geometry , height , and size .

windowFilePath : QString

This property holds the file path associated with a widget

This property only makes sense for windows. It associates a file path with a window. If you set the file path, but have not set the window title, Qt sets the window title to the file name of the specified path, obtained using QFileInfo::fileName ().

If the window title is set at any point, then the window title takes precedence and will be shown instead of the file path string.

Additionally, on macOS, this has an added benefit that it sets the proxy icon for the window, assuming that the file path exists.

If no file path is set, this property contains an empty string.

By default, this property contains an empty string.

Access functions:

See also windowTitle and windowIcon .

windowFlags : Qt::WindowFlags

Window flags are a combination of a type (e.g. Qt::Dialog ) and zero or more hints to the window system (e.g. Qt::FramelessWindowHint ).

If the widget had type Qt::Widget or Qt::SubWindow and becomes a window ( Qt::Window , Qt::Dialog , etc.), it is put at position (0, 0) on the desktop. If the widget is a window and becomes a Qt::Widget or Qt::SubWindow , it is put at position (0, 0) relative to its parent widget.

Note: This function calls setParent () when changing the flags for a window, causing the widget to be hidden. You must call show () to make the widget visible again..

Access functions:

See also windowType (), setWindowFlag (), and Window Flags Example .

windowIcon : QIcon

This property holds the widget's icon

This property only makes sense for windows. If no icon has been set, windowIcon() returns the application icon ( QApplication::windowIcon ()).

Note: On macOS, window icons represent the active document, and will not be displayed unless a file path has also been set using setWindowFilePath .

Access functions:

Notifier signal:

See also windowTitle and setWindowFilePath .

windowModality : Qt::WindowModality

This property holds which windows are blocked by the modal widget

This property only makes sense for windows. A modal widget prevents widgets in other windows from getting input. The value of this property controls which windows are blocked when the widget is visible. Changing this property while the window is visible has no effect; you must hide () the widget first, then show () it again.

By default, this property is Qt::NonModal .

Access functions:

See also isWindow (), QWidget::modal , and QDialog .

windowModified : bool

This property holds whether the document shown in the window has unsaved changes

A modified window is a window whose content has changed but has not been saved to disk. This flag will have different effects varied by the platform. On macOS the close button will have a modified look; on other platforms, the window title will have an '*' (asterisk).

The window title must contain a "[*]" placeholder, which indicates where the '*' should appear. Normally, it should appear right after the file name (e.g., "document1.txt[*] - Text Editor"). If the window isn't modified, the placeholder is simply removed.

Note that if a widget is set as modified, all its ancestors will also be set as modified. However, if you call setWindowModified(false) on a widget, this will not propagate to its parent because other children of the parent might have been modified.

This property holds the level of opacity for the window.

See also windowTitle .

windowOpacity : double

The valid range of opacity is from 1.0 (completely opaque) to 0.0 (completely transparent).

By default the value of this property is 1.0.

This feature is available on Embedded Linux, macOS, Windows, and X11 platforms that support the Composite extension.

Note: On X11 you need to have a composite manager running, and the X11 specific _NET_WM_WINDOW_OPACITY atom needs to be supported by the window manager you are using.

Warning: Changing this property from opaque to transparent might issue a paint event that needs to be processed before the window is displayed correctly. This affects mainly the use of QScreen::grabWindow (). Also note that semi-transparent windows update and resize significantly slower than opaque windows.

Access functions:

See also setMask ().

windowTitle : QString

This property holds the window title (caption)

This property only makes sense for top-level widgets, such as windows and dialogs. If no caption has been set, the title is based of the windowFilePath . If neither of these is set, then the title is an empty string.

If you use the windowModified mechanism, the window title must contain a "[*]" placeholder, which indicates where the '*' should appear. Normally, it should appear right after the file name (e.g., "document1.txt[*] - Text Editor"). If the windowModified property is false (the default), the placeholder is simply removed.

On some desktop platforms (including Windows and Unix), the application name (from QGuiApplication::applicationDisplayName ) is added at the end of the window title, if set. This is done by the QPA plugin, so it is shown to the user, but isn't part of the windowTitle string.

Access functions:

Notifier signal:

See also windowIcon , windowModified , and windowFilePath .

`[read-only]` x : const int

This property holds the x coordinate of the widget relative to its parent including any window frame

See the Window Geometry documentation for an overview of geometry issues with windows.

By default, this property has a value of 0.

Access functions:

See also frameGeometry , y , and pos .

`[read-only]` y : const int

This property holds the y coordinate of the widget relative to its parent and including any window frame

See the Window Geometry documentation for an overview of geometry issues with windows.

By default, this property has a value of 0.

Access functions:

See also frameGeometry , x , and pos .

Member Function Documentation

`[since 6.3]` QAction QWidget:: addAction (const QIcon & icon* , const QString & text )

`[since 6.3]` QAction QWidget:: addAction (const QIcon & icon* , const QString & text , const QKeySequence & shortcut )

`[since 6.3]` QAction QWidget:: addAction (const QString & text* )

`[since 6.3]` QAction QWidget:: addAction (const QString & text* , const QKeySequence & shortcut )

These convenience functions create a new action with text text , icon icon and shortcut shortcut , if any.

The functions add the newly created action to the widget's list of actions, and return it.

QWidget takes ownership of the returned QAction .

This function was introduced in Qt 6.3.

`[since 6.3]` QAction QWidget:: addAction (const QIcon & icon* , const QString & text , const QKeySequence & shortcut , const QObject * receiver , const char * member , Qt::ConnectionType type = Qt::AutoConnection)

`[since 6.3]` QAction QWidget:: addAction (const QIcon & icon* , const QString & text , const QObject * receiver , const char * member , Qt::ConnectionType type = Qt::AutoConnection)

`[since 6.3]` QAction QWidget:: addAction (const QString & text* , const QKeySequence & shortcut , const QObject * receiver , const char * member , Qt::ConnectionType type = Qt::AutoConnection)

`[since 6.3]` QAction QWidget:: addAction (const QString & text* , const QObject * receiver , const char * member , Qt::ConnectionType type = Qt::AutoConnection)

This convenience function creates a new action with the text text , icon icon , and shortcut shortcut , if any.

The action's triggered () signal is connected to the receiver 's member slot. The function adds the newly created action to the widget's list of actions and returns it.

QWidget takes ownership of the returned QAction .

This function was introduced in Qt 6.3.

`[since 6.3]` template <typename... Args, typename = QWidget::compatible_action_slot_args<Args...>> QAction QWidget:: addAction (const QIcon & icon* , const QString & text , Args &&... args )

`[since 6.3]` template <typename... Args, typename = QWidget::compatible_action_slot_args<Args...>> QAction QWidget:: addAction (const QIcon & icon* , const QString & text , const QKeySequence & shortcut , Args &&... args )

`[since 6.3]` template <typename... Args, typename = QWidget::compatible_action_slot_args<Args...>> QAction QWidget:: addAction (const QString & text* , Args &&... args )

`[since 6.3]` template <typename... Args, typename = QWidget::compatible_action_slot_args<Args...>> QAction QWidget:: addAction (const QString & text* , const QKeySequence & shortcut , Args &&... args )

These convenience functions create a new action with the text text , icon icon , and shortcut shortcut , if any.

The action's triggered () signal is connected as if by a call to QObject::connect (action, & QAction::triggered , args...), perfectly forwarding args , including a possible Qt::ConnectionType .

The function adds the newly created action to the widget's list of actions and returns it.

QWidget takes ownership of the returned QAction .

This function was introduced in Qt 6.3.

`[explicit]` QWidget:: QWidget ( QWidget * parent = nullptr, Qt::WindowFlags f = Qt::WindowFlags())

Constructs a widget which is a child of parent , with widget flags set to f .

If parent is nullptr , the new widget becomes a window. If parent is another widget, this widget becomes a child window inside parent . The new widget is deleted when its parent is deleted.

The widget flags argument, f , is normally 0, but it can be set to customize the frame of a window (i.e. parent must be nullptr ). To customize the frame, use a value composed from the bitwise OR of any of the window flags .

If you add a child widget to an already visible widget you must explicitly show the child to make it visible.

Note that the X11 version of Qt may not be able to deliver all combinations of style flags on all systems. This is because on X11, Qt can only ask the window manager, and the window manager can override the application's settings. On Windows, Qt can set whatever flags you want.

See also windowFlags .

`[virtual noexcept]` QWidget:: ~QWidget ()

Destroys the widget.

All this widget's children are deleted first. The application exits if this widget is the main widget.

`[virtual protected]` void QWidget:: actionEvent ( QActionEvent * event )

This event handler is called with the given event whenever the widget's actions are changed.

QList < QAction *> QWidget:: actions () const

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

void QWidget:: activateWindow ()

Sets the top-level widget containing this widget to be the active window.

An active window is a visible top-level window that has the keyboard input focus.

This function performs the same operation as clicking the mouse on the title bar of a top-level window. On X11, the result depends on the Window Manager. If you want to ensure that the window is stacked on top as well you should also call raise (). Note that the window must be visible, otherwise activateWindow() has no effect.

On Windows, if you are calling this when the application is not currently the active one then it will not make it the active window. It will change the color of the taskbar entry to indicate that the window has changed in some way. This is because Microsoft does not allow an application to interrupt what the user is currently doing in another application.

See also isActiveWindow (), window (), and show ().

void QWidget:: addAction ( QAction * action )

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

All QWidgets 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 QWidget 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.

The ownership of action is not transferred to this QWidget .

See also removeAction (), insertAction (), actions (), and QMenu .

void QWidget:: addActions (const QList < QAction > & actions* )

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

See also removeAction (), QMenu , and addAction ().

void QWidget:: adjustSize ()

Adjusts the size of the widget to fit its contents.

This function uses sizeHint () if it is valid, i.e., the size hint's width and height are >= 0. Otherwise, it sets the size to the children rectangle that covers all child widgets (the union of all child widget rectangles).

For windows, the screen size is also taken into account. If the sizeHint () is less than (200, 100) and the size policy is expanding , the window will be at least (200, 100). The maximum size of a window is 2/3 of the screen's width and height.

See also sizeHint () and childrenRect ().

QPalette::ColorRole QWidget:: backgroundRole () const

Returns the background role of the widget.

The background role defines the brush from the widget's palette that is used to render the background.

If no explicit background role is set, the widget inherits its parent widget's background role.

See also setBackgroundRole () and foregroundRole ().

QBackingStore *QWidget:: backingStore () const

Returns the QBackingStore this widget will be drawn into.

`[virtual protected]` void QWidget:: changeEvent ( QEvent * event )

This event handler can be reimplemented to handle state changes.

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

Change events include: QEvent::ToolBarChange , QEvent::ActivationChange , QEvent::EnabledChange , QEvent::FontChange , QEvent::StyleChange , QEvent::PaletteChange , QEvent::WindowTitleChange , QEvent::IconTextChange , QEvent::ModifiedChange , QEvent::MouseTrackingChange , QEvent::ParentChange , QEvent::WindowStateChange , QEvent::LanguageChange , QEvent::LocaleChange , QEvent::LayoutDirectionChange , QEvent::ReadOnlyChange .

QWidget *QWidget:: childAt ( int x , int y ) const

Returns the visible child widget at the position ( x , y ) in the widget's coordinate system. If there is no visible child widget at the specified position, the function returns nullptr .

QWidget *QWidget:: childAt (const QPoint & p ) const

Returns the visible child widget at point p in the widget's own coordinate system.

Returns the visible child widget at point p in the widget's own coordinate system.

`[since 6.8]` QWidget *QWidget:: childAt (const QPointF & p ) const

This function was introduced in Qt 6.8.

void QWidget:: clearFocus ()

Takes keyboard input focus from the widget.

If the widget has active focus, a focus out event is sent to this widget to tell it that it has lost the focus.

This widget must enable focus setting to get the keyboard input focus; that is, it must call setFocusPolicy ().

See also hasFocus (), setFocus (), focusInEvent (), focusOutEvent (), setFocusPolicy (), and QApplication::focusWidget ().

void QWidget:: clearMask ()

Removes any mask set by setMask ().

See also setMask ().

`[slot]` bool QWidget:: close ()

Closes this widget. Returns true if the widget was closed; otherwise returns false .

First it sends the widget a QCloseEvent . The widget is hidden if it accepts the close event. If it ignores the event, nothing happens. The default implementation of QWidget::closeEvent () accepts the close event.

If the widget has the Qt::WA_DeleteOnClose flag, the widget is also deleted. A close events is delivered to the widget no matter if the widget is visible or not.

The QGuiApplication::lastWindowClosed () signal is emitted when the last visible primary window (i.e. window with no parent) with the Qt::WA_QuitOnClose attribute set is closed. By default this attribute is set for all widgets except transient windows such as splash screens, tool windows, and popup menus.

`[virtual protected]` void QWidget:: closeEvent ( QCloseEvent * event )

This event handler is called with the given event when Qt receives a window close request for a top-level widget from the window system.

By default, the event is accepted and the widget is closed. You can reimplement this function to change the way the widget responds to window close requests. For example, you can prevent the window from closing by calling ignore () on all events.

Main window applications typically use reimplementations of this function to check whether the user's work has been saved and ask for permission before closing.

See also event (), hide (), close (), and QCloseEvent .

QMargins QWidget:: contentsMargins () const

The contentsMargins function returns the widget's contents margins.

QRect QWidget:: contentsRect () const

Returns the area inside the widget's margins.

`[virtual protected]` void QWidget:: contextMenuEvent ( QContextMenuEvent * event )

This event handler, for event event , can be reimplemented in a subclass to receive widget context menu events.

The handler is called when the widget's contextMenuPolicy is Qt::DefaultContextMenu .

The default implementation ignores the context event. See the QContextMenuEvent documentation for more details.

See also event (), QContextMenuEvent , and customContextMenuRequested ().

`[protected]` void QWidget:: create ( WId window = 0, bool initializeWindow = true, bool destroyOldWindow = true)

Creates a new widget window.

The parameters window , initializeWindow , and destroyOldWindow are ignored in Qt 5. Please use QWindow::fromWinId () to create a QWindow wrapping a foreign window and pass it to QWidget::createWindowContainer () instead.

See also createWindowContainer () and QWindow::fromWinId ().

`[static]` QWidget QWidget:: createWindowContainer ( QWindow window , QWidget * parent = nullptr, Qt::WindowFlags flags = Qt::WindowFlags())

Creates a QWidget that makes it possible to embed window into a QWidget -based application.

The window container is created as a child of parent and with window flags flags .

Once the window has been embedded into the container, the container will control the window's geometry and visibility. Explicit calls to QWindow::setGeometry (), QWindow::show () or QWindow::hide () on an embedded window is not recommended.

The container takes over ownership of window . The window can be removed from the window container with a call to QWindow::setParent ().

The window container is attached as a native child window to the toplevel window it is a child of. When a window container is used as a child of a QAbstractScrollArea or QMdiArea , it will create a native window for every widget in its parent chain to allow for proper stacking and clipping in this use case. Creating a native window for the window container also allows for proper stacking and clipping. This must be done before showing the window container. Applications with many native child windows may suffer from performance issues.

The window container has a number of known limitations:

Stacking order; The embedded window will stack on top of the widget hierarchy as an opaque box. The stacking order of multiple overlapping window container instances is undefined.

Rendering Integration; The window container does not interoperate with QGraphicsProxyWidget , QWidget::render () or similar functionality.

Focus Handling; It is possible to let the window container instance have any focus policy and it will delegate focus to the window via a call to QWindow::requestActivate (). However, returning to the normal focus chain from the QWindow instance will be up to the QWindow instance implementation itself. Also, whether QWindow::requestActivate () actually gives the window focus, is platform dependent.

Since 6.8, if embedding a Qt Quick based window, tab presses will transition in and out of the embedded QML window, allowing focus to move to the next or previous focusable object in the window container chain.

Using many window container instances in a QWidget -based application can greatly hurt the overall performance of the application.

Since 6.7, if window belongs to a widget (that is, window was received from calling windowHandle ()), no container will be created. Instead, this function will return the widget itself, after being reparented to parent . Since no container will be created, flags will be ignored. In other words, if window belongs to a widget, consider just reparenting that widget to parent instead of using this function.

`[signal]` void QWidget:: customContextMenuRequested (const QPoint & pos )

This signal is emitted when the widget's contextMenuPolicy is Qt::CustomContextMenu , and the user has requested a context menu on the widget. The position pos is the position of the context menu event that the widget receives. Normally this is in widget coordinates. The exception to this rule is QAbstractScrollArea and its subclasses that map the context menu event to coordinates of the viewport ().

See also mapToGlobal (), QMenu , and contextMenuPolicy .

`[protected]` void QWidget:: destroy ( bool destroyWindow = true, bool destroySubWindows = true)

Frees up window system resources. Destroys the widget window if destroyWindow is true.

destroy() calls itself recursively for all the child widgets, passing destroySubWindows for the destroyWindow parameter. To have more control over destruction of subwidgets, destroy subwidgets selectively first.

This function is usually called from the QWidget destructor.

`[virtual protected]` void QWidget:: dragEnterEvent ( QDragEnterEvent * event )

This event handler is called when a drag is in progress and the mouse enters this widget. The event is passed in the event parameter.

If the event is ignored, the widget won't receive any drag move events .

See the Drag-and-drop documentation for an overview of how to provide drag-and-drop in your application.

See also QDrag and QDragEnterEvent .

`[virtual protected]` void QWidget:: dragLeaveEvent ( QDragLeaveEvent * event )

This event handler is called when a drag is in progress and the mouse leaves this widget. The event is passed in the event parameter.

See the Drag-and-drop documentation for an overview of how to provide drag-and-drop in your application.

See also QDrag and QDragLeaveEvent .

`[virtual protected]` void QWidget:: dragMoveEvent ( QDragMoveEvent * event )

This event handler is called if a drag is in progress, and when any of the following conditions occur: the cursor enters this widget, the cursor moves within this widget, or a modifier key is pressed on the keyboard while this widget has the focus. The event is passed in the event parameter.

See the Drag-and-drop documentation for an overview of how to provide drag-and-drop in your application.

See also QDrag and QDragMoveEvent .

`[virtual protected]` void QWidget:: dropEvent ( QDropEvent * event )

This event handler is called when the drag is dropped on this widget. The event is passed in the event parameter.

See the Drag-and-drop documentation for an overview of how to provide drag-and-drop in your application.

See also QDrag and QDropEvent .

WId QWidget:: effectiveWinId () const

Returns the effective window system identifier of the widget, i.e. the native parent's window system identifier.

If the widget is native, this function returns the native widget ID. Otherwise, the window ID of the first native parent widget, i.e., the top-level widget that contains this widget, is returned.

Note: We recommend that you do not store this value as it is likely to change at run-time.

See also nativeParentWidget ().

void QWidget:: ensurePolished () const

Ensures that the widget and its children have been polished by QStyle (i.e., have a proper font and palette).

QWidget calls this function after it has been fully constructed but before it is shown the very first time. You can call this function if you want to ensure that the widget is polished before doing an operation, e.g., the correct font size might be needed in the widget's sizeHint () reimplementation. Note that this function is called from the default implementation of sizeHint ().

Polishing is useful for final initialization that must happen after all constructors (from base classes as well as from subclasses) have been called.

If you need to change some settings when a widget is polished, reimplement event () and handle the QEvent::Polish event type.

Note: The function is declared const so that it can be called from other const functions (e.g., sizeHint ()).

See also event ().

`[virtual protected]` void QWidget:: enterEvent ( QEnterEvent * event )

This event handler can be reimplemented in a subclass to receive widget enter events which are passed in the event parameter.

An event is sent to the widget when the mouse cursor enters the widget.

See also leaveEvent (), mouseMoveEvent (), and event ().

`[override virtual protected]` bool QWidget:: event ( QEvent * event )

Reimplements: QObject::event (QEvent *e).

This is the main event handler; it handles event event . You can reimplement this function in a subclass, but we recommend using one of the specialized event handlers instead.

Key press and release events are treated differently from other events. event() checks for Tab and Shift+Tab and tries to move the focus appropriately. If there is no widget to move the focus to (or the key press is not Tab or Shift+Tab), event() calls keyPressEvent ().

Mouse and tablet event handling is also slightly special: only when the widget is enabled , event() will call the specialized handlers such as mousePressEvent (); otherwise it will discard the event.

This function returns true if the event was recognized, otherwise it returns false . If the recognized event was accepted (see QEvent::accepted ), any further processing such as event propagation to the parent widget stops.

See also closeEvent (), focusInEvent (), focusOutEvent (), enterEvent (), keyPressEvent (), keyReleaseEvent (), leaveEvent (), mouseDoubleClickEvent (), mouseMoveEvent (), mousePressEvent (), mouseReleaseEvent (), moveEvent (), paintEvent (), resizeEvent (), QObject::event (), and QObject::timerEvent ().

`[static]` QWidget *QWidget:: find ( WId id )

Returns a pointer to the widget with window identifier/handle id .

The window identifier type depends on the underlying window system, see qwindowdefs.h for the actual definition. If there is no widget with this identifier, nullptr is returned.

`[virtual protected]` void QWidget:: focusInEvent ( QFocusEvent * event )

This event handler can be reimplemented in a subclass to receive keyboard focus events (focus received) for the widget. The event is passed in the event parameter

A widget normally must setFocusPolicy () to something other than Qt::NoFocus to receive focus events. (Note that the application programmer can call setFocus () on any widget, even those that do not normally accept focus.)

The default implementation updates the widget (except for windows that do not specify a focusPolicy ()).

See also focusOutEvent (), setFocusPolicy (), keyPressEvent (), keyReleaseEvent (), event (), and QFocusEvent .

`[protected]` bool QWidget:: focusNextChild ()

Finds a new widget to give the keyboard focus to, as appropriate for Tab , and returns true if it can find a new widget, or false if it can't.

See also focusPreviousChild ().

`[virtual protected]` bool QWidget:: focusNextPrevChild ( bool 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 can't.

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

Sometimes, you will want to reimplement this function. For example, a web browser might reimplement it to move its "current active link" forward or backward, and call focusNextPrevChild() only when it reaches the last or first link on the "page".

Child widgets call focusNextPrevChild() 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 thus gain control of focus traversal for all child widgets.

`[virtual protected]` void QWidget:: focusOutEvent ( QFocusEvent * event )

This event handler can be reimplemented in a subclass to receive keyboard focus events (focus lost) for the widget. The events is passed in the event parameter.

The default implementation updates the widget (except for windows that do not specify a focusPolicy ()).

See also focusInEvent (), setFocusPolicy (), keyPressEvent (), keyReleaseEvent (), event (), and QFocusEvent .

`[protected]` bool QWidget:: focusPreviousChild ()

Finds a new widget to give the keyboard focus to, as appropriate for Shift+Tab , and returns true if it can find a new widget, or false if it can't.

See also focusNextChild ().

QWidget *QWidget:: focusProxy () const

Returns the focus proxy, or nullptr if there is no focus proxy.

See also setFocusProxy ().

QWidget *QWidget:: focusWidget () const

Returns the last child of this widget that setFocus had been called on. For top level widgets this is the widget that will get focus in case this window gets activated

This is not the same as QApplication::focusWidget (), which returns the focus widget in the currently active window.

QFontInfo QWidget:: fontInfo () const

Returns the font info for the widget's current font. Equivalent to QFontInfo(widget->font()) .

See also font (), fontMetrics (), and setFont ().

QFontMetrics QWidget:: fontMetrics () const

Returns the font metrics for the widget's current font. Equivalent to QFontMetrics(widget->font()) .

See also font (), fontInfo (), and setFont ().

QPalette::ColorRole QWidget:: foregroundRole () const

Returns the foreground role.

The foreground role defines the color from the widget's palette that is used to draw the foreground.

If no explicit foreground role is set, the function returns a role that contrasts with the background role.

See also setForegroundRole () and backgroundRole ().

`[invokable]` QPixmap QWidget:: grab (const QRect & rectangle = QRect(QPoint(0, 0), QSize(-1, -1)))

Renders the widget into a pixmap restricted by the given rectangle . If the widget has any children, then they are also painted in the appropriate positions.

If a rectangle with an invalid size is specified (the default), the entire widget is painted.

Note: This function can be invoked via the meta-object system and from QML. See Q_INVOKABLE .

See also render () and QPixmap .

void QWidget:: grabGesture ( Qt::GestureType gesture , Qt::GestureFlags flags = Qt::GestureFlags())

Subscribes the widget to a given gesture with specific flags .

void QWidget:: grabKeyboard ()

Grabs the keyboard input.

This widget receives all keyboard events until releaseKeyboard () is called; other widgets get no keyboard events at all. Mouse events are not affected. Use grabMouse () if you want to grab that.

The focus widget is not affected, except that it doesn't receive any keyboard events. setFocus () moves the focus as usual, but the new focus widget receives keyboard events only after releaseKeyboard () is called.

If a different widget is currently grabbing keyboard input, that widget's grab is released first.

See also releaseKeyboard (), grabMouse (), releaseMouse (), and focusWidget ().

void QWidget:: grabMouse ()

Grabs the mouse input.

This widget receives all mouse events until releaseMouse () is called; other widgets get no mouse events at all. Keyboard events are not affected. Use grabKeyboard () if you want to grab that.

Warning: Bugs in mouse-grabbing applications very often lock the terminal. Use this function with extreme caution, and consider using the -nograb command line option while debugging.

It is seldom necessary to grab the mouse when using Qt, as Qt grabs and releases it sensibly. In particular, Qt grabs the mouse when a mouse button is pressed and keeps it until the last button is released.

Note: Only visible widgets can grab mouse input. If isVisible () returns false for a widget, that widget cannot call grabMouse().

Note: On Windows, grabMouse() only works when the mouse is inside a window owned by the process. On macOS, grabMouse() only works when the mouse is inside the frame of that widget.

See also releaseMouse (), grabKeyboard (), and releaseKeyboard ().

void QWidget:: grabMouse (const QCursor & cursor )

Grabs the mouse input and changes the cursor shape.

The cursor will assume shape cursor (for as long as the mouse focus is grabbed) and this widget will be the only one to receive mouse events until releaseMouse () is called().

Warning: Grabbing the mouse might lock the terminal.

Note: See the note in QWidget::grabMouse ().

This function overloads QWidget::grabMouse ().

See also releaseMouse (), grabKeyboard (), releaseKeyboard (), and setCursor ().

int QWidget:: grabShortcut (const QKeySequence & key , Qt::ShortcutContext context = Qt::WindowShortcut)

Adds a shortcut to Qt's shortcut system that watches for the given key sequence in the given context . If the context is Qt::ApplicationShortcut , the shortcut applies to the application as a whole. Otherwise, it is either local to this widget, Qt::WidgetShortcut , or to the window itself, Qt::WindowShortcut .

If the same key sequence has been grabbed by several widgets, when the key sequence occurs a QEvent::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.

See also releaseShortcut () and setShortcutEnabled ().

QGraphicsEffect *QWidget:: graphicsEffect () const

The graphicsEffect function returns a pointer to the widget's graphics effect.

If the widget has no graphics effect, nullptr is returned.

See also setGraphicsEffect ().

QGraphicsProxyWidget *QWidget:: graphicsProxyWidget () const

Returns the proxy widget for the corresponding embedded widget in a graphics view; otherwise returns nullptr .

bool QWidget:: hasEditFocus () const

Returns true if this widget currently has edit focus; otherwise false.

This feature is only available in Qt for Embedded Linux.

`[virtual]` bool QWidget:: hasHeightForWidth () const

Returns true if the widget's preferred height depends on its width; otherwise returns false .

`[virtual]` int QWidget:: heightForWidth ( int w ) const

Returns the preferred height for this widget, given the width w .

If this widget has a layout, the default implementation returns the layout's preferred height. if there is no layout, the default implementation returns -1 indicating that the preferred height does not depend on the width.

`[slot]` void QWidget:: hide ()

Hides the widget. This function is equivalent to setVisible (false).

Note: If you are working with QDialog or its subclasses and you invoke the show () function after this function, the dialog will be displayed in its original position.

See also hideEvent (), isHidden (), show (), setVisible (), isVisible (), and close ().

`[virtual protected]` void QWidget:: hideEvent ( QHideEvent * event )

This event handler can be reimplemented in a subclass to receive widget hide events. The event is passed in the event parameter.

Hide events are sent to widgets immediately after they have been hidden.

Note: A widget receives spontaneous show and hide events when its mapping status is changed by the window system, e.g. a spontaneous hide event when the user minimizes the window, and a spontaneous show event when the window is restored again. After receiving a spontaneous hide event, a widget is still considered visible in the sense of isVisible ().

See also visible , event (), and QHideEvent .

`[override virtual protected]` void QWidget:: initPainter ( QPainter * painter ) const

Initializes the painter pen, background and font to the same as the given widget's. This function is called automatically when the painter is opened on a QWidget .

`[virtual protected]` void QWidget:: inputMethodEvent ( QInputMethodEvent * event )

This event handler, for event event , can be reimplemented in a subclass to receive Input Method composition events. This handler is called when the state of the input method changes.

Note that when creating custom text editing widgets, the Qt::WA_InputMethodEnabled window attribute must be set explicitly (using the setAttribute () function) in order to receive input method events.

The default implementation calls event->ignore(), which rejects the Input Method event. See the QInputMethodEvent documentation for more details.

See also event () and QInputMethodEvent .

`[virtual]` QVariant QWidget:: inputMethodQuery ( Qt::InputMethodQuery query ) const

This method is only relevant for input widgets. It is used by the input method to query a set of properties of the widget to be able to support complex input method operations as support for surrounding text and reconversions.

query specifies which property is queried.

void QWidget:: insertAction ( QAction * before , QAction * action )

Inserts the action action to this widget's list of actions, before the action before . It appends the action if before is nullptr or before is not a valid action for this widget.

A QWidget should only have one of each action.

See also removeAction (), addAction (), QMenu , contextMenuPolicy , and actions ().

void QWidget:: insertActions ( QAction * before , const QList < QAction > & actions* )

Inserts the actions actions to this widget's list of actions, before the action before . It appends the action if before is nullptr or before is not a valid action for this widget.

A QWidget can have at most one of each action.

See also removeAction (), QMenu , insertAction (), and contextMenuPolicy .

bool QWidget:: isAncestorOf (const QWidget * child ) const

Returns true if this widget is a parent, (or grandparent and so on to any level), of the given child , and both widgets are within the same window; otherwise returns false .

bool QWidget:: isEnabledTo (const QWidget * ancestor ) const

Returns true if this widget would become enabled if ancestor is enabled; otherwise returns false .

This is the case if neither the widget itself nor every parent up to but excluding ancestor has been explicitly disabled.

isEnabledTo(0) returns false if this widget or any if its ancestors was explicitly disabled.

The word ancestor here means a parent widget within the same window.

Therefore isEnabledTo(0) stops at this widget's window, unlike isEnabled () which also takes parent windows into considerations.

See also setEnabled () and enabled .

bool QWidget:: isHidden () const

Returns true if the widget is hidden, otherwise returns false .

A hidden widget will only become visible when show () is called on it. It will not be automatically shown when the parent is shown.

To check visibility, use ! isVisible () instead (notice the exclamation mark).

isHidden() implies ! isVisible (), but a widget can be not visible and not hidden at the same time. This is the case for widgets that are children of widgets that are not visible.

Widgets are hidden if:

they were created as independent windows,

they were created as children of visible widgets,

hide () or setVisible (false) was called.

bool QWidget:: isVisibleTo (const QWidget * ancestor ) const

Returns true if this widget would become visible if ancestor is shown; otherwise returns false .

The true case occurs if neither the widget itself nor any parent up to but excluding ancestor has been explicitly hidden.

This function will still return true if the widget is obscured by other windows on the screen, but could be physically visible if it or they were to be moved.

isVisibleTo(0) is identical to isVisible ().

See also show (), hide (), and isVisible ().

bool QWidget:: isWindow () const

Returns true if the widget is an independent window, otherwise returns false .

A window is a widget that isn't visually the child of any other widget and that usually has a frame and a window title .

A window can have a parent widget . It will then be grouped with its parent and deleted when the parent is deleted, minimized when the parent is minimized etc. If supported by the window manager, it will also have a common taskbar entry with its parent.

QDialog and QMainWindow widgets are by default windows, even if a parent widget is specified in the constructor. This behavior is specified by the Qt::Window flag.

See also window (), isModal (), and parentWidget ().

`[virtual protected]` void QWidget:: keyPressEvent ( QKeyEvent * event )

This event handler, for event event , can be reimplemented in a subclass to receive key press events for the widget.

A widget must call setFocusPolicy () to accept focus initially and have focus in order to receive a key press event.

If you reimplement this handler, it is very important that you call the base class implementation if you do not act upon the key.

The default implementation closes popup widgets if the user presses the key sequence for QKeySequence::Cancel (typically the Escape key). Otherwise the event is ignored, so that the widget's parent can interpret it.

Note that QKeyEvent starts with isAccepted() == true, so you do not need to call QKeyEvent::accept () - just do not call the base class implementation if you act upon the key.

See also keyReleaseEvent (), setFocusPolicy (), focusInEvent (), focusOutEvent (), event (), and QKeyEvent .

`[virtual protected]` void QWidget:: keyReleaseEvent ( QKeyEvent * event )

This event handler, for event event , can be reimplemented in a subclass to receive key release events for the widget.

A widget must accept focus initially and have focus in order to receive a key release event.

If you reimplement this handler, it is very important that you call the base class implementation if you do not act upon the key.

The default implementation ignores the event, so that the widget's parent can interpret it.

Note that QKeyEvent starts with isAccepted() == true, so you do not need to call QKeyEvent::accept () - just do not call the base class implementation if you act upon the key.

See also keyPressEvent (), QEvent::ignore (), setFocusPolicy (), focusInEvent (), focusOutEvent (), event (), and QKeyEvent .

`[static]` QWidget *QWidget:: keyboardGrabber ()

Returns the widget that is currently grabbing the keyboard input.

If no widget in this application is currently grabbing the keyboard, nullptr is returned.

QLayout *QWidget:: layout () const

Returns the layout manager that is installed on this widget, or nullptr if no layout manager is installed.

The layout manager sets the geometry of the widget's children that have been added to the layout.

`[virtual protected]` void QWidget:: leaveEvent ( QEvent * event )

This event handler can be reimplemented in a subclass to receive widget leave events which are passed in the event parameter.

A leave event is sent to the widget when the mouse cursor leaves the widget.

See also enterEvent (), mouseMoveEvent (), and event ().

`[slot]` void QWidget:: lower ()

Lowers the widget to the bottom of the parent widget's stack.

After this call the widget will be visually behind (and therefore obscured by) any overlapping sibling widgets.

See also raise () and stackUnder ().

`[since 6.0]` QPointF QWidget:: mapFrom (const QWidget * parent , const QPointF & pos ) const

Translates the widget coordinate pos from the coordinate system of parent to this widget's coordinate system. The parent must not be nullptr and must be a parent of the calling widget.

See also mapTo (), mapFromParent (), mapFromGlobal (), and underMouse ().

QPoint QWidget:: mapFrom (const QWidget * parent , const QPoint & pos ) const

Translates the global screen coordinate pos to widget coordinates.

`[since 6.0]` QPointF QWidget:: mapFromGlobal (const QPointF & pos ) const

See also mapToGlobal (), mapFrom (), and mapFromParent ().

QPoint QWidget:: mapFromGlobal (const QPoint & pos ) const

Translates the parent widget coordinate pos to widget coordinates.

`[since 6.0]` QPointF QWidget:: mapFromParent (const QPointF & pos ) const

Same as mapFromGlobal () if the widget has no parent.

This function was introduced in Qt 6.0.

See also mapToParent (), mapFrom (), mapFromGlobal (), and underMouse ().

QPoint QWidget:: mapFromParent (const QPoint & pos ) const

Translates the widget coordinate pos to the coordinate system of parent . The parent must not be nullptr and must be a parent of the calling widget.

`[since 6.0]` QPointF QWidget:: mapTo (const QWidget * parent , const QPointF & pos ) const

See also mapFrom (), mapToParent (), mapToGlobal (), and underMouse ().

QPoint QWidget:: mapTo (const QWidget * parent , const QPoint & pos ) const

Translates the widget coordinate pos to global screen coordinates. For example, mapToGlobal(QPointF(0,0)) would give the global coordinates of the top-left pixel of the widget.

`[since 6.0]` QPointF QWidget:: mapToGlobal (const QPointF & pos ) const

See also mapFromGlobal (), mapTo (), and mapToParent ().

QPoint QWidget:: mapToGlobal (const QPoint & pos ) const

Translates the widget coordinate pos to a coordinate in the parent widget.

`[since 6.0]` QPointF QWidget:: mapToParent (const QPointF & pos ) const

Same as mapToGlobal () if the widget has no parent.

This function was introduced in Qt 6.0.

See also mapFromParent (), mapTo (), mapToGlobal (), and underMouse ().

QPoint QWidget:: mapToParent (const QPoint & pos ) const

Returns the mask currently set on a widget. If no mask is set the return value will be an empty region.

QRegion QWidget:: mask () const

See also setMask (), clearMask (), and QRegion::isEmpty ().

`[override virtual protected]` int QWidget:: metric ( QPaintDevice::PaintDeviceMetric m ) const

Reimplements: QPaintDevice::metric (QPaintDevice::PaintDeviceMetric metric) const.

Internal implementation of the virtual QPaintDevice::metric () function.

m is the metric to get.

`[virtual protected]` void QWidget:: mouseDoubleClickEvent ( QMouseEvent * event )

This event handler, for event event , can be reimplemented in a subclass to receive mouse double click events for the widget.

The default implementation calls mousePressEvent ().

Note: The widget will also receive mouse press and mouse release events in addition to the double click event. And if another widget that overlaps this widget disappears in response to press or release events, then this widget will only receive the double click event. It is up to the developer to ensure that the application interprets these events correctly.

See also mousePressEvent (), mouseReleaseEvent (), mouseMoveEvent (), event (), and QMouseEvent .

`[static]` QWidget *QWidget:: mouseGrabber ()

Returns the widget that is currently grabbing the mouse input.

If no widget in this application is currently grabbing the mouse, nullptr is returned.

`[virtual protected]` void QWidget:: mouseMoveEvent ( QMouseEvent * event )

This event handler, for event event , can be reimplemented in a subclass to receive mouse move events for the widget.

If mouse tracking is switched off, mouse move events only occur if a mouse button is pressed while the mouse is being moved. If mouse tracking is switched on, mouse move events occur even if no mouse button is pressed.

QMouseEvent::position () reports the position of the mouse cursor, relative to this widget. For press and release events, the position is usually the same as the position of the last mouse move event, but it might be different if the user's hand shakes. This is a feature of the underlying window system, not Qt.

If you want to show a tooltip immediately, while the mouse is moving (e.g., to get the mouse coordinates with QMouseEvent::position () and show them as a tooltip), you must first enable mouse tracking as described above. Then, to ensure that the tooltip is updated immediately, you must call QToolTip::showText () instead of setToolTip () in your implementation of mouseMoveEvent().

See also setMouseTracking (), mousePressEvent (), mouseReleaseEvent (), mouseDoubleClickEvent (), event (), QMouseEvent , and Scribble Example .

`[virtual protected]` void QWidget:: mousePressEvent ( QMouseEvent * event )

This event handler, for event event , can be reimplemented in a subclass to receive mouse press events for the widget.

If you create new widgets in the mousePressEvent() the mouseReleaseEvent () may not end up where you expect, depending on the underlying window system (or X11 window manager), the widgets' location and maybe more.

The default implementation implements the closing of popup widgets when you click outside the window. For other widget types it does nothing.

See also mouseReleaseEvent (), mouseDoubleClickEvent (), mouseMoveEvent (), event (), QMouseEvent , and Scribble Example .

`[virtual protected]` void QWidget:: mouseReleaseEvent ( QMouseEvent * event )

This event handler, for event event , can be reimplemented in a subclass to receive mouse release events for the widget.

void QWidget:: move ( int x , int y )

This corresponds to move( QPoint ( x , y )).

Note: Setter function for property pos .

This is an overloaded function.

`[virtual protected]` void QWidget:: moveEvent ( QMoveEvent * event )

This event handler can be reimplemented in a subclass to receive widget move events which are passed in the event parameter. When the widget receives this event, it is already at the new position.

The old position is accessible through QMoveEvent::oldPos ().

See also resizeEvent (), event (), move (), and QMoveEvent .

`[virtual protected]` bool QWidget:: nativeEvent (const QByteArray & eventType , void * message , qintptr * result )

This special event handler can be reimplemented in a subclass to receive native platform events identified by eventType which are passed in the message parameter.

In your reimplementation of this function, if you want to stop the event being handled by Qt, return true and set result . The result parameter has meaning only on Windows. If you return false, this native event is passed back to Qt, which translates the event into a Qt event and sends it to the widget.

Note: Events are only delivered to this event handler if the widget has a native window handle.

Note: This function superseedes the event filter functions x11Event(), winEvent() and macEvent() of Qt 4.

QWidget *QWidget:: nativeParentWidget () const

Returns the native parent for this widget, i.e. the next ancestor widget that has a system identifier, or nullptr if it does not have any native parent.

See also effectiveWinId ().

QWidget *QWidget:: nextInFocusChain () const

Returns the next widget in this widget's focus chain.

See also previousInFocusChain ().

void QWidget:: overrideWindowFlags ( Qt::WindowFlags flags )

Sets the window flags for the widget to flags , without telling the window system.

Warning: Do not call this function unless you really know what you're doing.

See also setWindowFlags ().

`[override virtual]` QPaintEngine *QWidget:: paintEngine () const

Reimplements: QPaintDevice::paintEngine () const.

Returns the widget's paint engine.

Note that this function should not be called explicitly by the user, since it's meant for reimplementation purposes only. The function is called by Qt internally, and the default implementation may not always return a valid pointer.

`[virtual protected]` void QWidget:: paintEvent ( QPaintEvent * event )

This event handler can be reimplemented in a subclass to receive paint events passed in event .

A paint event is a request to repaint all or part of a widget. It can happen for one of the following reasons:

repaint () or update () was invoked,

the widget was obscured and has now been uncovered, or

many other reasons.

Many widgets can simply repaint their entire surface when asked to, but some slow widgets need to optimize by painting only the requested region: QPaintEvent::region (). This speed optimization does not change the result, as painting is clipped to that region during event processing. QListView and QTableView do this, for example.

Qt also tries to speed up painting by merging multiple paint events into one. When update () is called several times or the window system sends several paint events, Qt merges these events into one event with a larger region (see QRegion::united ()). The repaint () function does not permit this optimization, so we suggest using update () whenever possible.

When the paint event occurs, the update region has normally been erased, so you are painting on the widget's background.

The background can be set using setBackgroundRole () and setPalette ().

Since Qt 4.0, QWidget automatically double-buffers its painting, so there is no need to write double-buffering code in paintEvent() to avoid flicker.

Note: Generally, you should refrain from calling update () or repaint () inside a paintEvent(). For example, calling update () or repaint () on children inside a paintEvent() results in undefined behavior; the child may or may not get a paint event.

Warning: If you are using a custom paint engine without Qt's backingstore, Qt::WA_PaintOnScreen must be set. Otherwise, QWidget::paintEngine () will never be called; the backingstore will be used instead.

See also event (), repaint (), update (), QPainter , QPixmap , QPaintEvent , and Analog Clock .

QWidget *QWidget:: parentWidget () const

Returns the parent of this widget, or nullptr if it does not have any parent widget.

QWidget *QWidget:: previousInFocusChain () const

The previousInFocusChain function returns the previous widget in this widget's focus chain.

See also nextInFocusChain ().

`[slot]` void QWidget:: raise ()

Raises this widget to the top of the parent widget's stack.

After this call the widget will be visually in front of any overlapping sibling widgets.

Note: When using activateWindow (), you can call this function to ensure that the window is stacked on top.

See also lower () and stackUnder ().

void QWidget:: releaseKeyboard ()

Releases the keyboard grab.

void QWidget:: releaseMouse ()

Releases the mouse grab.

void QWidget:: releaseShortcut ( int id )

Removes the shortcut with the given id from Qt's shortcut system. The widget will no longer receive QEvent::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.

See also grabShortcut () and setShortcutEnabled ().

void QWidget:: removeAction ( QAction * action )

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

See also insertAction (), actions (), and insertAction ().

void QWidget:: render ( QPaintDevice * target , const QPoint & targetOffset = QPoint(), const QRegion & sourceRegion = QRegion(), QWidget::RenderFlags renderFlags = RenderFlags(DrawWindowBackground | DrawChildren))

Renders the sourceRegion of this widget into the target using renderFlags to determine how to render. Rendering starts at targetOffset in the target . For example:

QPixmap pixmap(widget->size());
widget->render(&pixmap);

If sourceRegion is a null region, this function will use QWidget::rect () as the region, i.e. the entire widget.

Ensure that you call QPainter::end () for the target device's active painter (if any) before rendering. For example:

QPainter painter(this);
...
painter.end();
myWidget->render(this);

Note: To obtain the contents of a QOpenGLWidget , use QOpenGLWidget::grabFramebuffer () instead.

void QWidget:: render ( QPainter * painter , const QPoint & targetOffset = QPoint(), const QRegion & sourceRegion = QRegion(), QWidget::RenderFlags renderFlags = RenderFlags(DrawWindowBackground | DrawChildren))

Renders the widget into the painter 's QPainter::device ().

Transformations and settings applied to the painter will be used when rendering.

Note: The painter must be active. On macOS the widget will be rendered into a QPixmap and then drawn by the painter .

This is an overloaded function.

See also QPainter::device ().

`[slot]` void QWidget:: repaint ()

Repaints the widget directly by calling paintEvent () immediately, unless updates are disabled or the widget is hidden.

We suggest only using repaint() if you need an immediate repaint, for example during animation. In most circumstances update () is better, as it permits Qt to optimize for speed and minimize flicker.

Warning: If you call repaint() in a function which may itself be called from paintEvent (), you may get infinite recursion. The update () function never causes recursion.

Note: This slot is overloaded. To connect to this slot:

// Connect using qOverload:
connect(widget, qOverload<>(&QWidget::repaint),
        receiver, &ReceiverClass::slot);
// Or using a lambda:
connect(widget, qOverload<>(&QWidget::repaint),
        this, []() { /* handle repaint */ });

For more examples and approaches, see connecting to overloaded slots .

See also update (), paintEvent (), and setUpdatesEnabled ().

void QWidget:: repaint (const QRect & rect )

This version repaints a rectangle rect inside the widget.

This version repaints a region rgn inside the widget.

void QWidget:: repaint (const QRegion & rgn )

This version repaints a rectangle ( x , y , w , h ) inside the widget.

void QWidget:: repaint ( int x , int y , int w , int h )

If w is negative, it is replaced with width() - x , and if h is negative, it is replaced width height() - y .