QStyle Class

The QStyle class is an abstract base class that encapsulates the look and feel of a GUI. More…

Header	`#include <QStyle>`
CMake	`target_link_libraries(app PRIVATE Nt::Widgets)`
Module	Nt Widgets C++ Classes
Inherits	QObject

List of all members, including inherited members

Public Types

enum	StateFlag
typedef	State
enum	PrimitiveElement
enum	ControlElement
enum	SubElement
enum	PixelMetric
enum	ContentsType

Public Functions

	~QStyle()
virtual void	drawPrimitive(PrimitiveElement element, const QStyleOption *option, QPainter *painter, const QWidget *widget = nullptr) const
virtual void	drawControl(ControlElement element, const QStyleOption *option, QPainter *painter, const QWidget *widget = nullptr) const
virtual QRect	subElementRect(SubElement element, const QStyleOption *option, const QWidget *widget = nullptr) const
virtual int	pixelMetric(PixelMetric metric, const QStyleOption *option = nullptr, const QWidget *widget = nullptr) const
virtual QSize	sizeFromContents(ContentsType type, const QStyleOption *option, const QSize &contentsSize, const QWidget *widget = nullptr) const
virtual QPalette	standardPalette() const

Protected Functions

QStyle()

Detailed Description

Widgets do not draw themselves with fixed colors and sizes; they ask the style. A style draws the primitive elements (frames, panels) and controls (buttons) from a QStyleOption that describes the state and rectangle, and answers questions about sizes. Nt has one style, the default, which is like Qt's Fusion style, and QApplication::setStyle() installs another one.

QStyleOptionButton option;
option.initFrom(button);
option.text = button->text();
button->style()->drawControl(QStyle::CE_PushButton, &option, &painter, button);

Differences from Qt

The element set covers the widgets of Nt: buttons, check and radio buttons, line edits, sliders, progress bars, tabs, combo boxes, spin boxes and group boxes. There are no complex controls (drawComplexControl() and QStyle::ComplexControl), so the slider, combo box, spin box and group box are drawn as control elements with a QStyleOption subclass of their own, and no polish(), standardIcon(), styleHint(), hitTestComplexControl(), style sheets or QStyleFactory.

Member Type Documentation

enum QStyle::ContentsType

This enum names the widgets whose size sizeFromContents() computes.

Constant	Description
`QStyle::CT_PushButton`	A push button.
`QStyle::CT_CheckBox`	A check box.
`QStyle::CT_LineEdit`	A line edit.
`QStyle::CT_RadioButton`	A radio button.
`QStyle::CT_ProgressBar`	A progress bar.
`QStyle::CT_TabBarTab`	A tab of a tab bar.
`QStyle::CT_ComboBox`	A combo box.
`QStyle::CT_SpinBox`	A spin box.
`QStyle::CT_ToolButton`	A tool button with a text.
`QStyle::CT_MenuItem`	An entry of a menu: the size of its text becomes the size of the entry.
`QStyle::CT_MenuBarItem`	A title of a menu bar.

enum QStyle::ControlElement

This enum names the elements that a style draws with drawControl().

Constant	Description
`QStyle::CE_PushButton`	A push button: bevel and label.
`QStyle::CE_PushButtonBevel`	The bevel of a push button.
`QStyle::CE_PushButtonLabel`	The label of a push button.
`QStyle::CE_CheckBox`	A check box: indicator and label.
`QStyle::CE_CheckBoxLabel`	The label of a check box.
`QStyle::CE_RadioButton`	A radio button: indicator and label.
`QStyle::CE_RadioButtonLabel`	The label of a radio button.
`QStyle::CE_Slider`	A slider: groove and handle, described by a QStyleOptionSlider.
`QStyle::CE_ProgressBar`	A progress bar: groove, bar and text, described by a QStyleOptionProgressBar.
`QStyle::CE_TabBarTab`	One tab of a tab bar, described by a QStyleOptionTab.
`QStyle::CE_ComboBox`	A combo box without its popup, described by a QStyleOptionComboBox.
`QStyle::CE_SpinBox`	The frame and buttons of a spin box, described by a QStyleOptionSpinBox.
`QStyle::CE_GroupBox`	A group box: frame and title, described by a QStyleOptionGroupBox.
`QStyle::CE_ScrollBar`	A scroll bar: groove and handle, described by a QStyleOptionSlider.
`QStyle::CE_Header`	One section of a header: background and text, described by a QStyleOptionHeader.
`QStyle::CE_Dial`	A dial: the face, the handle and the notches, described by a QStyleOptionSlider.
`QStyle::CE_Splitter`	The handle of a splitter, which is horizontal if the state has State_Horizontal.
`QStyle::CE_MenuItem`	An entry of a menu, with a QStyleOptionMenuItem.
`QStyle::CE_MenuBarItem`	A title in a menu bar, with a QStyleOptionMenuItem.
`QStyle::CE_MenuBarEmptyArea`	The background of a menu bar.

enum QStyle::PixelMetric

This enum names the sizes that a style provides to pixelMetric().

Constant	Description
`QStyle::PM_ButtonMargin`	The margin between the edge of a button and its label.
`QStyle::PM_DefaultFrameWidth`	The width of the frame of a widget.
`QStyle::PM_IndicatorWidth`	The width of a check box indicator.
`QStyle::PM_IndicatorHeight`	The height of a check box indicator.
`QStyle::PM_CheckBoxLabelSpacing`	The space between a check box indicator and its label.
`QStyle::PM_LayoutLeftMargin`	The default left margin of a layout.
`QStyle::PM_LayoutTopMargin`	The default top margin of a layout.
`QStyle::PM_LayoutRightMargin`	The default right margin of a layout.
`QStyle::PM_LayoutBottomMargin`	The default bottom margin of a layout.
`QStyle::PM_LayoutHorizontalSpacing`	The default horizontal spacing of a layout.
`QStyle::PM_LayoutVerticalSpacing`	The default vertical spacing of a layout.
`QStyle::PM_ExclusiveIndicatorWidth`	The width of a radio button indicator.
`QStyle::PM_ExclusiveIndicatorHeight`	The height of a radio button indicator.
`QStyle::PM_SliderThickness`	The width of a slider across its direction, handle included.
`QStyle::PM_SliderLength`	The length of the handle of a slider.
`QStyle::PM_SpinBoxButtonWidth`	The width of the buttons of a spin box.
`QStyle::PM_ComboBoxArrowWidth`	The width of the part of a combo box that has the arrow.
`QStyle::PM_ScrollBarExtent`	The thickness of a scroll bar: the width of a vertical one, the height of a horizontal one.
`QStyle::PM_ScrollBarSliderMin`	The shortest that the handle of a scroll bar gets.
`QStyle::PM_HeaderMargin`	The space on each side of the text in a section of a header.
`QStyle::PM_HeaderDefaultSectionSizeHorizontal`	The width of a section of a horizontal header, or of a column of a table.
`QStyle::PM_HeaderDefaultSectionSizeVertical`	The height of a section of a vertical header, or of a row of a table.
`QStyle::PM_SplitterWidth`	The width of the handle of a splitter.
`QStyle::PM_MenuBarItemSpacing`	The space between the titles of a menu bar, which is also the space before the first.

enum QStyle::PrimitiveElement

This enum names the elements that a style draws with drawPrimitive().

Constant	Description
`QStyle::PE_Frame`	A generic frame.
`QStyle::PE_FrameFocusRect`	The rectangle that shows the keyboard focus.
`QStyle::PE_PanelButtonCommand`	The background of a push button.
`QStyle::PE_IndicatorCheckBox`	The indicator of a check box.
`QStyle::PE_PanelLineEdit`	The background of a line edit.
`QStyle::PE_FrameLineEdit`	The frame of a line edit.
`QStyle::PE_IndicatorRadioButton`	The indicator of a radio button.
`QStyle::PE_IndicatorArrowUp`	An arrow that points up, as on a spin box button.
`QStyle::PE_IndicatorArrowDown`	An arrow that points down, as on a combo box.
`QStyle::PE_FrameGroupBox`	The frame of a group box.
`QStyle::PE_FrameTabWidget`	The frame around the pages of a tab widget.
`QStyle::PE_PanelTipLabel`	The background and the frame of a tool tip.
`QStyle::PE_IndicatorArrowLeft`	An arrow that points left, as on a tool button.
`QStyle::PE_IndicatorArrowRight`	An arrow that points right, as on a tool button.
`QStyle::PE_PanelStatusBar`	The background of a status bar.
`QStyle::PE_PanelMenu`	The background and the frame of a menu.

typedef QStyle::State

The State type is a typedef for QFlags<StateFlag>. It stores an OR combination of StateFlag values.

enum QStyle::StateFlag

This enum describes the state of an element that is drawn. The State type is a typedef for QFlags<StateFlag>.

Constant	Description
`QStyle::State_None`	Nothing is set.
`QStyle::State_Enabled`	The element is enabled.
`QStyle::State_Raised`	The element is raised: not pressed.
`QStyle::State_Sunken`	The element is pressed.
`QStyle::State_Off`	A checkable element is not checked.
`QStyle::State_On`	A checkable element is checked.
`QStyle::State_HasFocus`	The element has the keyboard focus.
`QStyle::State_Selected`	The element is selected, as the current tab of a tab bar is.
`QStyle::State_MouseOver`	The mouse is over the element.
`QStyle::State_Active`	The window of the element is active.
`QStyle::State_Horizontal`	The element is horizontal, as the handle of a splitter that divides left from right.

enum QStyle::SubElement

This enum names the parts of an element that subElementRect() finds.

Constant	Description
`QStyle::SE_CheckBoxIndicator`	The indicator of a check box.
`QStyle::SE_CheckBoxContents`	The area of a check box that has the label.
`QStyle::SE_PushButtonContents`	The area of a push button that has the label.
`QStyle::SE_RadioButtonIndicator`	The indicator of a radio button.
`QStyle::SE_RadioButtonContents`	The area of a radio button that has the label.
`QStyle::SE_LineEditContents`	The area of a line edit in which the text is drawn.
`QStyle::SE_SliderGroove`	The groove of a slider.
`QStyle::SE_SliderHandle`	The handle of a slider, at the position in the QStyleOptionSlider.
`QStyle::SE_ProgressBarContents`	The area of a progress bar that the bar and the text use.
`QStyle::SE_ComboBoxArrow`	The part of a combo box that has the arrow.
`QStyle::SE_SpinBoxEditField`	The part of a spin box in which the text is edited.
`QStyle::SE_SpinBoxUp`	The button of a spin box that steps up.
`QStyle::SE_SpinBoxDown`	The button of a spin box that steps down.
`QStyle::SE_GroupBoxIndicator`	The check box in the title of a checkable group box.
`QStyle::SE_GroupBoxTitle`	The title of a group box, with the check box if it has one.
`QStyle::SE_GroupBoxContents`	The area inside the frame of a group box.
`QStyle::SE_ScrollBarSlider`	The handle of a scroll bar, from the position, range and page step of a QStyleOptionSlider.

Member Function Documentation

[protected] QStyle::QStyle()

Constructs a style.

[override] QStyle::~QStyle()

Destroys the style.

[virtual] void QStyle::drawControl(ControlElement element, const QStyleOption **option*, QPainter **painter*, const QWidget **widget* = nullptr) const

Draws element as option describes, with painter. widget is the widget that is drawn, and can be nullptr.

[virtual] void QStyle::drawPrimitive(PrimitiveElement element, const QStyleOption **option*, QPainter **painter*, const QWidget **widget* = nullptr) const

Draws element as option describes, with painter. widget is the widget that is drawn, and can be nullptr.

[virtual] int QStyle::pixelMetric(PixelMetric metric, const QStyleOption **option* = nullptr, const QWidget **widget* = nullptr) const

Returns the value of metric, in pixels. option and widget may be nullptr.

[virtual] QSize QStyle::sizeFromContents(ContentsType type, const QStyleOption **option, const QSize &contentsSize*, const QWidget **widget* = nullptr) const

Returns the size that a widget of type needs for contents of contentsSize: the contents plus the space that the style spends on frames and margins. option and widget describe the widget and may be nullptr.

[virtual] QPalette QStyle::standardPalette() const

Returns the palette that the application uses for its widgets when it has not been given one with QApplication::setPalette(). The default is the light palette of QPalette. A style that follows the color scheme of the desktop returns a dark palette when QStyleHints::colorScheme() is Qt::ColorScheme::Dark.

[virtual] QRect QStyle::subElementRect(SubElement element, const QStyleOption **option*, const QWidget **widget* = nullptr) const

Returns the rectangle of element for the widget that option describes. widget is that widget, and may be nullptr.