Shows a hidden menu bar while Alt is used, as browsers and file managers do. More...

#include <menubarpeek.h>

Inheritance diagram for MenuBarPeek:

Collaboration diagram for MenuBarPeek:

Public Member Functions
	MenuBarPeek (QMainWindow window, QAction toggle)
	Watch `window` for Alt while its menu bar is hidden.
auto	isPeeking () const -> bool
	Whether the bar is up for a peek rather than by choice.

Protected Member Functions
auto	eventFilter (QObject watched, QEvent event) -> bool override
	Follows Alt, Escape, clicks and focus for the whole application.

Private Member Functions
void	onKeyPress (QObject watched, const QKeyEvent event)
	Handle a key press seen by the application filter.
void	onKeyRelease (const QKeyEvent *event)
	Handle the release of Alt: a second lone tap hides the bar, an Alt+key chord that did not open a menu hides it once no menu is open, and the tap that showed it leaves it up.
auto	inWindow (QObject *watched) const -> bool
	Whether `watched` is a widget that belongs to the main window.
auto	onMenuBar (QObject *watched) const -> bool
	Whether `watched` is the menu bar itself or one of its children, so a click there must not end the peek.
void	show ()
	Show the menu bar and mark the peek as active.
void	hide ()
	End the peek; hides the menu bar unless the "Show menu bar" toggle was checked in the meantime.
void	hideWhenNoMenuIsOpen ()
	hide() on the next event-loop pass, and only if no popup is open and the bar has no active action. Deferred because a menu's aboutToHide also fires when the pointer moves on to the next menu, and Escape is seen before the bar leaves keyboard mode.

Private Attributes
QMainWindow *	m_window
	The main window whose menuBar() is shown and hidden; the parent.
QAction *	m_toggle
	The window's "Show menu bar" action; while checked the bar is up by choice and the peek state is cleared.
bool	m_peeking {false}
	true while the bar is shown because of Alt, not the toggle.
bool	m_altDown {false}
	true between an Alt press in the window and its release (or the window losing activation); filters repeats and propagated copies.
bool	m_altAlone {false}
	true while no other key has been pressed since Alt went down, i.e. the release will be a lone tap rather than a chord.
bool	m_shownByThisPress {false}
	true when the current Alt press is the one that showed the bar, so its release must not hide it again.

Detailed Description

Shows a hidden menu bar while Alt is used, as browsers and file managers do.

Pressing Alt in the window shows the bar, so Alt+F and the other mnemonics open their menus. A lone tap leaves it up until Alt is tapped again, Escape is pressed, the window is clicked or loses focus; after a menu closes, or after an Alt shortcut that was not a menu, it goes again. The stored "Show menu bar" choice is never touched: checking it during a peek keeps the bar.

Definition at line 29 of file menubarpeek.h.

Constructor & Destructor Documentation

◆ MenuBarPeek()

MenuBarPeek::MenuBarPeek	(	QMainWindow *	window,
		QAction *	toggle )

Watch window for Alt while its menu bar is hidden.

Parameters

window	The main window whose menuBar() is shown; also the parent.
toggle	The window's "Show menu bar" action. While it is checked the bar is simply there and Alt does nothing extra.

Definition at line 17 of file menubarpeek.cpp.

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Member Function Documentation

◆ eventFilter()

auto MenuBarPeek::eventFilter	(	QObject *	watched,
		QEvent *	event ) -> bool

overrideprotected

Follows Alt, Escape, clicks and focus for the whole application.

Parameters

watched	The object the event is for.
event	The event; never consumed.

Returns: Always false.

Definition at line 33 of file menubarpeek.cpp.

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◆ hide()

void MenuBarPeek::hide ( )

private

End the peek; hides the menu bar unless the "Show menu bar" toggle was checked in the meantime.

Definition at line 112 of file menubarpeek.cpp.

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◆ hideWhenNoMenuIsOpen()

void MenuBarPeek::hideWhenNoMenuIsOpen ( )

private

hide() on the next event-loop pass, and only if no popup is open and the bar has no active action. Deferred because a menu's aboutToHide also fires when the pointer moves on to the next menu, and Escape is seen before the bar leaves keyboard mode.

Definition at line 121 of file menubarpeek.cpp.

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◆ inWindow()

auto MenuBarPeek::inWindow ( QObject * watched ) const -> bool

nodiscardprivate

Whether watched is a widget that belongs to the main window.

Parameters

watched The object an event was sent to.

Returns: true if it is a widget whose top-level window is m_window.

Definition at line 96 of file menubarpeek.cpp.

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◆ isPeeking()

auto MenuBarPeek::isPeeking ( ) const -> bool

nodiscard

Whether the bar is up for a peek rather than by choice.

Returns: true between the Alt press that showed it and its hiding.

Definition at line 31 of file menubarpeek.cpp.

◆ onKeyPress()

void MenuBarPeek::onKeyPress	(	QObject *	watched,
		const QKeyEvent *	event )

private

Handle a key press seen by the application filter.

A first, non-repeated Alt press inside the window shows the bar when it is hidden; any other key marks the press as "Alt plus something", and Escape during a peek hides the bar. A key event reaches the filter once for every widget it propagates to and again as auto-repeat; m_altDown makes the second sighting a no-op.

Parameters

watched	The object the event was sent to.
event	The key press.

Definition at line 61 of file menubarpeek.cpp.

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◆ onKeyRelease()

void MenuBarPeek::onKeyRelease ( const QKeyEvent * event )

private

Handle the release of Alt: a second lone tap hides the bar, an Alt+key chord that did not open a menu hides it once no menu is open, and the tap that showed it leaves it up.

Parameters

event The key release; anything but a tracked Alt is ignored.

Definition at line 81 of file menubarpeek.cpp.

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◆ onMenuBar()

auto MenuBarPeek::onMenuBar ( QObject * watched ) const -> bool

nodiscardprivate

Whether watched is the menu bar itself or one of its children, so a click there must not end the peek.

Parameters

watched The object a mouse press was sent to.

Returns: true for the menu bar or a descendant of it.

Definition at line 101 of file menubarpeek.cpp.

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◆ show()

void MenuBarPeek::show ( )

private

Show the menu bar and mark the peek as active.

Definition at line 107 of file menubarpeek.cpp.

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Member Data Documentation

◆ m_altAlone

bool MenuBarPeek::m_altAlone {false}

private

true while no other key has been pressed since Alt went down, i.e. the release will be a lone tap rather than a chord.

Definition at line 128 of file menubarpeek.h.

◆ m_altDown

bool MenuBarPeek::m_altDown {false}

private

true between an Alt press in the window and its release (or the window losing activation); filters repeats and propagated copies.

Definition at line 123 of file menubarpeek.h.

◆ m_peeking

bool MenuBarPeek::m_peeking {false}

private

true while the bar is shown because of Alt, not the toggle.

Definition at line 118 of file menubarpeek.h.

◆ m_shownByThisPress

bool MenuBarPeek::m_shownByThisPress {false}

private

true when the current Alt press is the one that showed the bar, so its release must not hide it again.

Definition at line 133 of file menubarpeek.h.

◆ m_toggle

QAction* MenuBarPeek::m_toggle

private

The window's "Show menu bar" action; while checked the bar is up by choice and the peek state is cleared.

Definition at line 116 of file menubarpeek.h.

◆ m_window

QMainWindow* MenuBarPeek::m_window

private

The main window whose menuBar() is shown and hidden; the parent.

Definition at line 111 of file menubarpeek.h.

The documentation for this class was generated from the following files:

src/menubarpeek.h
src/menubarpeek.cpp

Public Member Functions

Protected Member Functions

Private Member Functions

Private Attributes

Detailed Description

Constructor & Destructor Documentation

◆ MenuBarPeek()

Member Function Documentation

◆ eventFilter()

◆ hide()

◆ hideWhenNoMenuIsOpen()

◆ inWindow()

◆ isPeeking()

◆ onKeyPress()

◆ onKeyRelease()

◆ onMenuBar()

◆ show()

Member Data Documentation

◆ m_altAlone

◆ m_altDown

◆ m_peeking

◆ m_shownByThisPress

◆ m_toggle

◆ m_window