KisGrabKeyboardFocusRecoveryWorkaround Class Reference

Background: For some reason, when using a combination of 'grabKeyboard' and 'releaseKeyboard' (e.g. the screen color sampling facility), the active window loses focus, or at least that is indicated by the change on the windows decorations (title bar, frame, etc.). Actually, the window seems to remain activated/focused regardless of the change on the window decorations. This is probably some bug on Qt/Plasma/X11 (a small and simple standalone test app gives the same results). More...

#include <KisGrabKeyboardFocusRecoveryWorkaround.h>

Classes
class	Private

Public Member Functions
void	recoverFocus ()

Static Public Member Functions
static KisGrabKeyboardFocusRecoveryWorkaround *	instance ()

Private Member Functions
	KisGrabKeyboardFocusRecoveryWorkaround ()

Private Attributes
QScopedPointer< Private >	m_d

Detailed Description

Background: For some reason, when using a combination of 'grabKeyboard' and 'releaseKeyboard' (e.g. the screen color sampling facility), the active window loses focus, or at least that is indicated by the change on the windows decorations (title bar, frame, etc.). Actually, the window seems to remain activated/focused regardless of the change on the window decorations. This is probably some bug on Qt/Plasma/X11 (a small and simple standalone test app gives the same results).

Workaround: This class uses a dummy top-level widget that is shown and closed immediately. This activates the dummy widget and then the previous window is reactivated, effectively restoring the focused look.

Usage: Use 'KisGrabKeyboardFocusRecoveryWorkaround::instance()->recoverFocus() when using a 'grabKeyboard'/'releaseKeyboard' if the top window seems to lose focus. Put that line right before 'releaseKeyboard' to prevent window decorations flickering.

Definition at line 34 of file KisGrabKeyboardFocusRecoveryWorkaround.h.

Constructor & Destructor Documentation

KisGrabKeyboardFocusRecoveryWorkaround()

KisGrabKeyboardFocusRecoveryWorkaround::KisGrabKeyboardFocusRecoveryWorkaround ( )

private

Definition at line 28 of file KisGrabKeyboardFocusRecoveryWorkaround.cpp.

    : m_d(new Private)
{}

Member Function Documentation

instance()

KisGrabKeyboardFocusRecoveryWorkaround * KisGrabKeyboardFocusRecoveryWorkaround::instance ( )

static

Definition at line 32 of file KisGrabKeyboardFocusRecoveryWorkaround.cpp.

{
    static KisGrabKeyboardFocusRecoveryWorkaround *instance_ {nullptr};
    if (!instance_) {
        instance_ = new KisGrabKeyboardFocusRecoveryWorkaround;
    }
    return instance_;
}

References KisGrabKeyboardFocusRecoveryWorkaround().

recoverFocus()

void KisGrabKeyboardFocusRecoveryWorkaround::recoverFocus

(

)

Definition at line 41 of file KisGrabKeyboardFocusRecoveryWorkaround.cpp.

{
#if defined(Q_OS_LINUX) && !defined(Q_OS_ANDROID)
    // Get the top-most window
    QWidget *activeWindow = qApp->activeWindow();
    QWidget *mainWindow = activeWindow;
    // It may be that the active window is some dialog (e.g. the color
    // selector). If the dummy widget is set as a child of that one, it may
    // interfere somehow with the task bar (a new entry may appear on some
    // window managers). So we get the parent window and use that as parent of
    // the dummy widget.
    while (mainWindow->parentWidget()) {
        mainWindow = mainWindow->parentWidget();
    }
    // The window flags have to be set as Qt::Dialog so that the workaround
    // works as expected
    m_d->dummyFocusRecoveryWidget->setParent(mainWindow, Qt::Dialog);
    // Perform the following a couple of times to ensure good results. Doing it
    // only once may fail sometimes for some unknown reason
    for (int i = 0; i < 2; ++i) {
        m_d->dummyFocusRecoveryWidget->show();
        m_d->dummyFocusRecoveryWidget->close();
        // Ensure that the previously activated window is again active. If the
        // active window was a dialog (e.g. the color selector), then the parent
        // window of the dummy widget will be the main window, so the main
        // window may be active at this point
        activeWindow->activateWindow();
    }
#endif
}

References m_d.

Member Data Documentation

m_d

QScopedPointer<Private> KisGrabKeyboardFocusRecoveryWorkaround::m_d

private

Definition at line 43 of file KisGrabKeyboardFocusRecoveryWorkaround.h.

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

• libs/ui/widgets/KisGrabKeyboardFocusRecoveryWorkaround.h
• libs/ui/widgets/KisGrabKeyboardFocusRecoveryWorkaround.cpp