Having trouble maximizing my window - It resizes too large

[ComServant]

I want my window to have four different modes:
- Fullscreen
- Maximized without a border (like fullscreen, but the taskbar is still visible)
- Maximized
- Windowed (non-resizable)

Windowed works fine, and maximized without a border works fine, but regular maximized isn't working.

Regular plain-vanilla Maximized is filling up the entire screen including under the taskbar.

Here's a screenshot showing what I mean:

screenshot.png
(editted, to cut down on resolution by cutting out blank space)

I've tried multiple different ways of setting maximized, including:

QWidget::setWindowFlags(Qt::Window);
QWidget::setWindowState(Qt::WindowActive, Qt::Maximized);

QWidget::setWindowFlags(Qt::Window);
QWidget::setWindowState(Qt::WindowActive, Qt::Maximized);

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I also tried manually re-sizing it, and I tried using QWidget::showMaximized().

Here's my current code:

void MainWindow::_recalculateWindowSize()
{
        //Undo any previous minimums and maximums.
        QWidget::setMinimumSize(0, 0);
        QWidget::setMaximumSize(1000000, 1000000);
 
        //Choose what settings to use, depending on WindowMode.
        if(this->windowMode == Engine::WindowMode::Fullscreen)
        {
            QWidget::setWindowFlags(Qt::Window);
            QWidget::resize( qApp->desktop()->size() );
            QWidget::showFullScreen();
        }
        else if(this->windowMode == Engine::WindowMode::Multitask)
        {
            QWidget::setWindowFlags(Qt::Window | Qt::FramelessWindowHint);
 
            QRect desktopGeometry = qApp->desktop()->availableGeometry();
            QWidget::resize(desktopGeometry.size());
            QWidget::move(desktopGeometry.x(), desktopGeometry.y());
 
            QWidget::setWindowState(Qt::WindowActive); //Qt::Maximized
        }
        else if(this->windowMode == Engine::WindowMode::Maximized)
        {
            QWidget::setWindowFlags(Qt::Window);
 
            //QWidget::setGeometry(qApp->desktop()->availableGeometry());
            QWidget::showMaximized();
        }
        else //Engine::WindowMode::Windowed
        {
            WindowSize windowSize = this->_calculateWindowSizeWithEditor(this->requestedWindowSize);
 
            QWidget::setWindowFlags(Qt::Window | Qt::WindowMinMaxButtonsHint);
 
            QWidget::showNormal();
            QWidget::resize(windowSize.ToQSize());
            //QWidget::setFixedSize(windowSize.ToQSize());
 
            QWidget::move(50, 50); //Temp, haven't cent
        }
 
        QWidget::show(); //Have to 'show()' to apply the new setWindowState() state.
        QWidget::grabKeyboard(); //Just incase we accidentally lost focus during the transition.
}

void MainWindow::_recalculateWindowSize()
{
        //Undo any previous minimums and maximums.
        QWidget::setMinimumSize(0, 0);
        QWidget::setMaximumSize(1000000, 1000000);

        //Choose what settings to use, depending on WindowMode.
        if(this->windowMode == Engine::WindowMode::Fullscreen)
        {
            QWidget::setWindowFlags(Qt::Window);
            QWidget::resize( qApp->desktop()->size() );
            QWidget::showFullScreen();
        }
        else if(this->windowMode == Engine::WindowMode::Multitask)
        {
            QWidget::setWindowFlags(Qt::Window | Qt::FramelessWindowHint);

            QRect desktopGeometry = qApp->desktop()->availableGeometry();
            QWidget::resize(desktopGeometry.size());
            QWidget::move(desktopGeometry.x(), desktopGeometry.y());

            QWidget::setWindowState(Qt::WindowActive); //Qt::Maximized
        }
        else if(this->windowMode == Engine::WindowMode::Maximized)
        {
            QWidget::setWindowFlags(Qt::Window);

            //QWidget::setGeometry(qApp->desktop()->availableGeometry());
            QWidget::showMaximized();
        }
        else //Engine::WindowMode::Windowed
        {
            WindowSize windowSize = this->_calculateWindowSizeWithEditor(this->requestedWindowSize);

            QWidget::setWindowFlags(Qt::Window | Qt::WindowMinMaxButtonsHint);

            QWidget::showNormal();
            QWidget::resize(windowSize.ToQSize());
            //QWidget::setFixedSize(windowSize.ToQSize());

            QWidget::move(50, 50); //Temp, haven't cent
        }

        QWidget::show(); //Have to 'show()' to apply the new setWindowState() state.
        QWidget::grabKeyboard(); //Just incase we accidentally lost focus during the transition.
}

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MainWindow private inherits QWidget (but brings QObject into the public interface), and has no parent.
(Note: It's not a QMainWindow, if that matters. I have no QMainWindow, just a parentless QWidget)

Any ideas what I'm doing wrong?

[blaquee]

Hello, quick question concerning the screenshot, is the windows taskbar set to auto hide? sometimes when thats the case the full screen is calculated as the space underneath the taskbar.

[ComServant]

No, it's not set to autohide. If it was set to autohide, I'd like it to fill that taskbar space, but it's not set to that.

Thanks for the good question, though. =)