Maximize window maintaining taskbar limits - c++

Question

I want to create a Qt application without the windows title bar (I want to create a customized one).
I've created three buttons for minimizing, maximizing and closing the window. Everything works except for considering that when I maximize the window, application doesn't take into account the taskbar, and the maximized window takes the entire screen, going under the taskbar. A normal maximize command from windows instead maximizes the application window avoiding to go under the taskbar.
If I don't use the Qt::CustomizeWindowHint the window title bar appears, and maximizing behaviour is correct; but if I use this flag, the title bar disappears and the application goes under the window: here you can find two screenshots explaning the behaviour:
With Windows title:
Without Windows title:
As you can see in latter case che "Close" button goes inside the taskbar because the application takes the entire screen.
How can I avoid this behaviour without using windows title bar? I want to recreate the same behaviour as with the window title bar.
SampleWindow.h
#ifndef SAMPLEWINDOW_H_
#define SAMPLEWINDOW_H_
#include <QMainWindow>
#include <QPushButton>
#include <QHBoxLayout>
class SampleWindow : public QMainWindow {
Q_OBJECT
public:
SampleWindow();
virtual ~SampleWindow() = default;
};
#endif // !SAMPLEWINDOW_H_
SampleWindow.cpp
#include "SampleWindow.h"
#include <QCoreApplication>
SampleWindow::SampleWindow() :
QMainWindow() {
// With uncommenting this line the title bar disappears
// but application goes under the taskbar when maximized
//
//setWindowFlags(Qt::CustomizeWindowHint);
auto centralWidget = new QWidget(this);
auto layout = new QHBoxLayout(this);
auto minimizeButton = new QPushButton("Minimize", this);
auto maximizeButton = new QPushButton("Maximize", this);
auto closeButton = new QPushButton("Close", this);
layout->addWidget(minimizeButton);
layout->addWidget(maximizeButton);
layout->addWidget(closeButton);
centralWidget->setLayout(layout);
setCentralWidget(centralWidget);
connect(closeButton, &QPushButton::clicked, [=]() {QCoreApplication::quit();});
connect(minimizeButton, &QPushButton::clicked, this, [=]() {setWindowState(Qt::WindowMinimized);});
connect(maximizeButton, &QPushButton::clicked, this, [=]() {setWindowState(Qt::WindowMaximized);});
}
Main.cpp
#include <QApplication>
#include "SampleWindow.h"
int main(int argc, char* argv[]) {
QApplication app(argc, argv);
SampleWindow mainWindow;
mainWindow.show();
return app.exec();
}

Answer 1

This behavior depends on system. I tested your code on Windows 7 and Linux Mint KDE and behavior was different. In Windows 7 taskbar has hidden and window has filled area of taskbar. In KDE I have noticed that window maximizes correctly (avoids widget panels and not hides them).
However when I try to run code in Windows 10 with compatibility mode, I was able to repeat behavior of Win7 only in compatibility with Windows Vista and older versions.
For Windows 10 I found another solution: you can maximize your window in fullscreen if that suits you:
mainWindow.showFullScreen();
or
setWindowState(Qt::WindowFullScreen);
UPD:
In addition to your solution I found another one:
setGeometry(QApplication::desktop()->availableGeometry().x(),
QApplication::desktop()->availableGeometry().y(),
QApplication::desktop()->availableGeometry().width(),
QApplication::desktop()->availableGeometry().height());

Answer 2

I think that I've found a solution by using this slot when maximize button is clicked:
void SampleWindow::maximize() {
//setWindowState(Qt::WindowFullScreen);
QDesktopWidget *desktop = QApplication::desktop();
QRect desktopGeometry = desktop->availableGeometry();
int desktopHeight = desktopGeometry.height();
int desktopWidth = desktopGeometry.width();
int padx = (frameGeometry().width() - geometry().width()) / 2;
setFixedSize(desktopWidth, desktopHeight);
move(-padx,0);
}
I need to test it more but at the moment the area seems correct.