Nana example #2

/////////// MainWindow.h

#pragma once
#include <nana/gui.hpp>
#include <nana/threads/pool.hpp>
#include <thread>
#include <iostream>
#include <atomic>

using namespace nana;
class MainWindow : public form
{
public:
	MainWindow();
	~MainWindow();

	static void draw(paint::graphics& graph);
private:
	void mainLoop();
	void wait(unsigned int wait = 0);
	threads::pool pool_;
	std::atomic_bool flag = true;

	static int x;
	static int y;
};

/////////// MainWindow.cpp

#include "MainWindow.h"

int MainWindow::x = 5;
int MainWindow::y = 5;

MainWindow::MainWindow()
{
	caption("Tetris");
	this->events().key_press([&](const nana::arg_keyboard&arg)
	{
	});
	this->events().expose(nana::threads::pool_push(pool_, *this, &MainWindow::mainLoop));
}

MainWindow::~MainWindow()
{
	flag = false;
	pool_.wait_for_finished();
}

void MainWindow::mainLoop()
{
	while (flag)
	{
		x++;
		y++;
		nana::API::refresh_window(*this);
		wait(1000);
	}
}

void MainWindow::wait(unsigned int wait)
{
	std::this_thread::sleep_for(std::chrono::milliseconds{ wait });
}

void MainWindow::draw(paint::graphics& graph)
{
	graph.rectangle(rectangle{ x, y, 50, 50 }, true, colors::red);
	graph.line(point(x, y), point(55, 55), colors::blue);
}

/////////// main.cpp

#include "MainWindow.h"

int main()
{
	MainWindow window;
	drawing dw(window);
	dw.draw(&window.draw);
	dw.update();
	window.show();
	::nana::exec();
}