captureExt.h

#pragma once
#include "typeDefs3D.h"

bool captureExternalDMD();
void captureDMDWindow(int w, int h, int offsetLeft, int offsetTop);
void processdmdBitMap(int w, int h);
bool capturePUP();
void capturePUPWindow(int w, int h, int offsetLeft, int offsetTop);
void processPUPBitMap(int w, int h);

// ThreadPool implementation from progschj https://github.com/progschj/ThreadPool
#include <vector>
#include <queue>
#include <memory>
#include <thread>
#include <mutex>
#include <condition_variable>
#include <future>
#include <functional>
#include <stdexcept>

class ThreadPool {
public:
   ThreadPool(size_t);
   template<class F, class... Args>
   auto enqueue(F&& f, Args&&... args)
      ->std::future<typename std::result_of<F(Args...)>::type>;
   ~ThreadPool();
private:
   // need to keep track of threads so we can join them
   std::vector< std::thread > workers;
   // the task queue
   std::queue< std::function<void()> > tasks;

   // synchronization
   std::mutex queue_mutex;
   std::condition_variable condition;
   bool stop;
};

// the constructor just launches some amount of workers
inline ThreadPool::ThreadPool(size_t threads)
   : stop(false)
{
   for (size_t i = 0; i < threads; ++i)
      workers.emplace_back(
         [this]
         {
            for (;;)
            {
               std::function<void()> task;

               {
                  std::unique_lock<std::mutex> lock(this->queue_mutex);
                  this->condition.wait(lock,
                     [this] { return this->stop || !this->tasks.empty(); });
                  if (this->stop && this->tasks.empty())
                     return;
                  task = std::move(this->tasks.front());
                  this->tasks.pop();
               }

               task();
            }
         }
         );
}

// add new work item to the pool
template<class F, class... Args>
auto ThreadPool::enqueue(F&& f, Args&&... args)
-> std::future<typename std::result_of<F(Args...)>::type>
{
   using return_type = typename std::result_of<F(Args...)>::type;

   auto task = std::make_shared< std::packaged_task<return_type()> >(
      std::bind(std::forward<F>(f), std::forward<Args>(args)...)
      );

   std::future<return_type> res = task->get_future();
   {
      std::unique_lock<std::mutex> lock(queue_mutex);

      // don't allow enqueueing after stopping the pool
      if (stop)
         throw std::runtime_error("enqueue on stopped ThreadPool");

      tasks.emplace([task]() { (*task)(); });
   }
   condition.notify_one();
   return res;
}

// the destructor joins all threads
inline ThreadPool::~ThreadPool()
{
   {
      std::unique_lock<std::mutex> lock(queue_mutex);
      stop = true;
   }
   condition.notify_all();
   for (std::thread &worker : workers)
      worker.join();
}