Question

I’m making a GUI API (for games, not an OS) and would like to implement animated buttons. I’d like to be able to create timed events, but, within the class.
example:

class TextBox
{
   void changeColor(int color);

    void createTimedEvent(func* or something, int ticks);
     void animate()
{

    createTimedEvent(changeColor(red),30);

}

};

So in this example, the timer would call the class instance’s changeColor function, with argument red, after 30 ms. Is there a way to do this?

Basically, a function to call a function, which could be a function from a instancable class, wit n arguments, after a given interval has expired.

The precision of the timer is not a big deal for me.

Thanks

Answer 1

I believe you could make this work portably using Boost.Asio – this is primarily designed for async I/O but I see no reason why the timer code cannot be used in other contexts. See this example for how to kick off a timer which calls back your code after expiry.

The only proviso I noticed is that you have to call ioservice::run in some thread with the ioservice instance you used here, or the callbacks will not happen.

#include <iostream>
#include <boost/asio.hpp>
#include <boost/date_time/posix_time/posix_time.hpp>

void print(const boost::system::error_code& /*e*/)
{
  std::cout << "Hello, world!\n";
}

int main()
{
  boost::asio::io_service io;

  boost::asio::deadline_timer t(io, boost::posix_time::seconds(5));

  t.async_wait(print);

  // ensure we call io.run() from some thread or callbacks will not happen

  // other app logic

  return(0);
}

There is also a discussion of this very topic on MSDN blogs here by the author of the library.