Event Handling

Events are triggered when a user clicks on a button, or closes a window. The WVL supports the following events

mouse_click	is triggered when a user right clicks the mouse
mouse_dblclick	is triggered when a user double clicks the mouse
mouse_down	is triggered when a user presss a button of mouse
mouse_up	is triggered when a user releases the button of mouse
mouse_move	is triggered when a user moves mouse on surface of a widget
resize	is triggered when a user changes a widget's size
key_press	is triggered when a user presses a key
tick	is triggered by timer in a specific interval

Every event can be answered after the event installed, call the make_event to install an event. But an event installation requirs an event answer function, and the event answer function will be called by the WVL as CALLBACK. For example, answering the mouse_click on a form

class MyForm: public wvl::form
{
public:
      MyForm()
      {
            this->make_event<wvl::event::mouse_click>(wvl::bind_mem_fun(this, &MyForm::OnClick));
            this->show();
      }
private:
      void OnClick()      //If you want to get some information of the event, you can use the parametor of the event, if so, you have to define the function as void OnClick(const wvl::event_args& args)
      {
           //When the member function is called, it denotes mouse was clicked on the form.
      }
};

as you see, in fact, the answering function is a functor, and it must have operator(), and the parameter must be const wvl::event_args&.

wvl::bind_mem_fun creates a binder_mem_fun_t, it holds the this pointer and the pointer to the member function.

Not every event can be used on every widget. e.g. the event tick just can be used on timer. Supposing that it is used on another widgets, and it will cause a compilation error that tells you set a wrong event

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