MiniLibX(3)

NAME
MiniLibX - Handle events

SYNOPSYS
int
mlx_loop ( void *mlx_ptr );
int
mlx_key_hook ( void *win_ptr, int (*funct_ptr)(), void *param );
int
mlx_mouse_hook ( void *win_ptr, int (*funct_ptr)(), void *param );
int
mlx_expose_hook ( void *win_ptr, int (*funct_ptr)(), void *param );
int
mlx_loop_hook ( void *mlx_ptr, int (*funct_ptr)(), void *param );

X-WINDOW EVENTS
The X-Window system is bi-directionnal. On one hand, the program sends orders to the screen to display pixels, images, and so on. On the other hand, it can get information from the keyboard and mouse associated to the screen. To do so, the program receives "events" from the keyboard or the mouse.

DESCRIPTION
To receive events, you must use mlx_loop (). This function never returns. It is an infinite loop that waits for an event, and then calls a user-defined function associated with this event. A single parameter is needed, the connection identifier mlx_ptr (see the mlx manual). You can assign different functions to the three following events:
- A key is pressed
- The mouse button is pressed
- A part of the window should be re-drawn (this is called an "expose" event, and it is your program's job to handle it).
Each window can define a different function for the same event. The three functions mlx_key_hook (), mlx_mouse_hook () and mlx_expose_hook () work exactly the same way. funct_ptr is a pointer to the function you want to be called when an event occurs. This assignment is specific to the window defined by the win_ptr identifier. The param adress will be passed to the function everytime it is called, and should be used to store the parameters it might need. The syntax for the mlx_loop_hook () function is identical to the previous ones, but the given function will be called when no event occurs. When it catches an event, the MiniLibX calls the corresponding function with fixed parameters:
  expose_hook(void *param);
  key_hook(int keycode,void *param);
  mouse_hook(int button,int x,int y,void *param);
  loop_hook(void *param);
These function names are arbitrary. They here are used to distinguish parameters according to the event. These functions are NOT part of the MiniLibX. param is the address specified in the mlx_*_hook calls. This address is never used nor modified by the MiniLibX. On key and mouse events, additional information is passed: keycode tells you which key is pressed (look for the X11 include file "keysymdef.h"), ( x , y ) are the coordinates of the mouse click in the window, and button tells you which mouse button was pressed.

GOING FURTHER WITH EVENTS
The MiniLibX provides a much generic access to all X-Window events. The mlx.h include define mlx_hook() in the same manner mlx_*_hook functions work. The event and mask values will be taken from the X11 include file "X.h". See source code of mlx_int_param_event.c to find out how the MiniLibX will call your own function for a specific event.

SEE ALSO
mlx(3), mlx_new_window(3), mlx_pixel_put(3), mlx_new_image(3)

AUTHOR
Copyright ol@ - 2002-2014 - Olivier Crouzet