MiniLibX(3)

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 );

EVENTS

   Both  X-Window  and MacOSX graphical systems are 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  man-
   ual).

   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 parame-
   ters:

     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 mod-
   ified by the MiniLibX. On key and mouse events, additional information is  passed:  keycode
   tells you which key is pressed (X11 : look for the include file "keysymdef.h", MacOS : cre-
   ate a small software and find out by yourself), ( 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 type of events.

The mlx.h include defines 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 (even for MacOSX, for compatibility purposes)

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@ - 2002-2015 - Olivier Crouzet

MiniLibX(3)