Basic introduction, tutorials, tips & tricks.
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);
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.
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 page).
You can assign different functions to the three following events:
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 address 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:
int expose_hook(void *param);
int key_hook(int keycode,void *param);
int mouse_hook(int button,int x,int y,void *param);
int loop_hook(void *param);
These function names are arbitrary. They 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 (X11: look for the include file “keysymdef.h”, MacOS: create 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.
The MiniLibX provides a much more generic access to all type of 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” (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.
The “expose” event is triggered, for example, when the window is brought into focus.
If you register more than one function to an event, only the last function will be called.
The C language provides a way to group data together in a way that allows you to pass it all to a single param.
int mlx_hook(void *win_ptr, int x_event, int x_mask, int (*funct)(), void *param);
x_mask is ignored on MacOSX.
If you look up what’s in “X.h”, you’ll find some really important events.
Mouse movement: x_event = 6, the function will be called like this:
int mouse_move(int x, int y, void *param);
Close button: x_event = 17, the function will be called like this:
int close_window(void *param);
And more, but these are by far the most useful for early projects.
Copyright ol@ - 2002-2015 - Olivier Crouzet
Re-format and spelling corrections by Gontjarow
Additional notes by Gontjarow