与 OCaml 图形的交互

Question

嘿伙计，我不太了解 OCaml，但我必须使用标准图形模块而不是 lablgtk 编写一个小型 GUI，我想知道它在图形中如何工作以监听按键和鼠标移动等事件，文档对我来说似乎有点神秘，可以给我一个小例子吗？

提前致谢，科林

Answer 1

此代码使用 OCaml 图形模块在图形中显示用户的鼠标位置和按键操作 window:

open Graphics
open Printf

(* Displays mouse position and keys pressed in the graphics window,                                                            
   and exits if q is pressed. *)
let rec loop () =
  let e = wait_next_event [Mouse_motion; Key_pressed] in

  let mouse_description = sprintf "Mouse position: %d,%d" e.mouse_x e.mouse_y in
  let key_description = if e.keypressed then sprintf "Key %c was pressed" e.key else "" in

  clear_graph ();
  moveto 0 100; draw_string key_description;
  moveto 0 0; draw_string mouse_description;

  if e.key <> 'q' then loop () else ()

let () =
  open_graph "";
  loop ();
  close_graph ();

与 OCaml 图形的交互

Interactivity with OCaml Graphics

events

user-interface

ocaml

action