(* A demo of how to use the simple widgets *)

open SimpleWidget

(* Create some simple label widgets *)
let l1 = label "Hello"
let l2 = label "World"
(* Compose them horizontally, adding some borders *)
let h =  border (hpair (border l1) (hpair (space (10,10)) (border l2)))

 
(* This paint function draws a fractal tree -- Google "L-systems" for  *)
(* more explanation / inspiration *)
let paint (g:Gctx.t) : unit =
    let gnew = Gctx.set_color g Gctx.green in
    let rec fractal ((x,y):int*int) (angle:int) (len:int) =
        if len <= 1 then () 
        else
            let lf = float_of_int len in
            let af = ((float_of_int angle) *. 3.14159) /. 180.0 in
          let nx = x + (int_of_float (lf *. (cos af))) in
            let ny = y + (int_of_float (lf *. (sin af))) in
            begin 
            Gctx.draw_line gnew (x,y) (nx, ny);
                fractal (nx, ny) (angle + 20) (len - 2);
                fractal (nx, ny) (angle - 10) (len - 1)
            end
    in 
      fractal (75,100) 270 15
        
(* Create a canvas widget that draws a fractal tree *)      
let c = border (canvas (150, 120) paint) 

(* Put h next to c, with some space and more borders, just for fun.*)
let w = border (hpair h (hpair (space (10, 10)) c))

let run () :unit =
	  (* open the window *)
    Graphics.open_graph "";
    let g = Gctx.create () in 
		(* draw the widget *)
		w.repaint g;
		(* infinite loop so we can see the window. *)
		let rec loop () : unit = loop () in
    loop ()

    
;; run ()