2D-Grafik-Ausgabe mit Cairo und OCaml

(* OCaml with Cairo bindings. Based on the sample on the Cairo website:
 * http://www.cairographics.org/cairo-ocaml/
 *
 * Compile with:
 *  
 * ocamlopt -I +cairo cairo.cmxa -o cairosample cairosample.ml
 *)

let draw_triangle cr =
    Cairo.set_line_width cr 15. ;
    Cairo.move_to     cr   200.  100. ;
    Cairo.line_to     cr   300.  300. ;
    Cairo.rel_line_to cr (-200.)   0. ;
    Cairo.close_path  cr ;
    Cairo.stroke cr

let create_png filename = 
    let img = Cairo.image_surface_create Cairo.FORMAT_ARGB32 400 400 in
    let cr = Cairo.create img in
    draw_triangle cr;
    Cairo_png.surface_write_to_file img filename 

let create_ps filename = 
    let out = open_out filename in
    let ps = Cairo_ps.surface_create_for_channel out 400. 400. in
    let cr = Cairo.create ps in
    draw_triangle cr;
    Cairo.surface_finish ps;
    close_out out

let create_pdf filename = 
    let out = open_out filename in
    let ps = Cairo_pdf.surface_create_for_channel out 400. 400. in
    let cr = Cairo.create ps in
    draw_triangle cr;
    Cairo.surface_finish ps;
    close_out out

let main = 
    create_png "triangle.png";
    create_ps "triangle.ps";
    create_pdf "triangle.pdf"