To: lablgtk at math.nagoya-u.ac.jp
Subject: Pixbuf combo box
From: Dmitry Bely <dbely at mail.ru>
Date: Fri, 16 Dec 2005 10:27:07 +0300
Message-ID: <lkylwlh0.fsf at mail.ru>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii

I am quite new to both Gtk and lablgtk, so excuse me if my question is
obvious to the local gurus :-) I am creating a simple image editor with
some custom fuctions. I need to select a brush there. I think of using the
combo box widget filled with pixbufs of the brushes available
(squares/circles of different sizes). But how to do this? I am looking into
combobox.ml demo, but don't understand how to fill empty pixbufs in
(setup_combobox_demo_grid) with something usable. All these cell renderers
etc. don't seems to be self-explaining and quite simple to use.

Here is my first attempt (modified combo box example):

let icon_width = 8
let icon_height = 8

let brush_pixbuf size =
  let x = (icon_width - size) / 2 in
  let y = (icon_height - size) / 2 in
  let pm = new GDraw.pixmap
    ~colormap:(Gdk.Rgb.get_cmap ())
    (Gdk.Pixmap.create ~width:icon_width ~height:icon_height ~depth:32 ()) in
    pm#set_foreground `WHITE;
    pm#rectangle ~x:0 ~y:0 ~width:icon_width ~height:icon_height ~filled:true ();
    pm#set_foreground `BLACK;
    pm#rectangle ~x ~y ~width:size ~height:size ~filled:true ();
    let pb = GdkPixbuf.create ~width:icon_width ~height:icon_height () in
      GdkPixbuf.get_from_drawable ~dest:pb pm#pixmap;
      pb
          
let changed_and_get_active (combo : #GEdit.combo_box) column cb =
  combo#connect#changed
    (fun () ->
      match combo#active_iter with
      | None -> ()
      | Some row -> 
	  let data = combo#model#get ~row ~column in
	  cb data)

let cols = new GTree.column_list
let col_pix: GdkPixbuf.pixbuf GTree.column = cols#add Gobject.Data.gobject

let create_and_fill_model () =
  let liststore = GTree.list_store cols in
  (* Append a row, and fill it with some data *)
  let append pix =
    let row = liststore#append () in
    liststore#set ~row ~column:col_pix pix
  in
  List.iter append [
    (brush_pixbuf 1);
    (brush_pixbuf 4);
    (brush_pixbuf 8);
  ];
  liststore

let setup_combobox packing =
  let tmp = GBin.frame ~label:"GtkComboBox (pixbuf)" ~packing () in
  let box = GPack.vbox ~border_width:5 ~packing:tmp#add () in

  let model = create_and_fill_model () in
  let combo = GEdit.combo_box ~model ~packing:box#pack () in
  let cell = GTree.cell_renderer_pixbuf [] in
    combo#pack cell ;
    combo#set_active 0 ;
    changed_and_get_active combo col_pix (fun id -> prerr_endline "");
  ()

let main () =
  let window = GWindow.window ~border_width:5 () in
  window#connect#destroy GMain.quit ;
  
  let mainbox = GPack.vbox ~spacing:2 ~packing:window#add () in
  setup_combobox mainbox#pack ;
  window#show () ;
  GMain.main ()

let _ = main ()

(* Local Variables: *)
(* compile-command: "ocamlc -I ../src -w s lablgtk.cma gtkInit.cmo combobox.ml" *)
(* End: *)

- don't work as expected.

Maybe you recommend some docs on that? The tutorial seems to cover only
text combo boxes. Or maybe another widget is more adequate for this
purpose?

- Dmitry Bely