Re: GnomeCanvas Enumerate Items

I was able to get most of this working using wrap_item. There are a few 
cases that it apparently doesn't handle though. Mainly group, text, 
rich_text, etc, the ones that aren't GnoCanvas.items. Here's the code 
that I have:


type annotated_item =
    Group of GnomeCanvas.group_p GnoCanvas.item (* I'd like this to be 
GnoCanvas.group *)
  | Line of GnoCanvas.line
  | Ellipse of GnoCanvas.ellipse
  | Polygon of GnoCanvas.polygon
  | Rect of GnoCanvas.rect
  | Bpath of GnoCanvas.bpath
  | Unknown
;;

let annotate ent =
  let item = ent#as_item in
  if GnomeCanvas.Types.is_a item GnomeCanvas.Types.ellipse then
    let el = GnoCanvas.wrap_item item GnomeCanvas.Types.ellipse in
    Ellipse el
  else if GnomeCanvas.Types.is_a item GnomeCanvas.Types.line then
    let ln = GnoCanvas.wrap_item item GnomeCanvas.Types.line in
    Line ln
  else if GnomeCanvas.Types.is_a item GnomeCanvas.Types.polygon then
    let pl = GnoCanvas.wrap_item item GnomeCanvas.Types.polygon in
    Polygon pl
  else if GnomeCanvas.Types.is_a item GnomeCanvas.Types.group then
    let gp = GnoCanvas.wrap_item item GnomeCanvas.Types.group in
    Group gp
  else if GnomeCanvas.Types.is_a item GnomeCanvas.Types.rect then
    let rt = GnoCanvas.wrap_item item GnomeCanvas.Types.rect in
    Rect rt
  else if GnomeCanvas.Types.is_a item GnomeCanvas.Types.bpath then
    let bp = GnoCanvas.wrap_item item GnomeCanvas.Types.bpath in
    Bpath bp
  else
    Unknown
;;

Does anyone know of a way to get a GnoCanvas.group rather than a 
GnomeCanvas.group_p GnoCanvas.item when performing the cast?

Thanks.

[email protected] wrote:
> Hello,
>
> I'm working on some graphing code using GnomeCanvas and I need to enumerate all
> of the items in a tree. Something like the following:
>
> let rec enumerate deep root =
>   whitespace deep;
>   match annotate root with
>     Group grp ->
>       print_string "- Group\r\n";
>       List.iter enumerate grp#get_items
>   | Line lne ->
>       print_string "- Line\r\n";
>   | Polygon poly ->
>       print_string "- Polygon\r\n";
>   | ...
>
> This is going to be part of a PostScript writer, so eventually I'll need to get
> the essential information about each of these but right now I'm just working on
> the enumeration part. How would you go about writing the annotate function? Or
> is there an easier way to do this?
>
> Thank you very much.
>
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>
>   

-- 
gregory malecha