Targeted canvas placement

src/ocamlCanvas.ml

@@ -542,7 +542,7 @@ module V1 = struct
     external createOnscreen :
       ?autocommit:bool -> ?decorated:bool -> ?resizeable:bool ->
       ?minimize:bool -> ?maximize:bool -> ?close:bool -> ?title:string ->
-      ?pos:(int * int) -> size:(int * int) -> unit -> t
+      ?target:string -> ?pos:(int * int) -> size:(int * int) -> unit -> t
       = "ml_canvas_create_onscreen" "ml_canvas_create_onscreen_n"
 
     external createOffscreen : size:(int * int) -> unit -> t

src/ocamlCanvas.mli

@@ -766,9 +766,9 @@ module V1 : sig
     val createOnscreen :
       ?autocommit:bool -> ?decorated:bool -> ?resizeable:bool ->
       ?minimize:bool -> ?maximize:bool -> ?close:bool -> ?title:string ->
-      ?pos:(int * int) -> size:(int * int) -> unit -> t
+      ?target:string -> ?pos:(int * int) -> size:(int * int) -> unit -> t
     (** [createOnscreen ?autocommit ?decorated ?resizeable ?minimize
-        ?maximize ?close ?title ?pos ~size ()] creates a windowed
+        ?maximize ?close ?title ?target ?pos ~size()] creates a windowed
         canvas of size [size]. The window title and position can be
         specified using the optional arguments [title] and [pos].
         The window decorations, which are active by default, can
@@ -777,6 +777,9 @@ module V1 : sig
         The [decorated] argument has a higher priority: if set to false,
         all other decoration arguments will be ignored (considered to be
         false), and all decorations will be removed from the window.
+        The [target] option is relevant only for the Javascript backend.
+        It indicates the element id in which the canvas should be placed,
+        default to the html body.
         The [autocommit] option, which is active by default, indicates whether
         the canvas should be automatically presented after each frame event.
         See {!Canvas.commit} for more info on [autocommit].

src/stubs/ml_canvas.c

@@ -673,12 +673,14 @@ ml_canvas_create_onscreen_n(
   value mlMaximize,   /* bool, optional, default = true */
   value mlClose,      /* bool, optional, default = true */
   value mlTitle,      /* string, optional, default = "" */
+  value mlTarget,     /* string, optional */
   value mlPos,        /* (int * int), optional */
   value mlSize,       /* (int * int), non-optional */
   value mlUnit)
 {
   CAMLparam5(mlAutocommit, mlDecorated, mlResizeable, mlMinimize, mlMaximize);
-  CAMLxparam5(mlClose, mlTitle, mlPos, mlSize, mlUnit);
+  CAMLxparam5(mlClose, mlTitle, mlTarget, mlPos, mlSize);
+  CAMLxparam1(mlUnit);
   CAMLlocal1(mlCanvas);
   _ml_canvas_ensure_initialized();
   int32_t width = Int31_val_clip(Field(mlSize, 0));
@@ -708,7 +710,7 @@ ml_canvas_create_onscreen_n(
   CAMLreturn(mlCanvas);
 }
 
-BYTECODE_STUB_10(ml_canvas_create_onscreen)
+BYTECODE_STUB_11(ml_canvas_create_onscreen)
 
 CAMLprim value
 ml_canvas_create_offscreen(

src/stubs/ml_canvas.js

@@ -112,7 +112,7 @@ function _header_down_handler(e) {
     _move.target = e.target.canvas.frame;
     _move.prev_x = e.pageX;
     _move.prev_y = e.pageY;
-    document.body.insertBefore(_move.target, null);
+    e.target.canvas.target.insertBefore(_move.target, null);
   }
   return false;
 }
@@ -123,7 +123,7 @@ function _header_down_handler(e) {
 function _surface_down_handler(e) {
   if (e.target !== null) {
     _focus = e.target.canvas;
-    document.body.insertBefore(e.target.canvas.frame, null);
+    e.target.canvas.target.insertBefore(e.target.canvas.frame, null);
     var evt = [EVENT_TAG.BUTTON_ACTION,
                [0, e.target.canvas,
                 caml_int64_of_float(e.timeStamp * 1000.0),
@@ -634,8 +634,8 @@ function _ml_canvas_decorate(header, minimize,
 //Requires: _ml_canvas_ensure_initialized, _ml_canvas_valid_canvas_size, _resize, _next_id, _header_down_handler
 //Requires: _surface_down_handler, _up_handler, _move_handler, _ml_canvas_decorate, Optional_bool_val, Optional_val
 //Requires: caml_invalid_argument
-function ml_canvas_create_onscreen(autocmmit, decorated, resizeable, minimize,
-                                   maximize, close, title, pos, size) {
+function ml_canvas_create_onscreen(autocommit, decorated, resizeable, minimize,
+                                   maximize, close, title, target, pos, size) {
 
   _ml_canvas_ensure_initialized();
 
@@ -656,11 +656,17 @@ function ml_canvas_create_onscreen(autocmmit, decorated, resizeable, minimize,
   var maximize = Optional_bool_val(maximize, true);
   var close = Optional_bool_val(close, true);
   var title = Optional_val(title, null);
+  var target = Optional_val(target, null);
+  target = document.getElementById(target);
+  if(target == null) {
+    target = document.body;
+  }
 
   var id = ++_next_id;
 
   var canvas = {
     name: title,
+    target: target,
     frame: null,
     header: null,
     surface: null,
@@ -691,7 +697,7 @@ function ml_canvas_create_onscreen(autocmmit, decorated, resizeable, minimize,
   frame.oncontextmenu = function() { return false; }
   frame.canvas = canvas;
   canvas.frame = frame;
-  document.body.appendChild(frame);
+  target.appendChild(frame);
 
   var header = null;
   if (decorated === true) {