Added initial support for circular annotations

pywwt_web/annotation.py

@@ -0,0 +1,54 @@
+import uuid
+from traitlets import Bool, Unicode, Float, HasTraits
+
+# The WWT web control API is described here:
+# https://worldwidetelescope.gitbooks.io/worldwide-telescope-web-control-script-reference/content/
+
+
+class Annotation(HasTraits):
+
+    shape = None
+
+    label = Unicode(help='Contains descriptive text '
+                         'for the annotation').tag(wwt='label')
+
+    opacity = Float(help='Specifies the opacity to be applied to the '
+                         'complete annotation').tag(wwt='opacity')
+
+    hover_label = Bool(help='Specifies whether to render the label '
+                            'if the mouse is hovering over the '
+                            'annotation').tag(wwt='showHoverLabel')
+
+    tag = Unicode(help='Contains a string for use by '
+                       'the web client').tag(wwt='tag')
+
+    def __init__(self, parent=None):
+        super(Annotation, self).__init__()
+        self.parent = parent
+        self.observe(self._on_trait_change, type='change')
+        self.id = str(uuid.uuid4())
+        self.parent._send_msg(event='annotation_create', id=self.id, shape=self.shape)
+
+    def _on_trait_change(self, changed):
+        # This method gets called anytime a trait gets changed. Since this class
+        # gets inherited by the Jupyter widgets class which adds some traits of
+        # its own, we only want to react to changes in traits that have the wwt
+        # metadata attribute (which indicates the name of the corresponding WWT
+        # setting).
+        wwt_name = self.trait_metadata(changed['name'], 'wwt')
+        if wwt_name is not None:
+            self.parent._send_msg(event='annotation_set',
+                                  id=self.id,
+                                  setting=wwt_name,
+                                  value=changed['new'])
+
+
+class Circle(Annotation):
+
+    shape = 'circle'
+
+    def set_center(self, coord):
+        coord_icrs = coord.icrs
+        self.parent._send_msg(event='circle_set_center', id=self.id,
+                              ra=coord_icrs.ra.degree,
+                              dec=coord_icrs.dec.degree)

pywwt_web/core.py

@@ -1,4 +1,10 @@
 from traitlets import Bool, HasTraits
+from astropy import units as u
+
+from .annotation import Circle
+
+# The WWT web control API is described here:
+# https://worldwidetelescope.gitbooks.io/worldwide-telescope-web-control-script-reference/content/
 
 
 class BaseWWTWidget(HasTraits):
@@ -29,7 +35,16 @@ class BaseWWTWidget(HasTraits):
 
     # TODO: need to add more methods here.
 
-    def center_on_coordinates(self, ra, dec, fov, instant=True):
-        # TODO: make this method take SkyCoord objects
+    def center_on_coordinates(self, coord, fov, instant=True):
+        coord_icrs = coord.icrs
         self._send_msg(event='center_on_coordinates',
-                       ra=ra, dec=dec, fov=fov, instant=instant)
+                       ra=coord_icrs.ra.deg,
+                       dec=coord_icrs.dec.deg,
+                       fov=fov.to(u.deg).value,
+                       instant=instant)
+
+    # TODO: need to implement more annotation types
+
+    def create_circle(self):
+        # TODO: could buffer JS call here
+        return Circle(self)

pywwt_web/wwt_json_api.js

@@ -5,6 +5,10 @@
 
 function wwt_apply_json_message(wwt, msg) {
 
+  if (!wwt.hasOwnProperty('annotations')) {
+    wwt.annotations = {};
+  }
+
   switch(msg['event']) {
 
     case 'center_on_coordinates':
@@ -16,6 +20,34 @@ function wwt_apply_json_message(wwt, msg) {
       wwt.settings["set_" + name](msg['value']);
       break;
 
+    case 'annotation_create':
+
+      switch(msg['shape']) {
+        case 'circle':
+          // TODO: check if ID already exists
+          circle = wwt.createCircle();
+          circle.set_id(msg['id']);
+          wwt.addAnnotation(circle);
+          wwt.annotations[msg['id']] = circle;
+      }
+      break;
+
+    case 'annotation_set':
+
+      var name = msg['setting'];
+      // TODO: nice error message if annotation doesn't exist
+      annotation = wwt.annotations[msg['id']];
+      annotation["set_" + name](msg['value']);
+      break;
+
+    case 'circle_set_center':
+
+      var name = msg["setting"];
+      // TODO: nice error message if annotation doesn't exist
+      circle = wwt.annotations[msg['id']];
+      circle.setCenter(msg['ra'], msg['dec']);
+      break;
+
   }
 
 }