Factored out functions to find closest matching overlaid Element

holoviews/plotting/bokeh/element.py

@@ -18,6 +18,7 @@
 from ...core import util
 from ...element import RGB
 from ..plot import GenericElementPlot, GenericOverlayPlot
+from ..util import dynamic_update
 from .callbacks import Callbacks
 from .plot import BokehPlot
 from .renderer import old_bokeh
@@ -694,10 +695,18 @@ def update_frame(self, key, ranges=None, element=None):
         for k, subplot in self.subplots.items():
             empty = False
             if isinstance(self.hmap, DynamicMap):
-                el = self.dynamic_update(subplot, k, element, items)
-                empty = el is None
+                idx = dynamic_update(self, subplot, k, element, items)
+                empty = idx is None
+                if empty:
+                    _, el = items.pop(idx)
             subplot.update_frame(key, ranges, element=el, empty=empty)
 
+
+        if isinstance(self.hmap, DynamicMap) and items:
+            raise Exception("Some Elements returned by the dynamic callback "
+                            "were not initialized correctly and could not be "
+                            "rendered.")
+
         if not self.overlaid and not self.tabs:
             self._update_ranges(element, ranges)
             self._update_plot(key, self.handles['plot'], element)

holoviews/plotting/mpl/element.py

@@ -11,6 +11,7 @@
                      CompositeOverlay, Element3D, Columns, NdElement)
 from ...element import Table, ItemTable, Raster
 from ..plot import GenericElementPlot, GenericOverlayPlot
+from ..util import dynamic_update
 from .plot import MPLPlot
 from .util import wrap_formatter
 
@@ -684,9 +685,16 @@ def update_frame(self, key, ranges=None, element=None):
         for k, subplot in self.subplots.items():
             el = element.get(k, None)
             if isinstance(self.hmap, DynamicMap):
-                el = self.dynamic_update(subplot, k, element, items)
+                idx = dynamic_update(self, subplot, k, element, items)
+                if idx is not None:
+                    _, el = items.pop(idx)
             subplot.update_frame(key, ranges, el)
 
+        if isinstance(self.hmap, DynamicMap) and items:
+            raise Exception("Some Elements returned by the dynamic callback "
+                            "were not initialized correctly and could not be "
+                            "rendered.")
+
         self._finalize_axis(key, ranges=ranges)
 
 

holoviews/plotting/plot.py

@@ -734,51 +734,6 @@ def _format_title(self, key, separator='\n'):
             return separator.join([title, dim_title])
 
 
-    def dynamic_update(self, subplot, key, overlay, items):
-        """
-        Function to assign layers in an Overlay to a new plot.
-        """
-        layer = overlay.get(key, None)
-        if layer is None:
-            match_spec = util.get_overlay_spec(self.current_frame,
-                                               util.wrap_tuple(key),
-                                               subplot.current_frame)
-            specs = [(i, util.get_overlay_spec(overlay, util.wrap_tuple(k), el))
-                     for i, (k, el) in enumerate(items)]
-            idx = self.closest_match(match_spec, specs)
-            k, layer = items.pop(idx)
-        return layer
-
-
-    def closest_match(self, match, specs, depth=0):
-        new_specs = []
-        match_lengths = []
-        for i, spec in specs:
-            if spec[0] == match[0]:
-                new_specs.append((i, spec[1:]))
-            else:
-                if util.isnumber(match[0]) and util.isnumber(spec[0]):
-                    match_length = -abs(match[0]-spec[0])
-                elif all(isinstance(s[0], basestring) for s in [spec, match]):
-                    match_length = max(i for i in range(len(match[0]))
-                                       if match[0].startswith(spec[0][:i]))
-                else:
-                    match_length = 0
-                match_lengths.append((i, match_length, spec[0]))
-        if not new_specs:
-            if depth == 0:
-                raise Exception("No plot with matching type found, ensure "
-                                "the first frame of the DynamicMap initializes "
-                                "all required plots.")
-            else:
-                return sorted(match_lengths, key=lambda x: -x[1])[0][0]
-        elif new_specs == 1:
-            return new_specs[0][0]
-        else:
-            depth = depth+1
-            return self.closest_match(match[1:], new_specs, depth)
-
-
 
 class GenericCompositePlot(DimensionedPlot):
 

holoviews/plotting/util.py

@@ -2,7 +2,7 @@
 
 from ..core import (HoloMap, DynamicMap, CompositeOverlay, Layout,
                     GridSpace, NdLayout, Store)
-from ..core.util import match_spec
+from ..core.util import match_spec, is_number, wrap_tuple, get_overlay_spec
 
 
 def displayable(obj):
@@ -159,3 +159,50 @@ def save_frames(obj, filename, fmt=None, backend=None, options=None):
     for i in range(len(plot)):
         plot.update(i)
         renderer.save(plot, '%s_%s' % (filename, i), fmt=fmt, options=options)
+
+
+def dynamic_update(plot, subplot, key, overlay, items):
+    """
+    Given a plot, subplot and dynamically generated (Nd)Overlay
+    find the closest matching Element for that plot.
+    """
+    match_spec = get_overlay_spec(overlay,
+                                  wrap_tuple(key),
+                                  subplot.current_frame)
+    specs = [(i, get_overlay_spec(overlay, wrap_tuple(k), el))
+             for i, (k, el) in enumerate(items)]
+    return closest_match(match_spec, specs)
+
+
+def closest_match(match, specs, depth=0):
+    """
+    Recursively iterates over type, group, label and overlay key,
+    finding the closest matching spec.
+    """
+    new_specs = []
+    match_lengths = []
+    for i, spec in specs:
+        print spec, match, depth
+        if spec[0] == match[0]:
+            new_specs.append((i, spec[1:]))
+        else:
+            if is_number(match[0]) and is_number(spec[0]):
+                match_length = -abs(match[0]-spec[0])
+            elif all(isinstance(s[0], basestring) for s in [spec, match]):
+                match_length = max(i for i in range(len(match[0]))
+                                   if match[0].startswith(spec[0][:i]))
+            else:
+                match_length = 0
+            match_lengths.append((i, match_length, spec[0]))
+
+    if len(new_specs) == 1:
+        return new_specs[0][0]
+    elif new_specs:
+        depth = depth+1
+        return closest_match(match[1:], new_specs, depth)
+    else:
+        if depth == 0 or not match_lengths:
+            return None
+        else:
+            return sorted(match_lengths, key=lambda x: -x[1])[0][0]
+