Added support for Empty adjoint plots in bokeh (#1561)

holoviews/core/layout.py

@@ -31,7 +31,7 @@ def __add__(self, obj):
 
 
     def __lshift__(self, other):
-        if isinstance(other, (ViewableElement, NdMapping)):
+        if isinstance(other, (ViewableElement, NdMapping, Empty)):
             return AdjointLayout([self, other])
         elif isinstance(other, AdjointLayout):
             return AdjointLayout(other.data.values()+[self])

holoviews/plotting/bokeh/plot.py

@@ -7,7 +7,8 @@
 from bokeh.models.widgets import Panel, Tabs
 
 from ...core import (OrderedDict, CompositeOverlay, Store, Layout, GridMatrix,
-                     AdjointLayout, NdLayout, Empty, GridSpace, HoloMap, Element)
+                     AdjointLayout, NdLayout, Empty, GridSpace, HoloMap, Element,
+                     Empty)
 from ...core.options import Compositor
 from ...core.util import basestring, wrap_tuple, unique_iterator
 from ...element import Histogram
@@ -61,7 +62,8 @@ def document(self, doc):
         self._document = doc
         if self.subplots:
             for plot in self.subplots.values():
-                plot.document = doc
+                if plot is not None:
+                    plot.document = doc
 
 
     def __init__(self, *args, **params):
@@ -561,7 +563,7 @@ def _create_subplots(self, layout, positions, layout_dimensions, ranges, num=0):
         for pos in positions:
             # Pos will be one of 'main', 'top' or 'right' or None
             element = layout.get(pos, None)
-            if element is None or not element.traverse(lambda x: x, [Element]):
+            if element is None or not element.traverse(lambda x: x, [Element, Empty]):
                 continue
 
             subplot_opts = dict(adjoined=main_plot)
@@ -573,22 +575,27 @@ def _create_subplots(self, layout, positions, layout_dimensions, ranges, num=0):
             if pos != 'main':
                 plot_type = AdjointLayoutPlot.registry.get(vtype, plot_type)
                 if pos == 'right':
-                    yaxis = 'right-bare' if 'bare' in plot_type.yaxis else 'right'
+                    yaxis = 'right-bare' if plot_type and 'bare' in plot_type.yaxis else 'right'
+                    width = plot_type.width if plot_type else 0
                     side_opts = dict(height=main_plot.height, yaxis=yaxis,
-                                     width=plot_type.width, invert_axes=True,
+                                     width=width, invert_axes=True,
                                      labelled=['y'], xticks=1, xaxis=main_plot.xaxis)
                 else:
-                    xaxis = 'top-bare' if 'bare' in plot_type.xaxis else 'top'
+                    xaxis = 'top-bare' if plot_type and 'bare' in plot_type.xaxis else 'top'
+                    height = plot_type.height if plot_type else 0
                     side_opts = dict(width=main_plot.width, xaxis=xaxis,
-                                     height=plot_type.height, labelled=['x'],
+                                     height=height, labelled=['x'],
                                      yticks=1, yaxis=main_plot.yaxis)
 
             # Override the plotopts as required
             # Customize plotopts depending on position.
             plotopts = dict(side_opts, **plotopts)
             plotopts.update(subplot_opts)
 
-            if plot_type is None:
+            if vtype is Empty:
+                subplots[pos] = None
+                continue
+            elif plot_type is None:
                 self.warning("Bokeh plotting class for %s type not found, object will "
                              "not be rendered." % vtype.__name__)
                 continue
@@ -754,13 +761,15 @@ def initialize_plot(self, ranges=None, plots=[]):
         """
         if plots is None: plots = []
         adjoined_plots = []
-        for pos in ['main', 'right', 'top']:
+        for pos in self.view_positions:
             # Pos will be one of 'main', 'top' or 'right' or None
             subplot = self.subplots.get(pos, None)
             # If no view object or empty position, disable the axis
             if subplot:
                 passed_plots = plots  + adjoined_plots
                 adjoined_plots.append(subplot.initialize_plot(ranges=ranges, plots=passed_plots))
+            else:
+                adjoined_plots.append(empty_plot(0, 0))
         self.drawn = True
         if not adjoined_plots: adjoined_plots = [None]
         return adjoined_plots

holoviews/plotting/plot.py

@@ -262,6 +262,8 @@ def traverse(self, fn=None, specs=None, full_breadth=True):
         # Assumes composite objects are iterables
         if hasattr(self, 'subplots') and self.subplots:
             for el in self.subplots.values():
+                if el is None:
+                    continue
                 accumulator += el.traverse(fn, specs, full_breadth)
                 if not full_breadth: break
         return accumulator

tests/testplotinstantiation.py

@@ -14,7 +14,7 @@
 import numpy as np
 from holoviews import (Dimension, Overlay, DynamicMap, Store, Dataset,
                        NdOverlay, GridSpace, HoloMap, Layout, Cycle,
-                       Palette, Element)
+                       Palette, Element, Empty)
 from holoviews.core.util import pd
 from holoviews.element import (Curve, Scatter, Image, VLine, Points,
                                HeatMap, QuadMesh, Spikes, ErrorBars,
@@ -1479,6 +1479,18 @@ def test_shared_axes_disable(self):
         self.assertEqual((x_range.start, x_range.end), (-.5, .5))
         self.assertEqual((y_range.start, y_range.end), (-.5, .5))
 
+    def test_empty_adjoint_plot(self):
+        adjoint = Curve([0,1,1,2,3]) << Empty() << Curve([0,1,1,0,1])
+        plot = bokeh_renderer.get_plot(adjoint)
+        adjoint_plot = plot.subplots[(0, 0)]
+        self.assertEqual(len(adjoint_plot.subplots), 3)
+        column = plot.state.children[1]
+        row1, row2 = column.children
+        self.assertEqual(row1.children[0].plot_height, row1.children[1].plot_height)
+        self.assertEqual(row1.children[1].plot_width, 0)
+        self.assertEqual(row2.children[1].plot_width, 0)
+        self.assertEqual(row2.children[0].plot_height, row2.children[1].plot_height)
+
     def test_layout_shared_source_synced_update(self):
         hmap = HoloMap({i: Dataset({chr(65+j): np.random.rand(i+2)
                                     for j in range(4)}, kdims=['A', 'B', 'C', 'D'])