Improved bokeh tabs padding

doc/Tutorials/Bokeh_Backend.ipynb

@@ -322,11 +322,11 @@
    },
    "outputs": [],
    "source": [
-    "%%opts Overlay [tabs=True width=600 height=600] RGB [width=600 height=600]\n",
+    "%%opts Overlay [tabs=True] Image [width=400 height=400]\n",
     "x,y = np.mgrid[-50:51, -50:51] * 0.1\n",
     "\n",
     "img = hv.Image(np.sin(x**2+y**2), bounds=(-1,-1,1,1))\n",
-    "img.relabel('Low') * img.clone(img.data*2).relabel('High') + img"
+    "img.relabel('Low') * img.clone(img.data*2).relabel('High')"
    ]
   },
   {

holoviews/plotting/bokeh/element.py

@@ -33,7 +33,7 @@
 from ..plot import GenericElementPlot, GenericOverlayPlot
 from ..util import dynamic_update, get_sources
 from .plot import BokehPlot
-from .util import (mpl_to_bokeh, convert_datetime, update_plot,
+from .util import (mpl_to_bokeh, convert_datetime, update_plot, get_tab_title,
                    bokeh_version, mplcmap_to_palette, py2js_tickformatter)
 
 if bokeh_version >= '0.12':
@@ -1112,20 +1112,17 @@ def initialize_plot(self, ranges=None, plot=None, plots=None):
 
         panels = []
         for key, subplot in self.subplots.items():
+            frame = None
             if self.tabs: subplot.overlaid = False
             child = subplot.initialize_plot(ranges, plot, plots)
+            if isinstance(element, CompositeOverlay):
+                frame = element.get(key, None)
+                subplot.current_frame = frame
             if self.batched:
                 self.handles['plot'] = child
             if self.tabs:
-                if self.hmap.type is Overlay:
-                    title = ' '.join(key)
-                else:
-                    title = ', '.join([d.pprint_value_string(k) for d, k in
-                                       zip(self.hmap.last.kdims, key)])
+                title = get_tab_title(key, frame, self.hmap.last)
                 panels.append(Panel(child=child, title=title))
-            if isinstance(element, CompositeOverlay):
-                frame = element.get(key, None)
-                subplot.current_frame = frame
 
         if self.tabs:
             self.handles['plot'] = Tabs(tabs=panels)

holoviews/plotting/bokeh/plot.py

@@ -532,14 +532,9 @@ def initialize_plot(self, ranges=None):
         if adjoined:
             plots = layout_padding(plots)
 
-        # Determine the most appropriate composite plot type
-        # If the object cannot be displayed in a single layout
-        # it will be split into Tabs, for 1-row or 1-column
-        # Layouts we use the vplot and hplots.
-        # If there is a table and multiple rows and columns
-        # everything will be forced to a vertical layout
+        # Wrap in appropriate layout model
         if self.tabs:
-            panels = [Panel(child=child, title=str(tab_titles.get(r, c)))
+            panels = [Panel(child=child, title=str(tab_titles.get((r, c))))
                       for r, row in enumerate(plots)
                       for c, child in enumerate(row)
                       if child is not None]

holoviews/plotting/bokeh/util.py

@@ -24,6 +24,7 @@
     from bokeh.layouts import WidgetBox
 
 from ...core.options import abbreviated_exception
+from ...core.overlay import Overlay
 
 # Conversion between matplotlib and bokeh markers
 markers = {'s': {'marker': 'square'},
@@ -346,7 +347,7 @@ def update_plot(old, new):
             old_r.data_source.data.update(emptied)
 
 
-def pad_plots(plots, padding=0.85):
+def pad_plots(plots, table_padding=0.85, tabs_padding=1.2):
     """
     Accepts a grid of bokeh plots in form of a list of lists and
     wraps any DataTable or Tabs in a WidgetBox with appropriate
@@ -360,10 +361,11 @@ def pad_plots(plots, padding=0.85):
                 width = np.max([p.width if isinstance(p, DataTable) else
                                 t.child.plot_width for t in p.tabs])
                 for p in p.tabs:
-                    p.width = int(padding*width)
+                    p.width = width
+                width = int(tabs_padding*width)
             elif isinstance(p, DataTable):
                 width = p.width
-                p.width = int(padding*width)
+                p.width = int(table_padding*width)
             elif p:
                 width = p.plot_width
             else:
@@ -402,3 +404,25 @@ def py2js_tickformatter(formatter, msg=''):
     match = re.search('(function \(.*\))', jsfunc )
     return jsfunc[:match.start()] + 'function ()' + jsfunc[match.end():]
 
+
+def get_tab_title(key, frame, overlay):
+    """
+    Computes a title for bokeh tabs from the key in the overlay, the
+    element and the containing (Nd)Overlay.
+    """
+    if isinstance(overlay, Overlay):
+        if frame is not None:
+            title = []
+            if frame.label:
+                title.append(frame.label)
+                if frame.group != frame.params('group').default:
+                    title.append(frame.group)
+            else:
+                title.append(frame.group)
+        else:
+            title = key
+        title = ' '.join(title)
+    else:
+        title = ' | '.join([d.pprint_value_string(k) for d, k in
+                            zip(overlay.kdims, key)])
+    return title