Ensure HoloViews plot ranges are merged correctly (#1495)

* Ensure HoloViews plot ranges are merged correctly

* Add test

* Fixed matplotlib bug

* Fixed test

.travis.yml

@@ -1,7 +1,7 @@
 git:
   depth: 100
 
-language: generic
+language: python
 
 os:
   - linux
@@ -18,7 +18,6 @@ addons:
 
 env:
   global:
-    - PYENV_VERSION=3.7
     - CHANS_DEV="-c pyviz/label/dev -c bokeh/label/dev -c conda-forge"
     - CHANS_REL="-c pyviz -c bokeh -c conda-forge"
     - LABELS_DEV="--label dev"

examples/reference/panes/Matplotlib.ipynb

@@ -128,6 +128,20 @@
    "metadata": {},
    "outputs": [],
    "source": [
+    "fig = Figure(figsize=(8, 6))\n",
+    "ax = fig.add_subplot(111)\n",
+    "\n",
+    "dx, dy = 0.05, 0.05\n",
+    "\n",
+    "# generate 2 2d grids for the x & y bounds\n",
+    "y, x = np.mgrid[slice(1, 5 + dy, dy),\n",
+    "                slice(1, 5 + dx, dx)]\n",
+    "\n",
+    "z = np.sin(x)**10 + np.cos(10 + y*x) * np.cos(x)\n",
+    "\n",
+    "cf = ax.contourf(x + dx/2., y + dy/2., z)\n",
+    "fig.colorbar(cf, ax=ax)\n",
+    "\n",
     "pn.pane.Matplotlib(fig, interactive=True, dpi=72)"
    ]
   },

panel/pane/holoviews.py

@@ -12,7 +12,7 @@
 
 import param
 
-from bokeh.models import Spacer as _BkSpacer
+from bokeh.models import Spacer as _BkSpacer, Range1d
 
 from ..io import state, unlocked
 from ..layout import Column, WidgetBox, HSpacer, VSpacer, Row
@@ -276,12 +276,12 @@ def _render(self, doc, comm, root):
         if backend == 'bokeh' and mode != renderer.mode:
             renderer = renderer.instance(mode=mode)
 
+        kwargs = {'margin': self.margin}
         if backend == 'bokeh' or LooseVersion(str(hv.__version__)) >= str('1.13.0'):
-            kwargs = {'doc': doc, 'root': root}
+            kwargs['doc'] = doc
+            kwargs['root'] = root
             if comm:
                 kwargs['comm'] = comm
-        else:
-            kwargs = {}
 
         return renderer.get_plot(self.object, **kwargs)
 
@@ -520,7 +520,7 @@ def link_axes(root_view, root_model):
         return
 
     from holoviews.core.options import Store
-    from holoviews.core.util import unique_iterator
+    from holoviews.core.util import unique_iterator, max_range
     from holoviews.plotting.bokeh.element import ElementPlot
 
     ref = root_model.ref['id']
@@ -548,6 +548,13 @@ def link_axes(root_view, root_model):
 
     for (tag), axes in range_map.items():
         fig, p, ax, axis = axes[0]
+        if isinstance(axis, Range1d):
+            start, end = max_range([
+                (ax[-1].start, ax[-1].end) for ax in axes
+                if isinstance(ax[-1], Range1d)
+            ])
+            axis.start = start
+            axis.end = end
         for fig, p, pax, _ in axes[1:]:
             changed = []
             if  type(ax) is not type(pax):

panel/pane/plot.py

@@ -133,6 +133,8 @@ class Matplotlib(PNG, IPyWidget):
         Automatically adjust the figure size to fit the
         subplots and other artist elements.""")
 
+    _rename = {'object': 'text', 'interactive': None, 'dpi': None,  'tight': None}
+
     _rerender_params = PNG._rerender_params + ['object', 'dpi', 'tight']
 
     @classmethod

panel/tests/pane/test_holoviews.py

@@ -407,6 +407,23 @@ def test_holoviews_linked_axes(document, comm):
     assert p1.y_range is p2.y_range
 
 
+@hv_available
+def test_holoviews_linked_axes_merged_ranges(document, comm):
+    c1 = hv.Curve([1, 2, 3])
+    c2 = hv.Curve([0, 1, 2, 3, 4])
+
+    layout = Row(HoloViews(c1, backend='bokeh'), HoloViews(c2, backend='bokeh'))
+
+    row_model = layout.get_root(document, comm=comm)
+
+    p1, p2 = row_model.select({'type': Figure})
+
+    assert p1.x_range is p2.x_range
+    assert p1.y_range is p2.y_range
+    assert p1.y_range.start == -0.4
+    assert p1.y_range.end == 4.4
+
+
 @hv_available
 def test_holoviews_linked_x_axis(document, comm):
     c1 = hv.Curve([1, 2, 3])