Expose setting hard navigable bounds

examples/user_guide/Plotting_with_Bokeh.ipynb

@@ -296,6 +296,78 @@
     " img.options(data_aspect=2, frame_width=300).relabel('data_aspect=2')).cols(2)"
    ]
   },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Navigable Bounds\n",
+    "\n",
+    "Users may set the `apply_hard_bounds` option to constrain the navigable range (extent one could zoom or pan to). If `True`, the navigable bounds of the plot will be constrained to the range of the data. Go ahead and try to zoom in a out in the plot below, you should find that you cannot zoom beyond the extents of the data.\n"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "x_values = np.linspace(0, 10, 100)\n",
+    "y_values = np.sin(x_values)\n",
+    "\n",
+    "hv.Curve((x_values, y_values)).opts(apply_hard_bounds=True)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "If `xlim` or `ylim` is set for an element, the navigable bounds of the plot will be set based\n",
+    "on the combined extremes of extents between the data and xlim/ylim ranges. In the plot below, the `xlim` constrains the initial view, but you should be able to pan to the x-range between 0 and 12 - the combined extremes of ranges between the data (0,10) and `xlim` (2,12)."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "x_values = np.linspace(0, 10, 100)\n",
+    "y_values = np.sin(x_values)\n",
+    "\n",
+    "hv.Curve((x_values, y_values)).opts(\n",
+    "    apply_hard_bounds=True,\n",
+    "    xlim=(2, 12),\n",
+    "    )"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "If a dimension range is specified (e.g. with `.redim.range`), this range will be used as the hard bounds, regardless of the data range or xlim/ylim. This is because the dimension range is itended to be an override on the minimum and maximum allowable values for the dimension. Read more in [Annotating your Data](./01-Annotating_Data.ipynb)."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "x_values = np.linspace(0, 10, 100)\n",
+    "y_values = np.sin(x_values)\n",
+    "\n",
+    "hv.Curve((x_values, y_values)).opts(\n",
+    "    apply_hard_bounds=True,\n",
+    ").redim.range(x=(4, 6))"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "In the plot above, you should not be able to navigate beyond the specified dimension ranges of `x` (4, 6). "
+   ]
+  },
   {
    "cell_type": "markdown",
    "metadata": {},

holoviews/plotting/bokeh/element.py

@@ -105,6 +105,11 @@ class ElementPlot(BokehPlot, GenericElementPlot):
     align = param.ObjectSelector(default='start', objects=['start', 'center', 'end'], doc="""
         Alignment (vertical or horizontal) of the plot in a layout.""")
 
+    apply_hard_bounds = param.Boolean(default=False, doc="""
+        If True, the navigable bounds of the plot will be set based
+        on the more extreme of extents between the data or xlim/ylim ranges.
+        If dim ranges are set, the hard bounds will be set to the dim ranges.""")
+
     autorange = param.ObjectSelector(default=None, objects=['x', 'y', None], doc="""
         Whether to auto-range along either the x- or y-axis, i.e.
         when panning or zooming along the orthogonal axis it will
@@ -1894,6 +1899,10 @@ def initialize_plot(self, ranges=None, plot=None, plots=None, source=None):
             if self._subcoord_overlaid:
                 if style_element.label in plot.extra_y_ranges:
                     self.handles['y_range'] = plot.extra_y_ranges.pop(style_element.label)
+
+        if self.apply_hard_bounds:
+            self._apply_hard_bounds(element, ranges)
+
         self.handles['plot'] = plot
 
         if self.autorange:
@@ -1919,6 +1928,29 @@ def initialize_plot(self, ranges=None, plot=None, plots=None, source=None):
 
         return plot
 
+    def _apply_hard_bounds(self, element, ranges):
+        """
+        Apply hard bounds to the x and y ranges of the plot. If xlim/ylim is set, limit the
+        initial viewable range to xlim/ylim, but allow navigation up to the abs max between
+        the data range and xlim/ylim. If dim range is set (e.g. via redim.range), enforce
+        as hard bounds.
+
+        """
+
+        def validate_bound(bound):
+            return bound if util.isfinite(bound) else None
+
+        min_extent_x, min_extent_y, max_extent_x, max_extent_y = map(
+            validate_bound, self.get_extents(element, ranges, range_type='combined', lims_as_soft_ranges=True)
+        )
+
+        def set_bounds(axis, min_extent, max_extent):
+            """Set the bounds for a given axis, using None if both extents are None or identical"""
+            self.handles[axis].bounds = None if min_extent == max_extent else (min_extent, max_extent)
+
+        set_bounds('x_range', min_extent_x, max_extent_x)
+        set_bounds('y_range', min_extent_y, max_extent_y)
+
     def _setup_data_callbacks(self, plot):
         if not self._js_on_data_callbacks:
             return
@@ -2044,6 +2076,9 @@ def update_frame(self, key, ranges=None, plot=None, element=None):
                 cds = self.handles['cds']
                 self._postprocess_hover(renderer, cds)
 
+        if self.apply_hard_bounds:
+            self._apply_hard_bounds(element, ranges)
+
         self._update_glyphs(element, ranges, self.style[self.cyclic_index])
         self._execute_hooks(element)
 

holoviews/plotting/plot.py

@@ -1423,7 +1423,7 @@ def _get_range_extents(self, element, ranges, range_type, xdim, ydim, zdim):
 
         return (x0, y0, x1, y1)
 
-    def get_extents(self, element, ranges, range_type='combined', dimension=None, xdim=None, ydim=None, zdim=None, **kwargs):
+    def get_extents(self, element, ranges, range_type='combined', dimension=None, xdim=None, ydim=None, zdim=None, lims_as_soft_ranges=False, **kwargs):
         """
         Gets the extents for the axes from the current Element. The globally
         computed ranges can optionally override the extents.
@@ -1444,6 +1444,12 @@ def get_extents(self, element, ranges, range_type='combined', dimension=None, xd
 
         This allows Overlay plots to obtain each range and combine them
         appropriately for all the objects in the overlay.
+
+        If lims_as_soft_ranges is set to True, the xlim and ylim will be treated as
+        soft ranges instead of the default case as hard ranges while computing the extents.
+        This is used e.g. when apply_hard_bounds is True and xlim/ylim is set, in which
+        case we limit the initial viewable range to xlim/ylim, but allow navigation up to
+        the abs max between the data range and xlim/ylim.
         """
         num = 6 if (isinstance(self.projection, str) and self.projection == '3d') else 4
         if self.apply_extents and range_type in ('combined', 'extents'):
@@ -1486,8 +1492,15 @@ def get_extents(self, element, ranges, range_type='combined', dimension=None, xd
         else:
             x0, y0, x1, y1 = combined
 
-        x0, x1 = util.dimension_range(x0, x1, self.xlim, (None, None))
-        y0, y1 = util.dimension_range(y0, y1, self.ylim, (None, None))
+        if lims_as_soft_ranges:
+            # run x|ylim through max_range to ensure datetime-dtype matching with ranges
+            xlim_soft_ranges = util.max_range([self.xlim])
+            ylim_soft_ranges = util.max_range([self.ylim])
+            x0, x1 = util.dimension_range(x0, x1, (None, None), xlim_soft_ranges)
+            y0, y1 = util.dimension_range(y0, y1, (None, None), ylim_soft_ranges)
+        else:
+            x0, x1 = util.dimension_range(x0, x1, self.xlim, (None, None))
+            y0, y1 = util.dimension_range(y0, y1, self.ylim, (None, None))
 
         if not self.drawn:
             x_range, y_range = ((y0, y1), (x0, x1)) if self.invert_axes else ((x0, x1), (y0, y1))

holoviews/tests/plotting/bokeh/test_elementplot.py

@@ -3,6 +3,7 @@
 
 import numpy as np
 import panel as pn
+import param
 import pytest
 from bokeh.document import Document
 from bokeh.models import (
@@ -16,7 +17,8 @@
     tools,
 )
 
-from holoviews.core import DynamicMap, HoloMap, NdOverlay
+from holoviews import opts
+from holoviews.core import DynamicMap, HoloMap, NdOverlay, Overlay
 from holoviews.core.util import dt_to_int
 from holoviews.element import Curve, HeatMap, Image, Labels, Scatter
 from holoviews.plotting.util import process_cmap
@@ -993,3 +995,96 @@ def test_clim_percentile(self):
         low, high = plot.ranges[('Image',)]['z']['robust']
         assert low > 0
         assert high < 1
+
+class TestApplyHardBounds(TestBokehPlot):
+    def test_apply_hard_bounds(self):
+        """Test `apply_hard_bounds` with a single element."""
+        x_values = np.linspace(10, 50, 5)
+        y_values = np.array([10, 20, 30, 40, 50])
+        curve = Curve((x_values, y_values)).opts(apply_hard_bounds=True)
+        plot = bokeh_renderer.get_plot(curve)
+        assert plot.handles['x_range'].bounds == (10, 50)
+
+    def test_apply_hard_bounds_overlay(self):
+        """Test `apply_hard_bounds` with an overlay of curves."""
+        x1_values = np.linspace(10, 50, 5)
+        x2_values = np.linspace(10, 90, 5)
+        y_values = np.array([10, 20, 30, 40, 50])
+        curve1 = Curve((x1_values, y_values))
+        curve2 = Curve((x2_values, y_values))
+        overlay = Overlay([curve1, curve2]).opts(opts.Curve(apply_hard_bounds=True))
+        plot = bokeh_renderer.get_plot(overlay)
+        # Check if the large of the data range can be navigated to
+        assert plot.handles['x_range'].bounds == (10, 90)
+
+    def test_apply_hard_bounds_with_xlim(self):
+        """Test `apply_hard_bounds` with `xlim` set. Initial view should be within xlim but allow panning to data range."""
+        x_values = np.linspace(10, 50, 5)
+        y_values = np.array([10, 20, 30, 40, 50])
+        curve = Curve((x_values, y_values)).opts(apply_hard_bounds=True, xlim=(15, 35))
+        plot = bokeh_renderer.get_plot(curve)
+        initial_view_range = (plot.handles['x_range'].start, plot.handles['x_range'].end)
+        assert initial_view_range == (15, 35)
+        # Check if data beyond xlim can be navigated to
+        assert plot.handles['x_range'].bounds == (10, 50)
+
+    def test_apply_hard_bounds_with_redim_range(self):
+        """Test `apply_hard_bounds` with `.redim.range(x=...)`. Hard bounds should strictly apply."""
+        x_values = np.linspace(10, 50, 5)
+        y_values = np.array([10, 20, 30, 40, 50])
+        curve = Curve((x_values, y_values)).redim.range(x=(25, None)).opts(apply_hard_bounds=True)
+        plot = bokeh_renderer.get_plot(curve)
+        # Expected to strictly adhere to any redim.range bounds, otherwise the data range
+        assert (plot.handles['x_range'].start, plot.handles['x_range'].end)  == (25, 50)
+        assert plot.handles['x_range'].bounds == (25, 50)
+
+    def test_apply_hard_bounds_datetime(self):
+        """Test datetime axes with hard bounds."""
+        target_xlim_l = dt.datetime(2020, 1, 3)
+        target_xlim_h = dt.datetime(2020, 1, 7)
+        dates = [dt.datetime(2020, 1, i) for i in range(1, 11)]
+        values = np.linspace(0, 100, 10)
+        curve = Curve((dates, values)).opts(
+            apply_hard_bounds=True,
+            xlim=(target_xlim_l, target_xlim_h)
+        )
+        plot = bokeh_renderer.get_plot(curve)
+        initial_view_range = (dt_to_int(plot.handles['x_range'].start), dt_to_int(plot.handles['x_range'].end))
+        assert initial_view_range == (dt_to_int(target_xlim_l), dt_to_int(target_xlim_h))
+        # Validate navigation bounds include entire data range
+        hard_bounds = (dt_to_int(plot.handles['x_range'].bounds[0]), dt_to_int(plot.handles['x_range'].bounds[1]))
+        assert hard_bounds == (dt_to_int(dt.datetime(2020, 1, 1)), dt_to_int(dt.datetime(2020, 1, 10)))
+
+    def test_dynamic_map_bounds_update(self):
+        """Test that `apply_hard_bounds` applies correctly when DynamicMap is updated."""
+
+        def curve_data(choice):
+            datasets = {
+                'set1': (np.linspace(0, 5, 100), np.random.rand(100)),
+                'set2': (np.linspace(0, 20, 100), np.random.rand(100)),
+            }
+            x, y = datasets[choice]
+            return Curve((x, y))
+
+        ChoiceStream = Stream.define(
+            'Choice',
+            choice=param.ObjectSelector(default='set1', objects=['set1', 'set2'])
+        )
+        choice_stream = ChoiceStream()
+        dmap = DynamicMap(curve_data, kdims=[], streams=[choice_stream])
+        dmap = dmap.opts(opts.Curve(apply_hard_bounds=True, xlim=(2,3), framewise=True))
+        dmap = dmap.redim.values(choice=['set1', 'set2'])
+        plot = bokeh_renderer.get_plot(dmap)
+
+        # Keeping the xlim consistent between updates, and change data range bounds
+        # Initially select 'set1'
+        dmap.event(choice='set1')
+        assert plot.handles['x_range'].start == 2
+        assert plot.handles['x_range'].end == 3
+        assert plot.handles['x_range'].bounds == (0, 5)
+
+        # Update to 'set2'
+        dmap.event(choice='set2')
+        assert plot.handles['x_range'].start == 2
+        assert plot.handles['x_range'].end == 3
+        assert plot.handles['x_range'].bounds == (0, 20)