[VTK] Add axes coordinates to VTK view

examples/reference/panes/VTK.ipynb

@@ -32,6 +32,20 @@
     "* **``orientation_widget``** (bool): A boolean to activate/deactivate the orientation widget in the 3D pane. This widget is clickable and allows to rotate the scene in one of the orthographic projections.\n",
     "* **``object``** (str or object): Can be a string pointing to a local or remote file with a `.vtkjs` extension, or a `vtkRenderWindow` object  \n",
     "* **``serialize_on_instantiation``** (bool): It defines when the serialization of the 3D scene occurs. If set to `True` (default) the scene object is serialized when the panel is created else when the panel is displayed to the screen. This parameter is constant, once set it can't be modified\n",
+    "* **``axes``** (dict): A dictionnary with the parameters of the axes to construct in the 3d view.\n",
+    "    Must contain at least ``xticker``, ``yticker`` and ``zticker``.\n",
+    "    - ``[x|y|z]ticker`` is a dictionary which contains:\n",
+    "        - ``ticks`` (array of numbers) - required. Positions in the scene coordinates\n",
+    "        of the coresponding axe ticks\n",
+    "        - ``labels`` (array of strings) - optional. Label displayed respectively to\n",
+    "        the `ticks` positions.\n",
+    "\n",
+    "        If `labels` are not defined they are infered from the `ticks` array.\n",
+    "    - ``digits``: number of decimal digits when `ticks` are converted to `labels`.\n",
+    "    - ``fontsize``: size in pts of the ticks labels.\n",
+    "    - ``show_grid``: boolean. If true (default) the axes grid is visible.\n",
+    "    - ``grid_opactity``: float between 0-1. Defines the grid opacity.\n",
+    "    - ``axes_opactity``: float between 0-1. Defines the axes lines opacity.\n",
     "___"
    ]
   },
@@ -314,6 +328,36 @@
     "pan = pn.panel(pl.ren_win, sizing_mode='stretch_width', orientation_widget=True)\n",
     "pn.Row(pn.Column(pan, pan.construct_colorbars()), pn.pane.Str(type(pl.ren_win), width=500))"
    ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "## Adding axes to the VTK scene\n",
+    "\n",
+    "Using the `axes` parameter, it is possible to add an axes into the 3d view.\n"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "axes = dict(\n",
+    "    origin = [-5, 5, -2],\n",
+    "    xticker = {'ticks': np.linspace(-5,5,5)},\n",
+    "    yticker = {'ticks': np.linspace(-5,5,5)},\n",
+    "    zticker = {'ticks': np.linspace(-2,2,5), 'labels': [''] + [str(int(item)) for item in np.linspace(-2,2,5)[1:]]},\n",
+    "    fontsize = 12,\n",
+    "    digits = 1,\n",
+    "    grid_opacity = 0.5,\n",
+    "    show_grid=True\n",
+    ")\n",
+    "pan.axes = axes"
+   ]
   }
  ],
  "metadata": {

panel/models/index.ts

@@ -10,5 +10,4 @@ export {State} from "./state"
 export {VegaPlot} from "./vega"
 export {Video} from "./video"
 export {VideoStream} from "./videostream"
-export {VTKPlot} from "./vtk"
-export {VTKVolumePlot} from "./vtkvolume"
+export {VTKAxes, VTKPlot, VTKVolumePlot} from "./vtk"

panel/models/vtk.py

@@ -2,11 +2,37 @@
 """
 Defines custom VTKPlot bokeh model to render VTK objects.
 """
-from bokeh.core.properties import String, Bool, Dict, Any, Override
-from bokeh.models import HTMLBox
+from bokeh.core.properties import (String, Bool, Dict, Any, Override,
+                                   Instance, Int, Float, PositiveInt)
+from bokeh.models import HTMLBox, Model
 
 vtk_cdn = "https://unpkg.com/vtk.js"
 
+
+class VTKAxes(Model):
+    """
+    A Bokeh model for axes
+    """
+
+    xticker = Dict(String, Any)
+
+    yticker = Dict(String, Any)
+
+    zticker = Dict(String, Any)
+
+    origin = Any()
+
+    digits = Int(default=1)
+
+    show_grid = Bool(default=True)
+
+    grid_opacity = Float(default=0.1)
+
+    axes_opacity = Float(default=1)
+
+    fontsize = PositiveInt(default=12)
+
+
 class VTKPlot(HTMLBox):
     """
     A Bokeh model that wraps around a vtk-js library and renders it inside
@@ -24,6 +50,8 @@ class VTKPlot(HTMLBox):
 
     camera = Dict(String, Any)
 
+    axes = Instance(VTKAxes)
+
     enable_keybindings = Bool(default=False)
 
     orientation_widget = Bool(default=False)

panel/models/vtk/index.ts

@@ -0,0 +1,3 @@
+export {VTKPlot} from "./vtk"
+export {VTKVolumePlot} from "./vtkvolume"
+export {VTKAxes} from "./vtkaxes"