Trac #22670: Make Three.js work offline redux

The Three.js scripts used by various backends for offline viewing should
be generated by methods in the backends, not in `plot3d/base.pyx`.

Continuation of discussion after #22488 was closed.

URL: https://trac.sagemath.org/22670
Reported by: paulmasson
Ticket author(s): Paul Masson, Andrey Novoseltsev
Reviewer(s): Andrey Novoseltsev, Paul Masson

src/sage/plot/plot3d/base.pyx

@@ -356,49 +356,23 @@ cdef class Graphics3d(SageObject):
 
         EXAMPLES::
 
-            sage: sphere()._rich_repr_threejs()
+            sage: sphere(online=True)._rich_repr_threejs()
             OutputSceneThreejs container
         """
-        options = {}
-        options['aspect_ratio'] = [float(i) for i in kwds.get('aspect_ratio', [1,1,1])]
-        options['axes'] = kwds.get('axes', False)
-        options['axes_labels'] = kwds.get('axes_labels', ['x','y','z'])
-        options['decimals'] = int(kwds.get('decimals', 2))
-        options['frame'] = kwds.get('frame', True)
-        options['online'] = kwds.get('online', False)
+        options = self._process_viewing_options(kwds)
+        # Threejs specific options
+        options.setdefault('axes_labels', ['x','y','z'])
+        options.setdefault('decimals', 2)
+        options.setdefault('online', False)
+        # Normalization of options values for proper JSONing
+        options['aspect_ratio'] = [float(i) for i in options['aspect_ratio']]
+        options['decimals'] = int(options['decimals'])
 
         if not options['frame']:
             options['axes_labels'] = False
 
         from sage.repl.rich_output import get_display_manager
-        backend = get_display_manager()._backend
-        from sage.repl.rich_output.backend_sagenb import BackendSageNB
-        if isinstance(backend, BackendSageNB):
-            options['online'] = True
-
-        if options['online']:
-            scripts = ( """
-<script src="https://cdn.rawgit.com/mrdoob/three.js/r80/build/three.min.js"></script>
-<script src="https://cdn.rawgit.com/mrdoob/three.js/r80/examples/js/controls/OrbitControls.js"></script>
-            """ )
-        else:
-            from sage.repl.rich_output.backend_ipython import BackendIPythonNotebook
-            if isinstance(backend, BackendIPythonNotebook):
-                scripts = ( """
-<script src="/nbextensions/threejs/three.min.js"></script>
-<script src="/nbextensions/threejs/OrbitControls.js"></script>
-<script>
-  if ( !window.THREE ) document.write('\
-<script src="https://cdn.rawgit.com/mrdoob/three.js/r80/build/three.min.js"><\/script>\
-<script src="https://cdn.rawgit.com/mrdoob/three.js/r80/examples/js/controls/OrbitControls.js"><\/script>');
-</script>
-                """ )
-            else:
-                from sage.env import SAGE_SHARE
-                scripts = ( """
-<script src="{0}/threejs/three.min.js"></script>
-<script src="{0}/threejs/OrbitControls.js"></script>
-                """.format( SAGE_SHARE ) )
+        scripts = get_display_manager().threejs_scripts(options['online'])
 
         b = self.bounding_box()
         bounds = '[{{"x":{}, "y":{}, "z":{}}}, {{"x":{}, "y":{}, "z":{}}}]'.format(
@@ -440,13 +414,14 @@ cdef class Graphics3d(SageObject):
         surfaces = '[' + ','.join(surfaces) + ']'
 
         from sage.env import SAGE_EXTCODE
-        filename = os.path.join(SAGE_EXTCODE, 'threejs', 'threejs_template.html')
-        f = open(filename, 'r')
-        html = f.read()
-        f.close()
+        with open(os.path.join(
+                SAGE_EXTCODE, 'threejs', 'threejs_template.html')) as f:
+            html = f.read()
 
         html = html.replace('SAGE_SCRIPTS', scripts)
-        html = html.replace('SAGE_OPTIONS', json.dumps(options))
+        js_options = dict((key, options[key]) for key in
+            ['aspect_ratio', 'axes', 'axes_labels', 'decimals', 'frame'])
+        html = html.replace('SAGE_OPTIONS', json.dumps(js_options))
         html = html.replace('SAGE_BOUNDS', bounds)
         html = html.replace('SAGE_LIGHTS', lights)
         html = html.replace('SAGE_AMBIENT', ambient)

src/sage/repl/rich_output/backend_base.py

@@ -1,9 +1,9 @@
 # -*- encoding: utf-8 -*-
 r"""
-Base class for Backends
+Base Class for Backends
 
 The display backends are the commandline, the SageNB notebook, the
-ipython notebook, the Emacs sage mode, the Sage doctester, .... All of
+IPython notebook, the Emacs sage mode, the Sage doctester, .... All of
 these have different capabilities for what they can display.
 
 To implement a new display backend, you need to subclass

src/sage/repl/rich_output/backend_ipython.py

@@ -396,6 +396,27 @@ def is_in_terminal(self):
         """
         return True
 
+    def threejs_offline_scripts(self):
+        """
+        Three.js scripts for the IPython command line
+
+        OUTPUT:
+
+        String containing script tags
+
+        EXAMPLES::
+
+            sage: from sage.repl.rich_output.backend_ipython import BackendIPythonCommandline
+            sage: backend = BackendIPythonCommandline()
+            sage: backend.threejs_offline_scripts()
+            '...<script ...</script>...'
+        """
+        from sage.env import SAGE_SHARE
+        return """
+<script src="{0}/threejs/three.min.js"></script>
+<script src="{0}/threejs/OrbitControls.js"></script>
+        """.format(SAGE_SHARE)
+
 
 IFRAME_TEMPLATE = \
 """
@@ -554,4 +575,27 @@ def displayhook(self, plain_text, rich_output):
         else:
             raise TypeError('rich_output type not supported')
 
-
+    def threejs_offline_scripts(self):
+        """
+        Three.js scripts for the IPython notebook
+
+        OUTPUT:
+
+        String containing script tags
+
+        EXAMPLES::
+
+            sage: from sage.repl.rich_output.backend_ipython import BackendIPythonNotebook
+            sage: backend = BackendIPythonNotebook()
+            sage: backend.threejs_offline_scripts()
+            '...<script src="/nbextensions/threejs/three.min...<\\/script>...'
+        """
+        from sage.repl.rich_output import get_display_manager
+        CDN_scripts = get_display_manager().threejs_scripts(online=True)
+        return """
+<script src="/nbextensions/threejs/three.min.js"></script>
+<script src="/nbextensions/threejs/OrbitControls.js"></script>
+<script>
+  if ( !window.THREE ) document.write('{}');
+</script>
+        """.format(CDN_scripts.replace('</script>', r'<\/script>'))

src/sage/repl/rich_output/backend_sagenb.py

@@ -452,3 +452,21 @@ def embed_video(self, video_output):
             url='cell://' + filename,
             link_attrs='class="file_link"',
         ))
+
+    def threejs_offline_scripts(self):
+        """
+        Three.js scripts for the Sage notebook
+
+        OUTPUT:
+
+        String containing script tags
+
+        EXAMPLES::
+
+            sage: from sage.repl.rich_output.backend_sagenb import BackendSageNB
+            sage: backend = BackendSageNB()
+            sage: backend.threejs_offline_scripts()
+            '...<script ...</script>...'
+        """
+        from sage.repl.rich_output import get_display_manager
+        return get_display_manager().threejs_scripts(online=True)

src/sage/repl/rich_output/display_manager.py

@@ -713,6 +713,48 @@ def graphics_from_save(self, save_function, save_kwds,
         buf = OutputBuffer.from_file(filename)
         return output_container(buf)
 
+    def threejs_scripts(self, online):
+        """
+        Return Three.js script tags for the current backend.
+
+        INPUT:
+
+        - ``online`` -- Boolean determining script usage context
+
+        OUTPUT:
+
+        String containing script tags
+
+        .. NOTE::
+
+            This base method handles ``online=True`` case only, serving CDN
+            script tags. Location of scripts for offline usage is
+            backend-specific.
+
+        EXAMPLES::
+
+            sage: from sage.repl.rich_output import get_display_manager
+            sage: get_display_manager().threejs_scripts(online=True)
+            '...<script src="https://cdn.rawgit.com/mrdoob/three.js/...'
+            sage: get_display_manager().threejs_scripts(online=False)
+            Traceback (most recent call last):
+            ...
+            ValueError: current backend does not support
+            offline threejs graphics
+        """
+        if online:
+            from sage.misc.package import installed_packages
+            version = installed_packages()['threejs']
+            return """
+<script src="https://cdn.rawgit.com/mrdoob/three.js/{0}/build/three.min.js"></script>
+<script src="https://cdn.rawgit.com/mrdoob/three.js/{0}/examples/js/controls/OrbitControls.js"></script>
+            """.format(version)
+        try:
+            return self._backend.threejs_offline_scripts()
+        except AttributeError:
+            raise ValueError(
+                'current backend does not support offline threejs graphics')
+
     def supported_output(self):
         """
         Return the output container classes that can be used.