Add json formatter

Which is used right now only by graphics3d

Author: rocky

mathics/builtin/drawing/graphics3d.py

@@ -641,7 +641,10 @@ def boxes_to_mathml(self, leaves=None, **options):
 
         elements._apply_boxscaling(boxscale)
 
-        json_repr = elements.to_json()
+        # FIXME: json is the only thing we can convert MathML into.
+        # Handle other graphics formats.
+        format_fn = lookup_method(elements, "json")
+        json_repr = format_fn(elements, **options)
 
         xmin, xmax, ymin, ymax, zmin, zmax, boxscale = calc_dimensions()
 
@@ -788,12 +791,6 @@ def _apply_boxscaling(self, boxscale):
         for element in self.elements:
             element._apply_boxscaling(boxscale)
 
-    def to_json(self):
-        result = []
-        for element in self.elements:
-            result.extend(element.to_json())
-        return result
-
     def get_style_class(self):
         return Style3D
 
@@ -805,25 +802,6 @@ def init(self, *args, **kwargs):
     def process_option(self, name, value):
         super(Point3DBox, self).process_option(name, value)
 
-    def to_json(self):
-        # TODO: account for point size
-        data = []
-
-        # Tempoary bug fix: default Point color should be black not white
-        face_color = self.face_color
-        if list(face_color.to_rgba()[:3]) == [1, 1, 1]:
-            face_color = RGBColor(components=(0, 0, 0, face_color.to_rgba()[3]))
-
-        for line in self.lines:
-            data.append(
-                {
-                    "type": "point",
-                    "coords": [coords.pos() for coords in line],
-                    "color": face_color.to_rgba(),
-                }
-            )
-        return data
-
     def extent(self):
         result = []
         for line in self.lines:
@@ -845,19 +823,6 @@ def init(self, *args, **kwargs):
     def process_option(self, name, value):
         super(Line3DBox, self).process_option(name, value)
 
-    def to_json(self):
-        # TODO: account for line widths and style
-        data = []
-        for line in self.lines:
-            data.append(
-                {
-                    "type": "line",
-                    "coords": [coords.pos() for coords in line],
-                    "color": self.edge_color.to_rgba(),
-                }
-            )
-        return data
-
     def extent(self):
         result = []
         for line in self.lines:
@@ -884,27 +849,6 @@ def process_option(self, name, value):
         else:
             super(Polygon3DBox, self).process_option(name, value)
 
-    def to_json(self):
-        # TODO: account for line widths and style
-        if self.vertex_colors is None:
-            face_color = self.face_color
-        else:
-            face_color = None
-
-        if face_color is not None:
-            face_color = face_color.to_js()
-
-        data = []
-        for line in self.lines:
-            data.append(
-                {
-                    "type": "polygon",
-                    "coords": [coords.pos() for coords in line],
-                    "faceColor": face_color,
-                }
-            )
-        return data
-
     def extent(self):
         result = []
         for line in self.lines:
@@ -1098,19 +1042,6 @@ def init(self, graphics, style, item):
         self.points = [Coords3D(graphics, pos=point) for point in points]
         self.radius = item.leaves[1].to_python()
 
-    def to_json(self):
-        face_color = self.face_color
-        if face_color is not None:
-            face_color = face_color.to_js()
-        return [
-            {
-                "type": "sphere",
-                "coords": [coords.pos() for coords in self.points],
-                "radius": self.radius,
-                "faceColor": face_color,
-            }
-        ]
-
     def extent(self):
         result = []
         result.extend(

mathics/core/definitions.py

@@ -125,8 +125,11 @@ def __init__(
             self.builtin.update(self.user)
             self.user = {}
             self.clear_cache()
-        import mathics.formatter.svg  # noqa
+
+        # FIXME load dynamically as we do other things
         import mathics.formatter.asy  # noqa
+        import mathics.formatter.json  # noqa
+        import mathics.formatter.svg  # noqa
 
     def load_pymathics_module(self, module, remove_on_quit=True):
         """

mathics/formatter/json.py

@@ -0,0 +1,117 @@
+# -*- coding: utf-8 -*-
+"""
+Format a Mathics object as json
+"""
+
+from mathics.builtin.graphics import RGBColor
+
+from mathics.builtin.drawing.graphics3d import (
+    Graphics3DElements,
+    Line3DBox,
+    Point3DBox,
+    Polygon3DBox,
+    Sphere3DBox,
+)
+
+from mathics.core.formatter import lookup_method, add_conversion_fn
+
+
+def graphics_3D_elements(self, **options):
+    result = []
+    for element in self.elements:
+        format_fn = lookup_method(element, "json")
+        if format_fn is None:
+            result += element.to_json()
+        else:
+            result += format_fn(element)
+
+    # print("### json Graphics3DElements", result)
+    return result
+
+
+add_conversion_fn(Graphics3DElements, graphics_3D_elements)
+
+
+def line_3d_box(self):
+    # TODO: account for line widths and style
+    data = []
+    for line in self.lines:
+        data.append(
+            {
+                "type": "line",
+                "coords": [coords.pos() for coords in line],
+                "color": self.edge_color.to_rgba(),
+            }
+        )
+    # print("### json Line3DBox", data)
+    return data
+
+
+add_conversion_fn(Line3DBox, line_3d_box)
+
+
+def point_3d_box(self):
+    # TODO: account for point size
+    data = []
+
+    # Tempoary bug fix: default Point color should be black not white
+    face_color = self.face_color
+    if list(face_color.to_rgba()[:3]) == [1, 1, 1]:
+        face_color = RGBColor(components=(0, 0, 0, face_color.to_rgba()[3]))
+
+    for line in self.lines:
+        data.append(
+            {
+                "type": "point",
+                "coords": [coords.pos() for coords in line],
+                "color": face_color.to_rgba(),
+            }
+        )
+    # print("### json Point3DBox", data)
+    return data
+
+
+add_conversion_fn(Point3DBox, point_3d_box)
+
+
+def polygon_3d_box(self):
+    # TODO: account for line widths and style
+    if self.vertex_colors is None:
+        face_color = self.face_color
+    else:
+        face_color = None
+
+    if face_color is not None:
+        face_color = face_color.to_js()
+
+    data = []
+    for line in self.lines:
+        data.append(
+            {
+                "type": "polygon",
+                "coords": [coords.pos() for coords in line],
+                "faceColor": face_color,
+            }
+        )
+    # print("### json Polygon3DBox", data)
+    return data
+
+
+add_conversion_fn(Polygon3DBox, polygon_3d_box)
+
+
+def sphere_3d_box(self):
+    face_color = self.face_color
+    if face_color is not None:
+        face_color = face_color.to_js()
+    return [
+        {
+            "type": "sphere",
+            "coords": [coords.pos() for coords in self.points],
+            "radius": self.radius,
+            "faceColor": face_color,
+        }
+    ]
+
+
+add_conversion_fn(Sphere3DBox, sphere_3d_box)