SVG graphics in matplotlib shell!

(via cairosvg to convert to PNG)

Author: rocky

mathicsscript/format.py

@@ -2,12 +2,41 @@
 Format Mathics objects
 """
 
-import random
 import math
 import networkx as nx
+import random
+from tempfile import NamedTemporaryFile
+
+try:
+ import matplotlib.pyplot as plt
+except ImportError:
+ plt = None
+
+try:
+ import matplotlib.image as mpimg
+except ImportError:
+ mpimg = None
+
+try:
+ from cairosvg import svg2png
+except ImportError:
+ svg2png = None
 
 
 def format_output(obj, expr, format=None):
+ def eval_boxes(result, fn, obj, **options):
+ try:
+ boxes = fn(evaluation=obj, **options)
+ except BoxError:
+ boxes = None
+ if not hasattr(obj, "seen_box_error"):
+ obj.seen_box_error = True
+ obj.message(
+ "General", "notboxes", Expression("FullForm", result).evaluate(obj)
+ )
+
+ return boxes
+
  if format is None:
  format = obj.format
 
@@ -28,12 +57,20 @@ def format_output(obj, expr, format=None):
  if len(leaves) == 1:
  expr = leaves[0]
  elif expr_type in ("System`Graphics", "System`Plot"):
- result = "-System Graphics-"
- result = Expression("StandardForm", expr)
- result = result.format(obj, "System`MathMLForm")
- # ml_str = result.leaves[0].leaves[0]
- # FIXME: not quite right. Need to parse out strings
- # display_svg(str(ml_str))
+ form_expr = Expression("StandardForm", expr)
+ result = form_expr.format(obj, "System`StandardForm")
+ svg_str = eval_boxes(result, result.boxes_to_svg, obj)
+ if plt:
+ temp_png = NamedTemporaryFile(
+ mode="w+b", suffix=".png", prefix="mathicsscript-"
+ )
+ svg2png(bytestring=svg_str, write_to=temp_png.name)
+ plt.axes().set_axis_off()
+ img = mpimg.imread(temp_png)
+ plt.imshow(img)
+ plt.show()
+ temp_png.close()
+ return expr_type
 
  if format == "text":
  result = expr.format(obj, "System`OutputForm")
@@ -359,7 +396,6 @@ def format_graph(G):
  Format a Graph
  """
  # FIXME handle graphviz as well
- import matplotlib.pyplot as plt
 
  global node_size
  global cached_pair

requirements-extra.txt

@@ -0,0 +1,3 @@
+PyYAML # Used for admin-tools/make-tables.sh to build JSON tables
+PyQT5 # For interactive display of graphs via matplotlib
+cairosvg # For rendering Plots and Graphs as SVGs via matplotlib