fix: fixed thumbnail generation from livecode

Due to the recent changes to livecode, the code to generate svg from
code got broken. Fixed that now.

community/lms/doctype/lms_sketch/livecode.py

@@ -4,23 +4,82 @@ import websocket
 import json
 from .svg import SVG
 
-def livecode_to_svg(livecode_ws_url, code, *, timeout=1):
+# Files to pass to livecode server
+# The same code is part of livecode-canvas.js
+# TODO: generate livecode-canvas.js from this file
+START = '''
+import sketch
+code = open("main.py").read()
+env = dict(sketch.__dict__)
+exec(code, env)
+'''
+
+SKETCH = '''
+import json
+
+def sendmsg(msgtype, function, args):
+  """Sends a message to the frontend.
+
+  The frontend will receive the specified message whenever
+  this function is called. The frontend can decide to some
+  action on each of these messages.
+  """
+  msg = dict(msgtype=msgtype, function=function, args=args)
+  print("--MSG--", json.dumps(msg))
+
+def _draw(func, **kwargs):
+  sendmsg(msgtype="draw", function=func, args=kwargs)
+
+def circle(x, y, d):
+    """Draws a circle of diameter d with center (x, y).
+    """
+    _draw("circle", x=x, y=y, d=d)
+
+def line(x1, y1, x2, y2):
+    """Draws a line from point (x1, y1) to point (x2, y2).
+    """
+    _draw("line", x1=x1, y1=y1, x2=x2, y2=y2)
+
+def rect(x, y, w, h):
+    """Draws a rectangle on the canvas.
+
+    Parameters
+    ----------
+    x: x coordinate of the top-left corner of the rectangle
+    y: y coordinate of the top-left corner of the rectangle
+    w: width of the rectangle
+    h: height of the rectangle
+    """
+    _draw("rect", x=x, y=y, w=w, h=h)
+
+def clear():
+    _draw("clear")
+
+# clear the canvas on start
+clear()
+'''
+
+def livecode_to_svg(livecode_ws_url, code, *, timeout=3):
     """Renders the code as svg.
     """
-    print("livecode_to_svg")
     ws = websocket.WebSocket()
     ws.settimeout(timeout)
     ws.connect(livecode_ws_url)
 
     msg = {
         "msgtype": "exec",
-        "runtime": "python-canvas",
-        "code": code
+        "runtime": "python",
+        "code": code,
+        "files": [
+            {"filename": "start.py", "contents": START},
+            {"filename": "sketch.py", "contents": SKETCH},
+        ],
+        "command": ["python", "start.py"]
     }
     ws.send(json.dumps(msg))
 
     messages = _read_messages(ws)
-    commands = [m['cmd'] for m in messages if m['msgtype'] == 'draw']
+    commands = [m for m in messages if m['msgtype'] == 'draw']
     img = draw_image(commands)
     return img.tostring()
 
@@ -32,17 +91,19 @@ def _read_messages(ws):
             if not msg:
                 break
             messages.append(json.loads(msg))
-    except websocket.WebSocketTimeoutException:
+    except websocket.WebSocketTimeoutException as e:
+        print("Error:", e)
         pass
     return messages
 
 def draw_image(commands):
     img = SVG(width=300, height=300, viewBox="0 0 300 300", fill='none', stroke='black')
     for c in commands:
+        args = c['args']
         if c['function'] == 'circle':
-            img.circle(cx=c['x'], cy=c['y'], r=c['d']/2)
+            img.circle(cx=args['x'], cy=args['y'], r=args['d']/2)
         elif c['function'] == 'line':
-            img.line(x1=c['x1'], y1=c['y1'], x2=c['x2'], y2=c['y2'])
+            img.line(x1=args['x1'], y1=args['y1'], x2=args['x2'], y2=args['y2'])
         elif c['function'] == 'rect':
-            img.rect(x=c['x'], y=c['y'], width=c['w'], height=c['h'])
+            img.rect(x=args['x'], y=args['y'], width=args['w'], height=args['h'])
     return img