Improve python to javascript conversion

ianthomas23 · ianthomas23 · commit 55117ee602a5 · 2025-05-07T16:11:06.000+01:00
diff --git a/lib/matplotlib/backends/backend_webagg.py b/lib/matplotlib/backends/backend_webagg.py
@@ -52,8 +52,8 @@ def show(self):
             """
         js_code = f"var fig_id = '{fignum}';" + js_code
 
-        js_fig = run_js(js_code)
-        web_socket = WebAggApplication.MockPythonWebSocket(self, js_fig.ws)
+        self.js_fig = run_js(js_code)
+        web_socket = WebAggApplication.MockPythonWebSocket(self, self.js_fig.ws)
         web_socket.open(fignum)
 
 
@@ -70,14 +70,18 @@ class MockPythonWebSocket:
         def __init__(self, manager, js_web_socket):
             self.manager = manager
             self.js_web_socket = js_web_socket
+            self.on_message_proxy = None
 
         def open(self, fignum):
-            self.js_web_socket.open(create_proxy(self.on_message))   # should destroy proxy on close/exit?
+            self.on_message_proxy = create_proxy(self.on_message)
+            self.js_web_socket.open(self.on_message_proxy)
             self.fignum = int(fignum)
             self.manager.add_web_socket(self)
 
         def on_close(self):
             self.manager.remove_web_socket(self)
+            self.on_message_proxy.destroy()
+            self.on_message_proxy = None
 
         def on_message(self, message):
             message = message.as_py_json()
diff --git a/lib/matplotlib/backends/web_backend/js/mpl.js b/lib/matplotlib/backends/web_backend/js/mpl.js
@@ -29,9 +29,14 @@ class MockJsWebSocket {
     }
 
     receive_binary(content, binary=true) {
-        content = content.toJs();
-        blob = new Blob([content]);
-        this.onmessage({ data: blob });
+        var buffer = content.getBuffer();
+        content.destroy();
+        try {
+            blob = new Blob([buffer.data]);
+            this.onmessage({ data: blob });
+        } finally {
+            buffer.release(); // Release the memory when we're done
+        }
     }
 
     receive_json(content) {
@@ -416,7 +421,7 @@ mpl.figure.prototype._init_toolbar = function () {
 
         var icon_img = new Image();
         this._toolbar_images.push(icon_img);
-        image_bytes = mpl.toolbar_image_callback(image).toJs();
+        image_bytes = mpl.toolbar_image_callback(image).toJs({create_pyproxies : false});
         blob = new Blob([image_bytes], { type: 'image/png' });
         icon_img.src = (window.URL || window.webkitURL).createObjectURL(blob);
         icon_img.alt = tooltip;
