Hook up the save_figure function

Author: blink1073

lib/matplotlib/backends/backend_webagg_core.py

@@ -329,7 +329,7 @@ def release_zoom(self, event):
 
     def save_figure(self, *args):
         """Save the current figure"""
-        warnings.warn('"Save figure" not implemented in Web Backend')
+        self.canvas.send_event('save')
 
 
 class FigureManagerWebAgg(backend_bases.FigureManagerBase):

lib/matplotlib/backends/web_backend/mpl.js

@@ -283,6 +283,14 @@ mpl.figure.prototype.send_draw_message = function() {
     }
 }
 
+
+mpl.figure.prototype.handle_save = function(fig, msg) {
+    var format_dropdown = fig.format_dropdown;
+    var format = format_dropdown.options[format_dropdown.selectedIndex].value;
+    fig.ondownload(fig, format);
+}
+
+
 mpl.figure.prototype.handle_resize = function(fig, msg) {
     var size = msg['size'];
     if (size[0] != fig.canvas.width || size[1] != fig.canvas.height) {