Add some additional debugging

matplotlib_pyodide/html5_canvas_backend.py

@@ -32,6 +32,7 @@
         "html5_canvas_backend is only supported in the browser in the main thread"
     ) from err
 from pyodide.ffi import create_proxy
+from pyodide.ffi.wrappers import set_timeout
 
 _capstyle_d = {"projecting": "square", "butt": "butt", "round": "round"}
 
@@ -311,14 +312,28 @@ def _draw_math_text_path(self, gc, x, y, s, prop, angle):
         angle : float
             The rotation angle in degrees
         """
+        import sys
+
+        print(f"Drawing math text: '{s}' at ({x}, {y})", file=sys.stderr)  # noqa: B907
+
         # Parse the math text to get paths and metrics
         width, height, depth, glyphs, rects = self.mathtext_parser.parse(
             s, dpi=self.dpi, prop=prop
         )
 
+        print(
+            f"Parsed text dimensions: {width}x{height} (depth: {depth})",
+            file=sys.stderr,
+        )
+        print(f"Number of glyphs: {len(glyphs)}", file=sys.stderr)
+        print(f"Number of rectangles: {len(rects)}", file=sys.stderr)
+
         # Save the canvas state
         self.ctx.save()
 
+        baseline_y = self.height - y + depth
+        self.ctx.translate(x, baseline_y)
+
         # Move to text position and apply rotation if needed
         self.ctx.translate(x, self.height - y)
         if angle != 0:
@@ -377,6 +392,24 @@ def _draw_math_text(self, gc, x, y, s, prop, angle):
         angle : float
             The rotation angle in degrees
         """
+
+        def check_fonts_loaded():
+            for url in self.fonts_loading:
+                if url in self.fonts_loading:
+                    return False
+            return True
+
+        if not check_fonts_loaded():
+            # if fonts aren't loaded, we shall schedule a redraw
+            def redraw_when_ready():
+                if check_fonts_loaded():
+                    self.fig.draw()
+                else:
+                    set_timeout(redraw_when_ready, 50)
+
+            set_timeout(redraw_when_ready, 50)
+            return
+
         try:
             # Try rendering directly with paths first
             self._draw_math_text_path(gc, x, y, s, prop, angle)