Blocked set_clim() callbacks to prevent inconsistent state (#29522)

prafulgulani · prafulgulani · commit e49d05ad8009 · 2025-02-11T22:38:46.000+05:30
diff --git a/lib/matplotlib/colorizer.py b/lib/matplotlib/colorizer.py
@@ -261,16 +261,24 @@ def set_clim(self, vmin=None, vmax=None):
              .. ACCEPTS: (vmin: float, vmax: float)
         """
         # If the norm's limits are updated self.changed() will be called
-        # through the callbacks attached to the norm
+        # through the callbacks attached to the norm, this causes an inconsistent
+        # state, to prevent this blocked context manager is used
         if vmax is None:
             try:
                 vmin, vmax = vmin
             except (TypeError, ValueError):
                 pass
-        if vmin is not None:
-            self.norm.vmin = colors._sanitize_extrema(vmin)
-        if vmax is not None:
-            self.norm.vmax = colors._sanitize_extrema(vmax)
+
+        # Blocked context manager prevents callbacks from being triggered
+        # until both vmin and vmax are updated
+        with self.norm.callbacks.blocked(signal='changed'):
+            if vmin is not None:
+                self.norm.vmin = colors._sanitize_extrema(vmin)
+            if vmax is not None:
+                self.norm.vmax = colors._sanitize_extrema(vmax)
+
+        # self.changed() will now emit a update signal after both the limits are set
+        self.changed()
 
     def get_clim(self):
         """
