BUG: fix normalizing image data contained in np.ndarray subclass

neutrinoceros · neutrinoceros · commit f6340d4baf83 · 2024-01-22T14:13:17.000+01:00
diff --git a/lib/matplotlib/image.py b/lib/matplotlib/image.py
@@ -461,12 +461,12 @@ def _make_image(self, A, in_bbox, out_bbox, clip_bbox, magnification=1.0,
                 vmid = np.float64(self.norm.vmin) + dv / 2
                 fact = 1e7 if scaled_dtype == np.float64 else 1e4
                 newmin = vmid - dv * fact
-                if newmin < a_min:
+                if newmin < np.float64(a_min):
                     newmin = None
                 else:
                     a_min = np.float64(newmin)
                 newmax = vmid + dv * fact
-                if newmax > a_max:
+                if newmax > np.float64(a_max):
                     newmax = None
                 else:
                     a_max = np.float64(newmax)
diff --git a/lib/matplotlib/transforms.py b/lib/matplotlib/transforms.py
@@ -2853,15 +2853,15 @@ def nonsingular(vmin, vmax, expander=0.001, tiny=1e-15, increasing=True):
     if (not np.isfinite(vmin)) or (not np.isfinite(vmax)):
         return -expander, expander
 
+    # Expand vmin, vmax to float: if they were integer types, they can wrap
+    # around in abs (abs(np.int8(-128)) == -128) and vmax - vmin can overflow.
+    vmin, vmax = map(np.float64, (vmin, vmax))
+
     swapped = False
     if vmax < vmin:
         vmin, vmax = vmax, vmin
         swapped = True
 
-    # Expand vmin, vmax to float: if they were integer types, they can wrap
-    # around in abs (abs(np.int8(-128)) == -128) and vmax - vmin can overflow.
-    vmin, vmax = map(float, [vmin, vmax])
-
     maxabsvalue = max(abs(vmin), abs(vmax))
     if maxabsvalue < (1e6 / tiny) * np.finfo(float).tiny:
         vmin = -expander
