WIP

lib/matplotlib/markers.py

@@ -261,7 +261,8 @@ def _recache(self):
         # set to 'none'. The marker function will override this for unfilled
         # markers.
         self._filled = self._fillstyle != 'none'
-        self._marker_function()
+        func = getattr(self, self._marker_function)
+        func()
 
     def __bool__(self):
         return bool(len(self._path.vertices))
@@ -308,23 +309,23 @@ def _set_marker(self, marker):
               `matplotlib.markers`.
         """
         if isinstance(marker, str) and cbook.is_math_text(marker):
-            self._marker_function = self._set_mathtext_path
+            self._marker_function = '_set_mathtext_path'
         elif isinstance(marker, (int, str)) and marker in self.markers:
-            self._marker_function = getattr(self, '_set_' + self.markers[marker])
+            self._marker_function = f'_set_{self.markers[marker]}'
         elif (isinstance(marker, np.ndarray) and marker.ndim == 2 and
                 marker.shape[1] == 2):
-            self._marker_function = self._set_vertices
+            self._marker_function = '_set_vertices'
         elif isinstance(marker, Path):
-            self._marker_function = self._set_path_marker
+            self._marker_function = '_set_path_marker'
         elif (isinstance(marker, Sized) and len(marker) in (2, 3) and
                 marker[1] in (0, 1, 2)):
-            self._marker_function = self._set_tuple_marker
+            self._marker_function = '_set_tuple_marker'
         elif isinstance(marker, MarkerStyle):
-            self.__dict__ = copy.deepcopy(marker.__dict__)
+            self.__dict__.update(copy.deepcopy(marker.__dict__))
         else:
             try:
                 Path(marker)
-                self._marker_function = self._set_vertices
+                self._marker_function = '_set_vertices'
             except ValueError as err:
                 raise ValueError(
                     f'Unrecognized marker style {marker!r}') from err

lib/matplotlib/testing/compare.py

@@ -392,7 +392,7 @@ def _load_image(path):
     return np.asarray(img)
 
 
-def compare_images(expected, actual, tol, in_decorator=False):
+def compare_images(expected, actual, tol, in_decorator=False, *, deadband=0):
     """
     Compare two "image" files checking differences within a tolerance.
 
@@ -469,11 +469,16 @@ def compare_images(expected, actual, tol, in_decorator=False):
         if np.array_equal(expected_image, actual_image):
             return None
 
-    rms, abs_diff = _image.calculate_rms_and_diff(expected_image, actual_image)
+    rms, abs_diff, max_difference = _image.calculate_rms_and_diff(
+        expected_image, actual_image
+    )
 
     if rms <= tol:
         return None
 
+    if max_difference <= deadband:
+        return None
+
     Image.fromarray(abs_diff).save(diff_image, format="png")
 
     results = dict(rms=rms, expected=str(expected),

pyproject.toml

@@ -234,7 +234,8 @@ exclude = [
   "lib/matplotlib/tests/",
   # tinypages is used for testing the sphinx ext,
   # stubtest will import and run, opening a figure if not excluded
-  ".*/tinypages"
+  ".*/tinypages",
+  "lib/matplotlib/pylab.py"
 ]
 files = [
   "lib/matplotlib",

src/_image_wrapper.cpp

@@ -249,6 +249,7 @@ calculate_rms_and_diff(py::array_t<unsigned char> expected_image,
     py::array_t<unsigned char> diff_image(diff_dims);
     auto diff = diff_image.mutable_unchecked<3>();
 
+    auto max_difference = 0;
     double total = 0.0;
     for (auto i = 0; i < height; i++) {
         for (auto j = 0; j < width; j++) {
@@ -257,7 +258,7 @@ calculate_rms_and_diff(py::array_t<unsigned char> expected_image,
                                   static_cast<double>(actual(i, j, k));
 
                 total += pixel_diff*pixel_diff;
-
+                max_difference = max_difference < abs(pixel_diff) ? abs(pixel_diff) : max_difference;
                 if (k != 3) { // Hard-code a fully solid alpha channel by omitting it.
                     diff(i, j, k) = static_cast<unsigned char>(std::clamp(
                         abs(pixel_diff) * 10, // Expand differences in luminance domain.
@@ -268,7 +269,7 @@ calculate_rms_and_diff(py::array_t<unsigned char> expected_image,
     }
     total = total / (width * height * depth);
 
-    return py::make_tuple(sqrt(total), diff_image);
+    return py::make_tuple(sqrt(total), diff_image, max_difference);
 }