ayshih · Oct 9, 2026 · Sep 12, 2026 · Sep 12, 2026 · Sep 12, 2026 · Sep 12, 2026
diff --git a/lib/matplotlib/backends/backend_cairo.py b/lib/matplotlib/backends/backend_cairo.py
@@ -135,6 +135,18 @@ def _fill_and_stroke(ctx, fill_c, alpha, alpha_overrides):
 
     def draw_path(self, gc, path, transform, rgbFace=None):
         # docstring inherited
+
+        # Use an isolated blend group if the path blend mode is other than "normal" and
+        # if more than one of fill/hatch/stroke is active to avoid internal blending
+        hatch_path = gc.get_hatch_path()
+        isolate = ((blend_mode := gc.get_blend_mode()) != "normal" and
+                   sum([rgbFace is not None,
+                        hatch_path is not None,
+                        gc.get_linewidth() > 0]) > 1)
+        if isolate:
+            self.open_blend_group(blend_mode)
+            gc.set_blend_mode("normal")
+
         ctx = gc.ctx
         # Clip the path to the actual rendering extents if it isn't filled.
         clip = (ctx.clip_extents()
@@ -149,7 +161,6 @@ def draw_path(self, gc, path, transform, rgbFace=None):
             _set_rgba(ctx, rgbFace, gc.get_alpha(), gc.get_forced_alpha())
             ctx.fill_preserve()
             ctx.restore()
-        hatch_path = gc.get_hatch_path()
         if hatch_path:
             dpi = int(self.dpi)
             hatch_surface = ctx.get_target().create_similar(
@@ -170,6 +181,9 @@ def draw_path(self, gc, path, transform, rgbFace=None):
             ctx.restore()
         ctx.stroke()
 
+        if isolate:
+            self.close_blend_group()
+
     def draw_markers(self, gc, marker_path, marker_trans, path, transform,
                      rgbFace=None):
         # docstring inherited

diff --git a/lib/matplotlib/backends/backend_pgf.py b/lib/matplotlib/backends/backend_pgf.py
@@ -437,15 +437,27 @@ def draw_markers(self, gc, marker_path, marker_trans, path, trans,
 
     def draw_path(self, gc, path, transform, rgbFace=None):
         # docstring inherited
-        _writeln(self.fh, r"\begin{pgfscope}")
-        # draw the path
-        self._print_pgf_blend(gc)
-        self._print_pgf_clip(gc)
-        self._print_pgf_path_styles(gc, rgbFace)
-        self._print_pgf_path(gc, path, transform, rgbFace)
-        self._pgf_path_draw(stroke=gc.get_linewidth() != 0.0,
-                            fill=rgbFace is not None)
-        _writeln(self.fh, r"\end{pgfscope}")
+
+        # Use an isolated blend group if the path blend mode is other than "normal" and
+        # if more than one of fill/hatch/stroke is active to avoid internal blending
+        isolate = ((blend_mode := gc.get_blend_mode()) != "normal" and
+                   sum([rgbFace is not None,
+                        gc.get_hatch() is not None,
+                        gc.get_linewidth() > 0]) > 1)
+        if isolate:
+            self.open_blend_group(blend_mode)
+            gc.set_blend_mode("normal")
+
+        # draw any fill, and/or draw any stroke if no hatches
+        if rgbFace is not None or (gc.get_linewidth() != 0.0 and not gc.get_hatch()):
+            _writeln(self.fh, r"\begin{pgfscope}")
+            self._print_pgf_blend(gc)
+            self._print_pgf_clip(gc)
+            self._print_pgf_path_styles(gc, rgbFace)
+            self._print_pgf_path(gc, path, transform, rgbFace)
+            self._pgf_path_draw(stroke=gc.get_linewidth() != 0.0 and not gc.get_hatch(),
+                                fill=rgbFace is not None)
+            _writeln(self.fh, r"\end{pgfscope}")
 
         # if present, draw pattern on top
         if gc.get_hatch():
@@ -473,14 +485,17 @@ def draw_path(self, gc, path, transform, rgbFace=None):
                      % hatch_rgba[:3])
             _writeln(self.fh, r"\pgfsetstrokecolor{currenthatch}")
             _writeln(self.fh, r"\pgfsetstrokeopacity{%f}" % hatch_rgba[3])
+            _writeln(self.fh, r"\pgfsetdash{}{0pt}")
+            _writeln(self.fh, r"\pgfsetfillcolor{currenthatch}")
+            _writeln(self.fh, r"\pgfsetfillopacity{%f}" % hatch_rgba[3])
 
             _writeln(self.fh,
                      r"\pgfpathrectangle"
                      r"{\pgfqpoint{0in}{0in}}{\pgfqpoint{1in}{1in}}")
             _writeln(self.fh, r"\pgfusepath{clip}")
             scale = mpl.transforms.Affine2D().scale(self.dpi)
             self._print_pgf_path(None, gc.get_hatch_path(), scale)
-            self._pgf_path_draw(stroke=True)
+            self._pgf_path_draw(stroke=True, fill=True)
             _writeln(self.fh, r"\end{pgfscope}")
             _writeln(self.fh, r"}")
             # repeat pattern, filling the bounding rect of the path
@@ -501,6 +516,19 @@ def draw_path(self, gc, path, transform, rgbFace=None):
 
             _writeln(self.fh, r"\end{pgfscope}")
 
+            # draw any stroke on top of hatches
+            if (gc.get_linewidth() != 0.0):
+                _writeln(self.fh, r"\begin{pgfscope}")
+                self._print_pgf_blend(gc)
+                self._print_pgf_clip(gc)
+                self._print_pgf_path_styles(gc, rgbFace)
+                self._print_pgf_path(gc, path, transform, rgbFace)
+                self._pgf_path_draw(stroke=True, fill=False)
+                _writeln(self.fh, r"\end{pgfscope}")
+
+        if isolate:
+            self.close_blend_group()
+
     def _print_pgf_blend(self, gc):
         if (blend_mode := gc.get_blend_mode()) not in _BlendModePDFSpec:
             _log.warning(f"The '{blend_mode}' blend mode is not supported by the "
@@ -648,7 +676,7 @@ def _print_pgf_path(self, gc, path, transform, rgbFace=None):
                 _writeln(self.fh, f"\\pgfmathsetseed{{{int(randomness)}}}")
                 _writeln(self.fh, r"\pgfdecoratecurrentpath{random steps}")
 
-    def _pgf_path_draw(self, stroke=True, fill=False):
+    def _pgf_path_draw(self, *, stroke, fill):
         actions = []
         if stroke:
             actions.append("stroke")

diff --git a/lib/matplotlib/tests/baseline_images/test_backend_pgf/pgf_rcupdate2.pdf b/lib/matplotlib/tests/baseline_images/test_backend_pgf/pgf_rcupdate2.pdf
diff --git a/lib/matplotlib/tests/baseline_images/test_backends_rendering/fill_rules_pgf.pdf b/lib/matplotlib/tests/baseline_images/test_backends_rendering/fill_rules_pgf.pdf
diff --git a/lib/matplotlib/tests/baseline_images/test_backends_rendering/patch_blending.pdf b/lib/matplotlib/tests/baseline_images/test_backends_rendering/patch_blending.pdf
diff --git a/lib/matplotlib/tests/baseline_images/test_backends_rendering/patch_blending.png b/lib/matplotlib/tests/baseline_images/test_backends_rendering/patch_blending.png