Merge pull request #16890 from mnmelo/patch-1

QuLogic · web-flow · commit db55918a2737 · 2020-03-24T02:33:27.000-04:00
Enables hatch alpha on SVG
diff --git a/doc/users/next_whats_new/2020-03-24-svg-hatch-alpha.rst b/doc/users/next_whats_new/2020-03-24-svg-hatch-alpha.rst
@@ -0,0 +1,6 @@
+The SVG backend can now render hatches with transparency
+--------------------------------------------------------
+
+The SVG backend now respects the hatch stroke alpha. Useful applications are,
+among others, semi-transparent hatches as a subtle way to differentiate columns
+in bar plots.
diff --git a/lib/matplotlib/backends/backend_svg.py b/lib/matplotlib/backends/backend_svg.py
@@ -391,16 +391,19 @@ def _write_hatches(self):
                 x="0", y="0", width=str(HATCH_SIZE+1),
                 height=str(HATCH_SIZE+1),
                 fill=fill)
-            writer.element(
-                'path',
-                d=path_data,
-                style=generate_css({
+            hatch_style = {
                     'fill': rgb2hex(stroke),
                     'stroke': rgb2hex(stroke),
                     'stroke-width': str(mpl.rcParams['hatch.linewidth']),
                     'stroke-linecap': 'butt',
                     'stroke-linejoin': 'miter'
-                    })
+                    }
+            if stroke[3] < 1:
+                hatch_style['stroke-opacity'] = str(stroke[3])
+            writer.element(
+                'path',
+                d=path_data,
+                style=generate_css(hatch_style)
                 )
             writer.end('pattern')
         writer.end('defs')
diff --git a/lib/matplotlib/tests/baseline_images/test_artist/clip_path_clipping.svg b/lib/matplotlib/tests/baseline_images/test_artist/clip_path_clipping.svg
