Merge pull request matplotlib#3722 from mdboom/fix-markers-with-nans

BUG : fix fill_between with semilog

merged by hand because I added a test-clean up commit

Author: tacaswell

lib/matplotlib/tests/test_agg.py

@@ -131,6 +131,19 @@ def report_memory(i):
 ##     # w/ text and w/ write_png  : Average memory consumed per loop: 0.32
 
 
+@cleanup
+def test_marker_with_nan():
+    # This creates a marker with nans in it, which was segfaulting the
+    # Agg backend (see #3722)
+    fig, ax = plt.subplots(1)
+    steps = 1000
+    data = np.arange(steps)
+    ax.semilogx(data)
+    ax.fill_between(data, data*0.8, data*1.2)
+    buf = io.BytesIO()
+    fig.savefig(buf, format='png')
+
+
 if __name__ == "__main__":
     import nose
     nose.runmodule(argv=['-s', '--with-doctest'], exit=False)

src/_backend_agg.cpp

@@ -665,7 +665,8 @@ Py::Object
 RendererAgg::draw_markers(const Py::Tuple& args)
 {
     typedef agg::conv_transform<PathIterator>                  transformed_path_t;
-    typedef PathSnapper<transformed_path_t>                    snap_t;
+    typedef PathNanRemover<transformed_path_t>                 nan_removed_t;
+    typedef PathSnapper<nan_removed_t>                         snap_t;
     typedef agg::conv_curve<snap_t>                            curve_t;
     typedef agg::conv_stroke<curve_t>                          stroke_t;
     typedef agg::pixfmt_amask_adaptor<pixfmt, alpha_mask_type> pixfmt_amask_type;
@@ -693,15 +694,17 @@ RendererAgg::draw_markers(const Py::Tuple& args)
 
     PathIterator       marker_path(marker_path_obj);
     transformed_path_t marker_path_transformed(marker_path, marker_trans);
-    snap_t             marker_path_snapped(marker_path_transformed,
+    nan_removed_t      marker_path_nan_removed(marker_path_transformed, true, marker_path.has_curves());
+    snap_t             marker_path_snapped(marker_path_nan_removed,
                                            gc.snap_mode,
                                            marker_path.total_vertices(),
                                            gc.linewidth);
     curve_t            marker_path_curve(marker_path_snapped);
 
     PathIterator path(path_obj);
     transformed_path_t path_transformed(path, trans);
-    snap_t             path_snapped(path_transformed,
+    nan_removed_t      path_nan_removed(path_transformed, false, false);
+    snap_t             path_snapped(path_nan_removed,
                                     SNAP_FALSE,
                                     path.total_vertices(),
                                     0.0);