Fix #3790. Correctly scale quadmesh linewidth to dpi in Agg backend.

mdboom · mdboom · commit 27186bea7440 · 2014-11-13T18:46:07.000-05:00
diff --git a/lib/matplotlib/tests/baseline_images/test_agg/quadmesh_linewidth.png b/lib/matplotlib/tests/baseline_images/test_agg/quadmesh_linewidth.png
diff --git a/lib/matplotlib/tests/test_agg.py b/lib/matplotlib/tests/test_agg.py
@@ -6,12 +6,14 @@
 import io
 import os
 
+import numpy as np
 from numpy.testing import assert_array_almost_equal
 
+from matplotlib import pyplot as plt
 from matplotlib.image import imread
 from matplotlib.backends.backend_agg import FigureCanvasAgg as FigureCanvas
 from matplotlib.figure import Figure
-from matplotlib.testing.decorators import cleanup
+from matplotlib.testing.decorators import image_comparison, cleanup
 
 
 @cleanup
@@ -47,6 +49,20 @@ def test_repeated_save_with_alpha():
                               decimal=3)
 
 
+@image_comparison(baseline_images=['quadmesh_linewidth'],
+                  remove_text=True,
+                  extensions=['png'],
+                  savefig_kwarg={'dpi': 400})
+def test_quadmesh_linewidth():
+    fig = plt.figure(figsize=(1, 5))
+    fig.add_subplot(111)
+    np.random.seed(0)
+    r = np.random.random((4, 4))
+    plt.contourf(r, interpolation="nearest", extend="both")
+    cb = plt.colorbar()
+    cb.solids.set_edgecolor("face")
+
+
 def report_memory(i):
     pid = os.getpid()
     a2 = os.popen('ps -p %d -o rss,sz' % pid).readlines()
diff --git a/src/_backend_agg.cpp b/src/_backend_agg.cpp
@@ -1925,7 +1925,7 @@ RendererAgg::draw_quad_mesh(const Py::Tuple& args)
 
     Py::Object transforms_obj = Py::List(0);
     Py::Tuple linewidths(1);
-    linewidths[0] = Py::Float(gc.linewidth);
+    linewidths[0] = Py::Float(gc.linewidth * 72.0 / dpi);
     Py::SeqBase<Py::Object> linestyles_obj;
     Py::Tuple antialiaseds(1);
     antialiaseds[0] = Py::Int(antialiased ? 1 : 0);
