Fix image alpha in PNG backend

mdboom · mdboom · commit 22806ae919dc · 2016-06-28T09:13:53.000-04:00
diff --git a/lib/matplotlib/tests/test_image.py b/lib/matplotlib/tests/test_image.py
@@ -176,10 +176,13 @@ def test_image_alpha():
     np.random.seed(0)
     Z = np.random.rand(6, 6)
 
-    plt.subplot(121)
+    plt.subplot(131)
+    plt.imshow(Z, alpha=1.0, interpolation='none')
+
+    plt.subplot(132)
     plt.imshow(Z, alpha=0.5, interpolation='none')
 
-    plt.subplot(122)
+    plt.subplot(133)
     plt.imshow(Z, alpha=0.5, interpolation='nearest')
 
 @cleanup
diff --git a/src/_backend_agg_wrapper.cpp b/src/_backend_agg_wrapper.cpp
@@ -299,6 +299,7 @@ static PyObject *PyRendererAgg_draw_image(PyRendererAgg *self, PyObject *args, P
     x = mpl_round(x);
     y = mpl_round(y);
 
+    gc.alpha = 1.0;
     CALL_CPP("draw_image", (self->x->draw_image(gc, x, y, image)));
 
     Py_RETURN_NONE;
