Merge pull request #8447 from anntzer/imshow-float128

tacaswell · web-flow · commit 0c9f7c2b33c0 · 2017-04-13T20:50:59.000-04:00
ENH: Let imshow handle float128 data.
diff --git a/lib/matplotlib/colors.py b/lib/matplotlib/colors.py
@@ -188,7 +188,7 @@ def _to_rgba_no_colorcycle(c, alpha=None):
         raise ValueError("Invalid RGBA argument: {!r}".format(orig_c))
     # tuple color.
     c = np.array(c)
-    if not np.can_cast(c.dtype, float) or c.ndim != 1:
+    if not np.can_cast(c.dtype, float, "same_kind") or c.ndim != 1:
         # Test the dtype explicitly as `map(float, ...)`, `np.array(...,
         # float)` and `np.array(...).astype(float)` all convert "0.5" to 0.5.
         # Test dimensionality to reject single floats.
@@ -934,6 +934,11 @@ def __call__(self, value, clip=None):
             resdat -= vmin
             resdat /= (vmax - vmin)
             result = np.ma.array(resdat, mask=result.mask, copy=False)
+        # Agg cannot handle float128.  We actually only need 32-bit of
+        # precision, but on Windows, `np.dtype(np.longdouble) == np.float64`,
+        # so casting to float32 would lose precision on float64s as well.
+        if result.dtype == np.longdouble:
+            result = result.astype(np.float64)
         if is_scalar:
             result = result[0]
         return result
diff --git a/lib/matplotlib/image.py b/lib/matplotlib/image.py
@@ -299,9 +299,9 @@ def _make_image(self, A, in_bbox, out_bbox, clip_bbox, magnification=1.0,
         space.
         """
         if A is None:
-            raise RuntimeError('You must first set the image'
-                               ' array or the image attribute')
-        if any(s == 0 for s in A.shape):
+            raise RuntimeError('You must first set the image '
+                               'array or the image attribute')
+        if A.size == 0:
             raise RuntimeError("_make_image must get a non-empty image. "
                                "Your Artist's draw method must filter before "
                                "this method is called.")
@@ -359,7 +359,7 @@ def _make_image(self, A, in_bbox, out_bbox, clip_bbox, magnification=1.0,
             created_rgba_mask = False
 
             if A.ndim not in (2, 3):
-                raise ValueError("Invalid dimensions, got %s" % (A.shape,))
+                raise ValueError("Invalid dimensions, got {}".format(A.shape))
 
             if A.ndim == 2:
                 A = self.norm(A)
@@ -591,11 +591,11 @@ def set_data(self, A):
             self._A = cbook.safe_masked_invalid(A, copy=True)
 
         if (self._A.dtype != np.uint8 and
-                not np.can_cast(self._A.dtype, float)):
-            raise TypeError("Image data can not convert to float")
+                not np.can_cast(self._A.dtype, float, "same_kind")):
+            raise TypeError("Image data cannot be converted to float")
 
-        if (self._A.ndim not in (2, 3) or
-                (self._A.ndim == 3 and self._A.shape[-1] not in (3, 4))):
+        if not (self._A.ndim == 2
+                or self._A.ndim == 3 and self._A.shape[-1] in [3, 4]):
             raise TypeError("Invalid dimensions for image data")
 
         self._imcache = None
diff --git a/lib/matplotlib/tests/test_image.py b/lib/matplotlib/tests/test_image.py
@@ -505,9 +505,9 @@ def test_jpeg_alpha():
 def test_nonuniformimage_setdata():
     ax = plt.gca()
     im = NonUniformImage(ax)
-    x = np.arange(3, dtype=np.float64)
-    y = np.arange(4, dtype=np.float64)
-    z = np.arange(12, dtype=np.float64).reshape((4, 3))
+    x = np.arange(3, dtype=float)
+    y = np.arange(4, dtype=float)
+    z = np.arange(12, dtype=float).reshape((4, 3))
     im.set_data(x, y, z)
     x[0] = y[0] = z[0, 0] = 9.9
     assert im._A[0, 0] == im._Ax[0] == im._Ay[0] == 0, 'value changed'
@@ -516,7 +516,7 @@ def test_nonuniformimage_setdata():
 def test_axesimage_setdata():
     ax = plt.gca()
     im = AxesImage(ax)
-    z = np.arange(12, dtype=np.float64).reshape((4, 3))
+    z = np.arange(12, dtype=float).reshape((4, 3))
     im.set_data(z)
     z[0, 0] = 9.9
     assert im._A[0, 0] == 0, 'value changed'
@@ -525,7 +525,7 @@ def test_axesimage_setdata():
 def test_figureimage_setdata():
     fig = plt.gcf()
     im = FigureImage(fig)
-    z = np.arange(12, dtype=np.float64).reshape((4, 3))
+    z = np.arange(12, dtype=float).reshape((4, 3))
     im.set_data(z)
     z[0, 0] = 9.9
     assert im._A[0, 0] == 0, 'value changed'
@@ -534,9 +534,9 @@ def test_figureimage_setdata():
 def test_pcolorimage_setdata():
     ax = plt.gca()
     im = PcolorImage(ax)
-    x = np.arange(3, dtype=np.float64)
-    y = np.arange(4, dtype=np.float64)
-    z = np.arange(6, dtype=np.float64).reshape((3, 2))
+    x = np.arange(3, dtype=float)
+    y = np.arange(4, dtype=float)
+    z = np.arange(6, dtype=float).reshape((3, 2))
     im.set_data(x, y, z)
     x[0] = y[0] = z[0, 0] = 9.9
     assert im._A[0, 0] == im._Ax[0] == im._Ay[0] == 0, 'value changed'
@@ -778,3 +778,8 @@ def test_empty_imshow():
 
     with pytest.raises(RuntimeError):
         im.make_image(fig._cachedRenderer)
+
+
+def test_imshow_float128():
+    fig, ax = plt.subplots()
+    ax.imshow(np.zeros((3, 3), dtype=np.longdouble))
