Skip to content

FIX: handle nans in RGBA input with ScalarMappables #27848

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 1 commit into from
Mar 7, 2024
Merged

FIX: handle nans in RGBA input with ScalarMappables #27848

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
8 changes: 7 additions & 1 deletion lib/matplotlib/cm.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -328,7 +328,7 @@ def to_rgba(self, x, alpha=None, bytes=False, norm=True):
treated as an RGB or RGBA array, and no mapping will be done.
The array can be `~numpy.uint8`, or it can be floats with
values in the 0-1 range; otherwise a ValueError will be raised.
If it is a masked array, any masked elements will be set to 0 alpha.
Any NaNs or masked elements will be set to 0 alpha.
If the last dimension is 3, the *alpha* kwarg (defaulting to 1)
will be used to fill in the transparency. If the last dimension
is 4, the *alpha* kwarg is ignored; it does not
Expand Down Expand Up @@ -360,6 +360,12 @@ def to_rgba(self, x, alpha=None, bytes=False, norm=True):
else:
raise ValueError("Third dimension must be 3 or 4")
if xx.dtype.kind == 'f':
# If any of R, G, B, or A is nan, set to 0
if np.any(nans := np.isnan(x)):
if xx.shape[2] == 4:
xx = xx.copy()
xx[np.any(nans, axis=2), :] = 0

if norm and (xx.max() > 1 or xx.min() < 0):
raise ValueError("Floating point image RGB values "
"must be in the 0..1 range.")
Expand Down
26 changes: 26 additions & 0 deletions lib/matplotlib/tests/test_colors.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1352,6 +1352,32 @@ def test_scalarmappable_to_rgba(bytes):
np.testing.assert_almost_equal(sm.to_rgba(xm[..., :3], bytes=bytes), expected)


@pytest.mark.parametrize("bytes", (True, False))
def test_scalarmappable_nan_to_rgba(bytes):
sm = cm.ScalarMappable()

# RGBA
x = np.ones((2, 3, 4), dtype=float) * 0.5
x[0, 0, 0] = np.nan
expected = x.copy()
expected[0, 0, :] = 0
if bytes:
expected = (expected * 255).astype(np.uint8)
np.testing.assert_almost_equal(sm.to_rgba(x, bytes=bytes), expected)
assert np.any(np.isnan(x)) # Input array should not be changed

# RGB
expected[..., 3] = 255 if bytes else 1
expected[0, 0, 3] = 0
np.testing.assert_almost_equal(sm.to_rgba(x[..., :3], bytes=bytes), expected)
assert np.any(np.isnan(x)) # Input array should not be changed

# Out-of-range fail
x[1, 0, 0] = 42
with pytest.raises(ValueError, match='0..1 range'):
sm.to_rgba(x[..., :3], bytes=bytes)


def test_failed_conversions():
with pytest.raises(ValueError):
mcolors.to_rgba('5')
Expand Down