Add support for world coordinates (WCSAxes)

pyproject.toml

@@ -44,6 +44,7 @@ test = [
     "coverage[toml]>=7.0.0",
     "typeguard>=4.4.0",
     "pandas",
+    "astropy"
 ]
 dev = [
     "tox",

requirements-310.txt

@@ -1,5 +1,9 @@
 # This file was autogenerated by uv via the following command:
 #    uv pip compile pyproject.toml --extra test --resolution highest --python 3.10 -o requirements-310.txt
+astropy==6.1.7
+    # via matplot2tikz (pyproject.toml)
+astropy-iers-data==0.2026.2.2.0.48.1
+    # via astropy
 colorama==0.4.6
     # via pytest
 contourpy==1.3.2
@@ -23,11 +27,14 @@ matplotlib==3.10.7
 numpy==2.2.6
     # via
     #   matplot2tikz (pyproject.toml)
+    #   astropy
     #   contourpy
     #   matplotlib
     #   pandas
+    #   pyerfa
 packaging==25.0
     # via
+    #   astropy
     #   matplotlib
     #   pytest
 pandas==2.3.3
@@ -40,6 +47,8 @@ pluggy==1.6.0
     # via
     #   pytest
     #   pytest-cov
+pyerfa==2.0.1.5
+    # via astropy
 pygments==2.19.2
     # via pytest
 pyparsing==3.2.5
@@ -56,6 +65,8 @@ python-dateutil==2.9.0.post0
     #   pandas
 pytz==2025.2
     # via pandas
+pyyaml==6.0.3
+    # via astropy
 six==1.17.0
     # via python-dateutil
 tomli==2.3.0

requirements-311.txt

@@ -1,5 +1,9 @@
 # This file was autogenerated by uv via the following command:
 #    uv pip compile pyproject.toml --extra test --resolution highest --python 3.11 -o requirements-311.txt
+astropy==7.2.0
+    # via matplot2tikz (pyproject.toml)
+astropy-iers-data==0.2026.2.2.0.48.1
+    # via astropy
 colorama==0.4.6
     # via pytest
 contourpy==1.3.3
@@ -21,11 +25,14 @@ matplotlib==3.10.7
 numpy==2.3.4
     # via
     #   matplot2tikz (pyproject.toml)
+    #   astropy
     #   contourpy
     #   matplotlib
     #   pandas
+    #   pyerfa
 packaging==25.0
     # via
+    #   astropy
     #   matplotlib
     #   pytest
 pandas==2.3.3
@@ -38,6 +45,8 @@ pluggy==1.6.0
     # via
     #   pytest
     #   pytest-cov
+pyerfa==2.0.1.5
+    # via astropy
 pygments==2.19.2
     # via pytest
 pyparsing==3.2.5
@@ -54,6 +63,8 @@ python-dateutil==2.9.0.post0
     #   pandas
 pytz==2025.2
     # via pandas
+pyyaml==6.0.3
+    # via astropy
 six==1.17.0
     # via python-dateutil
 tomli==2.3.0

requirements-312.txt

@@ -1,5 +1,9 @@
 # This file was autogenerated by uv via the following command:
 #    uv pip compile pyproject.toml --extra test --resolution highest --python 3.12 -o requirements-312.txt
+astropy==7.2.0
+    # via matplot2tikz (pyproject.toml)
+astropy-iers-data==0.2026.2.2.0.48.1
+    # via astropy
 colorama==0.4.6
     # via pytest
 contourpy==1.3.3
@@ -21,11 +25,14 @@ matplotlib==3.10.7
 numpy==2.3.4
     # via
     #   matplot2tikz (pyproject.toml)
+    #   astropy
     #   contourpy
     #   matplotlib
     #   pandas
+    #   pyerfa
 packaging==25.0
     # via
+    #   astropy
     #   matplotlib
     #   pytest
 pandas==2.3.3
@@ -38,6 +45,8 @@ pluggy==1.6.0
     # via
     #   pytest
     #   pytest-cov
+pyerfa==2.0.1.5
+    # via astropy
 pygments==2.19.2
     # via pytest
 pyparsing==3.2.5
@@ -54,6 +63,8 @@ python-dateutil==2.9.0.post0
     #   pandas
 pytz==2025.2
     # via pandas
+pyyaml==6.0.3
+    # via astropy
 six==1.17.0
     # via python-dateutil
 typeguard==4.4.4

requirements-313.txt

@@ -1,5 +1,9 @@
 # This file was autogenerated by uv via the following command:
 #    uv pip compile pyproject.toml --extra test --resolution highest --python 3.13 -o requirements-313.txt
+astropy==7.2.0
+    # via matplot2tikz (pyproject.toml)
+astropy-iers-data==0.2026.2.2.0.48.1
+    # via astropy
 colorama==0.4.6
     # via pytest
 contourpy==1.3.3
@@ -21,11 +25,14 @@ matplotlib==3.10.7
 numpy==2.3.4
     # via
     #   matplot2tikz (pyproject.toml)
+    #   astropy
     #   contourpy
     #   matplotlib
     #   pandas
+    #   pyerfa
 packaging==25.0
     # via
+    #   astropy
     #   matplotlib
     #   pytest
 pandas==2.3.3
@@ -38,6 +45,8 @@ pluggy==1.6.0
     # via
     #   pytest
     #   pytest-cov
+pyerfa==2.0.1.5
+    # via astropy
 pygments==2.19.2
     # via pytest
 pyparsing==3.2.5
@@ -54,6 +63,8 @@ python-dateutil==2.9.0.post0
     #   pandas
 pytz==2025.2
     # via pandas
+pyyaml==6.0.3
+    # via astropy
 six==1.17.0
     # via python-dateutil
 typeguard==4.4.4

requirements-314.txt

@@ -1,5 +1,9 @@
 # This file was autogenerated by uv via the following command:
 #    uv pip compile pyproject.toml --extra test --resolution highest --python 3.14 -o requirements-314.txt
+astropy==7.2.0
+    # via matplot2tikz (pyproject.toml)
+astropy-iers-data==0.2026.2.2.0.48.1
+    # via astropy
 colorama==0.4.6
     # via pytest
 contourpy==1.3.3
@@ -21,11 +25,14 @@ matplotlib==3.10.7
 numpy==2.3.4
     # via
     #   matplot2tikz (pyproject.toml)
+    #   astropy
     #   contourpy
     #   matplotlib
     #   pandas
+    #   pyerfa
 packaging==25.0
     # via
+    #   astropy
     #   matplotlib
     #   pytest
 pandas==2.3.3
@@ -38,6 +45,8 @@ pluggy==1.6.0
     # via
     #   pytest
     #   pytest-cov
+pyerfa==2.0.1.5
+    # via astropy
 pygments==2.19.2
     # via pytest
 pyparsing==3.2.5
@@ -54,6 +63,8 @@ python-dateutil==2.9.0.post0
     #   pandas
 pytz==2025.2
     # via pandas
+pyyaml==6.0.3
+    # via astropy
 six==1.17.0
     # via python-dateutil
 typeguard==4.4.4

src/matplot2tikz/__about__.py

@@ -1,3 +1,3 @@
 """Version number."""
 
-__version__ = "0.5.1"
+__version__ = "0.5.2"

src/matplot2tikz/_save.py

@@ -391,6 +391,10 @@ def _recurse(data: TikzData, obj: Artist) -> list:
         if isinstance(child, (Spine, XAxis, YAxis)):
             continue
 
+        # Skip WCS axes artist - it's a placeholder with no visible content
+        if type(child).__name__ == "_WCSAxesArtist":
+            continue
+
         if isinstance(child, Axes):
             _process_axes(data, child, content)
 

tests/test_wcs_axes.py

@@ -0,0 +1,62 @@
+"""Test plot with WCS axes."""
+
+import warnings
+
+import matplotlib as mpl
+import matplotlib.pyplot as plt
+import numpy as np
+from astropy.wcs import WCS
+
+import matplot2tikz
+
+mpl.use("Agg")
+
+
+def test_wcs_axes() -> None:
+    """Test that WCS axes are handled without warnings."""
+    # Create a simple WCS
+    wcs = WCS(naxis=2)
+    wcs.wcs.crpix = [50, 50]
+    wcs.wcs.cdelt = [0.1, 0.1]
+    wcs.wcs.crval = [0, -90]
+    wcs.wcs.ctype = ["RA---TAN", "DEC--TAN"]
+
+    # Create a figure with WCS projection
+    fig, ax = plt.subplots(subplot_kw={"projection": wcs})
+
+    # Add some data
+    rng = np.random.default_rng(1337)
+    data = rng.integers(5, size=(2, 4))
+    vmin = data.min()
+    vmax = data.max()
+    mappable = ax.imshow(data, vmin=vmin, vmax=vmax, origin="lower", cmap="viridis")
+    ax.grid(color="white", ls="solid", alpha=0.5)
+    ax.set(xlabel="Galactic Longitude", ylabel="Galactic Latitude")
+    _ = fig.colorbar(mappable, ax=ax, label="Test Unit")
+
+    with warnings.catch_warnings(record=True) as w:
+        warnings.simplefilter("always")
+        tikz_code = matplot2tikz.get_tikz_code()
+
+        # Filter warnings to only check for the specific warning about unknown objects
+        unknown_object_warnings = [
+            warning
+            for warning in w
+            if issubclass(warning.category, UserWarning)
+            and "Don't know how to handle object" in str(warning.message)
+            and "_WCSAxesArtist" in str(warning.message)
+        ]
+
+        # Assert that we didn't get the _WCSAxesArtist warning
+        assert len(unknown_object_warnings) == 0, (
+            f"Got unexpected warning about _WCSAxesArtist: "
+            f"{[str(warning.message) for warning in unknown_object_warnings]}"
+        )
+
+    # Basic checks that the output looks reasonable
+    assert "\\begin{tikzpicture}" in tikz_code
+    assert "\\end{tikzpicture}" in tikz_code
+    # Check that image is included
+    assert "\\addplot graphics" in tikz_code
+
+    plt.close("all")