add new method ScaleBar.set_rotation()

raphaelquast · raphaelquast · Sep 1, 2024 · Jun 4, 2024 · Jun 4, 2024 · Jun 13, 2024
commit e17df4e01ddc287ba33cd174d34e64a51f0f5880
diff --git a/eomaps/scalebar.py b/eomaps/scalebar.py
@@ -840,6 +840,29 @@ def set_position(self, pos=None, auto_pos=None, azim=None):
 
         self._update(BM_update=True)
 
+    def set_rotation(self, ang=0):
+        """
+        Set the absolute rotation angle of the first segment of the scalebar.
+
+        Note
+        ----
+        This method sets the "absolute rotation angle" in display units,
+        not the "azimuth angle" which can be set with :py:meth:`ScaleBar.set_position`.
+
+        Parameters
+        ----------
+        ang : float
+            The rotation angle.
+
+        """
+        lon, lat, _ = self.get_position()
+        x0, y0 = self._m._transf_lonlat_to_plot.transform(lon, lat)
+        x1, y1 = self._m._transf_lonlat_to_plot.transform(
+            *self._geod.fwd(lon, lat, -ang, self.get_scale())[:2]
+        )
+        azim = np.rad2deg(-np.arctan2(x1 - x0, y1 - y0))
+        self.set_position((lon, lat), azim=azim)
+
     def _set_position(self, lon=None, lat=None, azim=None, update=False):
         if lon is None:
             lon = self._lon

diff --git a/tests/baseline/test_scalebar.test_scalebar_display_rotation.png b/tests/baseline/test_scalebar.test_scalebar_display_rotation.png
diff --git a/tests/test_scalebar.py b/tests/test_scalebar.py
@@ -0,0 +1,20 @@
+import pytest
+from eomaps import Maps
+
+
+@pytest.mark.mpl_image_compare()
+def test_scalebar_display_rotation():
+
+    m = Maps(2154)
+    m.add_feature.preset.coastline()
+
+    scb1 = m.add_scalebar((-6, 43.45))
+    scb1.set_rotation(0)
+
+    scb2 = m.add_scalebar((2.5, 46))
+    scb2.set_rotation(45)
+
+    scb3 = m.add_scalebar((-7, 51))
+    scb3.set_rotation(90)
+
+    return m