Figure.text: Support non-ASCII characters in the 'text' parameter

pygmt/helpers/__init__.py

@@ -19,4 +19,5 @@
     data_kind,
     is_nonstr_iter,
     launch_external_viewer,
+    non_ascii_to_octal,
 )

pygmt/src/text.py

@@ -10,6 +10,7 @@
     fmt_docstring,
     is_nonstr_iter,
     kwargs_to_strings,
+    non_ascii_to_octal,
     use_alias,
 )
 
@@ -223,7 +224,9 @@ def text_(
 
     # Append text at last column. Text must be passed in as str type.
     if kind == "vectors":
-        extra_arrays.append(np.atleast_1d(text).astype(str))
+        extra_arrays.append(
+            list(map(non_ascii_to_octal, np.atleast_1d(text).astype(str)))
+        )
 
     with Session() as lib:
         file_context = lib.virtualfile_from_data(

pygmt/tests/baseline/test_text_nonascii.png.dvc

@@ -0,0 +1,5 @@
+outs:
+- md5: 75db22909db0fbdb2a31edab357ed8b9
+  size: 16418
+  hash: md5
+  path: test_text_nonascii.png

pygmt/tests/test_text.py

@@ -371,3 +371,16 @@ def test_text_nonstr_text():
         text=[1, 2, 3.0, 4.0],
     )
     return fig
+
+
+@pytest.mark.mpl_image_compare
+def test_text_nonascii():
+    """
+    Test passing text strings with non-ascii characters.
+    """
+    fig = Figure()
+    fig.basemap(region=[0, 10, 0, 10], projection="X10c", frame=True)
+    fig.text(position="TL", text="position-text:°α")
+    fig.text(x=1, y=1, text="xytext:°α")
+    fig.text(x=[5, 5], y=[3, 5], text=["xytext1:°α", "xytext2:°α"])
+    return fig