Add Pythonic argument options for colorbar frame parameters

pygmt/src/colorbar.py

@@ -27,7 +27,7 @@
 @kwargs_to_strings(
     R="sequence", G="sequence", I="sequence", c="sequence_comma", p="sequence"
 )
-def colorbar(self, **kwargs):
+def colorbar(self, frame=None, annotation=None, xlabel=None, ylabel=None, **kwargs):
     r"""
     Plot a gray or color scale-bar on maps.
 
@@ -47,6 +47,12 @@ def colorbar(self, **kwargs):
     ----------
     frame : str or list
         Set color bar boundary frame, labels, and axes attributes.
+    annotation : int or float or str
+        Set the interval for annotated gridlines on the colorbar.
+    xlabel : str
+        Set the label for the x-axis of the colorbar.
+    ylabel : str
+        Set the label for the y-axis of the colorbar.
     {cmap}
     position : str
         [**g**\|\ **j**\|\ **J**\|\ **n**\|\ **x**]\ *refpoint*\
@@ -105,6 +111,21 @@ def colorbar(self, **kwargs):
     {perspective}
     {transparency}
     """
+    if xlabel or ylabel or annotation:
+        if kwargs.get("B") is None:
+            frame = []
+        elif isinstance(kwargs.get("B"), list):
+            frame = kwargs.get("B")
+        else:
+            frame = [kwargs.get("B")]
+        if xlabel:
+            frame.append("x+l" + str(xlabel))
+        if ylabel:
+            frame.append("y+l" + str(ylabel))
+        if annotation:
+            frame.append("a" + str(annotation))
+    if frame:
+        kwargs["B"] = frame
     kwargs = self._preprocess(**kwargs)  # pylint: disable=protected-access
     with Session() as lib:
         lib.call_module(module="colorbar", args=build_arg_string(kwargs))

pygmt/tests/baseline/test_colorbar_frame_list_parameters.png.dvc

@@ -0,0 +1,4 @@
+outs:
+- md5: 69740a2512fd502e3d53d16bddc0f97c
+  size: 4878
+  path: test_colorbar_frame_list_parameters.png

pygmt/tests/baseline/test_colorbar_frame_parameters.png.dvc

@@ -0,0 +1,4 @@
+outs:
+- md5: b7fc503b09c1c610a22081edf9cc612f
+  size: 4840
+  path: test_colorbar_frame_parameters.png

pygmt/tests/baseline/test_colorbar_frame_string_parameters.png.dvc

@@ -0,0 +1,4 @@
+outs:
+- md5: 7a8bbd25a40214160f00a5c5bf83f69d
+  size: 3764
+  path: test_colorbar_frame_string_parameters.png

pygmt/tests/test_colorbar.py

@@ -65,3 +65,53 @@ def test_colorbar_shading_list():
     fig.basemap(region=[0, 10, 0, 10], projection="X15c", frame="a")
     fig.colorbar(cmap="geo", shading=[-0.7, 0.2], frame=True)
     return fig
+
+
+@pytest.mark.mpl_image_compare
+def test_colorbar_frame_parameters():
+    """
+    Create colorbar with arguments for xlabel, ylabel, and annotation, and no
+    argument passed to frame.
+    """
+    fig = Figure()
+    fig.colorbar(
+        cmap="rainbow",
+        position="x0c/0c+w1c/0.5c",
+        xlabel="test-x",
+        ylabel="test-y",
+        annotation=0.25,
+    )
+    return fig
+
+
+@pytest.mark.mpl_image_compare
+def test_colorbar_frame_list_parameters():
+    """
+    Create colorbar with a list passed to frame and an argument passed to
+    xlabel.
+    """
+    fig = Figure()
+    fig.colorbar(
+        cmap="rainbow",
+        position="x0c/0c+w1c/0.5c",
+        frame=["a.25", "y+lylabel"],
+        xlabel="test-x",
+    )
+    return fig
+
+
+@pytest.mark.mpl_image_compare
+def test_colorbar_frame_string_parameters():
+    """
+    Create colorbar with a string passed to frame and arguments passed to
+    xlabel and ylabel.
+    """
+    fig = Figure()
+    fig.colorbar(
+        cmap="rainbow",
+        position="x0c/0c+w1c/0.5c",
+        frame="a.5",
+        xlabel="test-x",
+        ylabel="test-y",
+    )
+    return fig