params.Frame: Add parameters for 3-D plots

pygmt/params/frame.py

@@ -105,6 +105,11 @@ class _Axes(BaseParam):
     title: str | None = None
     subtitle: str | None = None
     fill: str | None = None
+    box: bool = False
+    wall_pen: str | bool = False
+    yzfill: str | None = None
+    xzfill: str | None = None
+    xyfill: str | None = None
 
     @property
     def _aliases(self):
@@ -113,6 +118,11 @@ def _aliases(self):
             Alias(self.fill, name="fill", prefix="+g"),
             Alias(self.title, name="title", prefix="+t"),
             Alias(self.subtitle, name="subtitle", prefix="+s"),
+            Alias(self.box, name="box", prefix="+b"),
+            Alias(self.wall_pen, name="wall_pen", prefix="+w"),
+            Alias(self.yzfill, name="yzfill", prefix="+x"),
+            Alias(self.xzfill, name="xzfill", prefix="+y"),
+            Alias(self.xyfill, name="xyfill", prefix="+z"),
         ]
 
 
@@ -209,6 +219,22 @@ class Frame(BaseParam):
     #: fill].
     fill: str | None = None
 
+    #: Draw the foreground lines of a 3-D box. [For 3-D plots only]
+    box: bool = False
+
+    #: Draw the outlines of the x-z and y-z planes by the specified pen attributes.
+    #: If ``True``, use the default pen. [For 3-D plots only]
+    wall_pen: str | bool = False
+
+    #: Fill for the yz-plane (the plane normal to the x-axis). [For 3-D plots only]
+    yzfill: str | None = None
+
+    #: Fill for the xz-plane (the plane normal to the y-axis). [For 3-D plots only]
+    xzfill: str | None = None
+
+    #: Fill for the xy-plane (the plane normal to the z-axis). [For 3-D plots only]
+    xyfill: str | None = None
+
     #: Specify the attributes for axes by an :class:`Axis` object.
     #:
     #: The attributes for x and y axes can be specified in two ways: (1) specifying the
@@ -260,7 +286,15 @@ def _aliases(self):
         # _Axes() maps to an empty string, which becomes '-B' without arguments and is
         # invalid when combined with individual axis settings (e.g., '-B -Bxaf -Byaf').
         frame_settings = _Axes(
-            axes=self.axes, title=self.title, subtitle=self.subtitle, fill=self.fill
+            axes=self.axes,
+            title=self.title,
+            subtitle=self.subtitle,
+            fill=self.fill,
+            box=self.box,
+            wall_pen=self.wall_pen,
+            yzfill=self.yzfill,
+            xzfill=self.xzfill,
+            xyfill=self.xyfill,
         )
         has_secondary_xy_axis = any([self.axis2, self.xaxis2, self.yaxis2])
         return [

pygmt/tests/test_params_frame.py

@@ -42,6 +42,24 @@ def test_params_frame_only():
     frame = Frame(axes="WSEN", title="My Title", subtitle="My Subtitle", fill="red")
     assert str(frame) == "WSEN+gred+tMy Title+sMy Subtitle"
 
+    frame = Frame(axes="WSrtZ", box=True, wall_pen="1p,red")
+    assert str(frame) == "WSrtZ+b+w1p,red"
+
+    frame = Frame(axes="WSrtZ", yzfill="red", xzfill="green", xyfill="blue")
+    assert str(frame) == "WSrtZ+xred+ygreen+zblue"
+
+    frame = Frame(
+        axes="WSrtZ",
+        box=True,
+        title="My Title",
+        fill="gray",
+        wall_pen="0.5p,black",
+        yzfill="red",
+        xzfill="green",
+        xyfill="blue",
+    )
+    assert str(frame) == "WSrtZ+ggray+tMy Title+b+w0.5p,black+xred+ygreen+zblue"
+
 
 def test_params_frame_axis():
     """