WIP: Add the Axes, Axis, Frame classes for the frame parameter

pygmt/params/frame.py

@@ -0,0 +1,104 @@
+"""
+The frame parameter.
+"""
+
+from dataclasses import dataclass
+from typing import Any
+
+from pygmt.alias import Alias
+from pygmt.params.base import BaseParam
+
+
+@dataclass(repr=False)
+class Axes(BaseParam):
+    """
+    Class for setting up the axes, title, and fill of a plot.
+
+    Examples
+    --------
+    >>> from pygmt.params import Axes
+    >>> str(Axes("WSen", title="My Plot Title", fill="lightred"))
+    'WSen+glightred+tMy Plot Title'
+    """
+
+    axes: Any = None
+    fill: Any = None
+    title: Any = None
+
+    @property
+    def _aliases(self):
+        return [
+            Alias(self.axes),
+            Alias(self.fill, prefix="+g"),
+            Alias(self.title, prefix="+t"),
+        ]
+
+
+@dataclass(repr=False)
+class Axis(BaseParam):
+    """
+    Class for setting up one axis of a plot.
+
+    Examples
+    --------
+    >>> from pygmt.params import Axis
+    >>> str(Axis(10, angle=30, label="X axis", unit="km"))
+    '10+a30+lX axis+ukm'
+    """
+
+    interval: float | str
+    angle: float | str | None = None
+    label: str | None = None
+    unit: str | None = None
+
+    @property
+    def _aliases(self):
+        return [
+            Alias(self.interval),
+            Alias(self.angle, prefix="+a"),
+            Alias(self.label, prefix="+l"),
+            Alias(self.unit, prefix="+u"),
+        ]
+
+
+@dataclass(repr=False)
+class Frame(BaseParam):
+    """
+    Class for setting up the frame of a plot.
+
+    >>> from pygmt.alias import AliasSystem, Alias
+    >>> from pygmt.params import Frame, Axes, Axis
+    >>> frame = Frame(
+    ...     axes=Axes("WSen", title="My Plot Title", fill="lightred"),
+    ...     xaxis=Axis(10, angle=30, label="X axis", unit="km"),
+    ... )
+    >>> def func(frame):
+    ...     alias = AliasSystem(B=Alias(frame))
+    ...     return alias.kwdict
+    >>> dict(func(frame))
+    {'B': ['WSen+glightred+tMy Plot Title', 'x10+a30+lX axis+ukm']}
+    """
+
+    axes: Any = None
+    xaxis: Any = None
+    yaxis: Any = None
+    zaxis: Any = None
+
+    @property
+    def _aliases(self):
+        return [
+            Alias(self.axes),
+            Alias(self.xaxis, prefix="x"),
+            Alias(self.yaxis, prefix="y"),
+            Alias(self.zaxis, prefix="z"),
+        ]
+
+    def __iter__(self):
+        """
+        Iterate over the aliases of the class.
+
+        Yields
+        ------
+        The value of each alias in the class. None are excluded.
+        """
+        yield from (alias._value for alias in self._aliases if alias._value is not None)