POC: Figure.subplot: Pythonic implemention for the subplot tagging

examples/gallery/embellishments/colorbars_multiple.py

@@ -2,10 +2,9 @@
 Multiple colormaps
 ==================
 
-This gallery example shows how to create multiple colormaps for different
-subplots. To better understand how GMT modern mode maintains several levels of
-colormaps, please refer to
-:gmt-docs:`reference/features.html#gmt-modern-mode-hierarchical-levels` for
+This gallery example shows how to create multiple colormaps for different subplots. To
+better understand how GMT modern mode maintains several levels of colormaps, please
+refer to :gmt-docs:`reference/features.html#gmt-modern-mode-hierarchical-levels` for
 details.
 """
 
@@ -19,26 +18,24 @@
 subset_region = [-14, 30, 35, 60]
 grid_subset = pygmt.datasets.load_earth_relief(resolution="10m", region=subset_region)
 
-# Define a 1-row, 2-column subplot layout. The overall figure dimensions are
-# set to be 15 cm wide and 8 cm high. Each subplot is automatically labelled.
-# The space between the subplots is set to be 0.5 cm.
-with fig.subplot(
-    nrows=1, ncols=2, figsize=("15c", "8c"), autolabel=True, margins="0.5c"
-):
-    # Activate the first panel so that the colormap created by the makecpt
-    # function is a panel-level CPT
+# Define a 1-row, 2-column subplot layout. The overall figure dimensions are set to be
+# 15 cm wide and 8 cm high. Each subplot is automatically labelled. The space between
+# the subplots is set to be 0.5 cm.
+with fig.subplot(nrows=1, ncols=2, figsize=("15c", "8c"), autotag=True, margins="0.5c"):
+    # Activate the first panel so that the colormap created by the makecpt function is
+    # a panel-level CPT
     with fig.set_panel(panel=0):
         pygmt.makecpt(cmap="gmt/geo", series=[-8000, 8000])
-        # "R?" means Winkel Tripel projection with map width automatically
-        # determined from the subplot width.
+        # "R?" means Winkel Tripel projection with map width automatically determined
+        # from the subplot width.
         fig.grdimage(grid=grid_globe, projection="R?", region="g", frame="a")
         fig.colorbar(frame=["a4000f2000", "x+lElevation", "y+lm"])
-    # Activate the second panel so that the colormap created by the makecpt
-    # function is a panel-level CPT
+    # Activate the second panel so that the colormap created by the makecpt function is
+    # a panel-level CPT
     with fig.set_panel(panel=1):
         pygmt.makecpt(cmap="gmt/globe", series=[-6000, 3000])
-        # "M?" means Mercator projection with map width also automatically
-        # determined from the subplot width.
+        # "M?" means Mercator projection with map width also automatically determined
+        # from the subplot width.
         fig.grdimage(grid=grid_subset, projection="M?", region=subset_region, frame="a")
         fig.colorbar(frame=["a2000f1000", "x+lElevation", "y+lm"])
 

examples/tutorials/advanced/subplots.py

@@ -3,7 +3,7 @@
 ===============
 
 When you're preparing a figure for a paper, there will often be times when
-you'll need to put many individual plots into one large figure, and label them
+you'll need to put many individual plots into one large figure, and tag them
 'abcd'. These individual plots are called subplots.
 
 There are two main ways to create subplots in GMT:
@@ -100,7 +100,7 @@
     nrows=2,
     ncols=2,
     figsize=("15c", "6c"),
-    autolabel=True,
+    autotag=True,
     frame=["af", "WSne"],
     margins=["0.1c", "0.2c"],
     title="My Subplot Heading",
@@ -117,7 +117,7 @@
 # 15 cm wide and 6 cm high (``figsize=["15c", "6c"]``). In addition, we use
 # some optional parameters to fine-tune some details of the figure creation:
 #
-# - ``autolabel=True``: Each subplot is automatically labelled 'abcd'.
+# - ``autotag=True``: Each subplot is automatically tagged 'abcd'.
 # - ``margins=["0.1c", "0.2c"]``: Adjusts the space between adjacent subplots.
 #   In this case, it is set as 0.1 cm in the x-direction and 0.2 cm in the
 #   y-direction.
@@ -168,7 +168,7 @@
     nrows=2,
     ncols=2,
     figsize=("15c", "6c"),  # width of 15 cm, height of 6 cm
-    autolabel=True,
+    autotag=True,
     margins=["0.3c", "0.2c"],  # horizontal 0.3 cm and vertical 0.2 cm margins
     title="My Subplot Heading",
     sharex="b",  # shared x-axis on the bottom side
@@ -204,7 +204,7 @@
 
 fig = pygmt.Figure()
 # Bottom row, two subplots
-with fig.subplot(nrows=1, ncols=2, figsize=("15c", "3c"), autolabel="b)"):
+with fig.subplot(nrows=1, ncols=2, figsize=("15c", "3c"), autotag="b)"):
     fig.basemap(
         region=[0, 5, 0, 5], projection="X?", frame=["af", "WSne"], panel=[0, 0]
     )
@@ -214,7 +214,7 @@
 # Move plot origin by 1 cm above the height of the entire figure
 fig.shift_origin(yshift="h+1c")
 # Top row, one subplot
-with fig.subplot(nrows=1, ncols=1, figsize=("15c", "3c"), autolabel="a)"):
+with fig.subplot(nrows=1, ncols=1, figsize=("15c", "3c"), autotag="a)"):
     fig.basemap(
         region=[0, 10, 0, 10], projection="X?", frame=["af", "WSne"], panel=[0, 0]
     )
@@ -223,20 +223,20 @@
 fig.show()
 
 # %%
-# We start by drawing the bottom two subplots, setting ``autolabel="b)"`` so
-# that the subplots are labelled 'b)' and 'c)'. Next, we use
+# We start by drawing the bottom two subplots, setting ``autotag="b)"`` so
+# that the subplots are tagged 'b)' and 'c)'. Next, we use
 # :meth:`pygmt.Figure.shift_origin` to move the plot origin 1 cm above the
 # **h**\ eight of the entire figure that is currently plotted (i.e. the bottom
 # row subplots). A single subplot is then plotted on the top row. You may need
 # to adjust the ``yshift`` parameter to make your plot look nice. This top row
-# uses ``autolabel="a)"``, and we also plotted some text inside. Note that
+# uses ``autotag="a)"``, and we also plotted some text inside. Note that
 # ``projection="X?"`` was used to let GMT automatically determine the size of
 # the subplot according to the size of the subplot area.
 
 # %%
-# You can also manually override the ``autolabel`` for each subplot using for
+# You can also manually override the ``autotag`` for each subplot using for
 # example, ``fig.set_panel(..., fixedlabel="b) Panel 2")`` which would allow
-# you to manually label a single subplot as you wish. This can be useful for
+# you to manually tag a single subplot as you wish. This can be useful for
 # adding a more descriptive subtitle to individual subplots.
 
 # sphinx_gallery_thumbnail_number = 3

pygmt/src/subplot.py

@@ -6,27 +6,130 @@
 from collections.abc import Sequence
 from typing import Literal
 
+from pygmt._typing import AnchorCode
 from pygmt.alias import Alias, AliasSystem
 from pygmt.clib import Session
 from pygmt.exceptions import GMTInvalidInput, GMTValueError
 from pygmt.helpers import build_arg_list, fmt_docstring, kwargs_to_strings, use_alias
+from pygmt.params import Box, Position
+from pygmt.src._common import _parse_position
+
+
+def _alias_option_A(  # noqa: N802
+    autotag: str | bool = False,
+    tag_position: AnchorCode | Position | None = None,
+    tag_box: Box | None = None,
+    tag_number_style: Literal["arabic", "roman", "Roman"] | None = None,
+    tag_orientation: Literal["horizontal", "vertical"] | None = None,
+    autolabel: str | bool = False,
+):
+    """
+    Helper function to create the alias list for the -A option.
+
+    Examples
+    --------
+    >>> def parse(**kwargs):
+    ...     return AliasSystem(A=_alias_option_A(**kwargs)).get("A")
+    >>> parse(autotag="a)")
+    'a)'
+    >>> parse(tag_position="TL")
+    '+jTL'
+    >>> parse(tag_position=Position("TL", cstype="inside", offset=("2c", "2c")))
+    '+jTL+o2c/2c'
+    >>> parse(tag_position=Position("TL", cstype="outside", offset=("2c", "2c")))
+    '+JTL+o2c/2c'
+    >>> parse(tag_box=Box(pen="1p,red", clearance="2c"))
+    '+c2c+p1p,red'
+    >>> parse(tag_number_style="roman")
+    '+r'
+    >>> parse(tag_orientation="vertical")
+    '+v'
+    >>> parse(
+    ...     autotag="(1)",
+    ...     tag_position="TL",
+    ...     tag_box=Box(pen="1p,red"),
+    ...     tag_number_style="Roman",
+    ...     tag_orientation="horizontal",
+    ... )
+    '(1)+jTL+p1p,red+R'
+    """
+    # Check conflicts with deprecated 'autolabel' parameter.
+    if autolabel:
+        if any(
+            v is not None and v is not False
+            for v in [autotag, tag_position, tag_box, tag_number_style, tag_orientation]
+        ):
+            msg = (
+                "The 'autolabel' parameter is deprecated since v0.18.0. "
+                "Please use the parameters 'autotag', 'tag_position', 'tag_box', "
+                "'tag_number_style', 'tag_orientation', and 'tag_font' instead."
+            )
+            raise GMTInvalidInput(msg)
+        return Alias(autolabel, name="autolabel")
+
+    # Validate tag_box if provided.
+    if tag_box:
+        if any(
+            v is not None and v is not False
+            for v in {tag_box.inner_pen, tag_box.inner_gap, tag_box.radius}
+        ):
+            raise GMTValueError(
+                tag_box,
+                description="Box properties for 'tag_box' in 'Figure.subplot'",
+                reason="The 'inner_pen', 'inner_gap', and 'radius' properties are not supported.",
+            )
+        if tag_box.clearance and len(tag_box.clearance) > 2:
+            raise GMTValueError(
+                tag_box,
+                description="Box 'clearance' property for 'tag_box' in 'Figure.subplot'",
+                reason="Only one or two values are accepted.",
+            )
+    # Validate the tag_position if provided.
+    if getattr(tag_position, "cstype", None) in {
+        "mapcoords",
+        "plotcoords",
+        "boxcoords",
+    }:
+        raise GMTValueError(
+            tag_position,
+            description="tag position for 'Figure.subplot'.",
+            reason="Only 'inside' or 'outside' cstype is allowed.",
+        )
+
+    return [
+        Alias(autotag, name="autotag"),
+        Alias(
+            _parse_position(tag_position), name="tag_position", prefix="+"
+        ),  # Prefix is "+".
+        Alias(tag_box, name="tag_box"),
+        Alias(
+            tag_number_style,
+            name="tag_number_style",
+            mapping={"arabic": "", "roman": "+r", "Roman": "+R"},
+        ),
+        Alias(
+            tag_orientation,
+            name="tag_orientation",
+            mapping={"horizontal": "", "vertical": "+v"},
+        ),
+    ]
 
 
 @fmt_docstring
 @contextlib.contextmanager
-@use_alias(
-    Ff="figsize",
-    Fs="subsize",
-    A="autolabel",
-    C="clearance",
-    SC="sharex",
-    SR="sharey",
-)
+@use_alias(Ff="figsize", Fs="subsize", C="clearance", SC="sharex", SR="sharey")
 @kwargs_to_strings(Ff="sequence", Fs="sequence")
-def subplot(
+def subplot(  # noqa: PLR0913
     self,
     nrows: int = 1,
     ncols: int = 1,
+    autotag: str | bool = False,
+    tag_position: AnchorCode | Position | None = None,
+    tag_box: Box | None = None,
+    tag_orientation: Literal["horizontal", "vertical"] | None = None,
+    tag_number_style: Literal["arabic", "roman", "Roman"] | None = None,
+    tag_font: str | None = None,
+    autolabel: str | bool = False,
     margins: float | str | Sequence[float | str] | None = None,
     title: str | None = None,
     projection: str | None = None,
@@ -67,31 +170,59 @@ def subplot(
         Specify the dimensions of each subplot directly as [*width*, *height*].
         Note that only one of ``figsize`` or ``subsize`` can be provided at
         once.
+    autotag
+        Specify automatic tagging of each subplot. It can accept a number, or a letter.
+        The number or letter can be surrounded by parentheses on any side if these
+        should be typeset as part of the tag. This sets the tag of the first, top-left
+        subplot and others follow sequentially. If set to ``True``, default to ``"a)"``.
+
+        Examples are:
+
+        - ``autotag="a"``: tags are ``a``, ``b``, ``c``, ...
+        - ``autotag="1"``: tags are ``1``, ``2``, ``3``, ...
+        - ``autotag="a)"``: tags are ``a)``, ``b)``, ``c)``, ...
+        - ``autotag="(c)"``: tags are ``(c)``, ``(d)``, ``(e)``, ...
+        - ``autotag=True``: same as ``autotag="a)"``.
+    tag_position
+        Position of the subplot tag on the plot. It can be specified in two ways:
+
+        - A :doc:`2-character justification code </techref/justification_codes>` for a
+          position inside the plot, e.g., ``"TL"`` for Top Left corner inside the plot.
+        - A :class:`pygmt.params.Position` object to fully control the position and
+          offset. **Note**: the ``refpoint`` propterty of the Position object must be
+          an two-character justification code, and ``cstype`` must be set to either
+          ``"inside"`` or ``"outside"``,
+
+        If not specified, defaults to Top Left corner inside the plot with the offset
+        default to ``("4p", "4p")``, i.e., 20% of the :gmt-term:`FONT_TAG` size.
+    tag_box
+        Draw a box around the subplot tag. See :class:`pygmt.params.Box` for details on
+        how to specify the box.
+
+        **Notes on the use of the ``Box`` class:**
 
-    autolabel : bool or str
-        [*autolabel*][**+c**\ *dx*\ [/*dy*]][**+g**\ *fill*][**+j**\|\ **J**\
-        *refpoint*][**+o**\ *dx*\ [/*dy*]][**+p**\ *pen*][**+r**\|\ **R**]\ [**+v**].
-        Specify automatic tagging of each subplot. Append either a number or letter
-        [Default is ``"a"``]. This sets the tag of the first, top-left subplot and
-        others follow sequentially. Surround the number or letter by parentheses on
-        any side if these should be typeset as part of the tag [Default is ``")"``].
-        Use **+j**\|\ **J** for setting *refpoint* via a
-        :doc:`2-character justification code </techref/justification_codes>`
-        to specify where the tag should be placed in the subplot [Default is ``"TL"``
-        for the Top Left corner]. **Note**: **+j** sets the justification of the tag
-        to *refpoint* (suitable for interior tags) while **+J** instead selects the
-        mirror opposite (suitable for exterior tags). Append **+c**\ *dx*\[/*dy*] to
-        set the clearance between the tag and a surrounding text box requested via
-        **+g** or **+p** [Default is ``"3p/3p"``, i.e., 15 % of the
-        :gmt-term:`FONT_TAG` size dimension]. Append **+g**\ *fill* to paint the tag's
-        text box with *fill* [Default is no fill]. Append **+o**\ *dx*\ [/*dy*] to
-        offset the tag's reference point in the direction implied by the justification
-        [Default is ``"4p/4p"``, i.e., 20 % of the :gmt-term:`FONT_TAG` size]. Append
-        **+p**\ *pen* to draw the outline of the tag's text box using the selected *pen*
-        [Default is no outline]. Append **+r** to typeset your tag numbers using
-        lowercase Roman numerals; use **+R** for uppercase Roman numerals [Default is
-        Arabic numerals]. Append **+v** to increase tag numbers vertically down columns
-        [Default is horizontally across rows].
+        - The property ``clearance`` only accept one or two values.
+        - The property ``inner_pen``/``inner_gap``/``radius`` is not supported.
+    tag_number_style
+        Style of the subplot tag numbers. It can be:
+
+        - ``"arabic"``: Arabic numerals: 1, 2, 3, ... [Default].
+        - ``"roman"``: Lowercase Roman numerals: i, ii, iii, ...
+        - ``"Roman"``: Uppercase Roman numerals: I, II, III, ...
+    tag_orientation
+        Orientation of the subplot tag. It can be:
+
+        - ``"horizontal"``: Increase tag numbers horizontally across rows [Default].
+        - ``"vertical"``: Increase tag numbers vertically down columns.
+    tag_font
+        Font for the subplot tag [Default to ``"20p,Helvetica,black"``].
+    autolabel
+        Specify automatic tagging of each subplot.
+
+        .. deprecated:: v0.19.0
+
+           Use the parameters ``autotag``, ``tag_position``, ``tag_box``,
+           ``tag_number_style``, ``tag_orientation``, and ``tag_font`` instead.
     clearance : str or list
         [*side*]\ *clearance*.
         Reserve a space of dimension *clearance* between the margin and the
@@ -170,6 +301,14 @@ def subplot(
         raise GMTInvalidInput(msg)
 
     aliasdict = AliasSystem(
+        A=_alias_option_A(
+            autotag=autotag,
+            tag_position=tag_position,
+            tag_box=tag_box,
+            tag_number_style=tag_number_style,
+            tag_orientation=tag_orientation,
+            autolabel=autolabel,
+        ),
         M=Alias(margins, name="margins", sep="/", size=(2, 4)),
         T=Alias(title, name="title"),
     ).add_common(
@@ -180,6 +319,9 @@ def subplot(
     )
     aliasdict.merge(kwargs)
 
+    # Configure FONT_TAG if tag_font is set
+    confdict = {"FONT_TAG": tag_font} if tag_font is not None else {}
+
     # Need to use separate sessions for "subplot begin" and "subplot end".
     # Otherwise, "subplot end" will use the last session, which may cause
     # strange positioning issues for later plotting calls.
@@ -188,7 +330,11 @@ def subplot(
         with Session() as lib:
             lib.call_module(
                 module="subplot",
-                args=["begin", f"{nrows}x{ncols}", *build_arg_list(aliasdict)],
+                args=[
+                    "begin",
+                    f"{nrows}x{ncols}",
+                    *build_arg_list(aliasdict, confdict=confdict),
+                ],
             )
             yield
     finally: