Figure.paragraph: Initial implementation focusing on input data

pygmt/figure.py

@@ -424,6 +424,7 @@ def _repr_html_(self) -> str:
         legend,
         logo,
         meca,
+        paragraph,
         plot,
         plot3d,
         psconvert,

pygmt/src/__init__.py

@@ -38,6 +38,7 @@
 from pygmt.src.makecpt import makecpt
 from pygmt.src.meca import meca
 from pygmt.src.nearneighbor import nearneighbor
+from pygmt.src.paragraph import paragraph
 from pygmt.src.plot import plot
 from pygmt.src.plot3d import plot3d
 from pygmt.src.project import project

pygmt/src/paragraph.py

@@ -0,0 +1,113 @@
+"""
+paragraph - Typeset one or multiple paragraphs.
+"""
+
+import io
+from collections.abc import Sequence
+from typing import Literal
+
+from pygmt._typing import AnchorCode
+from pygmt.clib import Session
+from pygmt.exceptions import GMTInvalidInput
+from pygmt.helpers import (
+    _check_encoding,
+    build_arg_list,
+    is_nonstr_iter,
+    non_ascii_to_octal,
+)
+
+
+def _parse_option_f_upper(
+    font: float | str | None, angle: float | None, justify: AnchorCode | None
+) -> str | None:
+    """
+    Parse the font, angle, and justification arguments and return the string to be
+    appended to the module options.
+
+    Examples
+    --------
+    >>> _parse_font_angle_justify(None, None, None)
+    >>> _parse_font_angle_justify("10p", None, None)
+    '+f10p'
+    >>> _parse_font_angle_justify(None, 45, None)
+    '+a45'
+    >>> _parse_font_angle_justify(None, None, "CM")
+    '+jCM'
+    >>> _parse_font_angle_justify("10p,Helvetica-Bold", 45, "CM")
+    '+f10p,Helvetica-Bold+a45+jCM'
+    """
+    args = ((font, "+f"), (angle, "+a"), (justify, "+j"))
+    if all(arg is None for arg, _ in args):
+        return None
+    return "".join(f"{flag}{arg}" for arg, flag in args if arg is not None)
+
+
+def paragraph(
+    self,
+    x: float | str,
+    y: float | str,
+    text: str | Sequence[str],
+    parwidth: float | str,
+    linespacing: float | str,
+    font: float | str | None = None,
+    angle: float | None = None,
+    justify: AnchorCode | None = None,
+    alignment: Literal["left", "center", "right", "justified"] = "left",
+):
+    """
+    Typeset one or multiple paragraphs.
+
+    Parameters
+    ----------
+    x/y
+        The x, y coordinates of the paragraph.
+    text
+        The paragraph text to typeset. If a sequence of strings is provided, each
+        string is treated as a separate paragraph.
+    parwidth
+        The width of the paragraph.
+    linespacing
+        The spacing between lines.
+    font
+        The font of the text.
+    angle
+        The angle of the text.
+    justify
+        The justification of the block of text, relative to the given x, y position.
+    alignment
+        The alignment of the text. Valid values are ``"left"``, ``"center"``,
+        ``"right"``, and ``"justified"``.
+    """
+    self._preprocess()
+
+    # Validate 'alignment' argument.
+    if alignment not in {"left", "center", "right", "justified"}:
+        msg = (
+            "Invalid value for 'alignment': {alignment}. "
+            "Valid values are 'left', 'center', 'right', and 'justified'."
+        )
+        raise GMTInvalidInput(msg)
+
+    confdict = {}
+    # Prepare the keyword dictionary for the module options
+    kwdict = {"M": True, "F": _parse_option_f_upper(font, angle, justify)}
+
+    # Initialize a stringio object for storing the input data.
+    stringio = io.StringIO()
+    # The header line.
+    stringio.write(f"> {x} {y} {linespacing} {parwidth} {alignment[0]}\n")
+    # The text string to be written to the stringio object.
+    # Multiple paragraphs are separated by a blank line "\n\n".
+    _textstr: str = "\n\n".join(text) if is_nonstr_iter(text) else str(text)
+    # Check the encoding of the text string and convert it to octal if necessary.
+    if (encoding := _check_encoding(_textstr)) != "ascii":
+        _textstr = non_ascii_to_octal(_textstr, encoding=encoding)
+        confdict["PS_CHAR_ENCODING"] = encoding
+    # Write the text string to the stringio object.
+    stringio.write(_textstr)
+
+    with Session() as lib:
+        with lib.virtualfile_from_stringio(stringio) as vfile:
+            lib.call_module(
+                "text", args=build_arg_list(kwdict, infile=vfile, confdict=confdict)
+            )

pygmt/tests/test_paragraph.py

@@ -0,0 +1,67 @@
+"""
+Tests for Figure.paragraph.
+"""
+
+import pytest
+from pygmt import Figure
+
+
+@pytest.mark.mpl_image_compare
+def test_paragraph():
+    """
+    Test typesetting a single paragraph.
+    """
+    fig = Figure()
+    fig.basemap(region=[0, 10, 0, 10], projection="X10c/10c", frame=True)
+    fig.paragraph(
+        x=4,
+        y=4,
+        text="This is a long paragraph. " * 10,
+        parwidth="5c",
+        linespacing="12p",
+    )
+    return fig
+
+
+@pytest.mark.mpl_image_compare
+def test_paragraph_multiple_paragraphs_list():
+    """
+    Test typesetting a single paragraph.
+    """
+    fig = Figure()
+    fig.basemap(region=[0, 10, 0, 10], projection="X10c/10c", frame=True)
+    fig.paragraph(
+        x=4,
+        y=4,
+        text=[
+            "This is the first paragraph. " * 5,
+            "This is the second paragraph. " * 5,
+        ],
+        parwidth="5c",
+        linespacing="12p",
+    )
+    return fig
+
+
+@pytest.mark.mpl_image_compare
+def test_paragraph_multiple_paragraphs_blankline():
+    """
+    Test typesetting a single paragraph.
+    """
+    text = """
+This is the first paragraph.
+This is the first paragraph.
+This is the first paragraph.
+This is the first paragraph.
+This is the first paragraph.
+
+This is the second paragraph.
+This is the second paragraph.
+This is the second paragraph.
+This is the second paragraph.
+This is the second paragraph.
+"""
+    fig = Figure()
+    fig.basemap(region=[0, 10, 0, 10], projection="X10c/10c", frame=True)
+    fig.paragraph(x=4, y=4, text=text, parwidth="5c", linespacing="12p")
+    return fig