Function pdfRepr

lib/matplotlib/backends/backend_pdf.py:298–368

Map Python objects to PDF syntax.

(obj)

def pdfRepr(obj):
    """Map Python objects to PDF syntax."""

    # Some objects defined later have their own pdfRepr method.
    if hasattr(obj, 'pdfRepr'):
        return obj.pdfRepr()

    # Floats. PDF does not have exponential notation (1.0e-10) so we
    # need to use %f with some precision.  Perhaps the precision
    # should adapt to the magnitude of the number?
    elif isinstance(obj, (float, np.floating)):
        if not np.isfinite(obj):
            raise ValueError("Can only output finite numbers in PDF")
        r = b"%.10f" % obj
        return r.rstrip(b'0').rstrip(b'.')

    # Booleans. Needs to be tested before integers since
    # isinstance(True, int) is true.
    elif isinstance(obj, bool):
        return [b'false', b'true'][obj]

    # Integers are written as such.
    elif isinstance(obj, (int, np.integer)):
        return b"%d" % obj

    # Non-ASCII Unicode strings are encoded in UTF-16BE with byte-order mark.
    elif isinstance(obj, str):
        return pdfRepr(obj.encode('ascii') if obj.isascii()
                       else codecs.BOM_UTF16_BE + obj.encode('UTF-16BE'))

    # Strings are written in parentheses, with backslashes and parens
    # escaped. Actually balanced parens are allowed, but it is
    # simpler to escape them all. TODO: cut long strings into lines;
    # I believe there is some maximum line length in PDF.
    # Despite the extra decode/encode, translate is faster than regex.
    elif isinstance(obj, bytes):
        return (
            b'(' +
            obj.decode('latin-1').translate(_str_escapes).encode('latin-1')
            + b')')

    # Dictionaries. The keys must be PDF names, so if we find strings
    # there, we make Name objects from them. The values may be
    # anything, so the caller must ensure that PDF names are
    # represented as Name objects.
    elif isinstance(obj, dict):
        return _fill([
            b"<<",
            *[Name(k).pdfRepr() + b" " + pdfRepr(v) for k, v in obj.items()],
            b">>",
        ])

    # Lists.
    elif isinstance(obj, (list, tuple)):
        return _fill([b"[", *[pdfRepr(val) for val in obj], b"]"])

    # The null keyword.
    elif obj is None: