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"""

Low-level text helper utilities.

"""

from __future__ import annotations

import dataclasses

from . import _api

from .ft2font import FT2Font, Kerning, LoadFlags

@dataclasses.dataclass(frozen=True)

class LayoutItem:

ft_object: FT2Font

char: str

glyph_idx: int

x: float

prev_kern: float

def warn_on_missing_glyph(codepoint, fontnames):

_api.warn_external(

f"Glyph {codepoint} "

f"({chr(codepoint).encode('ascii', 'namereplace').decode('ascii')}) "

f"missing from font(s) {fontnames}.")

block = ("Hebrew" if 0x0590 <= codepoint <= 0x05ff else

"Arabic" if 0x0600 <= codepoint <= 0x06ff else

"Devanagari" if 0x0900 <= codepoint <= 0x097f else

"Bengali" if 0x0980 <= codepoint <= 0x09ff else

"Gurmukhi" if 0x0a00 <= codepoint <= 0x0a7f else

"Gujarati" if 0x0a80 <= codepoint <= 0x0aff else

"Oriya" if 0x0b00 <= codepoint <= 0x0b7f else

"Tamil" if 0x0b80 <= codepoint <= 0x0bff else

"Telugu" if 0x0c00 <= codepoint <= 0x0c7f else

"Kannada" if 0x0c80 <= codepoint <= 0x0cff else

"Malayalam" if 0x0d00 <= codepoint <= 0x0d7f else

"Sinhala" if 0x0d80 <= codepoint <= 0x0dff else

None)

if block:

_api.warn_external(

f"Matplotlib currently does not support {block} natively.")

def layout(string, font, *, kern_mode=Kerning.DEFAULT):

"""

Render *string* with *font*.

For each character in *string*, yield a LayoutItem instance. When such an instance

is yielded, the font's glyph is set to the corresponding character.

Parameters

----------

string : str

The string to be rendered.

font : FT2Font

The font.

kern_mode : Kerning

A FreeType kerning mode.

Yields

------

LayoutItem

"""

x = 0

prev_glyph_idx = None

char_to_font = font._get_fontmap(string)

base_font = font

for char in string:

# This has done the fallback logic

font = char_to_font.get(char, base_font)

glyph_idx = font.get_char_index(ord(char))

kern = (

base_font.get_kerning(prev_glyph_idx, glyph_idx, kern_mode) / 64

if prev_glyph_idx is not None else 0.

)

x += kern

glyph = font.load_glyph(glyph_idx, flags=LoadFlags.NO_HINTING)

yield LayoutItem(font, char, glyph_idx, x, kern)

x += glyph.linearHoriAdvance / 65536

prev_glyph_idx = glyph_idx