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""" |
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Low-level text helper utilities. |
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""" |
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from __future__ import annotations |
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import dataclasses |
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from . import _api |
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from .ft2font import FT2Font, Kerning, LoadFlags |
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@dataclasses.dataclass(frozen=True) |
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class LayoutItem: |
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ft_object: FT2Font |
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char: str |
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glyph_idx: int |
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x: float |
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prev_kern: float |
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def warn_on_missing_glyph(codepoint, fontnames): |
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_api.warn_external( |
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f"Glyph {codepoint} " |
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f"({chr(codepoint).encode('ascii', 'namereplace').decode('ascii')}) " |
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f"missing from font(s) {fontnames}.") |
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block = ("Hebrew" if 0x0590 <= codepoint <= 0x05ff else |
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"Arabic" if 0x0600 <= codepoint <= 0x06ff else |
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"Devanagari" if 0x0900 <= codepoint <= 0x097f else |
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"Bengali" if 0x0980 <= codepoint <= 0x09ff else |
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"Gurmukhi" if 0x0a00 <= codepoint <= 0x0a7f else |
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"Gujarati" if 0x0a80 <= codepoint <= 0x0aff else |
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"Oriya" if 0x0b00 <= codepoint <= 0x0b7f else |
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"Tamil" if 0x0b80 <= codepoint <= 0x0bff else |
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"Telugu" if 0x0c00 <= codepoint <= 0x0c7f else |
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"Kannada" if 0x0c80 <= codepoint <= 0x0cff else |
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"Malayalam" if 0x0d00 <= codepoint <= 0x0d7f else |
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"Sinhala" if 0x0d80 <= codepoint <= 0x0dff else |
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None) |
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if block: |
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_api.warn_external( |
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f"Matplotlib currently does not support {block} natively.") |
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def layout(string, font, *, kern_mode=Kerning.DEFAULT): |
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""" |
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Render *string* with *font*. |
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For each character in *string*, yield a LayoutItem instance. When such an instance |
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is yielded, the font's glyph is set to the corresponding character. |
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Parameters |
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---------- |
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string : str |
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The string to be rendered. |
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font : FT2Font |
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The font. |
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kern_mode : Kerning |
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A FreeType kerning mode. |
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Yields |
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------ |
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LayoutItem |
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""" |
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x = 0 |
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prev_glyph_idx = None |
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char_to_font = font._get_fontmap(string) |
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base_font = font |
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for char in string: |
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font = char_to_font.get(char, base_font) |
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glyph_idx = font.get_char_index(ord(char)) |
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kern = ( |
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base_font.get_kerning(prev_glyph_idx, glyph_idx, kern_mode) / 64 |
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if prev_glyph_idx is not None else 0. |
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) |
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x += kern |
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glyph = font.load_glyph(glyph_idx, flags=LoadFlags.NO_HINTING) |
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yield LayoutItem(font, char, glyph_idx, x, kern) |
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x += glyph.linearHoriAdvance / 65536 |
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prev_glyph_idx = glyph_idx |
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