Source code for pyface.util.font_parser

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GENERIC_FAMILIES = {
    'default', 'fantasy', 'decorative', 'serif', 'roman', 'cursive', 'script',
    'sans-serif', 'swiss', 'monospace', 'modern', 'typewriter', 'teletype'
}
WEIGHTS = {
    'thin', 'extra-light', 'light', 'regular', 'medium', 'demi-bold',
    'bold', 'extra-bold', 'heavy', 'extra-heavy'
}
STRETCHES = {
    'ultra-condensed', 'extra-condensed', 'condensed',
    'semi-condensed', 'semi-expanded', 'expanded', 'extra-expanded',
    'ultra-expanded'
}
STYLES = {'italic', 'oblique'}
VARIANTS = {'small-caps'}
DECORATIONS = {'underline', 'strikethrough', 'overline'}
NOISE = {'pt', 'point', 'px', 'family'}


[docs]class FontParseError(ValueError): """An exception raised when font parsing fails.""" pass
[docs]def simple_parser(description): """An extremely simple font description parser. The parser is simple, and works by splitting the description on whitespace and examining each resulting token for understood terms: Size The first numeric term is treated as the font size. Weight The following weight terms are accepted: 'thin', 'extra-light', 'light', 'regular', 'medium', 'demi-bold', 'bold', 'extra-bold', 'heavy', 'extra-heavy'. Stretch The following stretch terms are accepted: 'ultra-condensed', 'extra-condensed', 'condensed', 'semi-condensed', 'semi-expanded', 'expanded', 'extra-expanded', 'ultra-expanded'. Style The following style terms are accepted: 'italic', 'oblique'. Variant The following variant terms are accepted: 'small-caps'. Decorations The following decoration terms are accepted: 'underline', 'strikethrough', 'overline'. Generic Families The following generic family terms are accepted: 'default', 'fantasy', 'decorative', 'serif', 'roman', 'cursive', 'script', 'sans-serif', 'swiss', 'monospace', 'modern', 'typewriter', 'teletype'. In addtion, the parser ignores the terms 'pt', 'point', 'px', and 'family'. Any remaining terms are combined into the typeface name. There is no expected order to the terms. This parser is roughly compatible with the various ad-hoc parsers in TraitsUI and Kiva, allowing for the slight differences between them and adding support for additional options supported by Pyface fonts, such as stretch and variants. Parameters ---------- description : str The font description to be parsed. Returns ------- properties : dict Font properties suitable for use in creating a Pyface Font. Notes ----- This is not a particularly good parser, as it will fail to properly parse something like "10 pt times new roman" or "14 pt computer modern" since they have generic font names as part of the font face name. """ face = [] generic_family = "" size = None weight = "normal" stretch = "normal" style = "normal" variants = set() decorations = set() for word in description.lower().split(): if word in NOISE: continue elif word in GENERIC_FAMILIES: generic_family = word elif word in WEIGHTS: weight = word elif word in STRETCHES: stretch = word elif word in STYLES: style = word elif word in VARIANTS: variants.add(word) elif word in DECORATIONS: decorations.add(word) else: if size is None: try: size = float(word) continue except ValueError: pass face.append(word) family = [] if face: family.append(" ".join(face)) if generic_family: family.append(generic_family) if not family: family = ["default"] if size is None: size = 12 return { 'family': family, 'size': size, 'weight': weight, 'stretch': stretch, 'style': style, 'variants': variants, 'decorations': decorations, }