1573e1eed6
Summary: The ability to use pre-determined character widths will benefit alternative layout engines such as gagern's canvas layout engine. I would also like to experiment would using CSS transforms to absolutely position each glyph. This diff adds a new make rule, make extended_metrics, which generates metrics that also containing glyph widths. Test Plan: - run `make extended_metrics` - verify that fontMetricsData.js contains entries with 5 numbers instead of 4 Reviewers: emily alpert
116 lines
4.0 KiB
Python
Executable File
116 lines
4.0 KiB
Python
Executable File
#!/usr/bin/env python
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from fontTools.ttLib import TTFont
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import sys
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import json
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# map of characters to extract
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metrics_to_extract = {
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# Font name
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"AMS-Regular": {
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u"\u21e2": None, # \dashrightarrow
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u"\u21e0": None, # \dashleftarrow
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},
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"Main-Regular": {
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# Skew and italic metrics can't be easily parsed from the TTF. Instead,
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# we map each character to a "base character", which is a character
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# from the same font with correct italic and skew metrics. A character
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# maps to None if it doesn't have a base.
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u"\u2260": None, # \neq
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u"\u2245": None, # \cong
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u"\u0020": None, # space
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u"\u00a0": None, # nbsp
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u"\u2026": None, # \ldots
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u"\u22ef": None, # \cdots
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u"\u22f1": None, # \ddots
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u"\u22ee": None, # \vdots
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u"\u22ee": None, # \vdots
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u"\u22a8": None, # \models
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u"\u22c8": None, # \bowtie
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u"\u2250": None, # \doteq
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u"\u23b0": None, # \lmoustache
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u"\u23b1": None, # \rmoustache
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u"\u27ee": None, # \lgroup
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u"\u27ef": None, # \rgroup
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u"\u27f5": None, # \longleftarrow
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u"\u27f8": None, # \Longleftarrow
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u"\u27f6": None, # \longrightarrow
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u"\u27f9": None, # \Longrightarrow
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u"\u27f7": None, # \longleftrightarrow
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u"\u27fa": None, # \Longleftrightarrow
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u"\u21a6": None, # \mapsto
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u"\u27fc": None, # \longmapsto
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u"\u21a9": None, # \hookleftarrow
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u"\u21aa": None, # \hookrightarrow
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u"\u21cc": None, # \rightleftharpoons
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},
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"Size1-Regular": {
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u"\u222c": u"\u222b", # \iint, based on \int
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u"\u222d": u"\u222b", # \iiint, based on \int
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},
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"Size2-Regular": {
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u"\u222c": u"\u222b", # \iint, based on \int
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u"\u222d": u"\u222b", # \iiint, based on \int
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},
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}
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def main():
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start_json = json.load(sys.stdin)
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for font, chars in metrics_to_extract.iteritems():
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fontInfo = TTFont("../static/fonts/KaTeX_" + font + ".ttf")
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glyf = fontInfo["glyf"]
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unitsPerEm = float(fontInfo["head"].unitsPerEm)
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# We keep ALL Unicode cmaps, not just fontInfo["cmap"].getcmap(3, 1).
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# This is playing it extra safe, since it reports inconsistencies.
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# Platform 0 is Unicode, platform 3 is Windows. For platform 3,
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# encoding 1 is UCS-2 and encoding 10 is UCS-4.
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cmap = [t.cmap for t in fontInfo["cmap"].tables
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if (t.platformID == 0)
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or (t.platformID == 3 and t.platEncID in (1, 10))]
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for char, base_char in chars.iteritems():
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code = ord(char)
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names = set(t.get(code) for t in cmap)
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if not names:
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sys.stderr.write(
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"Codepoint {} of font {} maps to no name\n"
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.format(code, font))
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continue
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if len(names) != 1:
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sys.stderr.write(
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"Codepoint {} of font {} maps to multiple names: {}\n"
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.format(code, font, ", ".join(sorted(names))))
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continue
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name = names.pop()
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height = depth = italic = skew = width = 0
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glyph = glyf[name]
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if glyph.numberOfContours:
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height = glyph.yMax
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depth = -glyph.yMin
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width = glyph.xMax - glyph.xMin
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if base_char:
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base_char_str = str(ord(base_char))
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base_metrics = start_json[font][base_char_str]
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italic = base_metrics["italic"]
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skew = base_metrics["skew"]
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width = base_metrics["width"]
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start_json[font][str(code)] = {
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"height": height / unitsPerEm,
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"depth": depth / unitsPerEm,
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"italic": italic,
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"skew": skew,
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"width": width
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}
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sys.stdout.write(
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json.dumps(start_json, separators=(',', ':'), sort_keys=True))
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if __name__ == "__main__":
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main()
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