346 lines
11 KiB
Python
346 lines
11 KiB
Python
"""
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Post-nanoemoji processing of the Noto COLRv1 Emoji files.
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Adds additional sequences to properly support Safari, corrects 'name', etc.
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For now substantially based on copying from a correct bitmap build.
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"""
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from absl import app
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import functools
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from fontTools.feaLib.builder import addOpenTypeFeaturesFromString
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from fontTools import ttLib
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from fontTools.ttLib.tables import _g_l_y_f as glyf
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from fontTools.ttLib.tables import otTables as ot
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import map_pua_emoji
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from nototools import add_vs_cmap
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from nototools import font_data
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from nototools import unicode_data
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from pathlib import Path
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import re
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from colrv1_add_soft_light_to_flags import add_soft_light_to_flags
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_CBDT_FILE = Path("fonts/NotoColorEmoji.ttf")
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_COLR_FILES = {
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Path("fonts/Noto-COLRv1-noflags.ttf"),
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Path("fonts/Noto-COLRv1.ttf"),
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}
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def _is_colrv1(font):
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return "COLR" in font and font["COLR"].version == 1
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def _is_cbdt(font):
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return "CBDT" in font
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def _set_name(name_table, nameID):
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name_table.getName(value, nameID, 3, 1, 0x409)
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def _set_name(name_table, nameID, value):
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name_table.setName(value, nameID, 3, 1, 0x409)
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def _copy_names(colr_font, cbdt_font):
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colr_font["name"] = cbdt_font["name"]
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name_table = colr_font["name"]
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assert all(
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(n.platformID, n.platEncID, n.langID) == (3, 1, 0x409) for n in name_table.names
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), "Should only have names Android uses"
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# Amendments
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_set_name(name_table, 10, "Color emoji font using COLRv1.")
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_set_name(name_table, 11, "https://github.com/googlefonts/noto-emoji")
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_set_name(name_table, 12, "https://github.com/googlefonts/noto-emoji")
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# CBDT build step: @$(VS_ADDER) -vs 2640 2642 2695 --dstdir '.' -o "$@-with-pua-varsel" "$@-with-pua"
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def _add_vs_cmap(colr_font):
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emoji_variants = unicode_data.get_unicode_emoji_variants() | {
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0x2640,
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0x2642,
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0x2695,
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}
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add_vs_cmap.modify_font("COLRv1 Emoji", colr_font, "emoji", emoji_variants)
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def _is_variation_selector_cmap_table(table):
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assert table.format in {4, 12, 14}
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return table.format == 14
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def _lookup_in_cmap(colr_font, codepoint):
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result = set()
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for table in colr_font["cmap"].tables:
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if _is_variation_selector_cmap_table(table):
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continue
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assert codepoint in table.cmap
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result.add(table.cmap[codepoint])
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assert len(result) == 1, f"Ambiguous mapping for {codepoint}: {result}"
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return next(iter(result))
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def _add_cmap_entries(colr_font, codepoint, glyph_name):
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for table in colr_font["cmap"].tables:
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if _is_variation_selector_cmap_table(table):
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continue
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if not _is_bmp(codepoint) and table.format == 4:
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continue
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table.cmap[codepoint] = glyph_name
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#print(f"Map 0x{codepoint:04x} to {glyph_name}, format {table.format}")
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FLAG_TAGS = set(range(0xE0030, 0xE0039 + 1)) | set(range(0xE0061, 0xE007A + 1))
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CANCEL_TAG = 0xE007F
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def _map_missing_flag_tag_chars_to_empty_glyphs(colr_font):
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# Add all tag characters used in flags + cancel tag
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tag_cps = FLAG_TAGS | {CANCEL_TAG}
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# Anything already cmap'd is fine
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tag_cps -= set(_Cmap(colr_font).keys())
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# CBDT maps these to blank glyphs
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glyf_table = colr_font["glyf"]
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hmtx_table = colr_font["hmtx"]
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glyph_order_size = len(glyf_table.glyphOrder)
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for cp in tag_cps:
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#print(f"Map 0x{cp:04x} to a blank glyf")
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glyph_name = f"u{cp:04X}"
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assert glyph_name not in glyf_table, f"{glyph_name} already in glyf"
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assert glyph_name not in hmtx_table.metrics, f"{glyph_name} already in hmtx"
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glyf_table[glyph_name] = glyf.Glyph()
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hmtx_table[glyph_name] = (0, 0)
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_add_cmap_entries(colr_font, cp, glyph_name)
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def _is_bmp(cp):
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return cp in range(0x0000, 0xFFFF + 1)
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def _ligaset_for_glyph(lookup_list, glyph_name):
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for lookup in lookup_list.Lookup:
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if lookup.LookupType != 4:
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continue
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for liga_set in lookup.SubTable:
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if glyph_name in liga_set.ligatures:
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return liga_set.ligatures[glyph_name]
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return None
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def _Cmap(ttfont):
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def _Reducer(acc, u):
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acc.update(u)
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return acc
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unicode_cmaps = (t.cmap for t in ttfont["cmap"].tables if t.isUnicode())
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return functools.reduce(_Reducer, unicode_cmaps, {})
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def _add_vertical_layout_tables(cbdt_font, colr_font):
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upem_scale = colr_font["head"].unitsPerEm / cbdt_font["head"].unitsPerEm
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vhea = colr_font["vhea"] = ttLib.newTable("vhea")
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vhea.tableVersion = 0x00010000
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vhea.ascent = round(cbdt_font["vhea"].ascent * upem_scale)
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vhea.descent = round(cbdt_font["vhea"].descent * upem_scale)
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vhea.lineGap = 0
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# most of the stuff below is recalculated by the compiler, but still needs to be
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# initialized... ¯\_(ツ)_/¯
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vhea.advanceHeightMax = 0
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vhea.minTopSideBearing = 0
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vhea.minBottomSideBearing = 0
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vhea.yMaxExtent = 0
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vhea.caretSlopeRise = 0
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vhea.caretSlopeRun = 0
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vhea.caretOffset = 0
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vhea.reserved0 = 0
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vhea.reserved1 = 0
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vhea.reserved2 = 0
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vhea.reserved3 = 0
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vhea.reserved4 = 0
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vhea.metricDataFormat = 0
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vhea.numberOfVMetrics = 0
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# emoji font is monospaced -- except for an odd uni0000 (NULL) glyph which happens
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# to have height=0; but colrv1 font doesn't have that anyway, so I just skip it
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cbdt_heights = set(h for h, _ in cbdt_font["vmtx"].metrics.values() if h != 0)
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assert len(cbdt_heights) == 1, "NotoColorEmoji CBDT font should be monospaced!"
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height = round(cbdt_heights.pop() * upem_scale)
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vmtx = colr_font["vmtx"] = ttLib.newTable("vmtx")
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vmtx.metrics = {}
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for gn in colr_font.getGlyphOrder():
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vmtx.metrics[gn] = height, 0
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UNKNOWN_FLAG_PUA = 0xFE82B
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BLACK_FLAG = 0x1F3F4
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REGIONAL_INDICATORS = set(range(0x1F1E6, 0x1F1FF + 1))
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def _add_fallback_subs_for_unknown_flags(colr_font):
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"""Add GSUB lookups to replace unsupported flag sequences with the 'unknown flag'.
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In order to locate the unknown flag, the glyph must be mapped to 0xFE82B PUA code;
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the latter is removed from the cmap table after the GSUB has been updated.
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"""
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cmap = _Cmap(colr_font)
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unknown_flag = cmap[UNKNOWN_FLAG_PUA]
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black_flag = cmap[BLACK_FLAG]
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cancel_tag = cmap[CANCEL_TAG]
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flag_tags = sorted(cmap[cp] for cp in FLAG_TAGS)
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# in the *-noflags.ttf font there are no region flags thus this list is empty
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regional_indicators = sorted(cmap[cp] for cp in REGIONAL_INDICATORS if cp in cmap)
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classes = f'@FLAG_TAGS = [{" ".join(flag_tags)}];\n'
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if regional_indicators:
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classes += f"""
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@REGIONAL_INDICATORS = [{" ".join(regional_indicators)}];
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@UNKNOWN_FLAG = [{" ".join([unknown_flag] * len(regional_indicators))}];
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"""
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lookups = (
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# the first lookup is a dummy that stands for the emoji sequences ligatures
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# from the destination font; we only use it to ensure the lookup indices match.
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# We can't leave it empty otherwise feaLib optimizes it away.
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f"""
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lookup placeholder {{
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sub {unknown_flag} {unknown_flag} by {unknown_flag};
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}} placeholder;
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"""
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+ "\n".join(
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["lookup delete_glyph {"]
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+ [f" sub {g} by NULL;" for g in sorted(regional_indicators + flag_tags)]
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+ ["} delete_glyph;"]
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)
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+ (
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"""
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lookup replace_with_unknown_flag {
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sub @REGIONAL_INDICATORS by @UNKNOWN_FLAG;
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} replace_with_unknown_flag;
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"""
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if regional_indicators
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else "\n"
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)
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)
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features = (
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"languagesystem DFLT dflt;\n"
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+ classes
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+ lookups
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+ "feature ccmp {"
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+ f"""
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lookup placeholder;
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sub {black_flag} @FLAG_TAGS' lookup delete_glyph;
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sub {black_flag} {cancel_tag} by {unknown_flag};
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"""
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+ (
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"""
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sub @REGIONAL_INDICATORS' lookup replace_with_unknown_flag
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@REGIONAL_INDICATORS' lookup delete_glyph;
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"""
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if regional_indicators
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else ""
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)
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+ "} ccmp;"
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)
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# feaLib always builds a new GSUB table (can't update one in place) so we have to
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# use an empty TTFont and then update our GSUB with the newly built lookups
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temp_font = ttLib.TTFont()
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temp_font.setGlyphOrder(colr_font.getGlyphOrder())
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addOpenTypeFeaturesFromString(temp_font, features)
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temp_gsub = temp_font["GSUB"].table
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# sanity check
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assert len(temp_gsub.FeatureList.FeatureRecord) == 1
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assert temp_gsub.FeatureList.FeatureRecord[0].FeatureTag == "ccmp"
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temp_ccmp = temp_gsub.FeatureList.FeatureRecord[0].Feature
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colr_gsub = colr_font["GSUB"].table
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ccmps = [
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r.Feature for r in colr_gsub.FeatureList.FeatureRecord if r.FeatureTag == "ccmp"
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]
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assert len(ccmps) == 1, f"expected only 1 'ccmp' feature record, found {len(ccmps)}"
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colr_ccmp = ccmps[0]
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colr_lookups = colr_gsub.LookupList.Lookup
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assert (
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len(colr_lookups) == 1
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), f"expected only 1 lookup in COLRv1's GSUB.LookupList, found {len(colr_lookups)}"
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assert (
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colr_lookups[0].LookupType == 4
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), f"expected Lookup[0] of type 4 in COLRv1, found {colr_lookups[0].LookupType}"
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colr_lookups.extend(temp_gsub.LookupList.Lookup[1:])
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colr_gsub.LookupList.LookupCount = len(colr_lookups)
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colr_ccmp.LookupListIndex = temp_ccmp.LookupListIndex
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colr_ccmp.LookupCount = len(colr_ccmp.LookupListIndex)
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# get rid of the Unknown Flag private codepoint as no longer needed
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font_data.delete_from_cmap(colr_font, [UNKNOWN_FLAG_PUA])
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def _set_no_font_embedding_restrictions(colr_font):
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# The CBDT/CBLC NotoColorEmoji has OS/2.fsType = 0 (i.e. no embedding restrictions)
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# so the COLRv1 variant must also have no such restrictions.
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# https://github.com/notofonts/noto-fonts/issues/2408
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# https://github.com/google/fonts/issues/5729
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colr_font["OS/2"].fsType = 0
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def _set_head_version_to_name_version(colr_font):
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# head.fontRevision and the version on name 5 should match
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name_version = colr_font['name'].getName(5, 3, 1, 0x409)
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assert name_version is not None, "No version found in 'name'"
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name_version = name_version.toUnicode()
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match = re.match(r'^Version (\d+[.]\d+);GOOG;', name_version)
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assert match is not None, f"Unable to parse version from '{name_version}'"
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colr_font["head"].fontRevision = float(match.group(1))
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def _font(path, check_fn, check_fail_str):
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assert path.is_file(), path
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font = ttLib.TTFont(path)
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if not check_fn(font):
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raise ValueError(path + check_fail_str)
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return font
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def main(_):
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cbdt_font = _font(_CBDT_FILE, _is_cbdt, " must be a CBDT font")
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for colr_file in _COLR_FILES:
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colr_font = _font(colr_file, _is_colrv1, " must be a COLRv1 font")
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print(f"Updating {colr_file} from {_CBDT_FILE}")
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_copy_names(colr_font, cbdt_font)
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# CBDT build step: @$(PYTHON) $(PUA_ADDER) "$@" "$@-with-pua"
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map_pua_emoji.add_pua_cmap_to_font(colr_font)
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_add_vs_cmap(colr_font)
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_map_missing_flag_tag_chars_to_empty_glyphs(colr_font)
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add_soft_light_to_flags(colr_font)
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_add_vertical_layout_tables(cbdt_font, colr_font)
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_add_fallback_subs_for_unknown_flags(colr_font)
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_set_no_font_embedding_restrictions(colr_font)
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_set_head_version_to_name_version(colr_font)
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print("Writing", colr_file)
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colr_font.save(colr_file)
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if __name__ == "__main__":
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app.run(main)
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