use SVG emoji instead of system defaults, they scale better

.gitmodules

@@ -0,0 +1,3 @@
+[submodule "noto-emoji"]
+	path = noto-emoji
+	url = [email protected]:googlefonts/noto-emoji.git

src/app.jsx

@@ -85,7 +85,7 @@ function App() {
             key={emoji}
           >
             <div
-              className="emoji"
+              className={"emoji emoji-"+encodeURI(emoji).replace(/%/g, '')}
               style={{
                 opacity,
                 transform: `scale(${calculatedScale}) translateY(10%)`

src/index.js

@@ -1,4 +1,5 @@
 import "./style.css";
+import "./emoji.css";
 
 import React from 'react';
 import ReactDOM from 'react-dom';

src/style.css

@@ -56,6 +56,14 @@ a {
   text-align: center;
   line-height: 256px;
   transform-origin: bottom center;
+
+  color: transparent;
+  margin-bottom: 32px;
+}
+
+.emoji::selection {
+    color: transparent;
+    background: grey;
 }
 
 .emoji span {

svg_pack.py

@@ -0,0 +1,97 @@
+#!/usr/bin/python3
+
+import csv
+import glob
+import json
+import os
+import re
+import subprocess
+import sys
+import unicodedata
+
+
+def munge_svg(path, e=None, verbose=False):
+    svg_data = open(path).read()
+    svg_data = svg_data.replace('\n', ' ').strip()
+    if re.search(r'<svg[^>]*width', svg_data):
+        if 'ENTITY' in svg_data and False:
+            svg_data = subprocess.check_output(
+                ['npx', 'svgo', '-o', '-', path]).decode('utf8')
+        svg_data_before = svg_data
+        # explicit width/height screws up automatic scaling
+        dim_re = re.compile(r' (width|height)="[^"]*"')
+
+        def fix_header(m):
+            attrib = dict(re.findall(r'(\S+)="([^"]*)"', m.group(0)))
+            if 'viewBox' not in attrib:
+                attrib['viewBox'] = '0 0 %s %s' % (attrib['width'],
+                                                   attrib['height'])
+            attrib.pop('width')
+            attrib.pop('height')
+            return '<svg %s>' % ' '.join('%s="%s"' % i for i in attrib.items())
+
+        svg_data = re.sub(r'<svg[^>]*>', fix_header, svg_data)
+        if e and verbose:
+            print('stripping header dimensions from', e['char'], e['name'],
+                  svg_data == svg_data_before)
+    return svg_data
+
+
+def pack_svg(verbose=False):
+    ems = []
+    for fname in glob.glob('src/data/*.csv'):
+        ems.extend(csv.reader(open(fname)))
+
+    print(ems)
+
+    char_ems = {e[0]: e for e in ems}
+    svgs = {}
+
+    ems.sort(key=lambda e: float(e[1]) if e[1].isdigit() else 0)
+
+    aliases = {}
+    for line in open('noto-emoji/emoji_aliases.txt'):
+        m = re.match(r'(.*);(\S*)', line)
+        if m:
+            aliases[m.group(1)] = m.group(2)
+
+    c = 0
+    for e in ems:
+        em, size, name = e
+        em = unicodedata.normalize('NFKD', em)
+        if em == 'EMOJI' or size == '?':
+            continue
+        svg_path = ''
+        em_code = '_'.join('%04x' % ord(c) for c in em)
+        svg_path = 'noto-emoji/svg/emoji_u%s.svg' % em_code
+        print(svg_path)
+        if not os.path.exists(svg_path) and em_code in aliases:
+            svg_path = svg_path.replace(em_code, aliases[em_code])
+        if not os.path.exists(svg_path) and '_fe0f.' in svg_path:
+            svg_path = svg_path.replace('_fe0f.', '.')
+        assert os.path.exists(svg_path), (em, svg_path)
+        svg_data = munge_svg(svg_path, e, verbose)
+        if verbose:
+            print(em, e['name'], json.dumps(em), svg_path, len(svg_data))
+        svgs[em] = svg_data
+
+    with open('src/emoji.css', 'w') as f:
+        for char, svg in sorted(svgs.items()):
+            # based on https://yoksel.github.io/url-encoder/
+            # and https://mathiasbynens.be/notes/css-escapes
+            svg = svg.strip().replace("'", "\\'")
+            svg = svg.replace('\n', '\\A').replace('#', '%23')
+            f.write(
+                ".emoji-%s{background-image:url('data:image/svg+xml,%s')}\n" %
+                (''.join('%02X'%c for c in char_ems[char][0].encode('utf8')), svg))
+        size = f.tell()
+        print('wrote %.1dK (%d emoji, %dB each) to %s' %
+              (size / 1024, len(svgs), size / len(svgs), f.name))
+
+
+if __name__ == '__main__':
+    if sys.argv[1:]:
+        for fname in sys.argv[1:]:
+            print(fname, munge_svg(fname))
+    else:
+        pack_svg()