desktop: add emoji picker (#7708)

* desktop: add emoji picker data and generator

* desktop: emoji picker in compose field

* desktop: document compose emoji picker

scripts/desktop/generate-emoji-data.py

@@ -0,0 +1,44 @@
+#!/usr/bin/env python3
+# Generates the desktop emoji picker data from Unicode emoji-test.txt.
+# Emoji version must not exceed the bundled NotoColorEmoji font (2.038 covers Emoji 15.0):
+#   curl -O https://unicode.org/Public/emoji/15.0/emoji-test.txt
+#   python3 scripts/desktop/generate-emoji-data.py emoji-test.txt apps/multiplatform/common/src/desktopMain/resources/emoji/emoji.txt
+# Output: "@<group>" lines followed by "<emoji>\t<name>" lines, in CLDR order.
+
+import sys
+
+SKIPPED_GROUPS = {"Component"}
+SKIN_TONE_MODIFIERS = {0x1F3FB, 0x1F3FC, 0x1F3FD, 0x1F3FE, 0x1F3FF}
+
+
+def parse(lines):
+    group = None
+    for line in lines:
+        line = line.rstrip("\n")
+        if line.startswith("# group: "):
+            group = line[len("# group: "):]
+            if group not in SKIPPED_GROUPS:
+                yield "@" + group
+        elif line and not line.startswith("#") and group not in SKIPPED_GROUPS:
+            codes, rest = line.split(";", 1)
+            status, comment = rest.split("#", 1)
+            if status.strip() != "fully-qualified":
+                continue
+            code_points = [int(c, 16) for c in codes.split()]
+            if SKIN_TONE_MODIFIERS.intersection(code_points):
+                continue
+            # comment is "<emoji> E<version> <name>"
+            name = comment.strip().split(" ", 2)[2]
+            yield "".join(map(chr, code_points)) + "\t" + name
+
+
+def main():
+    src, dst = sys.argv[1], sys.argv[2]
+    with open(src, encoding="utf-8") as f:
+        out = list(parse(f))
+    with open(dst, "w", encoding="utf-8", newline="\n") as f:
+        f.write("\n".join(out) + "\n")
+
+
+if __name__ == "__main__":
+    main()