1 files changed, 90 insertions, 0 deletions
diff --git a/tools/make_terminal_widths.py b/tools/make_terminal_widths.py
new file mode 100644
index 0000000..850f67a
--- /dev/null
+++ b/tools/make_terminal_widths.py
@@ -0,0 +1,90 @@
+import subprocess
+from typing import List, Tuple
+import sys
+
+from rich.progress import Progress
+
+from wcwidth import wcwidth
+
+
+progress = Progress()
+
+
+def make_widths_table() -> List[Tuple[int, int, int]]:
+    table: List[Tuple[int, int, int]] = []
+    append = table.append
+
+    make_table_task = progress.add_task("Calculating table...")
+
+    widths = (
+        (codepoint, wcwidth(chr(codepoint)))
+        for codepoint in range(0, sys.maxunicode + 1)
+    )
+
+    _widths = [(codepoint, width) for codepoint, width in widths if width != 1]
+    iter_widths = iter(_widths)
+
+    endpoint, group_cell_size = next(iter_widths)
+    start_codepoint = end_codepoint = endpoint
+    for codepoint, cell_size in progress.track(
+        iter_widths, task_id=make_table_task, total=len(_widths) - 1
+    ):
+        if cell_size != group_cell_size or codepoint != end_codepoint + 1:
+            append((start_codepoint, end_codepoint, group_cell_size))
+            start_codepoint = end_codepoint = codepoint
+            group_cell_size = cell_size
+        else:
+            end_codepoint = codepoint
+    append((start_codepoint, end_codepoint, group_cell_size))
+    return table
+
+
+def get_cell_size(table: List[Tuple[int, int, int]], character: str) -> int:
+
+    codepoint = ord(character)
+    lower_bound = 0
+    upper_bound = len(table) - 1
+    index = (lower_bound + upper_bound) // 2
+    while True:
+        start, end, width = table[index]
+        if codepoint < start:
+            upper_bound = index - 1
+        elif codepoint > end:
+            lower_bound = index + 1
+        else:
+            return width
+        if upper_bound < lower_bound:
+            break
+        index = (lower_bound + upper_bound) // 2
+    return 1
+
+
+def test(widths_table):
+    for codepoint in progress.track(
+        range(0, sys.maxunicode + 1), description="Testing..."
+    ):
+        character = chr(codepoint)
+        width1 = get_cell_size(widths_table, character)
+        width2 = wcwidth(character)
+        if width1 != width2:
+            print(f"{width1} != {width2}")
+            break
+
+
+def run():
+    with progress:
+        widths_table = make_widths_table()
+        test(widths_table)
+    table_file = f"""# Auto generated by make_terminal_widths.py
+
+CELL_WIDTHS = {widths_table!r}
+
+"""
+    with open("../rich/_cell_widths.py", "wt") as fh:
+        fh.write(table_file)
+
+    subprocess.run("black ../rich/_cell_widths.py", shell=True)
+
+
+if __name__ == "__main__":
+    run()