From 9debcd3aaa5d6009bc00dbd4563d953c01e8a03e Mon Sep 17 00:00:00 2001
From: Solaris-star <820622658@qq.com>
Date: Mon, 20 Jul 2026 02:02:38 +0800
Subject: [PATCH] docs: add color and glyph legend under README Preview
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Document the default category → color/glyph mapping so the
preview screenshots are easier to read. Point readers at
--print-color-table for a live reference.

Closes #240.

Signed-off-by: Solaris-star <820622658@qq.com>
---
 README.md | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/README.md b/README.md
index e20d9124..080f4c66 100644
--- a/README.md
+++ b/README.md
@@ -17,6 +17,25 @@ of bytes (NULL bytes, printable ASCII characters, ASCII whitespace characters, o
 
 ![](https://i.imgur.com/f8nm8g6.png)
 
+### Color and character legend
+
+With the default character table and color scheme, each byte category is shown
+as follows (hex panel uses the color; the right-hand character panel uses the
+glyph):
+
+| Category | Default color | Glyph | Byte range |
+| --- | --- | --- | --- |
+| NULL bytes | bright black | `⋄` | `0x00` |
+| ASCII printable | cyan | as-is (`a`–`z`, …) | `0x20`–`0x7E` |
+| ASCII whitespace | green | space or `_` | `0x09`–`0x0D`, `0x20` |
+| Other ASCII (controls) | green | `•` | remaining `0x01`–`0x1F`, `0x7F` |
+| Non-ASCII | yellow | `×` | `0x80`–`0xFF` |
+
+You can print a live color reference with:
+
+```bash
+hexyl --print-color-table
+```
 
 ## Installation