From 6ef9b10a3a1a032b995d47b51eca99e0d9fc0581 Mon Sep 17 00:00:00 2001
From: OMOTO Tsukasa <tsukasa@oomo.to>
Date: Sun, 27 Aug 2023 14:49:07 +0900
Subject: [PATCH] Improve line breaking behavior for east asian characters

This commit aims to produce more natural line breaks in the rendered output.
---
 extension/cjk_test.go | 4 ++--
 renderer/html/html.go | 3 +--
 2 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/extension/cjk_test.go b/extension/cjk_test.go
index e97bb72..40a7a10 100644
--- a/extension/cjk_test.go
+++ b/extension/cjk_test.go
@@ -140,7 +140,7 @@ func TestEastAsianLineBreaks(t *testing.T) {
 			No:          no,
 			Description: "Soft line breaks between a western character and an east asian wide character are rendered as a newline",
 			Markdown:    "太郎は\\ **「こんにちわ」**\\ と言ったa\nんです",
-			Expected:    "<p>太郎は\\ <strong>「こんにちわ」</strong>\\ と言ったa\nんです</p>",
+			Expected:    "<p>太郎は\\ <strong>「こんにちわ」</strong>\\ と言ったaんです</p>",
 		},
 		t,
 	)
@@ -152,7 +152,7 @@ func TestEastAsianLineBreaks(t *testing.T) {
 			No:          no,
 			Description: "Soft line breaks between an east asian wide character and a western character are rendered as a newline",
 			Markdown:    "太郎は\\ **「こんにちわ」**\\ と言った\nbんです",
-			Expected:    "<p>太郎は\\ <strong>「こんにちわ」</strong>\\ と言った\nbんです</p>",
+			Expected:    "<p>太郎は\\ <strong>「こんにちわ」</strong>\\ と言ったbんです</p>",
 		},
 		t,
 	)
diff --git a/renderer/html/html.go b/renderer/html/html.go
index 3503688..73f7835 100644
--- a/renderer/html/html.go
+++ b/renderer/html/html.go
@@ -669,8 +669,7 @@ func (r *Renderer) renderText(w util.BufWriter, source []byte, node ast.Node, en
 					if siblingText := sibling.(*ast.Text).Text(source); len(siblingText) != 0 {
 						thisLastRune := util.ToRune(value, len(value)-1)
 						siblingFirstRune, _ := utf8.DecodeRune(siblingText)
-						if !(util.IsEastAsianWideRune(thisLastRune) &&
-							util.IsEastAsianWideRune(siblingFirstRune)) {
+						if !util.IsEastAsianWideRune(thisLastRune) && !util.IsEastAsianWideRune(siblingFirstRune) {
 							_ = w.WriteByte('\n')
 						}
 					}