From 89917d43283100e08f98d6662dd76ebfffe3ddc8 Mon Sep 17 00:00:00 2001
From: yumoqing <yumoqing@gmail.com>
Date: Tue, 1 Sep 2026 18:02:24 +0800
Subject: [PATCH] =?UTF-8?q?feat(AgentIO):=20=E4=BC=9A=E8=AF=9D=E5=8C=BA?=
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- chunk_response流式更新后scroll_to_bottom(rAF延迟到布局完成)
- show_input用户发消息强制滚底
- 用户上翻看历史暂停跟滚(_track_follow),滚回底部恢复——不强行打断阅读
---
 bricks/agent.js | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/bricks/agent.js b/bricks/agent.js
index 225d469..1a3b1a7 100644
--- a/bricks/agent.js
+++ b/bricks/agent.js
@@ -327,6 +327,31 @@ bricks.AgentIO = class extends bricks.VBox {
 		this.inputw.bind('inputed', this.user_inputed.bind(this));
 		this.add_widget(this.msg_box);
 		this.add_widget(this.inputw);
+		// 用户上翻看历史时暂停跟滚，滚回底部恢复（scroll_to_bottom 依据 _follow）
+		this.msg_box.bind('scroll', this._track_follow.bind(this));
+	}
+	// 会话区保持最后输出可见（2026-09-01）：内容超出显示范围时自动滚到底。
+	// 仅当用户本就停在底部附近才跟滚——用户主动上翻看历史时不强行拉回；
+	// 滚回底部或发送新消息后恢复跟滚。rAF 延迟到本帧布局完成后滚，
+	// 保证 scrollHeight 已是新内容的尺寸（同步滚会拿到旧高度）。
+	scroll_to_bottom(){
+		if (this._scroll_pending) return;
+		this._scroll_pending = true;
+		requestAnimationFrame(function(){
+			this._scroll_pending = false;
+			var e = this.msg_box && this.msg_box.dom_element;
+			if (!e) return;
+			if (this._follow === false) {
+				var near_bottom = (e.scrollHeight - e.scrollTop - e.clientHeight) < 80;
+				if (!near_bottom) return;
+			}
+			e.scrollTop = e.scrollHeight;
+		}.bind(this));
+	}
+	_track_follow(){
+		var e = this.msg_box && this.msg_box.dom_element;
+		if (!e) return;
+		this._follow = (e.scrollHeight - e.scrollTop - e.clientHeight) < 80;
 	}
 	chunk_response(mout, l){
 		l = l.trim();
@@ -338,6 +363,7 @@ bricks.AgentIO = class extends bricks.VBox {
 		}
 		console.log('l=', l, 'd=', d);
 		mout.update_data(d);
+		this.scroll_to_bottom();
 	}
 	chunk_ended(){
 		console.log('chunk end');
@@ -395,6 +421,9 @@ bricks.AgentIO = class extends bricks.VBox {
         box.add_widget(w);
         box.add_widget(img);
         this.msg_box.add_widget(box);
+        // 用户刚发的消息必须可见：强制跟滚到底
+        this._follow = true;
+        this.scroll_to_bottom();
     }   
 }