From 39af3b434aa4c86f6fd3edb31e28c5cf68187fbd Mon Sep 17 00:00:00 2001
From: Danilo Leal <67129314+danilo-leal@users.noreply.github.com>
Date: Wed, 26 Mar 2025 09:45:51 -0300
Subject: [PATCH] assistant2: Improve tool card header scrolling affordance
 (#27492)

Follow up to https://github.com/zed-industries/zed/pull/27489

Added this subtle gradient to the right side of the tool card header so
users know there is more content, suggesting it can be scrolled. Also
took the opportunity to extract out commonly used custom colors in all
of these cards into their own functions to ensure consistency.

Here's the final product:


https://github.com/user-attachments/assets/e44150f9-7751-46c7-8790-149b86cc5e0f

Release Notes:

- N/A
---
 crates/assistant2/src/active_thread.rs | 46 +++++++++++++++++---------
 1 file changed, 31 insertions(+), 15 deletions(-)

diff --git a/crates/assistant2/src/active_thread.rs b/crates/assistant2/src/active_thread.rs
index b2e16db1a75a5b7914e3412bb14ebe942a671cbe..27c29e3fa896b33d52100cec70116c8bdd360b6b 100644
--- a/crates/assistant2/src/active_thread.rs
+++ b/crates/assistant2/src/active_thread.rs
@@ -12,9 +12,9 @@ use editor::{Editor, MultiBuffer};
 use gpui::{
     linear_color_stop, linear_gradient, list, percentage, pulsating_between, AbsoluteLength,
     Animation, AnimationExt, AnyElement, App, ClickEvent, DefiniteLength, EdgesRefinement, Empty,
-    Entity, Focusable, Length, ListAlignment, ListOffset, ListState, ScrollHandle, StyleRefinement,
-    Subscription, Task, TextStyleRefinement, Transformation, UnderlineStyle, WeakEntity,
-    WindowHandle,
+    Entity, Focusable, Hsla, Length, ListAlignment, ListOffset, ListState, ScrollHandle,
+    StyleRefinement, Subscription, Task, TextStyleRefinement, Transformation, UnderlineStyle,
+    WeakEntity, WindowHandle,
 };
 use language::{Buffer, LanguageRegistry};
 use language_model::{LanguageModelRegistry, LanguageModelToolUseId, Role};
@@ -1145,6 +1145,17 @@ impl ActiveThread {
             )
     }
 
+    fn tool_card_border_color(&self, cx: &Context<Self>) -> Hsla {
+        cx.theme().colors().border.opacity(0.5)
+    }
+
+    fn tool_card_header_bg(&self, cx: &Context<Self>) -> Hsla {
+        cx.theme()
+            .colors()
+            .element_background
+            .blend(cx.theme().colors().editor_foreground.opacity(0.025))
+    }
+
     fn render_message_thinking_segment(
         &self,
         message_id: MessageId,
@@ -1160,26 +1171,25 @@ impl ActiveThread {
             .copied()
             .unwrap_or_default();
 
-        let lighter_border = cx.theme().colors().border.opacity(0.5);
         let editor_bg = cx.theme().colors().editor_background;
 
         div().py_2().child(
             v_flex()
                 .rounded_lg()
                 .border_1()
-                .border_color(lighter_border)
+                .border_color(self.tool_card_border_color(cx))
                 .child(
                     h_flex()
                         .group("disclosure-header")
                         .justify_between()
                         .py_1()
                         .px_2()
-                        .bg(cx.theme().colors().editor_foreground.opacity(0.025))
+                        .bg(self.tool_card_header_bg(cx))
                         .map(|this| {
                             if pending || is_open {
                                 this.rounded_t_md()
                                     .border_b_1()
-                                    .border_color(lighter_border)
+                                    .border_color(self.tool_card_border_color(cx))
                             } else {
                                 this.rounded_md()
                             }
@@ -1314,22 +1324,21 @@ impl ActiveThread {
             .copied()
             .unwrap_or_default();
 
-        let lighter_border = cx.theme().colors().border.opacity(0.5);
-
         div().py_2().child(
             v_flex()
                 .rounded_lg()
                 .border_1()
-                .border_color(lighter_border)
+                .border_color(self.tool_card_border_color(cx))
                 .overflow_hidden()
                 .child(
                     h_flex()
                         .group("disclosure-header")
+                        .relative()
                         .gap_1p5()
                         .justify_between()
                         .py_1()
                         .px_2()
-                        .bg(cx.theme().colors().editor_foreground.opacity(0.025))
+                        .bg(self.tool_card_header_bg(cx))
                         .map(|element| {
                             if is_open {
                                 element.border_b_1().rounded_t_md()
@@ -1337,7 +1346,7 @@ impl ActiveThread {
                                 element.rounded_md()
                             }
                         })
-                        .border_color(lighter_border)
+                        .border_color(self.tool_card_border_color(cx))
                         .child(
                             h_flex()
                                 .id("tool-label-container")
@@ -1350,7 +1359,7 @@ impl ActiveThread {
                                         .size(IconSize::XSmall)
                                         .color(Color::Muted),
                                 )
-                                .child(h_flex().text_ui_sm(cx).children(
+                                .child(h_flex().pr_8().text_ui_sm(cx).children(
                                     self.rendered_tool_use_labels.get(&tool_use.id).cloned(),
                                 )),
                         )
@@ -1410,7 +1419,14 @@ impl ActiveThread {
                                         icon.into_any_element()
                                     }
                                 }),
-                        ),
+                        )
+                        .child(div().h_full().absolute().w_8().bottom_0().right_12().bg(
+                            linear_gradient(
+                                90.,
+                                linear_color_stop(self.tool_card_header_bg(cx), 1.),
+                                linear_color_stop(self.tool_card_header_bg(cx).opacity(0.2), 0.),
+                            ),
+                        )),
                 )
                 .map(|parent| {
                     if !is_open {
@@ -1427,7 +1443,7 @@ impl ActiveThread {
                             .child(
                                 content_container()
                                     .border_b_1()
-                                    .border_color(lighter_border)
+                                    .border_color(self.tool_card_border_color(cx))
                                     .child(
                                         Label::new("Input")
                                             .size(LabelSize::XSmall)