input: Add to support horizontal scrolling to multi-line text. (#1131)

- Add `soft_wrap` option to build InputState, default true.

<img width="1156" height="1166" alt="image"
src="https://github.com/user-attachments/assets/2eab2db0-b3fc-48ce-83cb-1d6715313247"
/>

---------

Co-authored-by: Jason Lee <huacnlee@gmail.com>

crates/story/src/textarea_story.rs

@@ -23,6 +23,7 @@ pub fn init(cx: &mut App) {
 pub struct TextareaStory {
     textarea: Entity<InputState>,
     textarea_auto_grow: Entity<InputState>,
+    textarea_no_wrap: Entity<InputState>,
 }
 
 impl super::Story for TextareaStory {
@@ -84,9 +85,18 @@ impl TextareaStory {
                 .default_value("Hello 世界，this is GPUI component.")
         });
 
+        let textarea_no_wrap = cx.new(|cx| {
+            InputState::new(window, cx)
+                .multi_line()
+                .rows(6)
+                .soft_wrap(false)
+                .default_value("This is a very long line of text to test if the horizontal scrolling function is working properly, and it should not wrap automatically but display a horizontal scrollbar.\nThe second line is also very long text, used to test the horizontal scrolling effect under multiple lines, and you can input more content to test.\nThe third line: Here you can input other long text content that requires horizontal scrolling.\n")
+        });
+
         Self {
             textarea,
             textarea_auto_grow,
+            textarea_no_wrap,
         }
     }
 
@@ -141,8 +151,6 @@ impl Render for TextareaStory {
             .id("textarea-story")
             .on_action(cx.listener(Self::tab))
             .on_action(cx.listener(Self::tab_prev))
-            .size_full()
-            .justify_start()
             .gap_3()
             .child(
                 section("Textarea").child(
@@ -179,12 +187,11 @@ impl Render for TextareaStory {
                         ),
                 ),
             )
+            .child(section("Textarea Auto Grow").child(TextInput::new(&self.textarea_auto_grow)))
             .child(
-                section("Textarea Auto Grow").child(
-                    v_flex()
-                        .w_full()
-                        .child(TextInput::new(&self.textarea_auto_grow)),
-                ),
+                section("No Wrap")
+                    .max_w_md()
+                    .child(TextInput::new(&self.textarea_no_wrap).h(px(200.))),
             )
     }
 }

crates/ui/src/input/element.rs

@@ -660,7 +660,7 @@ impl Element for TextElement {
             vec![run]
         };
 
-        let wrap_width = if multi_line {
+        let wrap_width = if multi_line && state.soft_wrap {
             Some(bounds.size.width - line_number_width)
         } else {
             None

crates/ui/src/input/state.rs

@@ -266,6 +266,7 @@ pub struct InputState {
     pub(super) disabled: bool,
     pub(super) masked: bool,
     pub(super) clean_on_escape: bool,
+    pub(super) soft_wrap: bool,
     pub(super) pattern: Option<regex::Regex>,
     pub(super) validate: Option<Box<dyn Fn(&str, &mut Context<Self>) -> bool + 'static>>,
     pub(crate) scroll_handle: ScrollHandle,
@@ -335,6 +336,7 @@ impl InputState {
             disabled: false,
             masked: false,
             clean_on_escape: false,
+            soft_wrap: true,
             loading: false,
             pattern: None,
             validate: None,
@@ -751,6 +753,18 @@ impl InputState {
         self
     }
 
+    /// Set the soft wrap mode for multi-line input, default is true.
+    pub fn soft_wrap(mut self, wrap: bool) -> Self {
+        self.soft_wrap = wrap;
+        self
+    }
+
+    /// Update the soft wrap mode for multi-line input, default is true.
+    pub fn set_soft_wrap(&mut self, wrap: bool, _: &mut Window, cx: &mut Context<Self>) {
+        self.soft_wrap = wrap;
+        cx.notify();
+    }
+
     /// Set the regular expression pattern of the input field.
     pub fn pattern(mut self, pattern: regex::Regex) -> Self {
         self.pattern = Some(pattern);
@@ -2100,7 +2114,14 @@ impl InputState {
         // Update text_wrapper wrap_width if changed.
         if let Some(last_layout) = self.last_layout.as_ref() {
             if wrap_width_changed {
-                self.text_wrapper.set_wrap_width(last_layout.wrap_width, cx);
+                let wrap_width = if !self.soft_wrap {
+                    // None to disable wrapping (will use Pixels::MAX)
+                    None
+                } else {
+                    last_layout.wrap_width
+                };
+
+                self.text_wrapper.set_wrap_width(wrap_width, cx);
                 self.mode.update_auto_grow(&self.text_wrapper);
                 cx.notify();
             }

crates/ui/src/input/text_input.rs

@@ -301,6 +301,12 @@ impl RenderOnce for TextInput {
             .refine_style(&self.style)
             .when(state.mode.is_multi_line(), |this| {
                 if state.last_layout.is_some() {
+                    let scrollbar = if !state.soft_wrap {
+                        Scrollbar::both(&state.scroll_state, &state.scroll_handle)
+                    } else {
+                        Scrollbar::vertical(&state.scroll_state, &state.scroll_handle)
+                    };
+
                     this.relative().child(
                         div()
                             .absolute()
@@ -308,10 +314,7 @@ impl RenderOnce for TextInput {
                             .left_0()
                             .right(px(1.))
                             .bottom_0()
-                            .child(
-                                Scrollbar::vertical(&state.scroll_state, &state.scroll_handle)
-                                    .scroll_size(state.scroll_size),
-                            ),
+                            .child(scrollbar.scroll_size(state.scroll_size)),
                     )
                 } else {
                     this

crates/ui/src/input/text_wrapper.rs

@@ -64,7 +64,7 @@ impl TextWrapper {
 
         let mut wrapped_lines = vec![];
         let mut lines = vec![];
-        let wrap_width = self.wrap_width.unwrap_or(Pixels::MAX);
+        let wrap_width = self.wrap_width;
         let mut line_wrapper = cx
             .text_system()
             .line_wrapper(self.font.clone(), self.font_size);
@@ -73,10 +73,13 @@ impl TextWrapper {
             let mut line_wraps = vec![];
             let mut prev_boundary_ix = 0;
 
-            // Here only have wrapped line, if there is no wrap meet, the `line_wraps` result will empty.
-            for boundary in line_wrapper.wrap_line(&[LineFragment::text(line)], wrap_width) {
-                line_wraps.push(prev_boundary_ix..boundary.ix);
-                prev_boundary_ix = boundary.ix;
+            // If wrap_width is Pixels::MAX, skip wrapping to disable word wrap
+            if let Some(wrap_width) = wrap_width {
+                // Here only have wrapped line, if there is no wrap meet, the `line_wraps` result will empty.
+                for boundary in line_wrapper.wrap_line(&[LineFragment::text(line)], wrap_width) {
+                    line_wraps.push(prev_boundary_ix..boundary.ix);
+                    prev_boundary_ix = boundary.ix;
+                }
             }
 
             lines.push(LineWrap {