input: Fix wrong font being used in Input. (#1706)

Closes #1665

## Description

When `Input::new().font_family("font")` is used, the font hasn't been
applied yet in `Input::render`, therefore the `text_wrapper` will
calculate using the wrong font. This is why it's working when the font
is added to the parent element.

The fix moves the state update to `element` prepaint, where
`window.text_style()` has the correct styles. The only downside is that
there are now one additional state update.

## Screenshot

| Before                       | After                       |
| ---------------------------- | --------------------------- |
| <img width="1125" height="246" alt="Screenshot From 2025-11-30
20-03-11"
src="https://github.com/user-attachments/assets/1fa798a7-0b9c-4386-8940-ad5f6734b8a0"
/> | <img width="1125" height="246" alt="Screenshot From 2025-11-30
20-00-23"
src="https://github.com/user-attachments/assets/e970e7bc-1bfa-4a55-a342-3381d1684526"
/> |

## How to Test

Use some wide font, like `IBM Plex Mono`. Apply it to
`Input::new(&some_state).font_family("IBM Plex Mono")` where the input
state has `soft_wrap`. Here is a diff for `textarea_story.rs`.

```diff
diff --git a/crates/story/src/textarea_story.rs b/crates/story/src/textarea_story.rs
index f2c63d44..bd5cbb31 100644
--- a/crates/story/src/textarea_story.rs
+++ b/crates/story/src/textarea_story.rs
@@ -77,9 +77,9 @@ impl TextareaStory {
 
         let textarea_no_wrap = cx.new(|cx| {
             InputState::new(window, cx)
-                .multi_line(true)
                 .rows(6)
-                .soft_wrap(false)
+                .multi_line(true)
+                .soft_wrap(true)
                 .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")
         });
 
@@ -195,7 +185,7 @@ impl Render for TextareaStory {
             .child(
                 section("Auto Grow")
                     .max_w_md()
-                    .child(Input::new(&self.textarea_auto_grow)),
+                    .child(Input::new(&self.textarea_auto_grow).font_family("IBM Plex Mono")),
             )
             .child(
                 section("Auto Grow with No Wrap")
```


## Checklist

- [x] I have read the [CONTRIBUTING](../CONTRIBUTING.md) document and
followed the guidelines.
- [x] Reviewed the changes in this PR and confirmed AI generated code
(If any) is accurate.
- [x] Passed `cargo run` for story tests related to the changes.
- [ ] Tested macOS, Windows and Linux platforms performance (if the
change is platform-specific)

---------

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

crates/story/src/input_story.rs

@@ -85,8 +85,9 @@ impl InputStory {
                 fraction: Some(3),
             })
         });
-        let custom_input =
-            cx.new(|cx| InputState::new(window, cx).placeholder("here is a custom input"));
+        let custom_input = cx.new(|cx| {
+            InputState::new(window, cx).placeholder("Custom Input use monospace, 0123456789.")
+        });
 
         let code_input = cx.new(|cx| {
             InputState::new(window, cx)
@@ -247,11 +248,12 @@ impl Render for InputStory {
                     ))),
             )
             .child(
-                section("Appearance false").max_w_md().child(
+                section("Custom Appearance").max_w_md().child(
                     div()
                         .border_b_2()
                         .px_6()
                         .py_3()
+                        .font_family(cx.theme().mono_font_family.clone())
                         .border_color(cx.theme().border)
                         .bg(cx.theme().secondary)
                         .text_color(cx.theme().secondary_foreground)

crates/ui/src/input/element.rs

@@ -818,6 +818,15 @@ impl Element for TextElement {
         window: &mut Window,
         cx: &mut App,
     ) -> Self::PrepaintState {
+        let style = window.text_style();
+        let font = style.font();
+        let text_size = style.font_size.to_pixels(window.rem_size());
+
+        self.state.update(cx, |state, cx| {
+            state.text_wrapper.set_font(font, text_size, cx);
+            state.text_wrapper.prepare_if_need(&state.text, cx);
+        });
+
         let state = self.state.read(cx);
         let line_height = window.line_height();
 
@@ -840,8 +849,7 @@ impl Element for TextElement {
         let text = state.text.clone();
         let is_empty = text.len() == 0;
         let placeholder = self.placeholder.clone();
-        let style = window.text_style();
-        let font_size = style.font_size.to_pixels(window.rem_size());
+
         let mut bounds = bounds;
 
         let (display_text, text_color) = if is_empty {
@@ -862,7 +870,7 @@ impl Element for TextElement {
 
         // Calculate the width of the line numbers
         let (line_number_width, line_number_len) =
-            Self::layout_line_numbers(&state, &text, font_size, &text_style, window);
+            Self::layout_line_numbers(&state, &text, text_size, &text_style, window);
 
         let wrap_width = if multi_line && state.soft_wrap {
             Some(bounds.size.width - line_number_width - RIGHT_MARGIN)
@@ -956,7 +964,7 @@ impl Element for TextElement {
             &state,
             &display_text,
             &last_layout,
-            font_size,
+            text_size,
             &runs,
             &document_colors,
             window,
@@ -972,7 +980,7 @@ impl Element for TextElement {
                 .text_system()
                 .shape_line(
                     longest_line.clone(),
-                    font_size,
+                    text_size,
                     &[TextRun {
                         len: longest_line.len(),
                         font: style.font(),
@@ -1084,7 +1092,7 @@ impl Element for TextElement {
                 sub_lines.push(
                     window
                         .text_system()
-                        .shape_line(line_no, font_size, &runs, None),
+                        .shape_line(line_no, text_size, &runs, None),
                 );
                 for _ in 0..line.wrapped_lines.len().saturating_sub(1) {
                     sub_lines.push(ShapedLine::default());

crates/ui/src/input/input.rs

@@ -2,7 +2,7 @@ use gpui::prelude::FluentBuilder as _;
 use gpui::{
     AnyElement, App, DefiniteLength, Edges, EdgesRefinement, Entity, InteractiveElement as _,
     IntoElement, IsZero, MouseButton, ParentElement as _, Rems, RenderOnce, StyleRefinement,
-    Styled, Window, div, px, relative, rems,
+    Styled, Window, div, px, relative,
 };
 
 use crate::button::{Button, ButtonVariants as _};
@@ -241,16 +241,8 @@ impl Styled for Input {
 impl RenderOnce for Input {
     fn render(self, window: &mut Window, cx: &mut App) -> impl IntoElement {
         const LINE_HEIGHT: Rems = Rems(1.25);
-        let font = window.text_style().font();
-        let font_size = match self.size {
-            Size::Large => rems(1.),
-            _ => rems(0.875),
-        }
-        .to_pixels(window.rem_size());
 
-        self.state.update(cx, |state, cx| {
-            state.text_wrapper.set_font(font, font_size, cx);
-            state.text_wrapper.prepare_if_need(&state.text, cx);
+        self.state.update(cx, |state, _| {
             state.disabled = self.disabled;
             state.size = self.size;
         });
@@ -365,8 +357,8 @@ impl RenderOnce for Input {
             .input_px(self.size)
             .input_py(self.size)
             .input_h(self.size)
+            .input_text_size(self.size)
             .cursor_text()
-            .text_size(font_size)
             .items_center()
             .when(state.mode.is_multi_line(), |this| {
                 this.h_auto()

crates/ui/src/input/state.rs

@@ -368,11 +368,7 @@ impl InputState {
         Self {
             focus_handle: focus_handle.clone(),
             text: "".into(),
-            text_wrapper: TextWrapper::new(
-                text_style.font(),
-                text_style.font_size.to_pixels(window.rem_size()),
-                None,
-            ),
+            text_wrapper: TextWrapper::new(text_style.font(), window.rem_size(), None),
             blink_cursor,
             history,
             selected_range: Selection::default(),

crates/ui/src/input/text_wrapper.rs

@@ -1,6 +1,6 @@
 use std::ops::Range;
 
-use gpui::{point, px, size, App, Font, LineFragment, Pixels, Point, ShapedLine, Size, Window};
+use gpui::{App, Font, LineFragment, Pixels, Point, ShapedLine, Size, Window, point, px, size};
 use ropey::Rope;
 use smallvec::SmallVec;
 
@@ -500,7 +500,7 @@ impl LineLayout {
 #[cfg(test)]
 mod tests {
     use super::*;
-    use gpui::{px, Boundary, FontFeatures, FontStyle, FontWeight};
+    use gpui::{Boundary, FontFeatures, FontStyle, FontWeight, px};
 
     #[test]
     fn test_update() {

crates/ui/src/styled.rs

@@ -437,9 +437,9 @@ impl<T: Styled> StyleSized<T> for T {
         match size {
             Size::XSmall => self.text_xs(),
             Size::Small => self.text_sm(),
-            Size::Medium => self.text_base(),
-            Size::Large => self.text_lg(),
-            Size::Size(size) => self.text_size(size),
+            Size::Medium => self.text_sm(),
+            Size::Large => self.text_base(),
+            Size::Size(size) => self.text_size(size * 0.875),
         }
     }
 
@@ -477,7 +477,6 @@ impl<T: Styled> StyleSized<T> for T {
             Size::XSmall => self.h_5(),
             _ => self.h_6(),
         }
-        .input_text_size(size)
     }
 
     #[inline]