refactor: size usage-cell column to measured text width

Author: carlosresu

src/window.rs

@@ -1,5 +1,5 @@
 use std::path::PathBuf;
-use std::sync::atomic::{AtomicU32, Ordering};
+use std::sync::atomic::{AtomicI32, AtomicU32, Ordering};
 use std::sync::{Mutex, MutexGuard};
 use std::time::{Duration, Instant, SystemTime, UNIX_EPOCH};
 
@@ -491,6 +491,8 @@ fn refresh_usage_texts(state: &mut AppState) {
         state.codex_session_text = "!".to_string();
         state.codex_weekly_text = "!".to_string();
     }
+
+    update_measured_text_width(state);
 }
 
 fn set_window_title(hwnd: HWND, strings: Strings) {
@@ -883,6 +885,72 @@ fn active_model_count(show_claude_code: bool, show_codex: bool) -> i32 {
     (show_claude_code as i32 + show_codex as i32).max(1)
 }
 
+/// Small trailing padding (device px, unscaled) added after measured text.
+const TEXT_MEASURE_PAD: i32 = 6;
+
+/// Width (device px, already DPI-scaled) of the widest usage-cell text actually
+/// shown, recomputed whenever the texts change. The cell column sizes to real
+/// content (detailed time / ETD suffix only when present) instead of a fixed
+/// worst-case reservation. Falls back to the base column before first measure.
+static MEASURED_TEXT_WIDTH: AtomicI32 = AtomicI32::new(0);
+
+fn current_text_width() -> i32 {
+    MEASURED_TEXT_WIDTH.load(Ordering::Relaxed).max(sc(TEXT_WIDTH))
+}
+
+/// Measure a string's pixel width in the same font the widget renders with.
+fn measure_text_px(text: &str) -> i32 {
+    if text.is_empty() {
+        return 0;
+    }
+    unsafe {
+        let hdc = GetDC(HWND::default());
+        let mem = CreateCompatibleDC(hdc);
+        let font_name = native_interop::wide_str("Segoe UI");
+        let font = CreateFontW(
+            sc(-12),
+            0,
+            0,
+            0,
+            FW_MEDIUM.0 as i32,
+            0,
+            0,
+            0,
+            DEFAULT_CHARSET.0 as u32,
+            OUT_TT_PRECIS.0 as u32,
+            CLIP_DEFAULT_PRECIS.0 as u32,
+            CLEARTYPE_QUALITY.0 as u32,
+            (DEFAULT_PITCH.0 | FF_DONTCARE.0) as u32,
+            PCWSTR::from_raw(font_name.as_ptr()),
+        );
+        let old = SelectObject(mem, font);
+        let wide: Vec<u16> = text.encode_utf16().collect();
+        let mut size = SIZE::default();
+        let _ = GetTextExtentPoint32W(mem, &wide, &mut size);
+        SelectObject(mem, old);
+        let _ = DeleteObject(font);
+        let _ = DeleteDC(mem);
+        ReleaseDC(HWND::default(), hdc);
+        size.cx
+    }
+}
+
+/// Recompute the measured cell-text width from the currently-visible texts.
+fn update_measured_text_width(state: &AppState) {
+    let mut max_w = 0;
+    if state.show_claude_code {
+        max_w = max_w.max(measure_text_px(&state.session_text));
+        max_w = max_w.max(measure_text_px(&state.weekly_text));
+    }
+    if state.show_codex {
+        max_w = max_w.max(measure_text_px(&state.codex_session_text));
+        max_w = max_w.max(measure_text_px(&state.codex_weekly_text));
+    }
+    if max_w > 0 {
+        MEASURED_TEXT_WIDTH.store(max_w + sc(TEXT_MEASURE_PAD), Ordering::Relaxed);
+    }
+}
+
 fn row_bar_segment_count(active_models: i32) -> i32 {
     if active_models > 1 {
         5
@@ -895,7 +963,7 @@ fn total_widget_width_for(active_models: i32) -> i32 {
     let bar_segments = row_bar_segment_count(active_models);
     let model_width = (sc(SEGMENT_W) + sc(SEGMENT_GAP)) * bar_segments - sc(SEGMENT_GAP)
         + sc(BAR_RIGHT_MARGIN)
-        + sc(TEXT_WIDTH);
+        + current_text_width();
 
     sc(LEFT_DIVIDER_W)
         + sc(DIVIDER_RIGHT_MARGIN)
@@ -2946,7 +3014,7 @@ fn draw_row(
 fn model_usage_width(segment_count: i32) -> i32 {
     (sc(SEGMENT_W) + sc(SEGMENT_GAP)) * segment_count - sc(SEGMENT_GAP)
         + sc(BAR_RIGHT_MARGIN)
-        + sc(TEXT_WIDTH)
+        + current_text_width()
 }
 
 fn draw_usage_bar(
@@ -3112,7 +3180,7 @@ fn draw_usage_bar(
         let mut text_rect = RECT {
             left: text_x,
             top: y,
-            right: text_x + sc(TEXT_WIDTH),
+            right: text_x + current_text_width(),
             bottom: y + seg_h,
         };
         let _ = SetTextColor(hdc, COLORREF(text_color.to_colorref()));