WIP: better precision?

src/views/engine_view.rs

@@ -11,6 +11,7 @@ use crate::widgets::{Orientation, Scope, Spectrum};
 
 const HEADER_COLOR: Color = Color::Rgb(100, 160, 180);
 const DIVIDER_COLOR: Color = Color::Rgb(60, 65, 70);
+const SCROLL_INDICATOR_COLOR: Color = Color::Rgb(80, 85, 95);
 
 pub fn render(frame: &mut Frame, app: &App, area: Rect) {
     let [left_col, _, right_col] = Layout::horizontal([
@@ -40,20 +41,105 @@ fn render_settings_section(frame: &mut Frame, app: &App, area: Rect) {
         height: inner.height.saturating_sub(1),
     };
 
-    let devices_height = devices_section_height(app);
+    // Calculate section heights
+    let devices_lines = devices_section_height(app) as usize;
+    let settings_lines: usize = 8; // header(1) + divider(1) + 6 rows
+    let samples_lines: usize = 6; // header(1) + divider(1) + content(3) + hint(1)
+    let total_lines = devices_lines + 1 + settings_lines + 1 + samples_lines;
 
-    let [devices_area, _, settings_area, _, samples_area] = Layout::vertical([
-        Constraint::Length(devices_height),
-        Constraint::Length(1),
-        Constraint::Length(8),
-        Constraint::Length(1),
-        Constraint::Min(6),
-    ])
-    .areas(padded);
+    let max_visible = padded.height as usize;
 
-    render_devices(frame, app, devices_area);
-    render_settings(frame, app, settings_area);
-    render_samples(frame, app, samples_area);
+    // Calculate scroll offset based on focused section
+    let (focus_start, focus_height) = match app.audio.section {
+        EngineSection::Devices => (0, devices_lines),
+        EngineSection::Settings => (devices_lines + 1, settings_lines),
+        EngineSection::Samples => (devices_lines + 1 + settings_lines + 1, samples_lines),
+    };
+
+    let scroll_offset = if total_lines <= max_visible {
+        0
+    } else {
+        // Keep focused section in view (top-aligned when possible)
+        let focus_end = focus_start + focus_height;
+        if focus_end <= max_visible {
+            0
+        } else {
+            focus_start.min(total_lines.saturating_sub(max_visible))
+        }
+    };
+
+    let viewport_top = padded.y as i32;
+    let viewport_bottom = (padded.y + padded.height) as i32;
+
+    // Render each section at adjusted position
+    let mut y = viewport_top - scroll_offset as i32;
+
+    // Devices section
+    let devices_top = y;
+    let devices_bottom = y + devices_lines as i32;
+    if devices_bottom > viewport_top && devices_top < viewport_bottom {
+        let clipped_y = devices_top.max(viewport_top) as u16;
+        let clipped_height =
+            (devices_bottom.min(viewport_bottom) - devices_top.max(viewport_top)) as u16;
+        let devices_area = Rect {
+            x: padded.x,
+            y: clipped_y,
+            width: padded.width,
+            height: clipped_height,
+        };
+        render_devices(frame, app, devices_area);
+    }
+    y += devices_lines as i32 + 1; // +1 for blank line
+
+    // Settings section
+    let settings_top = y;
+    let settings_bottom = y + settings_lines as i32;
+    if settings_bottom > viewport_top && settings_top < viewport_bottom {
+        let clipped_y = settings_top.max(viewport_top) as u16;
+        let clipped_height =
+            (settings_bottom.min(viewport_bottom) - settings_top.max(viewport_top)) as u16;
+        let settings_area = Rect {
+            x: padded.x,
+            y: clipped_y,
+            width: padded.width,
+            height: clipped_height,
+        };
+        render_settings(frame, app, settings_area);
+    }
+    y += settings_lines as i32 + 1;
+
+    // Samples section
+    let samples_top = y;
+    let samples_bottom = y + samples_lines as i32;
+    if samples_bottom > viewport_top && samples_top < viewport_bottom {
+        let clipped_y = samples_top.max(viewport_top) as u16;
+        let clipped_height =
+            (samples_bottom.min(viewport_bottom) - samples_top.max(viewport_top)) as u16;
+        let samples_area = Rect {
+            x: padded.x,
+            y: clipped_y,
+            width: padded.width,
+            height: clipped_height,
+        };
+        render_samples(frame, app, samples_area);
+    }
+
+    // Scroll indicators
+    let indicator_style = Style::new().fg(SCROLL_INDICATOR_COLOR);
+    let indicator_x = padded.x + padded.width.saturating_sub(1);
+
+    if scroll_offset > 0 {
+        let up_indicator = Paragraph::new("▲").style(indicator_style);
+        frame.render_widget(up_indicator, Rect::new(indicator_x, padded.y, 1, 1));
+    }
+
+    if scroll_offset + max_visible < total_lines {
+        let down_indicator = Paragraph::new("▼").style(indicator_style);
+        frame.render_widget(
+            down_indicator,
+            Rect::new(indicator_x, padded.y + padded.height.saturating_sub(1), 1, 1),
+        );
+    }
 }
 
 fn render_visualizers(frame: &mut Frame, app: &App, area: Rect) {
@@ -241,6 +327,7 @@ fn render_settings(frame: &mut Frame, app: &App, area: Rect) {
     let buffer_focused = section_focused && app.audio.setting_kind == SettingKind::BufferSize;
     let polyphony_focused = section_focused && app.audio.setting_kind == SettingKind::Polyphony;
     let nudge_focused = section_focused && app.audio.setting_kind == SettingKind::Nudge;
+    let lookahead_focused = section_focused && app.audio.setting_kind == SettingKind::Lookahead;
 
     let nudge_ms = app.metrics.nudge_ms;
     let nudge_label = if nudge_ms == 0.0 {
@@ -249,6 +336,12 @@ fn render_settings(frame: &mut Frame, app: &App, area: Rect) {
         format!("{nudge_ms:+.1} ms")
     };
 
+    let lookahead_label = if app.audio.config.lookahead_ms == 0 {
+        "off".to_string()
+    } else {
+        format!("{} ms", app.audio.config.lookahead_ms)
+    };
+
     let rows = vec![
         Row::new(vec![
             Span::styled(
@@ -305,6 +398,17 @@ fn render_settings(frame: &mut Frame, app: &App, area: Rect) {
             ),
             render_selector(&nudge_label, nudge_focused, highlight, normal),
         ]),
+        Row::new(vec![
+            Span::styled(
+                if lookahead_focused {
+                    "> Lookahead"
+                } else {
+                    "  Lookahead"
+                },
+                label_style,
+            ),
+            render_selector(&lookahead_label, lookahead_focused, highlight, normal),
+        ]),
         Row::new(vec![
             Span::styled("  Sample rate", label_style),
             Span::styled(