Reorganize repository

crates/ratatui/src/vu_meter.rs

@@ -0,0 +1,81 @@
+use ratatui::buffer::Buffer;
+use ratatui::layout::Rect;
+use ratatui::style::Color;
+use ratatui::widgets::Widget;
+
+const DB_MIN: f32 = -48.0;
+const DB_MAX: f32 = 3.0;
+const DB_RANGE: f32 = DB_MAX - DB_MIN;
+
+pub struct VuMeter {
+    left: f32,
+    right: f32,
+}
+
+impl VuMeter {
+    pub fn new(left: f32, right: f32) -> Self {
+        Self { left, right }
+    }
+
+    fn amplitude_to_db(amp: f32) -> f32 {
+        if amp <= 0.0 {
+            DB_MIN
+        } else {
+            (20.0 * amp.log10()).clamp(DB_MIN, DB_MAX)
+        }
+    }
+
+    fn db_to_normalized(db: f32) -> f32 {
+        (db - DB_MIN) / DB_RANGE
+    }
+
+    fn row_to_color(row_position: f32) -> Color {
+        if row_position > 0.9 {
+            Color::Red
+        } else if row_position > 0.75 {
+            Color::Yellow
+        } else {
+            Color::Green
+        }
+    }
+}
+
+impl Widget for VuMeter {
+    fn render(self, area: Rect, buf: &mut Buffer) {
+        if area.width < 3 || area.height == 0 {
+            return;
+        }
+
+        let height = area.height as usize;
+        let half_width = area.width / 2;
+        let gap = 1u16;
+
+        let left_db = Self::amplitude_to_db(self.left);
+        let right_db = Self::amplitude_to_db(self.right);
+        let left_norm = Self::db_to_normalized(left_db);
+        let right_norm = Self::db_to_normalized(right_db);
+
+        let left_rows = (left_norm * height as f32).round() as usize;
+        let right_rows = (right_norm * height as f32).round() as usize;
+
+        for row in 0..height {
+            let y = area.y + area.height - 1 - row as u16;
+            let row_position = (row as f32 + 0.5) / height as f32;
+            let color = Self::row_to_color(row_position);
+
+            for col in 0..half_width.saturating_sub(gap) {
+                let x = area.x + col;
+                if row < left_rows {
+                    buf[(x, y)].set_char(' ').set_bg(color);
+                }
+            }
+
+            for col in 0..half_width.saturating_sub(gap) {
+                let x = area.x + half_width + gap + col;
+                if x < area.x + area.width && row < right_rows {
+                    buf[(x, y)].set_char(' ').set_bg(color);
+                }
+            }
+        }
+    }
+}