Simply Patrick Hopes can always go up, tears can only come down.

// Shared thread-safe storage for the latest encoded frame.
let frame_state = Arc::new(Mutex::new(initial_jpeg.to_vec()));
let frame_state_clone = Arc::clone(&frame_state);

// Watch channel to notify web clients of new frames.
let (watch_tx, watch_rx) = watch::channel(0u64);

// 將硬體 VideoCapture 迴圈隔離在獨立的 blocking worker 執行緒
let camera_index = args.camera_index;
let filters = args.filter.clone();
tokio::task::spawn_blocking(move || {
    if let Err(e) = camera::run_capture_loop(camera_index, filters, frame_state_clone, watch_tx) {
        error!("Capture loop exited with error: {:?}", e);
    }
});

// 計算即時動態 FPS
frame_count += 1;
let now = Instant::now();
let delta = now.duration_since(last_fps_time).as_secs_f64();
last_fps_time = now;
if delta > 0.0 {
    let instant_fps = 1.0 / delta;
    // 使用 EMA 演算法平滑化 FPS 數值
    fps = fps * 0.95 + instant_fps * 0.05;
}

FilterConfig::Scanner { margin } => {
    if let Ok(size) = current_frame.size() {
        let m = *margin;
        let box_w = std::cmp::max(1, size.width - m * 2);
        let box_h = std::cmp::max(1, size.height - m * 2);
        let roi_rect = Rect::new(m, m, box_w, box_h);

        // 畫出 HUD 外框與綠色四角標記
        let _ = imgproc::rectangle(&mut current_frame, roi_rect, Scalar::new(99.0, 102.0, 241.0, 0.0), 2, imgproc::LINE_AA, 0);

        // 計算雷射紅線上下掃描的位置
        let scan_period = 100;
        let scan_pos = (frame_count % scan_period) as i32;
        let scan_y = m + (scan_pos * box_h / scan_period as i32);
        let _ = imgproc::line(
            &mut current_frame,
            Point::new(m + 2, scan_y),
            Point::new(m + box_w - 2, scan_y),
            Scalar::new(0.0, 0.0, 255.0, 0.0), // 雷射紅光
            2,
            imgproc::LINE_AA,
            0,
        );
    }
}

let mut jpeg_buf = Vector::<u8>::new();
let mut encode_params = Vector::<i32>::new();
encode_params.push(imgcodecs::IMWRITE_JPEG_QUALITY);
encode_params.push(85); // 85% 品質：兼顧畫質與網路頻寬

imgcodecs::imencode(".jpg", &frame, &mut jpeg_buf, &encode_params)?;

// 將 compressed bytes 寫入共享記憶體，並發送 watch 廣播
{
    let mut lock = frame_state.lock().unwrap();
    *lock = jpeg_buf.to_vec();
}
let _ = watch_tx.send(watch_tx.borrow().wrapping_add(1));

pub async fn stream_handler(State(state): State<AppState>) -> impl IntoResponse {
    let rx = state.watch_rx.clone();
    let frame_state = state.frame_state.clone();

    // 利用 stream::unfold 打造非同步影格串流
    let stream = stream::unfold((true, rx, frame_state), move |(is_first, mut rx, frame_state)| async move {
        if !is_first {
            // 沒有新影格時，Task 在此處非同步休眠，不消耗 CPU！
            if rx.changed().await.is_err() {
                return None; // Sender dropped
            }
        }

        // 從共享記憶體讀取最新的 JPEG Bytes
        let jpeg_bytes = {
            let lock = frame_state.lock().unwrap();
            lock.clone()
        };

        // 封裝 multipart/x-mixed-replace boundary 封包
        let header = format!(
            "--frame\r\nContent-Type: image/jpeg\r\nContent-Length: {}\r\n\r\n",
            jpeg_bytes.len()
        );
        let mut body_bytes = Vec::new();
        body_bytes.extend_from_slice(header.as_bytes());
        body_bytes.extend_from_slice(&jpeg_bytes);
        body_bytes.extend_from_slice(b"\r\n");

        Some((
            Ok::<Bytes, std::io::Error>(Bytes::from(body_bytes)),
            (false, rx, frame_state),
        ))
    });

    let body = Body::from_stream(stream);
    let mut headers = HeaderMap::new();
    headers.insert(
        CONTENT_TYPE,
        HeaderValue::from_static("multipart/x-mixed-replace; boundary=frame"),
    );

    (headers, body)
}

// 繪製動態旋轉雷達綠光束與脈衝目標
let center = Point::new(size.width / 2, size.height / 2);
let angle = (frame_count as f64 * 0.05) % (2.0 * std::f64::consts::PI);
let radius = 120.0;
let radar_end = Point::new(
    (center.x as f64 + radius * angle.cos()) as i32,
    (center.y as f64 + radius * angle.sin()) as i32,
);
imgproc::line(&mut frame, center, radar_end, Scalar::new(0.0, 255.0, 0.0, 0.0), 1, imgproc::LINE_AA, 0)?;

imgproc::put_text(&mut frame, "⚠️ CAMERA OFFLINE - RUNNING IN SIMULATED MODE", Point::new(20, size.height - 20), ...)?;

# 編譯並運行 Release 版本
.\build.bat run --release

sudo apt update && sudo apt install -y build-essential clang libclang-dev pkg-config
cargo run --release

fn main() -> Result<()> {
    let cli = Cli::parse();
    let show_preview = !cli.no_preview;

    // 1. 建立跨執行緒 Channel
    let (tx, rx) = std::sync::mpsc::channel();

    // 2. 啟動視覺處理執行緒 (Vision Loop Thread)
    let vision_handle = thread::spawn(move || {
        if let Err(e) = vision::run_vision_loop(cli.camera, tx, show_preview) {
            eprintln!("Error in vision thread: {:?}", e);
        }
    });

    // 3. 在主執行緒運行 OS 輸入控制迴圈 (Controller Loop)
    controller::run_controller_loop(rx)?;

    // 4. 等待視覺執行緒安全結束
    if let Err(e) = vision_handle.join() {
        eprintln!("Failed to join vision thread: {:?}", e);
    }
    Ok(())
}

// 若兩掌心中心距離小於現有框尺寸的 75%，判定為同一隻手並進行抑制
let mut detections: Vec<PalmDetection> = Vec::new();
for det in raw_detections {
    let mut duplicate = false;
    for existing in &detections {
        let dx = existing.center.x - det.center.x;
        let dy = existing.center.y - det.center.y;
        let dist = (dx * dx + dy * dy).sqrt();
        let min_size = existing.bbox.width.min(existing.bbox.height) as f32;
        
        if dist < min_size * 0.75 {
            duplicate = true; // 抑制重複框
            break;
        }
    }
    if !duplicate {
        detections.push(det);
    }
}

// 手掌旋轉對齊：建立 2x3 Affine Rotation Matrix
let angle_rad = (palm.angle as f64) * std::f64::consts::PI / 180.0;
let alpha = angle_rad.cos();
let beta = angle_rad.sin();

let mut rotation_matrix = Mat::new_rows_cols_with_default(2, 3, CV_64F, Scalar::all(0.0))?;
*rotation_matrix.at_2d_mut::<f64>(0, 0)? = alpha;
*rotation_matrix.at_2d_mut::<f64>(0, 1)? = beta;
*rotation_matrix.at_2d_mut::<f64>(0, 2)? = (1.0 - alpha) * palm_center.x as f64 - beta * palm_center.y as f64;
*rotation_matrix.at_2d_mut::<f64>(1, 0)? = -beta;
*rotation_matrix.at_2d_mut::<f64>(1, 1)? = alpha;
*rotation_matrix.at_2d_mut::<f64>(1, 2)? = beta * palm_center.x as f64 + (1.0 - alpha) * palm_center.y as f64;

// 對整張影像進行仿射旋轉與 Crop 截取
let mut rotated_image = Mat::default();
imgproc::warp_affine(&frame, &mut rotated_image, &rotation_matrix, Size::new(frame.cols(), frame.rows()), ...)?;

let mut evaluate = |img: &Mat| -> Result<(f32, f32, Vector<Mat>)> {
    let blob = float_mat.reshape_nd(1, &[1, 224, 224, 3])?;
    net.set_input(&blob, "", 1.0, Scalar::default())?;
    
    let mut out_layers = Vector::<Mat>::new();
    net.forward(&mut out_layers, &net.get_unconnected_out_layers_names()?)?;
    
    let score = *out_layers.get(1)?.at_2d::<f32>(0, 0)?;      // Layer 1: 置信度
    let handedness = *out_layers.get(2)?.at_2d::<f32>(0, 0)?; // Layer 2: 右手性得分
    Ok((score, handedness, out_layers))
};

// 同時對原始 Crop 與水平翻轉 Crop (rgb_flipped) 進行推論
let (score_unflipped, handedness_unflipped, out_unflipped) = evaluate(&rgb)?;
let (score_flipped, handedness_flipped, out_flipped) = evaluate(&rgb_flipped)?;

// 模型永遠會給「看起來像右手」的影像更高的 Layer 2 分數
// 若翻轉後的影像分數更高，代表原始影像必定是「左手」！
let is_left_hand = handedness_flipped > handedness_unflipped;

// 若為左手，採用翻轉影像的推論結果，並將 X 座標鏡射還原 (224.0 - X)

#[derive(Clone)]
struct TrackedHand {
    keypoints: Vec<Point>,
    score: f32,
    center: Point,
    left_votes: i32,       // 遲滯投票計數器 [-30..+30]
    is_left_hand: bool,    // 最終鎖定的左右手標籤
    missed_frames: usize, // 遮擋遺失影格補償計數
}

if *is_left {
    tracker.left_votes = (tracker.left_votes + 1).min(30);
} else {
    tracker.left_votes = (tracker.left_votes - 1).max(-30);
}

// 遲滯門檻：防止單影格誤判造成的標籤閃爍
if tracker.left_votes >= 20 {
    tracker.is_left_hand = true;
} else if tracker.left_votes <= -20 {
    tracker.is_left_hand = false;
}

for (t_idx, tracker) in hand_trackers.iter_mut().enumerate() {
    if !matched_tracker[t_idx] {
        tracker.missed_frames += 1;
        if tracker.missed_frames < 5 {
            new_trackers.push(tracker.clone()); // 保持追蹤
        }
    }
}

let wrist = kps[0];
let index_ext = dist(wrist, kps[8]) > dist(wrist, kps[6]);   // 8: 食指尖, 6: 食指 PIP 關節
let middle_ext = dist(wrist, kps[12]) > dist(wrist, kps[10]); // 12: 中指尖, 10: 中指 PIP 關節
let ring_ext = dist(wrist, kps[16]) > dist(wrist, kps[14]);   // 16: 無名指尖, 14: 無名指 PIP 關節
let pinky_ext = dist(wrist, kps[20]) > dist(wrist, kps[18]);  // 20: 小指尖, 18: 小指 PIP 關節

let extended_count = (index_ext as usize) + (middle_ext as usize) + (ring_ext as usize) + (pinky_ext as usize);

pub fn run_controller_loop(rx: Receiver<GestureState>) -> Result<()> {
    let mut enigo = Enigo::new(&Settings::default())?;
    let (screen_w, screen_h) = get_screen_size(); // Win32 GetSystemMetrics
    let alpha = 0.20f32; // EMA 平滑係數

    while let Ok(state) = rx.recv() {
        match state {
            GestureState::Hover { x, y } => {
                if is_pressed {
                    enigo.button(Button::Left, Direction::Release)?;
                    is_pressed = false;
                }
                // EMA 平滑化算式
                let target_x = alpha * x + (1.0 - alpha) * last_x;
                let target_y = alpha * y + (1.0 - alpha) * last_y;

                let px = (target_x * (screen_w as f32)) as i32;
                let py = (target_y * (screen_h as f32)) as i32;

                enigo.move_mouse(px, py, Coordinate::Abs)?;
                last_x = target_x;
                last_y = target_y;
            }
            GestureState::Click { x, y } => {
                if !is_pressed {
                    enigo.button(Button::Left, Direction::Press)?;
                    is_pressed = true;
                }
                // 拖曳游標平滑移動...
            }
            GestureState::Scroll { dy } => {
                scroll_accumulator += dy;
                let scroll_clicks = scroll_accumulator.trunc() as i32;
                if scroll_clicks != 0 {
                    enigo.scroll(-scroll_clicks, Axis::Vertical)?;
                    scroll_accumulator -= scroll_clicks as f32;
                }
            }
            GestureState::WaveLeft => {
                // 觸發 Windows 切換虛擬桌面快捷鍵
                enigo.key(Key::Control, Direction::Press)?;
                enigo.key(Key::Meta, Direction::Press)?;
                enigo.key(Key::LeftArrow, Direction::Click)?;
                enigo.key(Key::Meta, Direction::Release)?;
                enigo.key(Key::Control, Direction::Release)?;
            }
            // ...
        }
    }
    Ok(())
}

let dx = (palm_pt.x as f32) - last_palm_x;
last_palm_x = palm_pt.x as f32;

let velocity = dx / dt;
let alpha_vel = (dt * 10.0).clamp(0.0, 1.0);
velocity_x_smoothed = alpha_vel * velocity + (1.0 - alpha_vel) * velocity_x_smoothed;

if debounced_count >= 4 && elapsed_wave > 1.2 {
    if velocity_x_smoothed < -450.0 {
        current_state = GestureState::WaveLeft;
    } else if velocity_x_smoothed > 450.0 {
        current_state = GestureState::WaveRight;
    }
}

.\download_models.ps1

cargo run --release -- --no-preview

#[test]
fn test_far_blank_image() {
    let mut net = dnn::read_net_def("models/palm_detection_mediapipe_2023feb.onnx").unwrap();
    let frame = Mat::new_rows_cols_with_default(480, 640, CV_8UC3, Scalar::all(0.0)).unwrap();
    let result = crate::palm::detect_mediapipe_palm(&mut net, &frame, 0.65).unwrap();
    assert!(result.is_empty(), "FAR Failure: Palm detected in solid black image!");
}

cargo test -- --nocapture

running 7 tests
test vision::tests::test_load_mediapipe_onnx_models ... ok
test vision::tests::test_far_blank_image ... ok
test vision::tests::test_far_noise_image ... ok
test vision::tests::test_far_geometric_shapes ... ok
test vision::tests::test_video_one_hand_flipping ... ok
test result: ok. 7 passed; 0 failed

fn check_and_download_model(model_path: &Path) -> Result<()> {
    if model_path.exists() {
        return Ok(());
    }
    println!("MiDaS model file '{}' not found.", model_path.display());
    println!("Downloading model-small.onnx (approx. 58MB)...");

    let url = "https://github.com/intel-isl/MiDaS/releases/download/v2_1/model-small.onnx";
    let status = std::process::Command::new("curl")
        .arg("-L").arg("-o").arg(model_path).arg(url)
        .status();

    // 支援 Windows 預設環境的 PowerShell 備援機制
    if status.is_err() || !status.unwrap().success() {
        // Invoke-WebRequest 備援...
    }
    Ok(())
}

pub fn estimate_depth_single(
    img: &Mat,
    model_path: &str,
    options: &DepthPostProcessOptions,
) -> Result<Mat> {
    let mut net = dnn::read_net_from_onnx_def(model_path)?;

    // 1. Resize 至 256x256
    let target_size = Size::new(256, 256);
    let mut resized = Mat::default();
    imgproc::resize(img, &mut resized, target_size, 0.0, 0.0, imgproc::INTER_CUBIC)?;

    // 2. BGR 轉 RGB 並進行 ImageNet Normalization
    let mut preprocessed = Mat::new_rows_cols_with_default(
        target_size.height, target_size.width, opencv::core::CV_32FC3, Scalar::default()
    )?;

    for y in 0..target_size.height {
        for x in 0..target_size.width {
            let bgr: opencv::core::Vec3b = *resized.at_2d::<opencv::core::Vec3b>(y, x)?;
            let r = (bgr[2] as f32) / 255.0;
            let g = (bgr[1] as f32) / 255.0;
            let b = (bgr[0] as f32) / 255.0;

            let r_norm = (r - 0.485) / 0.229;
            let g_norm = (g - 0.456) / 0.224;
            let b_norm = (b - 0.406) / 0.225;

            *preprocessed.at_2d_mut::<opencv::core::Vec3f>(y, x)? =
                opencv::core::Vec3f::from([r_norm, g_norm, b_norm]);
        }
    }

    // 3. 轉為 4D Blob 並執行 Forward 推理
    let blob = dnn::blob_from_image(&preprocessed, 1.0, target_size, Scalar::default(), false, false, CV_32F)?;
    net.set_input(&blob, "", 1.0, Scalar::default())?;

    let mut output = Mat::default();
    let out_blob_names = opencv::core::Vector::<String>::new();
    net.forward(&mut output, &out_blob_names)?;

    // 4. 提取原始 Raw Depth 矩陣
    // ...
    
    // 5. 進入深度圖後處理管線
    post_process_depth_map(&raw_depth, Some(img), options)
}

// 1. 收集有效深度像素值
let mut valid_vals: Vec<f32> = Vec::with_capacity(total_pixels);
for y in 0..h {
    for x in 0..w {
        let val = *raw_map.at_2d::<f32>(y, x)?;
        if val.is_finite() && val > -0.5 {
            valid_vals.push(val);
        }
    }
}

// 2. 分位數排序並計算 1% 與 99% 陣列索引
valid_vals.sort_by(|a, b| a.partial_cmp(b).unwrap_or(std::cmp::Ordering::Equal));
let num_valid = valid_vals.len();

let min_idx = ((num_valid - 1) as f32 * options.clip_min_quantile) as usize;
let max_idx = ((num_valid - 1) as f32 * options.clip_max_quantile) as usize;

let v_min = valid_vals[min_idx];
let v_max = valid_vals[max_idx];
let range = if (v_max - v_min).abs() > 1e-6 { v_max - v_min } else { 1.0 };

let mut norm_map = Mat::new_rows_cols_with_default(h, w, CV_32F, Scalar::default())?;
for y in 0..h {
    for x in 0..w {
        let val = *raw_map.at_2d::<f32>(y, x)?;
        if val <= -0.5 {
            *norm_map.at_2d_mut::<f32>(y, x)? = 0.0;
        } else {
            let clamped = val.clamp(v_min, v_max);
            let norm = (clamped - v_min) / range;
            // 套用 powf 進行 Gamma 對比擴充
            let final_val = norm.powf(options.gamma);
            *norm_map.at_2d_mut::<f32>(y, x)? = final_val;
        }
    }
}

// 高通細節提取函式
pub fn extract_high_pass_detail(img: &Mat, target_size: Size) -> Result<Mat> {
    let mut gray = Mat::default();
    imgproc::cvt_color(img, &mut gray, imgproc::COLOR_BGR2GRAY, 0, AlgorithmHint::ALGO_HINT_DEFAULT)?;

    let mut resized_gray = Mat::default();
    imgproc::resize(&gray, &mut resized_gray, target_size, 0.0, 0.0, imgproc::INTER_CUBIC)?;

    let mut f32_gray = Mat::default();
    resized_gray.convert_to(&mut f32_gray, CV_32F, 1.0 / 255.0, 0.0)?;

    // 低頻模糊層
    let mut blurred = Mat::default();
    imgproc::gaussian_blur(&f32_gray, &mut blurred, Size::new(15, 15), 3.0, 3.0, opencv::core::BORDER_DEFAULT, AlgorithmHint::ALGO_HINT_DEFAULT)?;

    // 計算高通殘差：原圖 - 低頻模糊 = 高頻細節
    let mut detail_map = Mat::new_rows_cols_with_default(target_size.height, target_size.width, CV_32F, Scalar::default())?;
    for y in 0..target_size.height {
        for x in 0..target_size.width {
            let hp = *f32_gray.at_2d::<f32>(y, x)? - *blurred.at_2d::<f32>(y, x)?;
            *detail_map.at_2d_mut::<f32>(y, x)? = hp;
        }
    }
    Ok(detail_map)
}

// 融合高頻細節至深度圖
if let Some(src_img) = opt_source_img {
    if options.detail_weight > 0.0 {
        let hp_detail = extract_high_pass_detail(src_img, Size::new(w, h))?;
        let weight = options.detail_weight;

        for y in 0..h {
            for x in 0..w {
                let base_val = *norm_map.at_2d::<f32>(y, x)?;
                let hp_val = *hp_detail.at_2d::<f32>(y, x)?;
                let blended = (base_val + weight * hp_val).clamp(0.0, 1.0);
                *norm_map.at_2d_mut::<f32>(y, x)? = blended;
            }
        }
    }
}

let mut smooth_map = if options.smooth_radius > 0 {
    let mut dst = Mat::default();
    let d = options.smooth_radius * 2 + 1;
    imgproc::bilateral_filter(
        &norm_map,
        &mut dst,
        d,
        0.1f64,                       // sigmaColor: 色彩/深度差異容許度
        options.smooth_radius as f64, // sigmaSpace: 空間濾波半徑
        opencv::core::BORDER_DEFAULT,
    )?;
    dst
} else {
    norm_map
};

if options.enable_clahe {
    let mut u8_map = Mat::default();
    smooth_map.convert_to(&mut u8_map, opencv::core::CV_8U, 255.0, 0.0)?;

    let mut clahe_obj = imgproc::create_clahe_def()?;
    clahe_obj.set_clip_limit(3.0)?;
    clahe_obj.set_tiles_grid_size(Size::new(8, 8))?;

    let mut clahe_out = Mat::default();
    clahe_obj.apply(&u8_map, &mut clahe_out)?;

    let mut f32_clahe = Mat::default();
    clahe_out.convert_to(&mut f32_clahe, CV_32F, 1.0 / 255.0, 0.0)?;
    smooth_map = f32_clahe;
}

fn calculate_normal(v1: Vertex, v2: Vertex, v3: Vertex) -> Vertex {
    let ax = v2.x - v1.x; let ay = v2.y - v1.y; let az = v2.z - v1.z;
    let bx = v3.x - v1.x; let by = v3.y - v1.y; let bz = v3.z - v1.z;

    let nx = ay * bz - az * by;
    let ny = az * bx - ax * bz;
    let nz = ax * by - ay * bx;

    let len = (nx * nx + ny * ny + nz * nz).sqrt();
    if len > 1e-6 {
        Vertex { x: nx / len, y: ny / len, z: nz / len }
    } else {
        Vertex { x: 0.0, y: 0.0, z: 0.0 }
    }
}

cargo run --release -- --mode single --input patrick-22.jpg --output-stl patrick-22.stl --width 100 --detail-weight 0.4 --gamma 0.7

// OpenSCAD 浮雕加框與掛鉤腳本
difference() {
    union() {
        // 1. 外圍相框底座
        cube([110, 110, 3], center = true);
        
        // 2. 匯入 depth-relief 產生的 STL 並置中
        translate([-50, -50, 1.5]) 
            import("patrick-22.stl");
    }

    // 3. 挖出後方壁掛螺絲孔
    translate([0, 50, 0])
        cylinder(h = 20, r = 2.5, center = true, $fn = 32);
}

let mut cap = videoio::VideoCapture::from_file(&input_path, videoio::CAP_ANY)?;
let fps = cap.get(videoio::CAP_PROP_FPS)?;
let width = cap.get(videoio::CAP_PROP_FRAME_WIDTH)? as i32;
let height = cap.get(videoio::CAP_PROP_FRAME_HEIGHT)? as i32;
let total_frames = cap.get(videoio::CAP_PROP_FRAME_COUNT)? as i64;

let mut writer = videoio::VideoWriter::new(
    &output_path,
    videoio::VideoWriter::fourcc('m', 'p', '4', 'v')?,
    fps,
    Size::new(width, height),
    true, // isColor
)?;

let mut frame = Mat::default();
let mut frame_count: i64 = 0;

loop {
    cap.read(&mut frame)?;
    if frame.empty() {
        break;
    }
    frame_count += 1;

    // 更新偵測器的輸入尺寸
    detector.set_input_size(frame.size()?)?;

    // 偵測人臉
    let mut faces = Mat::default();
    detector.detect(&frame, &mut faces)?;

    // 對每張偵測到的臉打碼
    for i in 0..faces.rows() {
        let x = *faces.at_2d::<f32>(i, 0)? as i32;
        let y = *faces.at_2d::<f32>(i, 1)? as i32;
        let w = *faces.at_2d::<f32>(i, 2)? as i32;
        let h = *faces.at_2d::<f32>(i, 3)? as i32;

        apply_mosaic(&mut frame, Rect::new(x, y, w, h))?;
    }

    writer.write(&frame)?;

    if frame_count % 100 == 0 {
        println!("Processed {}/{} frames", frame_count, total_frames);
    }
}

fn apply_blur(frame: &mut Mat, roi: Rect) -> Result<()> {
    // 確保 ROI 不會超出圖片邊界
    let roi = clamp_rect(roi, frame.size()?);
    let mut face_region = Mat::roi(frame, roi)?;
    let mut blurred = Mat::default();

    // kernel size 越大越模糊，必須是奇數
    imgproc::gaussian_blur(
        &face_region,
        &mut blurred,
        Size::new(99, 99),
        30.0, // sigmaX
        30.0, // sigmaY
        opencv::core::BORDER_DEFAULT,
    )?;

    blurred.copy_to(&mut face_region)?;
    Ok(())
}

fn apply_mosaic(frame: &mut Mat, roi: Rect) -> Result<()> {
    let roi = clamp_rect(roi, frame.size()?);
    let face_region = Mat::roi(frame, roi)?;

    let pixel_size = 10;
    let small_size = Size::new(
        (roi.width / pixel_size).max(1),
        (roi.height / pixel_size).max(1),
    );

    // 縮小
    let mut small = Mat::default();
    imgproc::resize(
        &face_region, &mut small,
        small_size, 0.0, 0.0,
        imgproc::INTER_LINEAR,
    )?;

    // 放大回原尺寸（最近鄰插值 = 馬賽克效果）
    let mut mosaic = Mat::default();
    imgproc::resize(
        &small, &mut mosaic,
        Size::new(roi.width, roi.height), 0.0, 0.0,
        imgproc::INTER_NEAREST,
    )?;

    let mut face_mut = Mat::roi_mut(frame, roi)?;
    mosaic.copy_to(&mut face_mut)?;
    Ok(())
}

fn clamp_rect(rect: Rect, size: Size) -> Rect {
    let x = rect.x.max(0);
    let y = rect.y.max(0);
    let w = rect.width.min(size.width - x);
    let h = rect.height.min(size.height - y);
    Rect::new(x, y, w.max(0), h.max(0))
}

vcpkg install opencv4:x64-windows

$env:OPENCV_LINK_LIBS = "opencv_world4"
$env:OPENCV_LINK_PATHS = "C:\path\to\vcpkg\installed\x64-windows\lib"
$env:OPENCV_INCLUDE_PATHS = "C:\path\to\vcpkg\installed\x64-windows\include"

[dependencies]
anyhow = "1"
clap = { version = "4", features = ["derive"] }
opencv = { path = "opencv-rust-patch", features = ["clang-runtime"] }

#[derive(Parser)]
#[command(name = "face-detect", version)]
struct Cli {
    /// Path to an image file. If omitted, opens the webcam.
    #[arg(short, long)]
    image: Option<PathBuf>,

    /// Path to the YuNet ONNX model file.
    #[arg(short, long, default_value = "face_detection_yunet_2023mar.onnx")]
    model: PathBuf,

    /// Minimum confidence score to keep a detection (0.0–1.0).
    #[arg(short, long, default_value_t = 0.9)]
    score_threshold: f32,

    /// NMS IoU threshold (0.0–1.0).
    #[arg(short, long, default_value_t = 0.3)]
    nms_threshold: f32,

    /// Path to save the annotated output image (image mode only).
    #[arg(short, long)]
    output: Option<PathBuf>,
}

let mut detector = FaceDetectorYN::create(
    model_path,
    "",                  // config（YuNet 不需要）
    Size::new(320, 320), // 初始 input_size，之後會根據實際圖片調整
    cli.score_threshold,
    cli.nms_threshold,
    5000,                // top_k：最多保留幾個候選框
    0,                   // backend：預設
    0,                   // target：CPU
)?;

let size = img.size()?;
let max_dim = 800.0;
let mut scale = 1.0;

let mut detect_img = img.clone();
if size.width > 800 || size.height > 800 {
    scale = f64::max(size.width as f64, size.height as f64) / max_dim;
    let new_w = (size.width as f64 / scale).round() as i32;
    let new_h = (size.height as f64 / scale).round() as i32;
    let new_size = Size::new(new_w, new_h);
    imgproc::resize(&img, &mut detect_img, new_size, 0.0, 0.0, imgproc::INTER_LINEAR)?;
}

if scale != 1.0 && count > 0 {
    for i in 0..count {
        for j in 0..14 {
            let v = *faces.at_2d::<f32>(i, j)?;
            *faces.at_2d_mut::<f32>(i, j)? = (v as f64 * scale) as f32;
        }
    }
}

fn detect_in_webcam(detector: &mut impl FaceDetectorYNTrait) -> Result<()> {
    let mut cam = videoio::VideoCapture::new(0, videoio::CAP_ANY)?;
    if !cam.is_opened()? {
        bail!("Cannot open default webcam (index 0)");
    }

    let window = "face-detect – webcam (press Q to quit)";
    highgui::named_window(window, highgui::WINDOW_AUTOSIZE)?;

    let mut frame = Mat::default();
    loop {
        cam.read(&mut frame)?;
        if frame.empty() { continue; }

        detector.set_input_size(frame.size()?)?;

        let mut faces = Mat::default();
        detector.detect(&frame, &mut faces)?;

        draw_detections(&mut frame, &faces)?;
        highgui::imshow(window, &frame)?;

        let key = highgui::wait_key(1)?;
        if key == b'q' as i32 || key == 27 { break; }
    }

    highgui::destroy_all_windows()?;
    Ok(())
}

const LANDMARK_COLORS: [(f64, f64, f64); 5] = [
    (255.0, 0.0, 0.0),     // 右眼  – 藍色
    (0.0, 0.0, 255.0),     // 左眼  – 紅色
    (0.0, 255.0, 0.0),     // 鼻尖  – 綠色
    (255.0, 0.0, 255.0),   // 右嘴角 – 粉色
    (0.0, 255.0, 255.0),   // 左嘴角 – 黃色
];

for (j, &(b, g, r)) in LANDMARK_COLORS.iter().enumerate() {
    let col = 4 + j as i32 * 2;
    let lx = *faces.at_2d::<f32>(i, col)? as i32;
    let ly = *faces.at_2d::<f32>(i, col + 1)? as i32;
    imgproc::circle(
        img,
        Point::new(lx, ly),
        3,
        Scalar::new(b, g, r, 0.0),
        imgproc::FILLED,
        imgproc::LINE_AA,
        0,
    )?;
}

#[test]
fn test_face_detection_lena() -> Result<()> {
    let mut detector = setup_detector(0.5)?;
    let count = detect_in_image(&mut detector, &"tests/lena.jpg".into(), Some(&"tests/lena_out.jpg".into()))?;
    assert_eq!(count, 1, "Should detect exactly 1 face in lena.jpg");
    Ok(())
}

let hit_rate = (hits as f32 / images.len() as f32) * 100.0;
assert!(hit_rate >= 80.0, "Hit rate {:.1}% is below acceptable 80% threshold", hit_rate);

let fp_rate = (false_positives as f32 / total) * 100.0;
assert!(fp_rate <= 5.0, "False positive rate {:.1}% is above acceptable 5% threshold", fp_rate);