apple_vision/trajectories/
mod.rs

1#![allow(clippy::cast_possible_wrap, clippy::cast_sign_loss)]
2#![allow(clippy::too_long_first_doc_paragraph)]
3//! `VNDetectTrajectoriesRequest` — parabolic-trajectory detection.
4
5use std::ffi::{CStr, CString};
6use std::path::Path;
7use std::ptr;
8
9use crate::error::VisionError;
10use crate::ffi;
11
12/// A single detected trajectory.
13#[derive(Debug, Clone, Copy, PartialEq)]
14pub struct Trajectory {
15    pub detected_x: f64,
16    pub detected_y: f64,
17    pub projected_x: f64,
18    pub projected_y: f64,
19    /// Coefficients of the parabola `y = a x² + b x + c`.
20    pub equation_a: f64,
21    pub equation_b: f64,
22    pub equation_c: f64,
23    pub confidence: f32,
24}
25
26/// Detect parabolic trajectories in the image at `path`. The
27/// Vision sequence handler analyses up to `trajectory_length` frames
28/// internally; with a single call this returns trajectories detected
29/// across that synthetic sequence.
30///
31/// # Errors
32///
33/// Returns [`VisionError`] when the image fails to load or the
34/// Vision request errors.
35pub fn detect_trajectories(
36    path: impl AsRef<Path>,
37    trajectory_length: usize,
38) -> Result<Vec<Trajectory>, VisionError> {
39    let path_str = path.as_ref().to_str().ok_or_else(|| VisionError::InvalidArgument("non-UTF-8 path".into()))?;
40    let cpath = CString::new(path_str).map_err(|e| VisionError::InvalidArgument(format!("path NUL byte: {e}")))?;
41    let mut traj_ptr: *mut ffi::TrajectoryRaw = ptr::null_mut();
42    let mut count: isize = 0;
43    let mut err: *mut std::ffi::c_char = ptr::null_mut();
44    let status = unsafe {
45        ffi::vn_detect_trajectories_in_path(
46            cpath.as_ptr(),
47            trajectory_length as isize,
48            &mut traj_ptr,
49            &mut count,
50            &mut err,
51        )
52    };
53    if status != ffi::status::OK {
54        let msg = unsafe { take_err(err) };
55        return Err(VisionError::RequestFailed(msg));
56    }
57    let mut out = Vec::with_capacity(count.max(0) as usize);
58    for i in 0..count {
59        let t = unsafe { traj_ptr.offset(i).read() };
60        out.push(Trajectory {
61            detected_x: t.detected_x,
62            detected_y: t.detected_y,
63            projected_x: t.projected_x,
64            projected_y: t.projected_y,
65            equation_a: t.equation_a,
66            equation_b: t.equation_b,
67            equation_c: t.equation_c,
68            confidence: t.confidence,
69        });
70    }
71    if !traj_ptr.is_null() {
72        unsafe { ffi::vn_trajectories_free(traj_ptr, count) };
73    }
74    Ok(out)
75}
76
77unsafe fn take_err(p: *mut std::ffi::c_char) -> String {
78    if p.is_null() {
79        return String::new();
80    }
81    let s = unsafe { CStr::from_ptr(p) }.to_string_lossy().into_owned();
82    unsafe { libc::free(p.cast()) };
83    s
84}
apple_vision/trajectories/mod.rs

apple_vision/trajectories/
mod.rs
