Function compute_rotated_aabb

src/math.rs:109–139

Computes the axis-aligned bounding box of a rounded rectangle after rotation. Uses the Minkowski-sum approach for equal corner radii: `AABB_w = |(w-2r)·cosθ| + |(h-2r)·sinθ| + 2r` `AABB_h = |(w-2r)·sinθ| + |(h-2r)·cosθ| + 2r` For non-uniform radii, uses the maximum radius as a conservative approximation. Returns `(effective_width, effective_height)`.

(
    width: f32,
    height: f32,
    corner_radius: &CornerRadius,
    rotation_radians: f32,
)

/// For non-uniform radii, uses the maximum radius as a conservative approximation.
/// Returns `(effective_width, effective_height)`.
pub fn compute_rotated_aabb(
    width: f32,
    height: f32,
    corner_radius: &CornerRadius,
    rotation_radians: f32,
) -> (f32, f32) {
    let angle = classify_angle(rotation_radians);
    match angle {
        AngleType::Zero => (width, height),
        AngleType::Straight180 => (width, height),
        AngleType::Right90 | AngleType::Right270 => (height, width),
        AngleType::Arbitrary(theta) => {
            let r = corner_radius
                .top_left
                .max(corner_radius.top_right)
                .max(corner_radius.bottom_left)
                .max(corner_radius.bottom_right)
                .min(width / 2.0)
                .min(height / 2.0);

            let cos_t = theta.cos().abs();
            let sin_t = theta.sin().abs();
            let inner_w = (width - 2.0 * r).max(0.0);
            let inner_h = (height - 2.0 * r).max(0.0);

            let eff_w = inner_w * cos_t + inner_h * sin_t + 2.0 * r;
            let eff_h = inner_w * sin_t + inner_h * cos_t + 2.0 * r;
            (eff_w, eff_h)
        }
    }
}