image-optimizer 1.3.0

#[must_use]
pub fn calculate_resize_dimensions(width: u32, height: u32, max_size: u32) -> (u32, u32) {
    let longer_edge = width.max(height);

    if longer_edge <= max_size {
        return (width, height);
    }

    let scale_factor = f64::from(max_size) / f64::from(longer_edge);
    #[allow(clippy::cast_possible_truncation, clippy::cast_sign_loss)]
    let new_width = (f64::from(width) * scale_factor).round() as u32;
    #[allow(clippy::cast_possible_truncation, clippy::cast_sign_loss)]
    let new_height = (f64::from(height) * scale_factor).round() as u32;

    (new_width, new_height)
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_no_resize_needed() {
        assert_eq!(calculate_resize_dimensions(800, 600, 1000), (800, 600));
        assert_eq!(calculate_resize_dimensions(100, 100, 200), (100, 100));
        assert_eq!(calculate_resize_dimensions(500, 300, 500), (500, 300));
    }

    #[test]
    fn test_width_longer_resize() {
        assert_eq!(calculate_resize_dimensions(1200, 800, 600), (600, 400));
        assert_eq!(calculate_resize_dimensions(2000, 1000, 800), (800, 400));
    }

    #[test]
    fn test_height_longer_resize() {
        assert_eq!(calculate_resize_dimensions(800, 1200, 600), (400, 600));
        assert_eq!(calculate_resize_dimensions(1000, 2000, 800), (400, 800));
    }

    #[test]
    fn test_square_image_resize() {
        assert_eq!(calculate_resize_dimensions(1000, 1000, 500), (500, 500));
        assert_eq!(calculate_resize_dimensions(2000, 2000, 800), (800, 800));
    }

    #[test]
    fn test_edge_cases() {
        assert_eq!(calculate_resize_dimensions(1, 1, 100), (1, 1));
        assert_eq!(calculate_resize_dimensions(u32::MAX, 100, 50), (50, 0));
    }

    #[test]
    fn test_rounding() {
        assert_eq!(calculate_resize_dimensions(1333, 1000, 800), (800, 600));
        assert_eq!(calculate_resize_dimensions(1001, 1000, 800), (800, 799));
    }
}