Filter application

gistfile1.rs

fn clamp<N: PartialOrd>(val: N, min: N, max: N) -> N {
    if val > max { max }
    else if val < min { min }
    else { val }
}

fn filter<P: Primitive + 'static, T: Pixel<P> + 'static, I: GenericImage<T>>(
    image: &I,
    kernel: &Matrix<f32>) -> ImageBuffer<Vec<P>, P, T> {
        let xcenter = kernel.rows() / 2;
        let ycenter = kernel.cols() / 2;
        let (width, height) = image.dimensions();

        let sum = match kernel.sum() {
            0.0 => 1.0,
            v   => v
        };
        let sumx4 = f32x4(sum, sum, sum, sum);
        let max : f32 = Primitive::max_value();

        let mut out = ImageBuffer::new(width, height);

        for i in (xcenter..width - xcenter) {
            for j in (ycenter..height - ycenter) {
                let mut sum = f32x4(0.0, 0.0, 0.0, 0.0);

                for x in (0..kernel.rows()) {
                    for y in (0..kernel.cols()) {
                        let diffx = x as isize - xcenter as isize;
                        let diffy = y as isize - ycenter as isize;
                        let x0 = i as isize + diffx;
                        let y0 = j as isize + diffy;
                        let k = kernel[(x, y)];
                        let kx4 = f32x4(k, k, k, k);
                        let pixel = image.get_pixel(x0 as u32, y0 as u32);

                        let (c1, c2, c3, c4) = pixel.channels4();
                        let vec = f32x4(
                            cast(c1).unwrap(),
                            cast(c2).unwrap(),
                            cast(c3).unwrap(),
                            cast(c4).unwrap());

                        sum += vec * kx4;
                    }
                }

                let f32x4(s1, s2, s3, s4) = sum / sumx4;
                let t: T = Pixel::from_channels(
                    cast(clamp(s1, 0.0, max)).unwrap(),
                    cast(clamp(s2, 0.0, max)).unwrap(),
                    cast(clamp(s3, 0.0, max)).unwrap(),
                    cast(clamp(s4, 0.0, max)).unwrap());

                out.put_pixel(i, j, t);
            }
        }

        out
    }