Function image::imageops::colorops::contrast

pub fn contrast<I, P, S>(image: &I, contrast: f32) -> ImageBuffer<P, Vec<S>> where
    I: GenericImageView<Pixel = P>,
    P: Pixel<Subpixel = S> + 'static,
    S: Primitive + 'static, 

Adjust the contrast of the supplied image. contrast is the amount to adjust the contrast by. Negative values decrease the contrast and positive values increase the contrast.