Function arithmetic

pub fn arithmetic(
    k1: f32,
    k2: f32,
    k3: f32,
    k4: f32,
    enforce_premul: bool,
) -> Option<RCHandle<SkBlender>>

Create a blender that implements the following: k1 * src * dst + k2 * src + k3 * dst + k4

• k1, k2, k3, k4 The four coefficients.
• enforce_premul If true, the RGB channels will be clamped to the calculated alpha.