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//! That module exports blending-related types and functions. //! //! Given two pixels *src* and *dst* – source and destination, we associate each pixel a blending //! factor – respectively, *srcK* and *dstK*. *src* is the pixel being computed, and *dst* is the //! pixel that is already stored in the framebuffer. //! //! The pixels can be blended in several ways. See the documentation of `Equation` for further //! details. //! //! The factors are encoded with `Factor`. /// Blending equation. Used to state how blending factors and pixel data should be blended. #[derive(Copy, Clone, Debug)] pub enum Equation { /// `Additive` represents the following blending equation: /// /// > `blended = src * srcK + dst * dstK` Additive, /// `Subtract` represents the following blending equation: /// /// > `blended = src * srcK - dst * dstK` Subtract, /// Because subtracting is not commutative, `ReverseSubtract` represents the following additional /// blending equation: /// /// > `blended = dst * dstK - src * srcK` ReverseSubtract, /// `Min` represents the following blending equation: /// /// > `blended = min(src, dst)` Min, /// `Max` represents the following blending equation: /// /// > `blended = max(src, dst)` Max } /// Blending factors. Pixel data are multiplied by these factors to achieve several effects driven /// by *blending equations*. #[derive(Copy, Clone, Debug)] pub enum Factor { /// `1 * color = factor` One, /// `0 * color = 0` Zero, /// `src * color` SrcColor, /// `(1 - src) * color` SrcColorComplement, /// `dst * color` DestColor, /// `(1 - dst) * color` DestColorComplement, /// `srcA * color` SrcAlpha, /// `(1 - src) * color` SrcAlphaComplement, /// `dstA * color` DstAlpha, /// `(1 - dstA) * color` DstAlphaComplement, SrcAlphaSaturate }