static var darken: GraphicsContext .BlendMode
A mode that creates composite image samples by choosing the darker samples from either the source image or the background.
static var multiply: GraphicsContext .BlendMode
A mode that multiplies the source image samples with the background image samples.
static var plusDarker : GraphicsContext .BlendMode
A mode that adds the inverse of the color components of the source and background images, and then inverts the result, producing a darkened composite.