Type Property 型プロパティ

sourceAtop

A mode that you use to paint the opaque parts of the source image onto the opaque parts of the background.

Declaration 宣言 

static var sourceAtop: GraphicsContext.BlendMode { get }

Discussion 議論

This mode implements the equation R = S*Da + D*(1 - Sa) where

  • R is the composite image.

  • S is the source image.

  • D is the background.

  • Sa is the source image’s alpha value.

  • Da is the source background’s alpha value.

See Also 参照

Accessing Porter-Duff Modes

static var clear: GraphicsContext.BlendMode
A mode that clears any pixels that the source image overwrites.
static var copy: GraphicsContext.BlendMode
A mode that replaces background image samples with source image samples.
static var sourceIn: GraphicsContext.BlendMode
A mode that you use to paint the source image, including its transparency, onto the opaque parts of the background.
static var sourceOut: GraphicsContext.BlendMode
A mode that you use to paint the source image onto the transparent parts of the background, while erasing the background.
static var destinationOver: GraphicsContext.BlendMode
A mode that you use to paint the source image under the background.
static var destinationIn: GraphicsContext.BlendMode
A mode that you use to erase any of the background that isn’t covered by opaque source pixels.
static var destinationOut: GraphicsContext.BlendMode
A mode that you use to erase any of the background that is covered by opaque source pixels.
static var destinationAtop: GraphicsContext.BlendMode
A mode that you use to paint the source image under the background, while erasing any of the background not matched by opaque pixels from the source image.
static var xor: GraphicsContext.BlendMode
A mode that you use to clear pixels where both the source and background images are opaque.