Type Property 型プロパティ

destinationAtop

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.

Declaration 宣言 

static var destinationAtop: GraphicsContext.BlendMode { get }

Discussion 議論

This mode implements the equation R = S*(1 - Da) + D*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 sourceAtop: GraphicsContext.BlendMode
A mode that you use to paint the opaque parts of the source image onto the opaque parts of 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 xor: GraphicsContext.BlendMode
A mode that you use to clear pixels where both the source and background images are opaque.