vImage.BlendMode.screen
Sets the destination pixel as the inverted product of the inverted corresponding source pixels.
Declaration
case screenDiscussion
The following image shows the result of compositing using the screen blend mode:
[Image]
The bottom-right quadrant in the result is identical to the corresponding quadrant in the bottom layer because the operation multiplies each bottom-layer pixel value by 1.0. For example, if the source pixel value is 0.5, the destination pixel value is 0.5:
dest = 1 - (1 - 0.5) * (1 - 0.0) // dest = 0.5The top-right quadrant in the result is brighter than the corresponding quadrant in the bottom layer. In this quadrant, the top-layer and bottom-layer pixel values are identical. For example, if the source pixel value is 0.5, the destination pixel value is 0.75:
dest = 1 - (1 - 0.5) * (1 - 0.5) // dest = 0.75