Instance Method

startTask(toClear:)

Fills the entire destination with black or clear depending on its alphaMode.

Declaration

func startTask(toClear destination: CIRenderDestination) throws -> CIRenderTask

Parameters

destination

The CIRenderDestination to clear.

error

Pointer to an error object should the task fail.

Return Value

The asynchronous CIRenderTask for clearing the destination.

Discussion

If the destination's alphaMode is CIRenderDestinationAlphaMode.none, this command fills the entire destination with black (0, 0, 0, 1).

If the destination's alphaMode is CIRenderDestinationAlphaMode.premultiplied or CIRenderDestinationAlphaMode.unpremultiplied, this command fills the entire destination with clear (0, 0, 0, 0).

See Also

Customizing Render Destination

func prepareRender(CIImage, from: CGRect, to: CIRenderDestination, at: CGPoint)

An optional call to warm up a CIContext so that subsequent calls to render with the same arguments run more efficiently.

func startTask(toRender: CIImage, to: CIRenderDestination) -> CIRenderTask

Renders an image to a destination so that point (0, 0) of the image maps to point (0, 0) of the destination.

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