The Remap Alpha tool lets you remap the alpha using a single curve manipulation interface similar to Blend Curves. The curve defaults to the identity mapping.
Original matte
Alpha remapped
Alpha inverted
An invert button provides inversion of the alpha after the curve mapping. This tool affects alpha only; the RGB channels, if present, are passed through unchanged. The pixel format of the output is the same as the pixel format of the image input. If the image has no alpha, then the output will have an alpha channel, properly modified by the curve remapping. See Manipulating Curve Control Points for information on how to add and delete control points on an Alpha Curve.
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