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alphaThreshold

Syntax

    member(whichMember).alphaThreshold
    the alphaThreshold of member whichMember

Description

Bitmap cast member property; governs how the bitmap's alpha channel affects hit detection. This property is a value from 0 to 255, that exactly matches alpha values in the alpha channel for a 32-bit bitmap image.

For a given `alphaThreshold` setting, Director detects a mouse click if the pixel value of the alpha map at that point is equal to or greater than the threshold. Setting the `alphaThreshold` to 0 makes all pixels opaque to hit detection regardless of the contents of the alpha channel.

The `alphaThreshold` setting only takes effect when a sprite's `ink` is set to matte.

See also

`useAlpha`