Lingo Dictionary > A-C > alphaThreshold |
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alphaThreshold
Syntax
member(
whichMember
)
.
alphaThreshold
the alphaThreshold of memberwhichMember
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
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