get
Look up the pixel at (x,y) and return its alpha component, normalized to 0..1. This is roughly equivalent to GetColorA(getColor()), but can be more efficent (and more precise if the pixels store more than 8 bits per component).
Return
alpha converted to normalized float
Parameters
x
column index, zero or greater, and less than getWidth()
y
row index, zero or greater, and less than getHeight()