Static functions for color manipulations

Static methods

staticgrayscale2argb(bytePair:Bytes):UInt

Converts a 16 bit (whiteness/alpha) color value of 0xWWAA to a 32 bit RGBA value 0xRRGGBBAA

staticindexed2argb(sprite:Aseprite, index:Int):Null<UInt>

Returns a 32 bit color value from the pallete or 0x00000000 if no such index in the palette

staticrgba2argb(rgba:Bytes):UInt

Converts an 0xRRGGBBAA value to a 0xAARRGGBB one

Can it be optimized by using bit shifting?