private static float alphaBlendingComponent(int foregroundComponent,float foregroundAlpha,int backgroundComponent,float backgroundAlpha){
  float alpha=foregroundAlpha + backgroundAlpha * (1 - foregroundAlpha);
  if (Math.abs(alpha) < 0.001) {
    return 1;
  }
  return (foregroundAlpha * foregroundComponent + backgroundAlpha * backgroundComponent * (1 - foregroundAlpha)) / (255.0f * alpha);
}

private static float alphaBlendingComponent ( int foregroundComponent , float foregroundAlpha , int backgroundComponent , float backgroundAlpha ) { float alpha = foregroundAlpha + backgroundAlpha * ( 1 - foregroundAlpha ) ; if ( Math . abs ( alpha ) < 0.001 ) { return 1 ; } return ( foregroundAlpha * foregroundComponent + backgroundAlpha * backgroundComponent * ( 1 - foregroundAlpha ) ) / ( 255.0f * alpha ) ; }
computes one rgb component for the blending of two colors
