Need help with non delay timing

Here is what I have, but still does not use the delay to shutdown each pixel:

/************************* Shutdown and helper functions ****************************/
// get the current time
  unsigned long currentMillis = millis();
unsigned long lastBarMillis_on = 0;   // bargraph on tracker
const int pd_interval = 100;     // interval at which to cycle lights (milliseconds).
 
void bargraph_shutdown(unsigned long currentMillis) {
   
  if(currentMillis - lastBarMillis_on > pd_interval){
  // save the last time you blinked the LED
    lastBarMillis_on = currentMillis;         
    for (int i=7; i>-1; i-- ){//Bargraph power down sequence
    barGraph.setPixelColor(i,0);
    barGraph.show();}
    safety=false;}

}