digital_clock_study.pde

import java.util.*;

void setup() {
  size(960, 540);
  colorMode(HSB, 360, 100, 100, 100);
  noStroke();
}

void draw() {
  background(0, 0, 50);
  noStroke();
  Calendar calendar = Calendar.getInstance();
  float h = map(calendar.get(Calendar.HOUR_OF_DAY), 0, 23, 0, width);
  float m = map(calendar.get(Calendar.MINUTE), 0, 59, 0, width);
  float s = map(calendar.get(Calendar.SECOND), 0, 59, 0, width);
  float m2 = map(calendar.get(Calendar.MILLISECOND), 0, 999, 0, width);
  fill(0,100,100);
  rect(0, height*0/4, h, height*1/4);
  fill(90,100,100);
  rect(0, height*1/4, m, height*1/4);
  fill(180,100,100);
  rect(0, height*2/4, s, height*1/4);
  fill(270,100,100);
  rect(0, height*3/4, m2, height*1/4);
  drawMeasure(0, height*0/4, width, height*1/4,23);
  drawMeasure(0, height*1/4, width, height*1/4,59);
  drawMeasure(0, height*2/4, width, height*1/4,59);
  drawMeasure(0, height*3/4, width, height*1/4,99);
}

  void drawMeasure(float x, float y, float w, float h, float divisions) {
  float len = w-x;
  float scale = len/divisions;
  for (float i = x; i < w; i+= scale) {
    stroke(0, 0, 0);
    strokeWeight(1);
    line(i, y, i, y+h);
  }
}