Charging Battery.

int scale;
int energy = 1;
int colour = 0;
void setup() {
  size(500, 500);
  stroke(225);
}
void draw() {
  background(0);
  frameRate(25);
  draw_battery(80, 140, 300, 120);
  scale = scale+energy;
  if (scale==300) {
    energy = 0;
    energy = energy-1;
    draw_using();
  }
  if (scale==0 && energy < 0) {
    energy = 0;
    energy = energy+1;
    draw_charging();
  }
  int per = (scale*100)/300;
  if (per >= 80 ) {
    colour = #008B00;
  } else if (per < 80 && per > 20) {
    colour = #FFFF00;
  } else if (per <= 20) {
    colour = #DD0000;
  }
  if (per == 0 || per == 1) {
    draw_charging();
  } else if (per == 99 || per == 100) {
    draw_using();
  }
  fill(225);
  textSize(50);
  text((int)(per)+"%", 200, 400);
}
void draw_charging() {

  fill(225);
  textSize(50);
  text("Charging", 150, 100);
}

void draw_using() {

  fill(225);
  textSize(50);
  text("Using", 150, 100);
}

void draw_battery(int x, int y, int h, int w) {
  strokeWeight(5);
  fill(0);
  rect(x+300, y+35, w/9, h-250);
  fill(225);
  rect(x, y, h, w);
  fill(colour);
  rect(x, y, scale, h-180);
  line(x+250, y+25, x+250, y+85);
  line(x+220, y+55, x+280, y+55);
  line(x+20, y+55, x+70, y+55);
}