BFont f;
int[] data;
color col;

void setup() {
  size(240,180);
  f = loadFont("Meta-Bold.vlw.gz");
  load();
  col = color(255,0,0);
}

void loop() {
  background(0);
  textFont(f,20);
  text("A graph of data from file: data.csv",10,30);
  graph(data);
}

void load() {
  //load text file as a string
  String[] stuff = loadStrings("data.csv");
  //convert string into an array of integers using ',' as a delimiter
  data = splitInts(stuff[0],',');
}

void graph(int[] d) {
  stroke(col);
  for (int j = 0; j < d.length-1; j++) {
    int stretch = 30;
    line(j*stretch,height-d[j],(j+1)*stretch,height-d[j+1]);
  }
}