// PGraphics save sample

PGraphics pg;
PImage img;
PImage bg;
int scrw;
int scrh;
float ang = 0;
boolean exitfg = false;
boolean saveframe_enable;
int sframecount;

void setup() {
  size(512, 288, P2D);
  scrw = width;
  scrh = height;
  println("size=" + scrw + "," + scrh);

  frameRate(24);

  img = loadImage("./chara.png");
  bg = loadImage("./bg.png");
  pg= createGraphics(scrw, scrh, P2D);
  exitfg = false;
  saveframe_enable = false;
  sframecount = 0;
}

void draw() {
  background(40, 80, 160);

  //draw to PGraphics
  pg.beginDraw();
  pg.clear();
  pg.push();
  pg.imageMode(CENTER);
  float x =(scrw / 2) * 0.9 * sin(radians(ang * 2.0)) +(scrw / 2);
  float y =(scrh / 2) * 0.9 * sin(radians(ang * 5.0)) +(scrh / 2);
  pg.translate(x, y);
  pg.rotate(radians(ang));
  pg.image(img, 0, 0);
  pg.pop();
  pg.endDraw();

  // draw Background
  image(bg, 0, 0);
  
  // draw PGraphics to canvas
  image(pg, 0, 0);

  if (saveframe_enable) {
    String fn = "frames/" + get_seq(sframecount, 8) + ".png";
    noStroke();
    fill(255);
    textSize(24);
    text("capture " + sframecount + " frame", 8, 24);
    text("save " + fn, 8, 48);
    pg.save(fn);

    sframecount++;
  }
  ang += 1.0;

  if (exitfg) {
    exit();
  }
}

void keyTyped() {
  if (key == 's') {
    // frame save enable / disable
    saveframe_enable = !saveframe_enable;
    if (saveframe_enable) sframecount = 0;
  }
  else if (key == 'q') {
    // set exit
    exitfg = true;
  }
}

String get_seq(int n, int k) {
  String s = "000000000000" + n;
  return s.substring(s.length() - k);
}