FG = color(17, 17, 17, 10)  # foreground color
BG = "#f3f3f3"              # background color

WIDTH = 1000
ASPECT_RATIO = 0.666  # !!! copy from console

TOTAL_FRAMES = 10  # higher means darker & covering higher percentage of picture

LINE_LENGTH = 65    # higher means more blurry & darker
GRID_DISTANCE = 15 # if GRID_DISTANCE >> LINE_LENGTH, picture may be incomplete; higher -> lighter
MAX_LINES_PER_STAR = 50   # higher means higher sensitivity (more shades), darker with less visible stars,
                         # should be typically >> GRID_DISTANCE
LINE_LENGTH_RATIO_DARK = 0.5  # how much shorter (relatively) should be the lines for darkest areas

X_SHIFT = 3  # to prevent a boring rectangular grid
Y_SHIFT = 4

def setup():
  global img

  img = loadImage("picture.jpg")  # !!! this file needs to be in the sketch folder
  aspect_ratio = float(img.height) / float(img.width)
  println("Aspect ratio: " + str(aspect_ratio))
  img.resize(WIDTH, int(WIDTH * aspect_ratio))

  size(WIDTH, int(WIDTH * ASPECT_RATIO))
  background(BG)
  stroke(FG)


def draw():
  if frameCount <= TOTAL_FRAMES:
      for x in range((frameCount * X_SHIFT) % GRID_DISTANCE, img.width, GRID_DISTANCE):
          for y in range((frameCount * Y_SHIFT) % GRID_DISTANCE,
                         img.height, GRID_DISTANCE):
              c = img.get(x, y)
              b = map(brightness(c), 0, 255, 1, 0)
              for i in range(int(b * MAX_LINES_PER_STAR)):
                  random_line(x, y, LINE_LENGTH * (1 - LINE_LENGTH_RATIO_DARK))


def random_line(x, y, w):
    pushMatrix()
    translate(x, y)
    rotate(random(0, TWO_PI))
    line(-w/2, 0, w/2, 0)
    popMatrix()

def keyPressed():
    if key == 's':
        saveFrame("frame-######.png")
        println("Frame saved")