def increaseRed(pict):
  for p in getPixels(pict):
    value1 = getRed(p)
    value2 = value1 * 1.2
    setRed(p, value2)

def mod2():
  file = pickAFile()
  pict = makePicture (file)
  increaseRed (pict)
  show (pict)
  writePictureTo(pict, pickAFile())

def makeSunset(pict):
  for p in getPixels(pict):
    value1 = getGreen(p)
    value2 = value1 * 0.7
    setGreen(p, value2)
    value1 = getBlue(p)
    value2 = value1 * 0.7
    setBlue(p, value2)

def mod3():
  file = pickAFile()
  pict = makePicture (file)
  makeSunset (pict)
  show (pict)
  writePictureTo(pict, pickAFile())

def makeNegative(pict):
  for p in getPixels(pict):
    value1 = getRed(p)
    value2 = 255 - value1 
    setRed(p, value2)
    value1 = getGreen(p)
    value2 = 255 - value1
    setGreen(p, value2)
    value1 = getBlue(p)
    value2 =255 -  value1
    setBlue(p, value2)

def makeNegative2(pict):
  width = getWidth(pict)
  height = getHeight(pict)

  for x in range(1,width):
    for y in range(1,height):
      p = getPixel(pict,x,y)
      value1 = getRed(p)
      value2 = 255 - value1 
      setRed(p, value2)
      value1 = getGreen(p)
      value2 = 255 - value1
      setGreen(p, value2)
      value1 = getBlue(p)
      value2 =255 -  value1
      setBlue(p, value2)


def mod4():
  file = pickAFile()
  pict = makePicture (file)
  makeNegative2 (pict)
  show (pict)
  writePictureTo(pict, pickAFile())

def decreaseRed(pict):
  for p in getPixels(pict):
    value1 = getRed(p)
    value2 = value1 * 0.5
    setRed(p, value2)

def modifyPictAndSave():
  file = pickAFile()
  pict = makePicture (file)
  reduceRed (pict)
  show (pict)
  writePictureTo(pict, pickAFile())

def showPict():
  file = pickAFile()
  pict = makePicture (file)
  show (pict)