Funzione collage

# Funzione che partendo da due immagini: flower1.jpg , flower2.jpg
# contenute nella cartella mediasources: http://www.cc.gatech.edu/~mark.guzdial/mediacomp/mediasources-py2ed.zip
# realizza un collage di 5 immagini con:
# 1a flower1 originale
# 2a flower2 originale
# 3a flower1 in negativo
# 4a flower2 senza il colore blu
# 5a flower1 in negativo senza il colore rosso

def collage(pict1, pict2):
# @param pict1: Picture. flower1.jpg
# @param pict1: Picture. flower2.jpg
   canvas = createCanvas(pict1)
   negPict1 = negative(pict1)
   noBluePict2 = removeBlue(pict2)
   noRedPict1 = removeRed(negPict1)
   allPicture = (pict1, pict2, negPict1, noBluePict2, noRedPict1)
   finalCollage = applyCollage(canvas, allPicture)
   show(finalCollage)

def createCanvas(pict):
# @param pict: Picture
  canvas = makeEmptyPicture(5*getWidth(pict), getHeight(pict))
  return canvas

def negative(pict):
# @param pict: Picture
  negPict1 = makeEmptyPicture( getWidth(pict), getHeight(pict))
  for x in range(getWidth(pict)):
    for y in range(getHeight(pict)):
      pxOriginal = getPixel(pict, x, y)
      pxNegative = getPixel(negPict1, x, y)
      setColor(pxNegative, makeColor(255 - getRed(pxOriginal), 255 - getGreen(pxOriginal), 255 - getBlue(pxOriginal)))
  return negPict1

def removeBlue(pict):
# @param pict: Picture
  noBluePict2 =  makeEmptyPicture( getWidth(pict), getHeight(pict))
  for x in range(getWidth(pict)):
    for y in range(getHeight(pict)):
      pxOriginal = getPixel(pict, x, y)
      pxNoBlue = getPixel(noBluePict2, x, y)
      setColor(pxNoBlue, makeColor(getRed(pxOriginal), getGreen(pxOriginal), 0*getBlue(pxOriginal)))
  return noBluePict2

def removeRed(pict):
# @param pict: Picture
  noRedPict1 =  makeEmptyPicture( getWidth(pict), getHeight(pict))
  for x in range(getWidth(pict)):
    for y in range(getHeight(pict)):
      pxOriginal = getPixel(pict, x, y)
      pxNoRed = getPixel(noRedPict1, x, y)
      setColor(pxNoRed, makeColor(0*getRed(pxOriginal), getGreen(pxOriginal), getBlue(pxOriginal)))
  return noRedPict1

def applyCollage(canvas, allPicture):
# @param canvas: Picture
# @param allPicture: String
  startX = 0
  for pic in allPicture:
    for sourceX in range(getWidth(pic)):
      targetX = sourceX + startX
      for sourceY in range(getHeight(pic)):
        targetY = sourceY
        color = getColor(getPixel(pic, sourceX, sourceY))
        setColor(getPixel(canvas ,targetX, targetY), color)
    startX = targetX
  return canvas