def reduceImage():
  # select picture to reduce
  file = pickAFile()
  opict = makePicture (file)

  # get the width, heigh
  owid = getWidth (opict)
  ohgt = getHeight(opict)

  # determine width and height of reduced image
  rwid = owid/2
  rhgt = ohgt/2

  # create an empty image with the "reduced" dimensions
  rpict = makeEmptyPicture(rwid, rhgt)

  # loop for the x and y positions from the original image
  for ox in range(1,owid,2):
     for oy in range(1,ohgt,2):
       # get pixel from original picture
       opixel = getPixel (opict, ox, oy)

       # get pixel from reduced picture
       rx = (ox+1)/2
       ry = (oy+1)/2
       rpixel = getPixel (rpict, rx, ry)

       # copy color from original pixel to reduced pixel
       c = getColor (opixel)
       setColor (rpixel, c)

  show (opict)
  show (rpict)


def reduceImage2():
  # select picture to reduce
  file = pickAFile()
  opict = makePicture (file)

  # get the width, heigh
  owid = getWidth (opict)
  ohgt = getHeight(opict)

  # determine width and height of reduced image
  rwid = owid/2
  rhgt = ohgt/2

  # create an empty image with the "reduced" dimensions
  rpict = makeEmptyPicture(rwid, rhgt)

  # loop for the x and y positions from the original image
  for ox in range(1,owid,2):
     for oy in range(1,ohgt,2):
       # get pixel from original picture
       opixel1 = getPixel (opict, ox, oy)
       opixel2 = getPixel (opict, ox+1, oy)
       opixel3 = getPixel (opict, ox, oy+1)
       opixel4 = getPixel (opict, ox+1, oy+1)

       # get pixel from reduced picture
       rx = (ox+1)/2
       ry = (oy+1)/2
       rpixel = getPixel (rpict, rx, ry)

       # copy color from original pixel to reduced pixel
       redTotal = getRed (opixel1) + getRed(opixel2) + getRed(opixel3) + getRed (opixel4)
       setRed (rpixel, redTotal/4)
       greenTotal = getGreen (opixel1) + getGreen(opixel2) + getGreen(opixel3) + getGreen (opixel4)
       setGreen (rpixel, greenTotal/4)
       blueTotal = getBlue (opixel1) + getBlue(opixel2) + getBlue(opixel3) + getBlue (opixel4)
       setBlue (rpixel, blueTotal/4)
       

  show (opict)
  show (rpict)

def enlargeImage():
  # select picture to enlarge
  file = pickAFile()
  opict = makePicture (file)

  # get the width, heigh
  owid = getWidth (opict)
  ohgt = getHeight(opict)

  # determine width and height of reduced image
  nwid = 2 * owid
  nhgt = 2 * ohgt

  # create an empty image with the "reduced" dimensions
  npict = makeEmptyPicture(nwid, nhgt)

  # loop for the x and y positions from the original image
  for ox in range(1,owid,):
     for oy in range(1,ohgt,):
       # get pixel from original picture
       opixel = getPixel (opict, ox, oy)

       # get pixel from reduced picture
       nx = (2 * ox) - 1
       ny = (2 * oy) - 1
       npixel1 = getPixel (npict, nx, ny)
       npixel2 = getPixel (npict, nx+1, ny)
       npixel3 = getPixel (npict, nx, ny+1)
       npixel4 = getPixel (npict, nx+1, ny+1)

       # copy color from original pixel to reduced pixel
       c = getColor (opixel)
       setColor (npixel1, c)
       setColor (npixel2, c)
       setColor (npixel3, c)
       setColor (npixel4, c)

  show (opict)
  show (npict)

def addLines():
   file = pickAFile()
   source = makePicture(file)
   spaceAmount = 10
   for x in range(1,getWidth(source)):
      for y in range(spaceAmount,getHeight(source),spaceAmount):
         pix = getPixel(source,x,y)
         c = makeColor (0,0,0)
         setColor (pix, c)
   for x in range(spaceAmount,getWidth(source),spaceAmount):
      for y in range(1,getHeight(source)):
         pix = getPixel(source,x,y)
         c = makeColor (0,0,0)
         setColor (pix, c)

   show (source)

def cropBanner():
  # crop pixels 400 to 500 in the x direction
  # crop pixels 10 to 100 in the y direction 

  # select picture to enlarge
  file = pickAFile()
  opict = makePicture (file)

  # get the width, heigh
  owid = getWidth (opict)
  ohgt = getHeight(opict)

  # determine width and height of reduced image
  nwid = 100
  nhgt = 90

  # create an empty image with the "reduced" dimensions
  npict = makeEmptyPicture(nwid, nhgt)

  # loop for the x and y positions from the original image
  for nx in range(1,nwid+1):
     for ny in range(1,nhgt+1):
       # determine pixels in new Picture
       ox = nx + 400
       oy = ny + 10

       # get pixel from original picture
       opixel = getPixel (opict, ox, oy)

       # get the pixel from the new picture
       npixel = getPixel (npict, nx, ny)

       # copy color from original pixel to new pixel
       c = getColor (opixel)
       setColor (npixel, c)

  show (opict)
  show (npict)