CS 100 - Homework 2 Solution

CS 100 - Computer Literacy, Spring 2005

Homework 7 Solution

Here is the equivalent tabular image from lab 7 solution.

**Original Image**
(1,1)	(2,1)	(3,1)	(4,1)
(1,2)	(2,2)	(3,2)	(4,2)
(1,3)	(2,3)	(3,3)	(4,3)

**New Image**
(1,1)	(2,1)	(3,1)	(4,1)	(5,1)	(6,1)	(7,1)	(8,1)
(1,2)	(2,2)	(3,2)	(4,2)	(5,2)	(6,2)	(7,2)	(8,2)
(1,3)	(2,3)	(3,3)	(4,3)	(5,3)	(6,3)	(7,3)	(8,3)
(1,4)	(2,4)	(3,4)	(4,4)	(5,4)	(6,4)	(7,4)	(8,4)
(1,5)	(2,5)	(3,5)	(4,5)	(5,5)	(6,5)	(7,5)	(8,5)
(1,6)	(2,6)	(3,6)	(4,6)	(5,6)	(6,6)	(7,6)	(8,6)

Here are some important points:

The width of the new image is twice the width of original image. In the example shown above, original width is 4 pixels and new width is 8 pixels.
The height of the new image is twice the height of the original image. In the example, 3 pixels is original height, 6 pixels is the height of the new image.
For each pixel in the original image, we have four pixels in the new image (since we are making three copies).

Let's try to figure out how the colors are copied from original image to new one:

Pixel in original image

Corresponding pixels in new image

(2,1)

(6,1)

(2,4)

(6,4)

(1,2)

(5,2)

(1,5)

(5,5)

(4,2)

(8,2)

(4,5)

(8,5)

(3,3)

(7,3)

(3,6)

(7,6)

So for each original pixel (x,y), the corresponding four pixels in the new image have following property:

(x,y)

(x + origWidth, y)

(x,y + origHeight)

(x + origWidth, y + origHeight)

So we can modify the original program given as part of Lab 7 solution as follows

**Program for collage (2x2 table)**
def makeCollage(): #Allow the user to pick up an image file file = pickAFile() #now convert the image in JES format pic = makePicture(file) # get the size of the originalimage origWidth = getWidth(pic) origHeight = getHeight(pic) # determine the size of new image newWidth = origWidth * 2 newHeight = origHeight * 2 #now creat a new image in JES format new_pic = makeEmptyPicture(newWidth, newHeight) # Loop for each pixel in the original image. # Put that pixels color information in three positions # in the new duplicated image. for orig_pixel in getPixels(pic): # get X and Y positions of pixel from new image x = getX(orig_pixel) y = getY(orig_pixel) # get the color from original pixel c = getColor(orig_pixel) # set the color to the pixel in the upper left copy to c pixel1 = getPixel(new_pic, x, y) setColor(pixel1, c) # set the color to the pixel in the upper right copy to c pixel2 = getPixel(new_pic, x+origWidth, y) setColor(pixel2, c) # set the color to the pixel in the lower left copy to c pixel3 = getPixel(new_pic, x, y+origHeight) setColor(pixel3, c) # set the color to the pixel in the lower right copy to c pixel2 = getPixel(new_pic, x+origWidth, y+origHeight) setColor(pixel2, c) #Now display the new image show(new_pic) # save the new image writePictureTo(new_pic, pickAFile())

def makeCollage():
  
  #Allow the user to pick up an image file
  file = pickAFile()

  #now convert the image in JES format
  pic = makePicture(file)

  # get the size of the originalimage
  origWidth = getWidth(pic)
  origHeight = getHeight(pic)

  # determine the size of new image
  newWidth = origWidth * 2
  newHeight = origHeight * 2

  #now creat a new image in JES format
  new_pic = makeEmptyPicture(newWidth, newHeight)

  # Loop for each pixel in the original image.
  # Put that pixels color information in three positions
  # in the new duplicated image.

  for orig_pixel in getPixels(pic):

      # get X and Y positions of pixel from new image
      x = getX(orig_pixel)
      y = getY(orig_pixel)

      # get the color from original pixel
      c = getColor(orig_pixel)

      # set the color to the pixel in the upper left copy to c
      pixel1 = getPixel(new_pic, x, y)
      setColor(pixel1, c)

      # set the color to the pixel in the upper right copy to c
      pixel2 = getPixel(new_pic, x+origWidth, y)
      setColor(pixel2, c)

      # set the color to the pixel in the lower left copy to c
      pixel3 = getPixel(new_pic, x, y+origHeight)
      setColor(pixel3, c)

      # set the color to the pixel in the lower right copy to c
      pixel2 = getPixel(new_pic, x+origWidth, y+origHeight)
      setColor(pixel2, c)

  #Now display the new image
  show(new_pic)

  # save the new image
  writePictureTo(new_pic, pickAFile())

So this one will make four copies of the original image. But what we need is color modifications in the original image. So we will do following:

Upper left portion of the new image is exact copy of the original one.
Upper right portion of the new image is black and white copy of the original one.
Lower left portion of the new image is with red component set to 0.
Lower right portion is negative of the original image.

So instead of setting all the pixel colors to the same color, we will first compose these four colors and put them in four pixels. This is how modified program looks:

**Program for collage (2x2 table) Modified Colors**
def makeCollage(): #Allow the user to pick up an image file file = pickAFile() #now convert the image in JES format pic = makePicture(file) # get the size of the originalimage origWidth = getWidth(pic) origHeight = getHeight(pic) # determine the size of new image newWidth = origWidth * 2 newHeight = origHeight * 2 #now creat a new image in JES format new_pic = makeEmptyPicture(newWidth, newHeight) # Loop for each pixel in the original image. # Put that pixels color information in three positions # in the new duplicated image. for orig_pixel in getPixels(pic): # get X and Y positions of pixel from new image x = getX(orig_pixel) y = getY(orig_pixel) # get the color from original pixel c1 = getColor(orig_pixel) # get the color components original pixel red = getRed(orig_pixel) green = getGreen(orig_pixel) blue = getBlue(orig_pixel) # compute the average avg = (red + green + blue) / 3 # make black and white color c2 = makeColor(avg, avg, avg) # make color without red component c3 = makeColor(0, green, blue) # make the negative color c4 = makeColor(255-red, 255-green, 255-blue) # set the color to the pixel in the upper left copy to c1 pixel1 = getPixel(new_pic, x, y) setColor(pixel1, c1) # set the color to the pixel in the upper right copy to c2 pixel2 = getPixel(new_pic, x+origWidth, y) setColor(pixel2, c2) # set the color to the pixel in the lower left copy to c3 pixel3 = getPixel(new_pic, x, y+origHeight) setColor(pixel3, c3) # set the color to the pixel in the lower right copy to c4 pixel2 = getPixel(new_pic, x+origWidth, y+origHeight) setColor(pixel2, c4) #Now display the new image show(new_pic) # save the new image writePictureTo(new_pic, pickAFile())

def makeCollage():
  
  #Allow the user to pick up an image file
  file = pickAFile()

  #now convert the image in JES format
  pic = makePicture(file)

  # get the size of the originalimage
  origWidth = getWidth(pic)
  origHeight = getHeight(pic)

  # determine the size of new image
  newWidth = origWidth * 2
  newHeight = origHeight * 2

  #now creat a new image in JES format
  new_pic = makeEmptyPicture(newWidth, newHeight)

  # Loop for each pixel in the original image.
  # Put that pixels color information in three positions
  # in the new duplicated image.

  for orig_pixel in getPixels(pic):

      # get X and Y positions of pixel from new image
      x = getX(orig_pixel)
      y = getY(orig_pixel)

      # get the color from original pixel
      c1 = getColor(orig_pixel)

      # get the color components original pixel
      red = getRed(orig_pixel)
      green = getGreen(orig_pixel)
      blue = getBlue(orig_pixel)

      # compute the average
      avg = (red + green + blue) / 3

      # make black and white color
      c2 = makeColor(avg, avg, avg)

      # make color without red component
      c3 = makeColor(0, green, blue)

      # make the negative color
      c4 = makeColor(255-red, 255-green, 255-blue)

      # set the color to the pixel in the upper left copy to c1
      pixel1 = getPixel(new_pic, x, y)
      setColor(pixel1, c1)

      # set the color to the pixel in the upper right copy to c2
      pixel2 = getPixel(new_pic, x+origWidth, y)
      setColor(pixel2, c2)

      # set the color to the pixel in the lower left copy to c3
      pixel3 = getPixel(new_pic, x, y+origHeight)
      setColor(pixel3, c3)

      # set the color to the pixel in the lower right copy to c4
      pixel2 = getPixel(new_pic, x+origWidth, y+origHeight)
      setColor(pixel2, c4)

  #Now display the new image
  show(new_pic)

  # save the new image
  writePictureTo(new_pic, pickAFile())

Grading Criteria

If you did not have proper code for making a new picture, you will only get 20 points in credit.
If the code does produce an empty picture, but there is some problem with making four copies, you may get credit up to 75 points.
If you have everything working fine, the credit will, of course, be 100 points.