mount_hood.jpg

graduates.jpg

goalkeeper.jpg

student1.jpg

student2.jpg

green_screen.jpg

scooter.jpg

logo.jpg

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9.9. Chapter Exercises

Fix the indention below to correctly set the red to the green, the green to the blue, and the blue to the red.

# STEP 1: USE THE IMAGE LIBRARY from image import * # STEP 2: PICK THE IMAGE img = Image("mount_hood.jpg") # STEP 3: LOOP THROUGH THE PIXELS pixels = img.getPixels() for p in pixels: # STEP 4: GET THE DATA r = p.getRed() g = p.getGreen() b = p.getBlue() # STEP 5: MODIFY THE COLOR p.setRed(g) p.setGreen(b) p.setBlue(r) # STEP 6: UPDATE THE IMAGE img.updatePixel(p) # STEP 7: SHOW THE RESULT win = ImageWin(img.getWidth(), img.getHeight()) img.draw(win) ==== from unittest.gui import TestCaseGui class myTests(TestCaseGui): def testOne(self): testPixel = img.getPixel(3, 4) self.assertEqual(testPixel.getRed(), 111, "Testing you set right red value for a particular pixel") self.assertEqual(testPixel.getGreen(), 180, "Testing you set right green value for a particular pixel") self.assertEqual(testPixel.getBlue(), 71, "Testing you set right blue value for a particular pixel") myTests().main()

Fix 4 syntax errors in the code below so that it correctly sets the green in all pixels to 0.

from image import # CREATE AN IMAGE FROM A FILE img = Image("mount_hood.jpg" # LOOP THROUGH THE PIXELS pixelList = img.getPixels() for p in pixelList: # SET THE GREEN TO 0 p.setGreen() # UPDATE THE IMAGE img.updatePixel() # SHOW THE RESULT win = ImageWin(img.getWidth(), img.getHeight()) img.draw(win) ==== from unittest.gui import TestCaseGui class myTests(TestCaseGui): def testOne(self): testPixel = img.getPixel(3, 4) self.assertEqual(testPixel.getGreen(), 0, "Testing you set right red value for a particular pixel") myTests().main()

Fill in the missing code on lines 9, 12, and 18 below to set the blue to half the original value in all pixels in the picture.

# STEP 1: USE THE IMAGE LIBRARY from image import * # STEP 2: PICK THE IMAGE img = Image("mount_hood.jpg") # STEP 3: LOOP THROUGH THE PIXELS pixels = img.getPixels(); for p # STEP 4: GET THE DATA r = p. # STEP 5: MODIFY THE COLOR p.setBlue(r * 0.5); # STEP 6: UPDATE THE IMAGE img. # STEP 7: SHOW THE RESULT win = ImageWin(img.getWidth(), img.getHeight()) img.draw(win) ==== from unittest.gui import TestCaseGui class myTests(TestCaseGui): def testOne(self): testPixel = img.getPixel(3, 4) self.assertEqual(testPixel.getRed(), 0, "Testing you set right red value for a particular pixel") myTests().main()

Fix the indention below to correctly so that the red and green values for each pixel are set to be the same as its blue value. This should make a black & white version of the image.

# STEP 1: USE THE IMAGE LIBRARY from image import * # STEP 2: PICK THE IMAGE img = Image("mount_hood.jpg") # STEP 3: LOOP THROUGH THE PIXELS for x in range(img.getWidth()): for y in range(img.getHeight()): # STEP 4: GET THE DATA p = img.getPixel(x, y) r = p.getRed() # STEP 5: MODIFY THE COLOR p.setGreen(r) p.setBlue(r) # STEP 6: UPDATE THE IMAGE img.updatePixel(p) # STEP 7: SHOW THE RESULT win = ImageWin(img.getWidth(), img.getHeight()) img.draw(win) ==== from unittest.gui import TestCaseGui class myTests(TestCaseGui): def testOne(self): testPixel = img.getPixel(3, 4) self.assertEqual(testPixel.getRed(), 71, "Testing you set right red value for a particular pixel") self.assertEqual(testPixel.getGreen(), 71, "Testing you set right green value for a particular pixel") self.assertEqual(testPixel.getBlue(), 71, "Testing you set right blue value for a particular pixel") myTests().main()

Write code that for each pixel, adds the y value of its location to the red. You will have to use the nested-loop approach to iterating through all of the pixels so that you have access to the x and y coordinates of the pixel you are working with.

# STEP 1: USE THE IMAGE LIBRARY from image import * # STEP 2: PICK THE IMAGE img = Image("mount_hood.jpg") # STEP 3: LOOP THROUGH THE PIXELS # STEP 4: GET THE DATA # STEP 5: MODIFY THE COLOR # STEP 6: UPDATE THE IMAGE # STEP 7: SHOW THE RESULT win = ImageWin(img.getWidth(), img.getHeight()) img.draw(win) ==== from unittest.gui import TestCaseGui class myTests(TestCaseGui): def testOne(self): testPixel = img.getPixel(3, 40) testPixel2 = img.getPixel(3, 42) self.assertEqual(testPixel.getRed(), 129, "Testing you set right red value for a particular pixel") self.assertEqual(testPixel2.getRed(), 132, "Testing you set right red value for a particular pixel") myTests().main()

Write code that blacks out the top half of the image by setting just the pixels in the top half to have a color value of 0, 0, 0. You will have to use the nested-loop approach and only visit the pixels in the top half.

Remember to use // when dividing the width or height so that you don’t get a decimal (float) answer.

# STEP 1: USE THE IMAGE LIBRARY from image import * # STEP 2: PICK THE IMAGE img = Image("mount_hood.jpg") # STEP 3: LOOP THROUGH THE PIXELS pixels = img.getPixels(); # STEP 4: GET THE DATA # STEP 5: MODIFY THE COLOR # STEP 6: UPDATE THE IMAGE # STEP 7: SHOW THE RESULT win = ImageWin(img.getWidth(), img.getHeight()) img.draw(win) ==== from unittest.gui import TestCaseGui class myTests(TestCaseGui): def testOne(self): testPixel = img.getPixel(3, 99) testPixel2 = img.getPixel(3, 100) self.assertEqual(testPixel.getRed(), 0, "Testing you blacked out pixels in the top half") self.assertEqual(testPixel2.getRed(), 144, "Testing you did not black out the bottom half") myTests().main()

Write code top copy the top half of the image to the bottom half. You should use the same loops as the previous problem to just visit each pixel in the top half. Then use setPixel to copy the pixel that you get from x, y to x, y + half the height of the image.

The image should end up with two copies of the top half.

# STEP 1: USE THE IMAGE LIBRARY from image import * # STEP 2: PICK THE IMAGE img = Image("mount_hood.jpg") # STEP 3: LOOP THROUGH THE PIXELS # STEP 4: GET THE DATA # STEP 6: UPDATE THE IMAGE # STEP 7: SHOW THE RESULT win = ImageWin(img.getWidth(), img.getHeight()) img.draw(win) ==== from unittest.gui import TestCaseGui class myTests(TestCaseGui): def testOne(self): testPixel = img.getPixel(3, 5) testPixel2 = img.getPixel(3, 105) self.assertEqual(testPixel.getRed(), testPixel2.getRed(), "Testing you copied from top half to bottom half.") myTests().main()

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