CS 101 - Intro to Computing, Spring 2008

Lab 13

Images Using a GrayScale

r = 0 g = 0 b = 0

r = 63 g = 63 b = 63

r = 127 g = 127 b = 127

r = 191 g = 191 b = 191

r = 255 g = 255 b = 255

Changing the color in a pixel

Determining the amount of gray

Lab Assignment 13

Write three Java programs that will do the following:

1. Program 1: Make Black And White

   1. The program is to be named: lab13a
   2. Print out your name and your net-id
   3. Allow the user to select a picture from a file stored on the local machine
   4. Change the image to black and white (i.e. grayscale) using the average intensity method. You may use which ever method you wish. Note, the code is given in the book. This modification will need to be done for every pixel in the selected image. Refer to the java examples page for the examples from Lecture on 4/10/08. In particular the example Lect410c.java, you will see code that almost does what you need to do. Your loop should be patterned after the loop in the code.
   5. Display the modified image
   6. Save the modfied image to a file on the local machine

2. Program 2: Make Black And Red

   1. The function is to be named: lab13b
   2. Print out your name and your net-id
   3. Allow the user to select a picture from a file stored on the local machine
   4. Change the image to a "red scale" image. This is done in a similar manner as the creation of a grayscale image, except the values for green and blue are kept at zero. Only the red value for each pixel will range from 0 to 255. Where the grayscale image is black, the red scale image will also be black. Where the grayscale image is white, the red scale image will be red. Where the grayscale image is gray, this image will range from black to red (the middle values will be a shade of maroon).
   5. Display the modified image
   6. Save the modfied image to a file on the local machine

3. program 3: Make Red And White

   1. The function is to be named: lab13c
   2. Print out your name and your net-id
   3. Allow the user to select a picture from a file stored on the local machine
   4. Change the image to a version of a red scale image. This is done in a similar manner as the creation of a grayscale image, but with a twist. Where the grayscale image is black, this image will be red. Where the grayscale image is white, this image will also be white. Where the grayscale image is gray, this image will range from red to white (the middle values will be rather "pinky"). Look at the table below to determine which color value need to change and which one need to remain constant.
   5. Display the modified image
   6. Save the modfied image to a file on the local machine

   Some of the resulting colors will appear as:

   makeBlackAndWhite()	r = 0 g = 0 b = 0	r = 63 g = 63 b = 63	r = 127 g = 127 b = 127	r = 191 g = 191 b = 191	r = 255 g = 255 b = 255
   makeBlackAndRed()	r = 0 g = 0 b = 0	r = 63 g = 0 b = 0	r = 127 g = 0 b = 0	r = 191 g = 0 b = 0	r = 255 g = 0 b = 0
   makeRedAndWhite()	r = 255 g = 0 b = 0	r = 255 g = 63 b = 63	r = 255 g = 127 b = 127	r = 255 g = 191 b = 191	r = 255 g = 255 b = 255

   Be sure to change comment with the name of the author to contain the following:

   • your name
   • day and time of your CS 101 lab section (i.e. Wednesday at 9:00)
   • A description of the project.

4. You are also to submit the Java file electronically by using the UNIX turnin command.

   To use the UNIX turnin command to electronically hand-in your html file using the project name of lab13. To submit the files in lab13a.java, lab13b.java and lab13c.java for lab13, the turnin command is entered as:

        turnin -c cs101 -p lab13 lab13a.java lab13b.java lab13c.java
   

   To verify what you submitted using the turnin command type:

        turnin -c cs101 -p lab13 -v
   

Grading Criteria

• Identifying Info
• Grayscale
• Redblackscale
• Redwhitescale