Project 3: Image Modification
Deadline: 6:00pm , 2nd Oct, Monday.
Read this document carefully and completely before you attempt to solve programming project3.
Description:
For this assignment you will be extending image.hpp functionality to take an image and write
member functions for the class Image to scale, read, write, rotate 90 clockwise and rotate 90
counter clockwise.
The image that you will use is in the /data directory of your directory structure, and it is of JPEG
format. If you would like to view the image, you can simply open it up in paint/gimp or a similar
program that supports JPEG images. You will not be doing direct manipulation on the JPEG file
format itself but converted format called PPM (Portable Pixel Map). This format is much larger in
size than the JPEG format, however it is much easier to manipulate and process (and human
readable). There are different versions of the PPM file format, and the one we will be using for
this project is ‘plain PPM format’. This is like the raw PPM file format except that ‘plain PPM’
has some limitations on the format of the image.
Ex) Example of ‘plain PPM’ format
P3
4 4
15
0 0 0 0 0 0 0 0 0 15 0 15
0 0 0 0 15 7 0 0 0 0 0 0
0 0 0 0 0 0 0 15 7 0 0 0
15 0 15 0 0 0 0 0 0 0 0 0
Don’t worry about the P3, this is just a magic number that designates the type of file format, in
this case it is ppm. If the input is not a plain ppm, you should exit after printing an error. As you
may have noticed the file is broken up into a simple format.
• 4 4 : Represents 4 x 4 rows and columns.
• 15: Represents the max color value.. In the case of your program when you
convert a JPEG image to this ‘plain ppm’ format this value will be transformed to
256 as each pixel in a JPEG image uses 2^8 bits to represent its color value.
• Each sample in the raster is represented by an ASCII value
o A raster is a row in an image.
• Notice even though it is 4x4 it is broken up into three rows. This is a typical RGB
format. These three values across make up one pixel and in an image, and they
repeat.
o First element: Is RED, the higher the value the more red the color will be.
o Second element: Is GREEN, the higher the value the more green it will be.
o Third element: BLUE, same as above.
• It is important to note that there is a white space between all BLUE columns and
RED columns.
