Date: Wed, 05 Mar 2003 22:41:53 -0600 (CST)
   From: Mark Jacobson <jacobson@math-cs.cns.uni.edu>
     To: 810-021-01@uni.edu
Subject: QUIZ RESULTS FOR Greenlaw : Chapter 8 : Web Graphics : take by 3/12

Author Name    : Greenlaw
Site Name     : Inline/Online
Chapter       : Chapter 8 : Web Graphics
Quiz          : Multiple Choice Quiz

The purpose of this quiz is to provide the student with a large number of
  supplemental exercises for Chapter 8. This quiz can be used to perform a
  self-evaluation. This quiz consists of twenty five multiple choice
  questions.

Take the Web Graphics quiz by Wednesday, March 12th, on or before 3/12.

     http://www.cns.uni.edu/~jacobson/c021.html

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We talked about Graphics today, including levels of color and the
  color depth of a bitmapped pixel.

Number of colors:   Pixel depth (Number of bits)
      2                     1
      8                     3
     16                     4
    256                     8 bits or 1 byte per pixel
    16 million             24 bits or 3 bytes per pixel
                                      1  byte for RED level (0 to 255)
                                      1  byte for GREEN value
                                      1  byte for BLUE amount

                            Or you can think of 24 bit color
                            as having 8 bits for red phosphor,
                                      8 bits for green phosphor,
                                  and 8 bits for the blue phosphor.

                                    3     24
     With 24 bit color there are 256  or 2   possible colors.

      10
     2  = 1024 = 1K or about 1000 but called a kilobyte or 1K or 1 K.

      20              2              2
     2  = 1024K = 1024  or about 1000  = 1,000,000 but called a megabyte
                                                   or 1M or 1 Meg.
      21            22           23
     2   = 2 Meg   2   = 4 Meg  2   = 8 Meg and, now you have it,

                                 24
                                2   = 16 Meg, which is about 16 million,

                                but is exactly 16 x 1024 x 1024, which is

                                                16,777,216
Here is some output from the bc calculator
        on cowboy.cns.uni.edu to illustrate.  * is multiply and
                                              ^ is raise to the power of
                                                   so that
2^10                                                                    8
1,024        <---------- about 1,000 = 1K                    2^8 means 2

2^20                                                      or 2*2*2*2*2*2*2*2
1,048,576    <---------- about 1,000,000 = 1M

1024*1024                                              20
1,048,576    <---------- 1,024 squared is the same as 2

2^24                                                         24
16,777,216   <---------- about 16 million, is exactly 16M = 2

    Sixteen, by the way, is a very sweet number.

For a fun mind-reading program based on number theory, go see the brand
new 2nd link on my web page

    http://www.cns.uni.edu/~jacobson

    Mark