Computer Science - Representing Characters and Images in a computer + graphics 💻

Question 1

What is a character set?

Answer 1

The set of symbols that may be represented by a computer at a particular time.

Question 2

What are the two main internationally agreed character sets?

Answer 2

ASCII and Unicode

Question 3

What does ASCII stand for?

Answer 3

American Standard Code for Information Interchange.

Question 4

Initially, how many bits did ASCII use and how many characters could it represent?

Answer 4

It used 7 bits out of the 8 bit byte, which meant it could represent 128 different characters (2⁷)

Question 5

How many bits does the extended ASCII use and how many characters can it represent?

Answer 5

It uses all 8 bits and can represent up to 256 characters (2⁸)

Question 6

In ASCII, upper case letters are stored as the numbers:

Answer 6

65 to 90

Question 7

In ASCII, lower case letters are stored as the numbers:

Answer 7

97 to 122

Question 8

In ASCII, numeric digits are stored as the numbers:

Answer 8

48 to 57

Question 9

In ASCII, the space character is stored as the number:

Answer 9

32

Question 10

What is unicode?

Answer 10

Unicode is an international standard character set which uses 16 bits to represent the character set.

Question 11

What is the goal of unicode?

Answer 11

The goal of unicode is to specify a code matching every character needed by every written human language, It aims to be understood by all computer platforms.

Question 12

The first 256 characters of unicode are…

Answer 12

Identical to ASCII

Question 13

What are graphics?

Answer 13

Graphics are the display of images and drawings on the computer. It is digitized, meaning that it is turned into a sequence of numbers understandable by the computer.

Question 14

What is a pixel?

Answer 14

A tiny square of colour, many of these together can form a digital image.

Question 15

What is “pixel” short for?

Answer 15

It is short for “picture element”

Question 16

How does a computer know what colour a pixel is?

Answer 16

Each pixel has a specific number which tells the computer what colour the pixel should be.

Question 17

What is the process of digitization?

Answer 17

The process that takes an image and turns it into a set of pixels.

Question 18

A computer monitor is made up of…

Answer 18

A computer monitor is made up of millions of tiny squares (pixels)

Question 19

The more pixels, the…

Answer 19

The more pixels, the better an image looks

Question 20

What are the two types of graphics?

Answer 20

Bitmapped/raster graphics and Vector graphics.

Question 21

What is a bitmap?

Answer 21

A bitmap is a method for storing images using pixels.

Question 22

Why are bitmap graphics called bitmap graphics?

Answer 22

Because it is a “map” of where the “bits” of information are stored.

Question 23

The information in bitmap graphics are stored as…

Answer 23

The information in bitmap graphics are stored as a sequence of numbers defining the colour of each pixel.

Question 24

In a simple black and white image, what does a bitmap need to know?

Answer 24

It needs to know if a pixel is “on” or “off”, which can be stored as a 0 or a 1.

Question 25

In a colour image, what does a bitmap need to know?

Answer 25

It needs lot of bits, normally 24, to store the colour values of each pixel.

Question 26

What are the common bitmap file formats?

Answer 26

.jpeg, .jpg, .png, .tiff, .gif, .psd (photoshop)

Question 27

What are the common bitmap editing programs?

Answer 27

Microsoft paint, Adobe photoshop, Corel photo paint & Corel photo paint shop pro (what even is corel-), and The GIMP (all hail THE GIMP)

Question 28

What is vector?

Answer 28

Graphics made out of geometric shapes (lines, curves) and coordinates to precisely define the parts of the image. Information is stored as formulas.

Question 29

What are the common vector file formats?

Answer 29

.ai, .cdr, .cmx, .svg, .cgm, .dxf, .wmf

Question 30

What are the common vector editing programs?

Answer 30

Adobe illustrator, CorelDraw, Xara Xtreme, Serif DrawPlus, Inkscape

Question 31

What are some key points about vector images?

Answer 31

• Scalable
• Resolution independent
• No background
• Cartoon-like
• Innapropriate for photorealistic images

Question 32

What are some key points about bitmap images?

Answer 32

• Made with pixels in a grid
• Resolution dependent
• Resizing to a larger size reduces quality
• Easily converted
• Restricted to rectangle
• Minimal support for transparency

Question 33

Which type of graphic is scalable without loss in quality?

Answer 33

Vector

Question 34

Which type of graphic is suitable for photographic images?

Answer 34

Bitmap

Question 35

Which type of graphic takes up more storage?

Answer 35

Bitmap

Question 36

Which type of graphic uses more processing power?

Answer 36

Vector

Question 37

Which type of graphic is suitable for logo designs?

Answer 37

Mostly vector, but bitmap graphics can still be used for logos to create a more natural brand.

Question 38

Which type of graphic is suitable for digital painting/art?

Answer 38

Bitmap

Question 39

Which type of graphic can group individual elements?

Answer 39

Vector

Question 40

Which type of graphic can be more easily edited in any program?

Answer 40

Vector

Question 41

Which type of graphic can create more detailed images?

Answer 41

Bitmap

Question 42

Why do bitmap graphics take up more storage?

Answer 42

Each pixel has to be stored, and even “blank” pixels contribute to file size.