5. Bitmapped Graphics

Question 1

Resolution

Answer 1

Resolution means how many pixels an image or display contains, the higher the resolution, the more pixels available and therefore can increase image quality.

Resolution can be defined in two ways

• Width x Length
• PPI/DPI

Question 2

Colour Depth

Answer 2

Colour is represented in bits and the more bits available, the more colours can be represented.

Colour depth describes the amount of bits we assign per colour.

Let n be the number of bits.
2^n = amount of colours that can be represented.

Question 3

Calculating File Size

Answer 3

If the resolution is given in Width and Length:
Width x Length x Colour Depth

If it is given in PPI/DPI:
DPI x Inch x Colour depth

Question 4

Pixels

Answer 4

“Pixel Element”
Pixels are the smallest distinguishable feature displayed.

Hence why a monitor’s pixel is different from a video game pixel.

Question 5

Metadata

Answer 5

Stored alongside the image raw data and is needed to display the image correctly.
E.g. Resolution, file name, file format.

Question 6

Vector Graphics

Answer 6

A set of commands used to define a vector image.

Pros:
-Smaller file size, can resize without distortion, can manipulate individual objects in an image, can search for particular objects.

Cons:
-Isn’t suitable for storing photographs

Question 7

Why do vector graphics maintain the same quality when resized?

Answer 7

Essentially, vector graphics and its objects are all made mathematically and therefore scale in proportion to its properties.

Question 8

Why are vector graphics not appropriate for photographs?

Answer 8

Most devices such as cameras, scanners etc essentially continuous tone bitmap graphics that are impractical to convert to vector and lose their image.

Question 9

Bitmapped Image Problems

Answer 9

• When zoomed in, you can see the pixels and the initial image quality is lost.
• When enlarged, ‘pixelation’ occurs and the image will start to become blurry

Question 10

Calculate File Size (KB)

{1024 x 769 Res, 16 Colours per pixel}

Answer 10

393.2KB

Question 11

Calculate File Size (MB)

{1920 x 1080 Res, 32 Colour Depth}

Answer 11

8.3MB

Question 12

Calculate File Size (MB)

{1024 x 1024 Res, 256 Colours per pixel}

Answer 12

1.2MB

Question 13

Calculate transfer speed (MB/second)

{1920 x 1080 Res, 16 Colour Depth, 24 FPS}

Answer 13

99.5MB/s