Unit 1 Binary and online graphics

A set of question-and-answer flashcards covering vector vs bitmap graphics, image properties, bandwidth basics, and compression concepts from the lecture notes.

What is a vector image and how is it created using coordinates?

A vector image is created on a computer by following a sequence of coordinates (x and y) from a starting point to an end point using a simple algorithm: starting point, end point, type of line, curves or angles, and line and fill colours.

List the key benefits of vector graphics.

They can be scaled without losing image quality, have a small file size, are easily edited, and are ideally suited for geometric shapes.

Give real-world applications of vector graphics.

Used in 2D and 3D animation, gaming, and advertising (logos to cartoon characters).

What is a bitmap?

An image file made up of dots or pixels, where each pixel can be a different colour; more pixels mean more detail.

How does a vector differ from a bitmap in terms of scalability?

Vector graphics are scalable without quality loss, whereas bitmaps are resolution-dependent and can become pixelated when enlarged.

Name common bitmap filetypes.

BMP, JPG, GIF, TIFF, PNG, PICT.

What is a pixel?

A tiny coloured square that makes up an image.

What does resolution mean in digital images?

The number of pixels in one square inch of the image; higher resolution means more detail.

What are the four key image properties?

Pixel size, dimension (height and width), resolution, colour depth.

How do you calculate file size in bits?

File size = number of pixels (height × width) × colour depth (in bits).

Calculate the file size for a 7×6 image with 1-bit colour depth.

Pixels = 7×6 = 42; File size = 42 × 1 = 42 bits.

What is colour depth?

The number of bits used to encode the colour information of each pixel.

What is bandwidth?

The amount of data that can be sent in one second, measured in bits per second (bps).

What are base-2 data units used in these notes?

Kibibytes (KiB) and mebibytes (MiB); 1 KiB = 1024 bytes; 1 MiB = 1024 KiB.

Convert KiB to bits in your head.

1 KiB = 1024 bytes = 8192 bits.

Why is bandwidth often measured in Mbps instead of bps?

Because modern connections transfer large amounts of data, using base-10 units (Mbps) is more convenient; notes also reference base-2 units (MiB).

What is lossy compression?

Compression that reduces file size by deleting data, which cannot be fully restored; commonly used for images (JPEG) and audio (MP3).

What is lossless compression?

Compression that allows exact restoration of the original file after decompression; used for text and some image formats (PNG, GIF, TIFF).

Why would you compress files?

To attach to emails (size limits), save storage space, transfer files on devices with limited space, and speed up downloads.

What is meant by image dimension and pixel size?

Dimension is the image's height and width in pixels; pixel size is the total number of pixels (height × width).

What is the relationship between image properties and file size?

File size depends on the number of pixels and colour depth; higher resolution and greater colour depth increase file size.