Unit 4.6 - 4.8 | Graphics Flashcards
What two things can graphics be made up of?
Raster (GIF, JPEG, PNG) or Vector (SVG)
What are graphics made up of? [4]
Graphics are made up of pixels (or dots)
Each pixel has a position and a colour
The pixels are very small and fool the eye in thinking they are
connected
The larger the image, the greater the number of pixels required
Bitmaps are sometimes known as raster graphics
What are vector images ?
Vector Images are:
graphics that use pivots, lines, curves, shapes or polygons
They are based on mathematical equations
They can be scaled up without a loss of quality
Explain the term colour depth:
Colour depth is the number of bits used to encode the colour of each pixel. The more bits used to encode the colour, the greater the number of actual colours can be represented.
If a graphic has 8 bits, what colour depth does it have?
If it has 8 bits it has 256 (2^8) Colours.
What is Metadata?
Metadata is extra information about the image stored within a file. These can include:
Image dimensions, Image size, Camera used, Exposure time, GPS location, Date and time
A simple bitmap graphic has the following characteristics:
8-bit colour depth
10 * 300 pixels
Calculate the file size of this graphic in kilobytes. Show your workings. (3)
10x300x8=24,000Bits
24,000/8=3000Bytes
3000/1000= 3 Kilobytes
Graphics, sound and text are all stored using a computer system. Explain how a Graphic is stored on a computer system
One mark for Each of the following:
Images on a computer system are made up of thousands of small coloured dots, known as pixels.
Bitmap images are stored as an array of pixels. A black and white bitmap image will store a 1 for a black pixel and 0 for a white pixel.
A colour bitmap image is stored by as a longer number that represents how much red, green and blue (RGB) is required in the colour of each pixel this is known as colour depth.
Vectors do not store the data by pixels, but are a set of instructions for drawing a geometric shape
