Vector Graphics (Cambridge International A-Level Computer Science)

Vector graphics

What is a vector graphic?

• A vector graphic is created from mathematical equations and points

• Only the mathematics used to create the image are stored

• For example, to create a circle the data stored would be:

  • Centre point (x, y coordinates)
  • Radius

• Typical examples of vector images are logos and clipart

• Vector images are infinitely scalable

• Ideal for situations where the same image will be made bigger and smaller and a loss of quality is unacceptable

  • For example, the same logo used on both a pencil and a billboard

• A vector graphic contains a drawing list (included in the file header)

• A typical drawing list will contain:

  • Commands used to create each object in the image
  • Attributes that define the properties of each object
  • Relative position of each object

• Dimensions of the image are not defined, meaning scaling up does not result in a loss of quality

Bitmap vs vector

• When choosing to use a bitmap or vector based image, the following should be considered:

  • Does the image need to be resized?
  • Does the image need to be drawn to scale?
  • Does the image need to look real?