An introduction to vector graphics
Computer Science · Key Stage 2 · The School
Drawing with shapes
A VECTOR picture is built from shapes: circles, rectangles, lines, curves. Each shape remembers its own size, position and colour. A drawing of a house might use one triangle, one rectangle and two small squares. Even a detailed picture can be just a few dozen shapes. Each one is remembered exactly. Nothing about a shape is guessed once it has been drawn.
Resizing without blurring
Stretch a vector picture bigger, and each shape simply redraws itself larger. It stays perfectly sharp. A photo works very differently. Stretch a photo and it quickly turns blocky and blurred. It has no shapes to redraw, only fixed dots. A vector picture the size of a postage stamp can become a poster with no loss of quality. A photo blown up the same amount would look nothing like as sharp.
Editing one shape at a time
Every shape in a vector picture can be selected and changed on its own. Making the roof triangle red does not touch the rectangle underneath it. That separation is what makes vector pictures easy to edit later. It stays easy long after they were first drawn.
A logo that must work at every size
A school logo needs to look sharp tiny on a letterhead. It also needs to look sharp huge on a banner. Drawn as shapes, it can be stretched either way with no loss of quality. Drawn as a photo-style image instead, the giant banner version would look blocky and rough. One vector file can serve every size the school will ever need.