Raster or Vector – That is the Question?
Nowadays there are numerous image formats but basically they all can be divided into two main groups – raster and vector images. This is it, the all-time rivalry between pixels and paths. In our contemporary world, where everything is digitalized, people often interact with computer graphics and pictures. What is the difference between raster and vector and which one is better? Raster Images We are going to begin with raster images. They are also popular as bitmaps. These graphics are composed of groups of pixels – tiny squares, each one painted in different color. The main characteristic of raster images is the number of pixels (dots) per inch (dpi). Practically it is like a small puzzle of differently-colored parts, but they are so small that the human eye is unable to spot the slight difference between them. Practically all digital pictures or scanned images are BMP, JPEG, PNG, TIFF or GIF (bitmap formats). Vector Images Vector images adopt different technique – they use vectors instead of dots. To make it simpler for understanding, you probably know the type of games “connect the dots”. Well vector graphics work on the same principle – there are millions of dots connected, forming lines (vectors). The way these lines are curved and positioned is described with mathematical formulas. Vector drawings can be created in Adobe Illustrator or Corel Draw and saved as EPS, WMF, AI, CDR or SVG (all of these are vector formats). Scalability If you need an image for a poster – 1.5m on 1m – it will be extremely hard to create a picture with such dimensions. The solution is to create small one and scale it before printing. Sounds easy but there is one problem – the quality could be diminished. Bitmaps consist of pixels and when you scale the picture, you actually scale the small squares. The result may be disappointing – ragged figures and a complete eyesore. There is an anti-aliased function that fixes the problem, but only partially – the picture becomes blurred and still unpleasant. Vector images, on the other side, don’t have such problems. According to some mathematical principles you can enlarge or shrink a vector by multiplying it with a number. When scaling a vector image you practically change the multiplier in the formulas of the vectors. In the end there is bigger/smaller and crystal-clear image with no issues. Perfect! Effects and complexity Vector objects are made of curved or straight lines and this makes the borders between them very clear. Bitmaps, as I already said, are made of small squares and every square can be painted in different tint. Consequently shadows, effects or any other kind...
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