Rasterisation

Rasterisation is a process used in computer graphics to convert vector graphics, which are defined by mathematical equations, into a raster image, which is a grid of pixels. This conversion is essential for displaying graphics on screens, as screens are inherently raster devices. The process involves several steps:

First, the vector data is scaled and transformed to fit the desired output size and orientation. Then, the edges of the shapes are determined using algorithms such as the Bresenham's line algorithm or the Xiaolin Wu's line algorithm. These algorithms calculate the pixels that best approximate the mathematical lines.

Next, the interior of the shapes is filled using techniques such as scanline filling or flood filling. These methods determine which pixels lie inside the shape and should be colored. The color of each pixel is determined by the color of the shape and any shading or texture applied.

Finally, the raster image is created by combining the pixels from all the shapes. This image can then be displayed on a screen or used in further processing.

Rasterisation is a fundamental technique in computer graphics, enabling the creation of complex images from simple mathematical descriptions. It is used in a wide range of applications, from video games and animations to scientific visualization and medical imaging.