Computer Graphics Zooming
Zooming is a transformation often provided with an imaginary software. The transformation effectively scales down or blows up a pixel map or a portion of it with the instructions from the user. Such scaling is commonly implemented at the pixel level rather than at the coordinates level. A video display or an image is necessarily a pixel map, i.e., a collection of pixels which are the smallest addressable elements of a picture. The process of zooming replicates pixels along successive scan lines.
Example: for a zoom factor of two
Each pixel value is used four times twice on each of the two successive scan lines.
Figure shows the effect of zooming by a factor of 2.
Such integration of pixels sometimes involves replication using a set of ordered patterns, commonly known as Dithering.
The two most common dither types are:
There are widely used, especially when the grey levels (share of brightness) are synthetically generated.