continuous edge graphics (CEG)

The representation of circles and oblique lines on displays is staircase-shaped. This is due to the fact that the display is line-by-line and a part of the oblique line is drawn in each line.

This problem used to be visible at low screen resolutions. As the resolution increased, the human eye could no longer resolve the staircase structure and interpreted a continuous, slanted line.

In the early years of display technology, graphics cards with high resolution were correspondingly expensive, so a Japanese company developed the CEG technique, which stands for Continuous Edge Graphics (CEG). In CEG technology, the staircase structure is not achieved by higher resolution, but by dithering. With dithering, the abrupt stair steps from light to dark, or vice versa, are filled with different shades of gray. The eye recognizes the brightness steps as a continuous line.