Jaggies is slang for the jagged, blurred lines that can appear in computer graphics. They typically occur in raster images, also known as bitmaps, with reduced resolution. The lines resemble ladder rungs and appear in place of straight or curved lines at the edges of the image.
Jaggies often occur with bitmap images, because they rely on small squares that work together to form a recognizable image.
Bitmap images are often anti-aliased because they are made up of separate square pixels of varying colors and tones. When its size changes, a process called aliasing adds or removes pixels in such a way that a misrepresentation, also known as an artifact, arises. Artifacts often have a ladder-like appearance due to this addition or subtraction of pixels around the edges of the image. Non-raster graphics, known as vector graphics, rely on a mathematical formula instead of pixels to represent the images. That’s why vector graphics don’t produce bumps.
Temporal anti-aliasing, also known as motion blur, can correct irregularities in graphics or animated videos.
Animated computer graphics or videos may also be anti-aliased. Temporal posterization is responsible for producing these artifacts in motion graphics. This process visually describes what happens when the number of frames in a video is reduced but its speed remains the same.
Jaggies can be reduced in CGI through anti-aliasing. Anti-aliasing adds shaded pixels to the areas around the edges of the image to create a smoother appearance. Temporal anti-aliasing, also known as motion blur, can correct irregularities in graphics or animated videos. In video, this process considers the scene or image being captured over a period of time, not just in one instance. Temporal anti-aliasing makes the image appear as if it were shooting across the screen.
Full-screen anti-aliasing (FSAA) is used on three-dimensional graphics cards to reduce aliasing in video game systems. The method applies anti-aliasing to all three-dimensional images on the screen. The most commonly used anti-aliasing technique in FSAA is oversampling. Oversampling involves doubling or quadrupling the resolution of each frame. The frames are then sampled to match the screen resolution.
The term “jaggies” is believed to have come from the video game Atari Rescue on Fractalus! , which was released in 1985. One of the game’s computer graphics lacked anti-aliasing. Due to the low resolution of the Atari system, artifacts were never eliminated from the image and the developers described the effect as “jaggy”. They later called the game’s enemies “Jaggi” and even reportedly wanted to call the video game Behind Jaggi Lines.