Raster graphics
In computer graphics, raster graphics refers to an image based on points.
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About Raster Graphics
Raster graphics uses a dot matrix data structure to represent a rectilinear grid of pixels, or points of color. These pixels are rendering via a monitor, paper, or other display medium.
Raster images are stored in image files with varying file formats.
A bitmap, a single-bit raster, corresponds bit-for-bit with an image displayed on a screen, generally in the same format used for storage in the display's video memory, or maybe as a device-independent bitmap.
A raster is technically characterized by the width and height of the image in pixels and by the number of bits per pixel (a color depth, which determines the number of colors it can represent).
Contones
The printing and prepress industries know raster graphics as contones (from "continuous tones").
Line Work, Vector Graphics
The opposite to contones is "line work", usually implemented as vector graphics in digital systems.
Etymology
The word "raster" has its origins in the latin rastrum (a rake), which is derived from radere (to scrape).
It originates from the raster scan of cathode ray tube (CRT) video monitors, which paint the image line by line by magnetically steering a focused electron beam.
By association, it came also to refer to a rectangular grid of pixels.
External Links
- Raster graphics @ Wikipedia
