Raster graphics

In computer graphics and digital photography, a raster graphic represents a two-dimensional picture as a rectangular matrix or grid of square pixels, viewable via a computer display, paper, or other display medium. A raster is technically characterized by the width and height of the image in pixels and by the number of bits per pixel. Raster images are stored in image files with varying dissemination, production, generation, and acquisition formats.

The smiley face in the top left corner is a raster image. When enlarged, individual pixels appear as squares. Enlarging further, each pixel can be analyzed, with their colors constructed through combination of the values for red, green and blue.

The printing and prepress industries know raster graphics as contones (from continuous tones). In contrast, line art is usually implemented as vector graphics in digital systems.[1]

Transposing an image to covert raster organization (a relatively costly operation for packed formats with less than a byte per pixel); composing an additional raster line reflection (almost free), either before or afterwards, amounts to a 90° image rotation in one direction or the other.

Many raster manipulations map directly onto the mathematical formalisms of linear algebra, where mathematical objects of matrix structure are of central concern.


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This article uses material from the Wikipedia article Raster graphics, and is written by contributors. Text is available under a CC BY-SA 4.0 International License; additional terms may apply. Images, videos and audio are available under their respective licenses.