bitmap

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bitmap

Computing
a picture created on a visual display unit where each pixel corresponds to one or more bits in memory, the number of bits per pixel determining the number of available colours

bitmap

(graphics, file format)
A data file or structure which corresponds bit for bit with an image displayed on a screen, probably in the same format as it would be stored in the display's video memory or maybe as a device independent bitmap. A bitmap is characterised by the width and height of the image in pixels and the number of bits per pixel which determines the number of shades of grey or colours it can represent. A bitmap representing a coloured image (a "pixmap") will usually have pixels with between one and eight bits for each of the red, green, and blue components, though other colour encodings are also used. The green component sometimes has more bits that the other two to cater for the human eye's greater discrimination in this component.

See also vector graphics, image formats.

bitmap

A binary representation in which a bit or set of bits corresponds to some part of an object such as an image or font. For example, in monochrome systems, one bit represents one pixel on screen. For gray scale or color, several bits in the bitmap represent one pixel. The term may refer to the image itself or to the memory area that holds the bits that represent the image. See pixel.

Graphics and Tables
A bitmap is usually associated with graphics, in which the bits are a direct representation of the pixels in the image. However, bitmaps can be used as tables to represent and keep track of anything, where each set of bits is assigned a value or condition. See bitmapped graphics. For graphics fundamentals, see graphics.


A Monochrome Bitmap
The left half of this diagram shows the bits in the bitmap, and the right half depicts what would show on screen. In monochrome systems, one bit is used to represent one pixel. Images that are scanned into the computer are turned into bitmaps, and bitmaps can be created in a paint program.
References in periodicals archive ?
I recently purchased Perly's CD-ROM map of the Greater Toronto Area, If I save a single map page in colour, those 256 colours produce a BMP file that is more than 6 MB in size.
McAfee customers using the 4328 DATs or newer may detect threats exploiting the Malformed BMP File Buffer Overrun Vulnerability as Exploit-BMP.
The product features a SCSI interface for fast transfer speed, supports the TIFF, TGH, PCX and BMP file formats and does not require a video capture board.
PenOffice SE also allows ideas to be jotted down on an electronic scratch pad that can be attached to email, and for comments and notes to be added to any document on the screen for saving as a BMP file.
In addition, they include a fancy scan show feature for easy preview of all available channel programs, are Intel(r) InterCast ready, and also offer arbitrary scaling video window and snap picture to BMP file functions.
Use the software to render the photo into a jpeg, png, gif, or bmp file.
This algorithm hides a message inside a BMP file, obtained by applying jpeg-tobmp function to the cover file.
Appraisers often need to reduce a two- or three-megabyte BMP file to a much smaller JPG format.
An image saved as a JPEG file will be approximately 10 times smaller than the same image saved as a BMP file but the processing power that is required to decode the BMP is roughly 10 times smaller than that required to work through the JPEG compression algorithms.
BMP files can be drastically reduced in size by these compression programs.