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 ?
For small or medium cardinality columns (assuming that multiple synchronisation processes are not updating the same index) bit map indexes may be acceptable.
The new Transactional Bit Map Indexing available in CACHE 5 will be especially useful for complex queries, such as DNA testing for infectious diseases, molecular oncology, mutational analysis, and human identity testing.
It indexes the database using a combination of bit map and inverse list indexes and creates both multidimensional and aggregate indexes.
The EM6126 is an ultra low power bit map controller and driver for full dot matrix monochrome STN LCD displays.
To our knowledge we are the first company to provide full bit map capture display and analysis for 4 Gigabit memories, such as the latest NAND Flash devices.
For small to medium cardinality columns -- assuming that multiple synchronisation processes are not updating the same index -- bit map indexes may be acceptable, but some care still has to be exercised to avoid contention between the synchronisation process and user queries.
The Super Bit Map remastering has not only clarified the sound, it has eliminated most of the background noise between the notes.
For example, Bit Map indexes do not handle high cardinality keys well.
Recorded in 1965, it is a Super Bit Map remaster of a Vanguard vinyl LP, with no added material.
Vanguard's sound, remastered using Super Bit Map technology, belies its 1964 origins.
The 12-bit qVGA display, which is capable of handling both bit map and text input, shows images from compatible devices via MicroOptical's MOBILS protocol and the Bluetooth short-range wireless specification.