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

Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005

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.

This article is provided by FOLDOC - Free Online Dictionary of Computing (foldoc.org)

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 and rasterize.

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.

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References in periodicals archive

You must be careful when enlarging bitmapped graphics.

In addition to the black-and-white bitmapped image, the anchor image can be presented as a grayscale bitmapped image, as shown in Figure 3 (p.

In certain cases you would want to use bitmapped images.

In contrast to bitmapped graphics, vector graphics do not contain pixels; rather, they are composed of shapes.

With a graphics program, vector graphics can be created automatically from a bitmapped file.

If you save an image using a vector graphic file format, you can change the file to a bitmapped file format.

* Encapsulated PostScript format (.EPS) -- This file format can contain bitmapped graphics.

Although this file format can contain bitmapped graphics, it usually contains vector graphics.

* WordPerfect/DrawPerfect graphic (.WPG) -- This format can handle either vector or bitmapped graphics.

If so, you will probably be using a bitmapped graphics file format.

When creating graphics files for your SGML documents, determine which major graphics file type (bitmapped or vector) is better suited to your needs.

Nuts and bolts of SGML