device independent bitmap

graphics, file format (DIB) An image format in which the

sequence and depth of pixels in the file is not specifically

related to their layout in any particular device. This allows

any device dependent bitmap (DDB) image to be converted to or

DIB format without loss of information, and this can then

later be converted to other DDB formats for, e.g., printing or

display. Rather than requiring converters from each DDB

format to all other formats, only converters to and from DIB

are needed.

DIB images are normally transferred in metafiles, bmp

files, and the clipboard.

Transferring colour bitmaps from one device to another was not

possible in versions of Microsoft Windows earlier than 3.0.

Application programs can build DIB images without any

interaction with Windows. If Windows lacks a drawing

primitive, the application can simulate it directly into the

DIB instead of using the existing graphics device interface

(GDI) primitives. Unfortunately, under Windows versions 3.0

and 3.1, GDI cannot perform output operations directly to a

DIB.

Conversion between DIB and DDB is performed by the devicedriver. Where the driver does not have this facility, the

conversion is performed by GDI but only in monochrome. DIBs

are slower to use than device dependent bitmaps due to the

conversions required.

(1996-09-20)