device independent bitmap
(foldoc) | device independent bitmap
DDB
DIB
(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 {device
driver}. 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)
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