INF: Microsoft Windows GDI Defines Monochrome Bitmap Format

ID Number: Q74402

3.00 3.10

WINDOWS

Summary:

In the Microsoft Windows graphical environment, a display driver can

generally define its own color bitmap format based on the particular

hardware it supports. However, a display driver cannot define its own

monochrome bitmap format. The Windows graphics device interface (GDI)

defines the monochrome bitmap format as follows: each byte contains 8

pixels with the most significant bit representing the left-most pixel.

For example, to activate the pixel at the upper-left corner of the

bitmap, set bit 7 of the first bitmap byte to 1.

Due to hardware design, it might be more convenient to define the

monochrome bitmap format in some other fashion. However, Windows

requires the particular monochrome bitmap format described above.

More Information:

The main reason that the monochrome bitmap format cannot be redefined

is to enforce a common standard across all devices. Windows can render

a bitmap in this format on any display or any raster printer device.

GDI assumes the monochrome format for device-independent bitmap (DIB)

simulations, StretchBlt simulations, and to allow Windows to select a

monochrome bitmap in any device context regardless of the color

resolution.

Additional reference words: 3.00 3.10 DDKDISPLAY