A bitmap is a set of pixels arranged in lines and columns and is fully described by its width and height, its color depth (bits per pixel) and its compression scheme. The common format is true color (24 bits per pixel). An additional color component, called Alpha component, may be used to define the transparency of each pixel. The bitmap format generally supports compression (either lossless or lossy). Some of these bitmaps are coded on 8 bits and the pixels are indexed on a color table, called the palette.
The advantage of bitmap files is that they can reproduce complex scenes (for instance photographic or photo-realistic images) that could not be reproduced using basic geometrical shapes.
When working in the Drafting or 2D Layout for 3D Design workbench, 2D polygons can be filled with a texture. Such polygons are correctly drawn when saved or printed in CGM, PS, PDF or SVG format.
However, when using a Microsoft driver to print 2D textured polygons, the
result depends on the driver's ability to deal with the transparency in bitmap
images.
For instance in HPGL2 format, textured polygons are partially saved because of
a restriction regarding areas outside the polygon's boundaries that might hide
nearby entities.
As HPGL format does not support images, polygons are thus saved without any
texture.