AutoCAD® 2002 - Autodesk

Slide Files
The type of data following a group is determined from the group code by the
same rules used in decoding ASCII DXF files. Translation of angles to degrees
and dates to fractional Julian date representation is performed for binary
files, as well as for ASCII DXF files. The comment group, 999, is not used in
binary DXF files.
Extended data group codes are represented in binary DXF as a single byte
with the value 255, followed by a 2-byte integer value containing the actual
group code, followed by the actual value.
Extended data long (group code 1071) values occupy 4 bytes of data.
Extended data binary chunks (group code 1004) are represented as a singlebyte,
unsigned integer length, followed by the specified number of bytes of
chunk data. For example, to transfer an extended data long group, the following
values would appear, occupying 1, 2, and 4 bytes respectively.
255 Escape group code
1071 True group code
999999 Value for the 1071 group code
SAVEAS writes binary DXF files with the same file type (.dxf) as for ASCII DXF
files. The OPEN and INSERT commands automatically recognizes a binary file
by means of its sentinel string. You need not identify it as a binary file.
If the OPEN and INSERT commands encounter an error in a binary DXF file,
AutoCAD reports the byte address within the file where the error was
detected.
NOTE This information is for experienced programmers, and is subject to
change without notice.
AutoCAD slide files are screen images written by the MSLIDE command and
read by the VSLIDE command. This section describes the format of slide files
for the benefit of developers who wish to incorporate support for slides into
their programs.
A slide file consists of a header portion (31 bytes) and one or more data
records of variable length. All coordinates and sizes written to the slide file
reflect the drawing area of the display device from which the slide was created
with point (0,0) located at the lower-left corner of the drawing area. For
Slide Files | 159