Appendix A -- Drawing Interchange File Formats
Slide Files
Old Slide Header

The slide format described in the previous section is produced by AutoCAD Release 9 and later, and is portable among all computers running AutoCAD Release 9 or later. Previous versions of AutoCAD (as well as AutoShade 1.0 and AutoSketch 1.02) produce slides with a somewhat different header, as shown in the following table.

Old slide file header
Field Bytes Description

ID string

17

"AutoCAD Slide" CR LF ^Z NUL

Type indicator

1

56 (decimal)

Level indicator

1

1 (old format)

High X dot

2

Width of the drawing area: 1, in pixels

High Y dot

2

Height of the drawing area: 1, in pixels

Aspect ratio

8

Drawing area aspect ratio (horizontal size/vertical size in inches), written as a floating-point number

Hardware fill

2

Either 0 or 2 (value is unimportant)

Filler byte

1

Unused

Note that the old-format header does not contain a test number field. The floating-point aspect ratio value and all 2-byte integers are written in the native format of the CPU that was used to create the file (for 8086-family CPUs, IEEE double-precision, and low-order byte first). Old-format slide files are not portable across machine types, but they can be read by any version of AutoCAD running on the same CPU type as the CPU with which the slide was created.