Apple II
File Type Notes
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                                                  Developer Technical Support


File Type:         $08
Auxiliary Type:    $4001

Full Name:     Packed Apple II Double Hi-Res Graphics File
Short Name:    Packed Double Hi-Res File

Written by:    Matt Deatherage                                  November 1988

Files of this type and auxiliary type contain a packed Apple II Double Hi-Res 
graphics screen.
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Files of type $08 and auxiliary type $4001 contain a packed Apple II Double 
Hi-Res graphics screen which has been packed with the same algorithm that 
PackBytes on the Apple IIGS uses.  This algorithm takes the 16K graphics 
screen (auxiliary memory portion first) and produces a file with an 
indeterminate length and internal format, so no "mode byte" at offset +121 is 
supported as it is with other files of type $08.

You can display a file of this type and auxiliary type by loading it, using 
UnPackBytes to decrypt the data, moving the first half into auxiliary memory 
at location $2000, moving the second half into main memory at location $2000, 
then simply toggling the display soft switches and annunciators to turn on 
double high-resolution mode.

File type $08 was originally defined as an Apple /// FotoFile, but now it is 
useful for those applications that wish to save high-resolution or double 
high-resolution data with a file type other than $06, which is a standard 
binary file.  If you choose to use this type, you should remember that older 
applications which do not check the auxiliary type may attempt to interpret 
these files incorrectly.

