Blown Away - The Interactive Game
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ART file variants

ART FILES BY IMAGINATION PILOTS
Technical overview by Daniel Marschall						15 Feb 2018


		VERSION 1.x (16-bit era, "IPE16")
		=================================

Version 1.0	For game: "Blown Away" (1994)
		* File signature "Art" + 20 NUL bytes
		* Image names up to 23 characters
		  (unsure if the 23th byte must be a zero terminator)
		* LZW implementation: GIF standard implementation
		  - variable code length between 9 and 12 bits
		  - clear code (256)
		  - end code (257)
		* Pictures can only be 8-bit
		* Each picture can either be LZW compressed (code "P")
		  or uncompressed (code "p", lower case)
		* Decompressed/raw data: Top-down pixel data
		* Attached: Optional palette (R,G,B), uncompressed.
		  (Sprites usually do not have a palette, so the game
		   will use the palette of the parent picture)

Version 1.1	For games: "Panic in the Park" (1995)
		           "Where's Waldo? At the Circus" (1995)
		* Codes for compression/raw are now "Q" and "q" instead of
                  "P" and "p"
		* Each picture has now a relative X- and Y-offsets for 'fine-tuning'.
		  These offsets cannot be negative, though.

		VERSION 2.x (32-bit era, "IPE32")
		=================================

Version 2.0	For games: "Where's Waldo? Exploring Geography" (1996)
		           "Eraser Turnabout" (1997)
		           "Virtual K'Nex" (1998)
		* File signature "ART_DATA"
		* Image names up to 8 characters;
		  no zero termination required after the 8 characters.
		* LZW implementation by Mark R. Nelson and Shawn M. Regan
		  - variable code length between 9 and 13 bits
		  - clear code (256)
		  - end code (257)
		* Pictures are divided into chunks. Each chunk can be compressed or
		  uncompressed. Limitations:
		  - Each compressed chunk (except the last one) must decode into
		    exactly 16382 (0x3FFE) bytes of uncompressed data.
		  - The size of the compressed data of a chunk must not exceed the
		    size of the original uncompressed data.
		* The size of each chunk (raw or compressed) is limited
		  to max. 32767 Bytes (0x7FFF).
		* Decompressed/raw data: Windows Bitmap (without file header);
		  therefore, theoretically every color depth/compression/etc. can be used.
		  For 8-bit pictures, the palette is included in the Bitmap.
		* Re-using of parent palette is not possible.

© 2020 Daniel Marschall - - www.daniel-marschall.de

Please also see my pages for other Imagination Pilots games:
Blown Away | Panic in the Park | Waldo at the Circus | Waldo Exploring Geography | Eraser Turnabout | Virtual K'Nex