The thought of utilizing the Apple II residence pc for digital images functions could appear considerably daft contemplating that this isn’t a goal that they have been ever designed for, but that is the objective that [Colin Leroy-Mira] had, requiring some picture decoder optimizations. That stated, it’s much less loopy than one may assume at first look, contemplating that the Apple II was manufactured till 1993, whereas the Apple QuickTake digital cameras that [Colin] wished to make use of for his nefarious functions noticed their first launch in 1994.
These QuickTake cameras function an astounding picture decision of as much as 640×480, utilizing 24-bit coloration. Utilizing the official QuickTake software program for Apple Macintosh System 7 by way of 9 the images in proprietary QTK format could possibly be fetched for show and processing. Doing the identical on an Apple II would clearly require a bit extra work, to not point out adapting of the picture to the restrictions of the 8-bit Apple II in comparison with the Motorola 68K and PowerPC-based Macs that the QuickTake was designed for use with.
Focusing on the everyday ~1 MHz 6502 CPU in an Apple II, the dcraw QTK decoder shaped the idea for an preliminary decoder. Many reminiscence and buffer optimizations later, an early conversion to monochrome and varied different tweaks later – together with a conversion to 6502 ASM for velocity causes – the decoder because it stands immediately manages to decode and render a QTK picture in a couple of minute, in comparison with effectively over an hour beforehand.
Contemplating how anemic the Apple II is in comparison with even a finances Macintosh Traditional II system, it’s superb that displaying bitmap photos works in any respect, although [Colin] reckons that extra optimizations are potential.
