Apple //e, //c, IIGS Double Hires Graphics RGB converter

[resman]

I've recently been focusing my PLASMA development efforts towards the DHGR mode on the 128K Apple //e and later. Getting decent images displayed in DHGR mode has always been a bit of a challenge. Quite a few years ago I experimented with artifact color with the IIGS using it's advanced graphics modes to good effect, but always meant to take lessons learned from that project back to the //e and //c. That time came and with a little bit of an epiphany into the conversion process, I've got a pretty good method (I think) to get a decent facsimile of a photograph displayed from the Apple. Since the algorithm I came up with thinks in NTSC as produced by the Apple //e, it looks best on a physical composite color CRT. Emulators and RGB cards use approximations to generate their colors. So I actually took a video of a slide show I created from a few curated images:

Here is a link to the 800K disk image that auto-boots into the slide show: https://github.com/dschmenk/PLASMA/blob/master/images/apple/DHGR-BIGSHOW.PO

Here is a smaller slideshow will fit on a 140K floppy: https://github.com/dschmenk/PLASMA/blob/master/images/apple/DCGR-RGB.PO

Perhaps unsurprisingly, this same approach would work with the IBM CGA displaying to a color composite CRT.