Super Hi-Res Graphics on Apple IIGS: Pushing the Limits of Image Quality - KansasFest 2022

Explore the intricacies of Super Hi-Res graphics on the Apple //gs in this KansasFest 2022 conference talk. Delve into the 320x200 resolution display mode with 256 colors from a 4096-color palette, understanding the constraints and challenges in image conversion. Learn how Kris Kennaway extended the ][-Pix tool to support 320x200 SHR, pushing the limits of Apple //gs image quality. Discover the memory layout, Scanline Control Byte, color palettes, and pixel color mapping for both 320 and 640 modes. Follow the image conversion process, including scanline-to-palette mapping, brute force computation, and heuristics. Gain insights into iterative approaches, palette selection, pixel cloud analysis, and k-means clustering for optimal image quality. Examine examples showcasing quality progression, discuss limitations, and explore future possibilities for Super Hi-Res graphics on the Apple //gs.

Intro
16 bits are too much for me
8-bit Apple II graphics
Memory layout
Scanline Control Byte
A lot of flexibility
Third table: Colour palettes
Mapping pixels to colours
320-mode pixel colours
Colours in 640 mode
640-mode pixel colours
Image conversion
Mapping scanlines to palettes
Brute force computation
Heuristics?
Iterative approach
Palette selection
Pixel cloud
k-means clustering
Examples
Quality progression
Limitations
Future work
Questions?