PNG/JPEG/WebP → Commodore Amiga and Atari ST/STE graphics. Produces IFF ILBM, Degas .PI1/.PI2, C headers, raw bitplanes, and self-contained AmigaOS executables that boot from a floppy image and display the image.

Try it in your browser at png2amiga.app — live preview via WebAssembly, compile to Amiga executables server-side.

Built for Amiga and Atari demoscene production. All color operations use OKLab perceptual color space. Beats ham_convert's highest-quality HAM8 profile by 2–4 dB PSNR on typical test images. Sister project to png2c64.

Amiga modes: Lores / Hires (+ interlace), HAM6 (OCS) + HAM8 (AGA) with hires and/or interlace variants, EHB. 1–8 bitplanes per chipset limits. Copper per-line palette changes (sliced) for more than 16/32 colors per line in any bitmap mode.

Atari modes: STF Low/Medium (9-bit palette), STE Low/Medium (12-bit palette), Degas Elite .PI1/.PI2 output.

Palette quantizers: OCS brute-force (histogram + greedy over all 4096 OCS colors), PNN agglomerative (auto-selected for HAM8 / AGA), and median-cut + k-means refinement in OKLab.

Dithering: 22 methods including Floyd-Steinberg, Atkinson, Sierra-Lite, Stucki, Jarvis, Ostromoukhov variable-coefficient, Gilbert space-filling-curve, Bayer, blue-noise, and several analytical per-pixel patterns. All operate in OKLab.

HAM encoding: DP beam search with a triple-pixel refinement pass (default on) that catches the fringe-lag artifacts 1-pixel DP misses. --ham-fast switches to the greedy encoder (~15× faster, ~0.04 dB quality cost) for live preview or batch video processing.

Output: .png preview, .iff ILBM, .h C header, .cpp standalone viewer source, .exe compiled AmigaOS executable, .adf bootable floppy image, .pi1/.pi2 Degas, .raw + .pal raw bitplanes with palette.

# Native CLI (requires GCC 15 for C++26)
cmake -B build -DCMAKE_C_COMPILER=gcc-15 -DCMAKE_CXX_COMPILER=g++-15 .
cmake --build build
ctest --test-dir build --output-on-failure

# WASM (requires Emscripten)
emcmake cmake -B build-wasm -DCMAKE_BUILD_TYPE=Release .
cmake --build build-wasm

# Web frontend
cd web && npm install && npm run dev

# Production web bundle (writes to docs/)
./build-web.sh

Pre-built Linux / macOS / Windows binaries are attached to each GitHub release.

# Basic conversion
./build/png2amiga input.png output.iff
./build/png2amiga input.jpg output.png

# HAM8 on AGA (default — triple refinement, FS pre-dither, PNN palette)
./build/png2amiga --mode ham8 --chipset aga input.png output.iff

# HAM8 realtime / batch profile (greedy, ~15× faster)
./build/png2amiga --mode ham8 --chipset aga --ham-fast input.png output.png

# Per-line palette (sliced) — more colors per line via Copper
./build/png2amiga --mode lores --depth 5 --copper input.png output.iff
./build/png2amiga --mode ham6 --copper input.png output.iff

# Generate a bootable Amiga floppy that displays the image
./build/png2amiga --mode ham6 input.png viewer.cpp
./build-amiga.sh viewer.cpp viewer.adf

# Launch in fs-uae (A1200 by default)
./run-amiga.sh viewer.adf
./run-amiga.sh viewer.adf A500 ntsc

# Atari ST/STE
./build/png2amiga --mode stf-low input.png output.pi1
./build/png2amiga --mode ste-low input.png output.pi1

Run ./build/png2amiga --help for the full flag reference.

Add --copper to any bitmap mode (lores, hires, EHB, HAM6, HAM8) to let the Copper coprocessor rewrite palette registers between scanlines and get more colors per frame than the base palette allows.

The encoder respects the real-hardware post-DDFSTOP DMA budget: 14 MOVE instructions per line. Safe static budget is 14 palette swaps on OCS and 3 on AGA (banked). Auto-mode then tries K+3, K+2, K+1 and picks the highest K whose worst-case cost fits the budget — typically 6 swaps/line at depths 3–5 on AGA.

--copper-changes N overrides the budget entirely; use if you want to experiment with configurations that may exceed real hardware limits but still display correctly on emulators.

The project includes vscode-amiga-debug as a submodule, which provides the m68k-amiga-elf-gcc cross-compiler, elf2hunk, exe2adf, fs-uae, and AmigaOS SDK headers — everything needed to produce bootable disk images locally.

git submodule update --init

./build/png2amiga --mode ham6 input.png viewer.cpp
./build-amiga.sh viewer.cpp viewer.adf
./run-amiga.sh viewer.adf

The generated viewer takes the system, sets up the Copper list (including per-line palette changes if --copper was used), and waits for the left mouse button to exit.

MIT