Rainstar Paint 0.3.9 — Spirograph, pattern canvas and dithering

Rainstar Paint 0.3.9 adds drawing apparatus, custom pattern editing and perceptual color reduction to the native application.

• Custom pattern canvas: choose Materials → Edit custom pattern. Edit a black-and-white tile from 1–128 pixels per side, with a repeating preview, separate Undo/Redo and saved tile. Return to main canvas restores the image, selection, view and drawing history. New classic patterns include Buttons, Cargo Net, Circuits, Cobblestones and Straw Mat.
• Spirograph: 16 guides and 23 inserts, including rings, shaped frames and racks. Place and fill ink pegs, select a peg to assign its own brush medium, and drag the insert to draw. The translucent apparatus follows ordinary Guide dismissal rules.
• Gel pen: a solid stroke with subtle brightness variation and glints, available both as a brush and as peg ink.
• Tool cursors: original Paint-drawn pointer artwork with precise contact points. Magnifier and Stamp previews remain unobstructed.
• Selection dithering: Selection → Dither / posterize… offers 2–32 colors, Crosswind, Weave, Scrambled, Drift and plain posterization. Preview and cancellation leave the image untouched; Apply commits the preview as one undoable edit. Alpha and unselected pixels are preserved.
• Dithering brush: scattered, center-weighted changes to existing pixels. The default moves each affected pixel halfway toward its neighborhood average; the Tool tab offers gentle brightness/saturation noise instead. Both modes respect the active selection and preserve alpha.

The dither palette uses bounded OKLab sampling with local variation and Student-t coverage. The allocator is a practical first version for experimentation on different materials; it does not claim an optimal minimum palette. The new renderer needs no Fourier library.

Packages are provided for Apple Silicon Mac, Windows x64, Linux x64 and Linux ARM64. Linux archives include their musl loader, libraries and fonts, and require X11 or XWayland. The Mac app requires macOS 26 or newer, is ad-hoc signed, and is not Developer ID notarized. The familiar Windows 7/10 interface does not imply verified Windows 7 compatibility.

SHA256SUMS lists the release downloads. Verification details accompany the release.

Validation: 10/10 Paint suites on macOS ARM64 and Windows x64; 11/11 on Linux x64 and ARM64. The native toolkit passes 62/62 checks on Windows and 67/67 on each Linux architecture. Both Linux packages pass startup and native interaction checks on an Ubuntu host without its own musl loader. All Windows/Linux package manifest hashes and twelve bundled fonts verify; all 81 Mac installer payload files match the signed app. The packaged Mac app was visually checked for dithering and the custom pattern canvas, including return to the original canvas. No new sanitizer or heap-audit result is claimed.