brushkit

Rust crates that read brush files and render their tip shapes. They read only. Nothing here writes or converts a brush file.

• Photoshop .abr, versions 1, 2, 6, 7, 9 and 10: brush names (v1 files have none), sampled tip bitmaps (8 or 16 bit, raw, RLE or zlib), computed-tip geometry, the full brush descriptor and embedded patterns.
• Procreate .brush and .brushset: brush names, set order from brushset.plist, tip shapes from Shape.png.
• Tip rendering: grayscale bitmaps, thumbnails sized for a grid, contact sheets.

Crates

Usage

[dependencies]
brushkit = "0.2"

use brushkit::abr::parse_abr_deferred_without_patterns;
use brushkit::preview::{preview_abr, PreviewOptions, TipPreview};

fn main() {
    let bytes = std::fs::read("pack.abr").unwrap();

    let pack = parse_abr_deferred_without_patterns(&bytes).unwrap().pack;
    println!(
        "{:?}: {} sampled brushes, {} computed presets",
        pack.version,
        pack.brushes.len(),
        pack.computed_presets.len()
    );

    let set = preview_abr(&bytes, PreviewOptions { max_cell: 128 }).unwrap();
    for entry in &set.entries {
        match &entry.tip {
            TipPreview::Available(bitmap) => {
                println!("{}: {}x{}", entry.name, bitmap.width, bitmap.height)
            }
            TipPreview::Unavailable(reason) => println!("{}: {reason:?}", entry.name),
        }
    }
}

The same code is crates/brushkit/examples/readme.rs. A test checks the two are identical, so the block compiles whenever the test suite does.

preview_abr, preview_brush and preview_brushset return every brush in file order exactly once, available or not. A brush whose tip cannot be rendered carries a reason (NoShapePng, UnsupportedTipKind, Corrupt, TooLarge) rather than being dropped, so a caller can lay out a complete grid. Each entry also carries optional source_dimensions for the original raster, independent of the preview size and retained if pixel decoding fails. Computed tips have no source raster dimensions. No returned bitmap has a side larger than max_cell, and a tip that already fits keeps its size. A .brushset without brushset.plist is read in zip order and has no set name.

parse_abr decodes every tip up front. parse_abr_deferred and parse_abr_deferred_without_patterns keep tips as byte ranges to decode on demand. The preview path uses the latter, so previewing a pack with a large pattern block does not copy or decode the patterns.

Features

• text (default, brushkit and brushkit-preview): the contact-sheet API. Labels need a font, so it pulls in ab_glyph and an embedded copy of Inter Regular.
• serde (brushkit and brushkit-abr): Serialize on the raw descriptor dump in brushkit_abr::dump.

Every crate builds for wasm32-unknown-unknown. The readers take &[u8] and touch neither the filesystem nor threads.

Untrusted input

Every size, count and dimension read from a file is checked against a ceiling before anything is allocated, and malformed input is an error, not a panic. Four libFuzzer targets under fuzz/ cover both readers. CI replays their committed seed corpus and fuzzes each target for 30 seconds on every pull request and push to main.

Building

cargo build
cargo test
cargo +nightly fuzz run abr_parse   # needs cargo-fuzz

See fuzz/README.md for the other targets and seed regeneration.

Real-file tests

Real brush packs are copyrighted and are not in the repository. Tests that assert facts about real files read BRUSHKIT_CORPUS_DIR and are skipped when it is unset. Synthetic files in the unit tests and the fuzz corpus cover the parsing mechanics without it.

Versioning

The crates are at 0.x. Minor releases may change the public API. Pin the minor version. Every release is a git tag vX.Y.Z on this repository.

License

MIT, see LICENSE. The Inter font embedded by the text feature is under the SIL Open Font License 1.1, see crates/preview/assets/fonts/OFL.txt.