mirror of
https://github.com/storytold/craft-libs.git
synced 2026-11-12 08:52:32 +00:00
Dylan M. Taylor
219f63f64c
* Add craft-xcf: GIMP XCF reader from PhotoCraft The format half of PhotoCraft's XCF import (crates/io/src/xcf.rs at abeb16c96): the header, precisions, property lists with their length repairs, parasites, layer structures and item paths, channels, and the uncompressed, RLE and zlib tiles. The mapping onto a document (blend modes, surfaces, profiles, warnings) stays in the app. * craft-xcf: an RLE run of zero length is an error A long run (op 127 or 128) with a 16-bit length of 0 consumed input without producing output, so a tile of them was work the pixel budget never charged. Ported from storytold/photocraft#11138. * craft-xcf: channel names are charged to the metadata budget Layer names already were. Many channel pointers to one channel with a large name made a copy per read, multiplying a small file into gigabytes of retained names. Ported from storytold/photocraft#11138.
41 lines
2.2 KiB
Markdown
41 lines
2.2 KiB
Markdown
# craft-xcf
|
|
|
|
GIMP XCF images (`.xcf`, `.xcf.gz`), read. Written from the public specification
|
|
(<https://developer.gimp.org/core/standards/xcf/>, versions 0 to 26) and from files GIMP 3.2
|
|
writes; no GIMP code is used.
|
|
|
|
- `is_xcf`, `is_gzipped_xcf`, `gunzip`: recognise a file and inflate a compressed one.
|
|
- `Xcf::parse`: the header, the image properties and every layer structure, as an `Image`:
|
|
version, canvas, base type, `Precision`, `Compression`, colormap, resolution, guides, the ICC
|
|
profile and comment parasites, the path count, and each `Layer` with its properties as GIMP
|
|
wrote them (mode, opacity, offsets, locks, colour tag, composite mode and spaces, group flag,
|
|
item path, text / vector / link flags, effect count). No pixel is decoded.
|
|
- `Xcf::layer_pixels`, `Xcf::layer_mask`, `Xcf::channel`: one drawable's pixels as normalised
|
|
`f32` samples (`Pixels`), from uncompressed, RLE or zlib tiles at every precision (8, 16 and
|
|
32-bit integer; 16, 32 and 64-bit float). Indexed pixels are expanded through the colormap.
|
|
Each call takes its samples from a byte budget the caller owns, and a `keep_going` callback.
|
|
- `Image::tree`: the layers arranged by their item paths, with the ones whose path leads nowhere
|
|
or nests too deep reported.
|
|
|
|
The reader repairs what GIMP writes wrongly: the length words of `PROP_COLORMAP`,
|
|
`PROP_USER_UNIT` and `PROP_LINK_LAYER` are measured, not trusted.
|
|
|
|
Layer modes, colour tags and composite settings stay numbers: what they mean to an application
|
|
is not decided here. Paths, layer effects and text or vector layer data are not read (their
|
|
presence is reported). There is no writer.
|
|
|
|
## Limits
|
|
|
|
| Limit | Value |
|
|
| --- | --- |
|
|
| Canvas or drawable side | 300,000 px (`MAX_SIDE`) |
|
|
| Canvas area | 1 GiB at 16 bytes per pixel (`MAX_PIXEL_BYTES`) |
|
|
| Decoded pixels | the caller's budget, charged 4 bytes a sample before allocation |
|
|
| Layers | 8192 (`MAX_LAYERS`); channels 1024 (`MAX_CHANNELS`) |
|
|
| Layer effects on one layer | 1024 |
|
|
| Properties in one list | 4096; a payload 64 MiB (`MAX_PAYLOAD`) |
|
|
| A string | 1 MiB (`MAX_STRING`) |
|
|
| Copied layer and channel names and item paths | 32 MiB in all (`MAX_METADATA_BYTES`) |
|
|
| Group nesting in `Image::tree` | 64 (`MAX_DEPTH`) |
|
|
| A gzipped file, inflated | 1 GiB (`MAX_INFLATED`) |
|