Module image::codecs

Expand description

Encoding and decoding for various image file formats.

Supported formats

Format	Decoding	Encoding
PNG	All supported color types	Same as decoding
JPEG	Baseline and progressive	Baseline JPEG
GIF	Yes	Yes
BMP	Yes	RGB8, RGBA8, Gray8, GrayA8
ICO	Yes	Yes
TIFF	Baseline(no fax support) + LZW + PackBits	RGB8, RGBA8, Gray8
WebP	Lossy(Luma channel only)	No
AVIF	Only 8-bit	Lossy
PNM	PBM, PGM, PPM, standard PAM	Yes
DDS	DXT1, DXT3, DXT5	No
TGA	Yes	RGB8, RGBA8, BGR8, BGRA8, Gray8, GrayA8
farbfeld	Yes	Yes

A note on format specific features

One of the main goals of image is stability, in runtime but also for programmers. This ensures that performance as well as safety fixes reach a majority of its user base with little effort. Re-exporting all details of its dependencies would run counter to this goal as it linked all major version bumps between them and image. As such, we are wary of exposing too many details, or configuration options, that are not shared between different image formats.

Nevertheless, the advantage of precise control is hard to ignore. We will thus consider wrappers, not direct re-exports, in either of the following cases:

A standard specifies that configuration x is required for decoders/encoders and there exists an essentially canonical way to control it.
At least two different implementations agree on some (sub-)set of features in practice.
A technical argument including measurements of the performance, space benefits, or otherwise objectively quantified benefits can be made, and the added interface is unlikely to require breaking changes.

Features that fulfill two or more criteria are preferred.

Re-exports of dependencies that reach version 1 will be discussed when it happens.