Breaking change after png moved to codecs module

[okaneco]

I received an issue that my crate fails to build when installing with cargo from crates.io.
okaneco/kmeans-colors#35

I believe this was caused by #1328 which relocated png to the codecs module. This was a breaking change that prevents my crate from being compiled and installed. I have the image version in the Cargo.toml at "0.23", the image version in Cargo.lock is at "0.23.6". The change seems too large and non-backwards compatible to be included as a semver compatible minor or patch version. I had no idea it was broken until today.

Expected

The crate should install successfully.

Actual behaviour

The crate fails to compile and install.

   Compiling kmeans_colors v0.3.3
error[E0433]: failed to resolve: could not find `CompressionType` in `png`
  --> C:\Users\user\.cargo\registry\src\github.com-1ecc6299db9ec823\kmeans_colors-0.3.3\src\bin\kmeans_colors\utils.rs:89:25
   |
89 |             image::png::CompressionType::Best,
   |                         ^^^^^^^^^^^^^^^ could not find `CompressionType` in `png`

error[E0433]: failed to resolve: could not find `FilterType` in `png`
  --> C:\Users\user\.cargo\registry\src\github.com-1ecc6299db9ec823\kmeans_colors-0.3.3\src\bin\kmeans_colors\utils.rs:90:25
   |
90 |             image::png::FilterType::NoFilter,
   |                         ^^^^^^^^^^ could not find `FilterType` in `png`

error[E0433]: failed to resolve: could not find `CompressionType` in `png`
   --> C:\Users\user\.cargo\registry\src\github.com-1ecc6299db9ec823\kmeans_colors-0.3.3\src\bin\kmeans_colors\utils.rs:127:25
    |
127 |             image::png::CompressionType::Best,
    |                         ^^^^^^^^^^^^^^^ could not find `CompressionType` in `png`

error[E0433]: failed to resolve: could not find `FilterType` in `png`
   --> C:\Users\user\.cargo\registry\src\github.com-1ecc6299db9ec823\kmeans_colors-0.3.3\src\bin\kmeans_colors\utils.rs:128:25
    |
128 |             image::png::FilterType::NoFilter,
    |                         ^^^^^^^^^^ could not find `FilterType` in `png`

error: aborting due to 4 previous errors

Reproduction steps

Try to install kmeans_colors using cargo.

cargo install kmeans_colors

The repository
https://github.com/okaneco/kmeans-colors

The lines of code are located here
https://github.com/okaneco/kmeans-colors/blob/e8543480c3173154b7bd4eab7ce22e89d8ae4570/src/bin/kmeans_colors/utils.rs#L89-L90
https://github.com/okaneco/kmeans-colors/blob/e8543480c3173154b7bd4eab7ce22e89d8ae4570/src/bin/kmeans_colors/utils.rs#L127-L128

I can fix the issue by changing the fully qualified path.

image::codecs::png::CompressionType::Best,
image::codecs::png::FilterType::NoFilter,
//...
image::codecs::png::CompressionType::Best,
image::codecs::png::FilterType::NoFilter,

[okaneco]

This broke identical code in another of my crates. https://github.com/okaneco/rscolorq
https://github.com/okaneco/rscolorq/blob/ce4205323ecbd45c3056678352780596cb497dc5/src/bin/rscolorq/utils.rs#L76-L77

The Cargo.lock has image version = "0.23.10".

Expected

The crate should install successfully.

Actual behaviour

The crate fails to compile and install.

error[E0433]: failed to resolve: could not find `CompressionType` in `png`
  --> C:\Users\user\.cargo\registry\src\github.com-1ecc6299db9ec823\rscolorq-0.1.0\src\bin\rscolorq\utils.rs:76:21
   |
76 |         image::png::CompressionType::Best,
   |                     ^^^^^^^^^^^^^^^ could not find `CompressionType` in `png`

error[E0433]: failed to resolve: could not find `FilterType` in `png`
  --> C:\Users\user\.cargo\registry\src\github.com-1ecc6299db9ec823\rscolorq-0.1.0\src\bin\rscolorq\utils.rs:77:21
   |
77 |         image::png::FilterType::NoFilter,
   |                     ^^^^^^^^^^ could not find `FilterType` in `png`

error: aborting due to 2 previous errors

Reproduction steps

Try to install rscolorq using cargo.

cargo install rscolorq

[HeroicKatora]

Sorry, you're right. The change had missed to re-exports: png::{CompressionType, FilterType}. Guess we'll best yank the version once the correction is published.