ImageMagick should be in the [deps] section in Project.toml

[EvertSchippers]

I use Images.jl only to save a jpg image, using this statement:

using Images
...
save("filename.jpg", someUInt8Matrix)

But my project/enviroment needs ImageMagick to be added before this works. I'm not using it myself directly (I don't have a "using ImageMagick" in my code).

Somewhere Images.jl does use it. I should not have to add "ImageMagick" to my project, it should automatically be added to my Manifest when I Pkg.add Images.

You can replicate by temporarily removing your enviroment, add just Images, and try and use it...

[johnnychen94]

FileIO specifies a set of general file I/O APIs such as load and save. It doesn't have codes on specific file formats, which means you need to install an image IO package (e.g., ImageMagick) to read image files, and CSV to read .csv files, etc.

Adding ImageMagick as a hard dependency of FileIO might free you from installing it manually once, in the cost of adding it for all downstream projects (even for those unrelated to images), which is much more expensive. So I think this request won't be considered.

I use Images.jl only to save a jpg image

In this case, you don't need using Images, instead using FileIO with ImageMagick installed is sufficient.

[timholy]

Exactly. Moreover, depending on platform the user may prefer different packages (e.g., QuartzImageIO on macs).

[EvertSchippers]

You are totally right, I feel a bit stupid... Thanks for responding - and solving this!

[mbaz]

This seems related; let me know if you'd prefer that I open a new issue...

I tried following the "Getting started" instructions:

using TestImages
img = testimage("mandrill")

Fatal error:
ERROR: ArgumentError: Package ImageMagick not found in current path:
- Run `import Pkg; Pkg.add("ImageMagick")` to install the ImageMagick package.

It seems to me like ImageMagick should in fact be installed as a dep of Images.jl...

[johnnychen94]

FileIO used to prompt to install image io backends if not available, now it doesn't do this anymore and just throw an error for that.

We've updated the docs recently JuliaImages/juliaimages.github.io#115. Unfortunately, the documentation CI is continuously hitting failures during deployment, you can view the latest version of "getting started" by this: https://juliaimages.org/previews/PR115/install/

[johnnychen94]

I believe the reason we didn't do this for Images.jl is that binary dependency was a maintenance nightmare.

Now with the artifact system provided by Julia >= 1.3, bundling a default backend into Images looks like a good choice for me. However, we might not want to do this right now because people here are too busy to maintain two Images versions(one for Julia < v1.3 and one for Julia >= v1.3). We can do this when we upgrade to the next Julia LTS version.

[timholy]

Yes, that was written when FileIO installed packages for you.

ImageMagick may be a good choice on Linux, though with ImageIO that's getting less clear. It's even less obviously so on Mac, where QuartzImageIO was at least once the default option.

[mbaz]

Thanks! BTW, I only installed ImageMagick.jl because that's what the error message prompted me to do.

[IanButterworth]

Just bringing this discussion here.

What would we consider the minimum feature set that ImageIO would need to be the one?

[johnnychen94]

Adding these backends won't increase the loading time of Images, and since adding these backends are no longer a nightmare since Julia 1.3, I think it would be acceptable to add all of them.

QuartzImageIO is reserved for macOS and that makes default load and save behavior different across platforms. Keywords arguments are different, too. For this reason, I suggest we don't add QuartzImageIO to Project.toml.

That said, I think it's would be sufficient to add ImageMagick and ImageIO into Images' Project.toml, and when ImageIO has higher priority in the FileIO's registry for every image file types, we're in essence sunsetting ImageMagick. A quick look at the registry, I find GIF, JPEG, BMP and PCX are supported by ImageMagick.

Adding this requires us to bump Julia compat in Project.toml to >= 1.3, otherwise, Julia 1.0 users might suffer from risks of installing these backends. ImageIO requires Julia 1.3, too.

I heard rumors that Julia 1.6 will be the next LTS version, if that's the case, then the perfect time is when Julia 1.6 is released. ( I don't feel good to discontinue the support to the current LTS version)

[johnnychen94]

In the Juliacon 2020 talk "State of Julia 2020", YouTube, it's officially announced that 1.6 will be the next LTS version.

We could add ImageMagick and ImageIO to the Project.toml of Images when 1.6 is out.