reexport MosaicViews

[johnnychen94]

Don't merge this until JuliaArrays/MosaicViews.jl#14 get merged, I will rebuild the test when MosaicViews v0.2.0 is registered.

TODO:

• tests are needed because MosaicViews isn't under JuliaImages :P

I bumped a minor version because from now on this package isn't invisible to users anymore. After this, I'll also reexport ImageShow from Images, and then draft a democard in juliaimages.org

Another choice is to reexport it in ImageCore because ImageCore is a collection of different views.

---

MosaicViews provides a handy tool mosaicview, which can be seen as an enhanced version of cat to make visualization easier. Here're two main usages:

1. Compare images of different sizes and colorants (not necessarily two images)

using ImageShow, TestImages
using ColorVectorSpaces # for zero(RGB{N0f8})

lena = testimage("lena") # 256*256 RGB image
cameraman = testimage("cameraman") # 512*512 Gray image
mosaicview(lena, cameraman; nrow=1)

2. give a nice looking 2d view for higher-dimensional image (or images)

using ImageShow, TestImages
img = testimage("mri") # 226×186×27

mosaicview(img; fillvalue=0.5, npad=2, ncol=7, rowmajor=true)

[johnnychen94]

Since MosaicView depends on OffsetArrays, I think it's ok to revert #17. With OffsetArray 1.0 released, the main motivation of that is "outdated" now.

Edit: just realized that ImageCore also depends on OffsetArrays

[RalphAS]

Looks fine so far. Do you have a design for a test?

[johnnychen94]

Do you have a design for a test?

ReferenceTests are designed for such usages 😄 -- the 22 reference images occupy 88K storage, which is small enough to manage with git.

[johnnychen94]

The test fails because ColorVectorSpace isn't compatible with ColorTypes v0.10

JuliaGraphics/ColorVectorSpace.jl#128

With a modified Project.toml, it's passed locally.

[johnnychen94]

@timholy do you think it's appropriate to move this PR to ImageCore?