Can warp also be used as a remap like in opencv?

[jc211]

Is it possible/recommended to add an overload to warp that takes a lookup table instead of a transform. The functionality would be similar to OpenCVs remap found here.

[johnnychen94]

Absolutely, tform can be any function or function-like object that accepts StaticArrays.SVector as input and also outputs an SVector.

The default range inference does not apply to generic function, so in this case you have to specify indices as well.

A quick example:

using ImageTransformations, ImageCore, ImageShow, TestImages
using StaticArrays

function shrink_to(R0)
    function _shrink(I)
        I_first, I_last = first(R0).I, last(R0).I
        ntuple(ndims(R0)) do n
            i, from, to = I[n], I_first[n], I_last[n]
            clamp(i, from, to)
        end |> SVector
    end
end

img = testimage("cameraman")

imgs = warp(img, shrink_to(CartesianIndices((64:448, 64:448))), axes(img))

mosaic(img, imgs; nrow=1)

which gives

I just came up with this very "meaningless" demo, if you have a better showcase, please share it here, or add a demo card to https://juliaimages.org/dev/examples/