compat fix for Julia < v1.3

Author: johnnychen94

src/ImageCore.jl

@@ -12,7 +12,9 @@ using OffsetArrays # for show.jl
 using .ColorTypes: colorant_string
 using Colors: Fractional
 using MappedArrays: AbstractMultiMappedArray
-@reexport using StructArrays: StructArray # for struct of array layout
+@static if VERSION >= v"1.3"
+    @reexport using StructArrays: StructArray # for struct of array layout
+end
 
 using Base: tail, @pure, Indices
 import Base: float

src/matlab.jl

@@ -89,10 +89,19 @@ end
 
 # Step 3: colorspace conversion
 _im_from_matlab(::Type{CT}, X::AbstractArray{CT}) where CT<:Colorant = X
-function _im_from_matlab(::Type{CT}, X::AbstractArray{T}) where {CT<:Colorant, T<:Real}
-    _CT = isconcretetype(CT) ? CT : base_colorant_type(CT){T}
-    # FIXME(johnnychen94): not type inferrable here
-    return StructArray{_CT}(X; dims=3)
+@static if VERSION >= v"1.3"
+    # use StructArray to inform that this is a struct of array layout
+    function _im_from_matlab(::Type{CT}, X::AbstractArray{T,3}) where {CT<:Colorant, T<:Real}
+        _CT = isconcretetype(CT) ? CT : base_colorant_type(CT){T}
+        # FIXME(johnnychen94): not type inferrable here
+        return StructArray{_CT}(X; dims=3)
+    end
+else
+    function _im_from_matlab(::Type{CT}, X::AbstractArray{T,3}) where {CT<:Colorant, T<:Real}
+        _CT = isconcretetype(CT) ? CT : base_colorant_type(CT){T}
+        # FIXME(johnnychen94): not type inferrable here
+        return colorview(_CT, PermutedDimsArray(X, (3, 1, 2)))
+    end
 end
 _im_from_matlab(::Type{CT}, X::AbstractArray{T}) where {CT<:Gray, T<:Real} = colorview(CT, X)