noop for singleton dimension (#8)

Author: johnnychen94

src/restrict.jl

@@ -160,7 +160,8 @@ function __restrict_eltype(::Type{C}) where C
 end
 
 function restrict!(out::AbstractArray{T,N}, A::AbstractArray, dim) where {T,N}
-    if dim > N
+    # a no-op for singleton dimension
+    if size(A, dim) == 1 # this includes `dim > N` cases
         return copyto!(out, A)
     end
     indsout, indsA = axes(out), axes(A)

test/restrict.jl

@@ -51,6 +51,13 @@
                    14.09375    32.875    18.78125;
                    11.0390625  25.59375  14.5546875], dims=3) ≈ B
     end
+
+    @testset "singleton dimension" begin
+        # https://github.com/JuliaImages/ImageTransformations.jl/issues/47
+        @test restrict([1]) == [1.0]
+        @test restrict([0 1 0]) == [0.25 0.25]
+        @test restrict([0, 1, 0], 5) == [0, 1, 0]
+    end
 
     @testset "OffsetArray" begin
         A = rand(5, 4, 3)