Math operations with explicit types (#185)

When called with explicit type we should return a result of that type.

Author: nicolamos

src/ColorVectorSpace.jl

@@ -221,7 +221,7 @@ end
 eps(::Type{Gray{T}}) where {T} = Gray(eps(T))
 
 for f in (:trunc, :floor, :round, :ceil)
-    @eval $f(::Type{T}, g::Gray) where {T<:Integer} = Gray{T}($f(T, gray(g)))
+    @eval $f(::Type{T}, g::Gray) where {T<:Integer} = $f(T, gray(g))
 end
 
 for f in (:mod, :rem, :mod1)

test/runtests.jl

@@ -300,7 +300,13 @@ ColorTypes.comp2(c::RGBA32) = alpha(c)
         for g in (Gray{N0f8}(0.4), Gray{N0f8}(0.6))
             for op in (:trunc, :floor, :round, :ceil)
                 v = @eval $op(Bool, gray($g))
-                @test @eval($op(Bool, $g)) === Gray(v)
+                @test @eval($op(Bool, $g)) === v
+            end
+        end
+        for g in (Gray(1.4), Gray(1.6))
+            for op in (:trunc, :floor, :round, :ceil)
+                v = @eval $op(Int, gray($g))
+                @test @eval($op(Int, $g)) === v
             end
         end
         for (g1, g2) in ((Gray(0.4), Gray(0.3)), (Gray(N0f8(0.4)), Gray(N0f8(0.3))))