From f502412f349c4bf8b388809a3fcdc999c869dffc Mon Sep 17 00:00:00 2001
From: kimikage <kimikage.ceo@gmail.com>
Date: Mon, 26 Oct 2026 01:39:37 +0900
Subject: [PATCH] Derive the rounding functions from the 2-/3-arg `round`

---
 src/ColorVectorSpace.jl | 29 +++++++++++++++++++++--------
 test/runtests.jl        |  2 ++
 2 files changed, 23 insertions(+), 8 deletions(-)

diff --git a/src/ColorVectorSpace.jl b/src/ColorVectorSpace.jl
index 5f4fa55..c83914d 100644
--- a/src/ColorVectorSpace.jl
+++ b/src/ColorVectorSpace.jl
@@ -10,7 +10,7 @@ using FixedPointNumbers: ShorterThanInt
 import Base: ==, +, -, *, /, ^, <, ~
 import Base: abs, abs2, clamp, convert, copy, div, eps, float,
     length, mapreduce,
-    promote_op, promote_rule, zero, trunc, floor, round, ceil, bswap,
+    promote_op, promote_rule, zero, round, bswap,
     mod, mod1, rem, atan, hypot, max, min, real, typemin, typemax
 # More unaryops (mostly math functions)
 import Base:      conj, sin, cos, tan, sinh, cosh, tanh,
@@ -176,13 +176,21 @@ Base.reduce_empty(::typeof(Base.add_sum), ::Type{T}) where {T<:MathTypes{Bool}}
 
 
 ## Rounding & mod
-for f in (:trunc, :floor, :round, :ceil, :eps, :bswap)
-    @eval $f(g::Gray{T}) where {T} = Gray{T}($f(gray(g)))
-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} = $f(T, gray(g))
+round(x::Gray{T}, r::RoundingMode) where {T} = Gray{T}(round(gray(x), r))
+round(::Type{Ti}, g::Gray, r::RoundingMode) where {Ti<:Integer} = round(Ti, gray(g), r)
+for (m, f) in ((:(:Nearest), :round),
+               (:(:ToZero), :trunc),
+               (:(:Up), :ceil),
+               (:(:Down), :floor))
+    @eval begin
+        if !hasmethod($f, Tuple{Gray}) || which($f, Tuple{Gray}).module !== Base
+            Base.$f(x::Gray) = round(x, RoundingMode{$m}())
+        end
+        if !hasmethod($f, Tuple{Type{<:Integer}, Gray}) ||
+            which($f, Tuple{Type{<:Integer}, Gray}).module !== Base
+            Base.$f(::Type{Ti}, x::Gray) where {Ti <: Integer} = round(Ti, x, RoundingMode{$m}())
+        end
+    end
 end
 
 for f in (:mod, :rem, :mod1)
@@ -190,6 +198,11 @@ for f in (:mod, :rem, :mod1)
     @eval $f(x::Gray, m::Real) = Gray($f(gray(x), m))
 end
 
+bswap(g::Gray{T}) where {T} = Gray{T}(bswap(gray(g)))
+
+eps(g::Gray{T}) where {T} = Gray{T}(eps(gray(g)))
+eps(::Type{Gray{T}}) where {T} = Gray(eps(T))
+
 dotc(x::T, y::T) where {T<:Real} = acc(x)*acc(y)
 dotc(x::Real, y::Real) = dotc(promote(x, y)...)
 
diff --git a/test/runtests.jl b/test/runtests.jl
index f6a11a6..38898ef 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -349,6 +349,8 @@ ColorTypes.comp2(c::RGBA32) = alpha(c)
                 @test @eval($op(Int, $g)) === v
             end
         end
+        @test round(Gray(0.4), RoundNearest) === round(Gray(0.4))
+        @test round(Int8, Gray(0.4), RoundToZero) === trunc(Int8, Gray(0.4))
         @testset "$op" for op in (:mod, :rem, :mod1)
             for (g1, g2) in ((Gray(0.4), Gray(0.3)), (Gray(N0f8(0.4)), Gray(N0f8(0.3))))
                 v = @eval $op(gray($g1), gray($g2))