Add and subtract for XY; < and > for CairoUnit (#36)

src/graphics_interaction.jl

@@ -7,6 +7,8 @@ using Gtk.GConstants.GdkEventMask: KEY_PRESS, SCROLL
 
 Base.:+{U<:CairoUnit}(x::U, y::U) = U(x.val + y.val)
 Base.:-{U<:CairoUnit}(x::U, y::U) = U(x.val - y.val)
+Base.:<{U<:CairoUnit}(x::U, y::U) = Bool(x.val < y.val)
+Base.:>{U<:CairoUnit}(x::U, y::U) = Bool(x.val > y.val)
 Base.abs{U<:CairoUnit}(x::U) = U(abs(x.val))
 Base.min{U<:CairoUnit}(x::U, y::U) = U(min(x.val, y.val))
 Base.max{U<:CairoUnit}(x::U, y::U) = U(max(x.val, y.val))
@@ -100,6 +102,9 @@ Base.show(io::IO, xy::XY) = print(io, "XY(", xy.x, ", ", xy.y, ')')
 Base.convert{T}(::Type{XY{T}}, xy::XY{T}) = xy
 Base.convert{T}(::Type{XY{T}}, xy::XY) = XY(T(xy.x), T(xy.y))
 
+Base.:+{T}(xy1::XY{T}, xy2::XY{T}) = XY{T}(xy1.x+xy2.x,xy1.y+xy2.y)
+Base.:-{T}(xy1::XY{T}, xy2::XY{T}) = XY{T}(xy1.x-xy2.x,xy1.y-xy2.y)
+
 """
     MouseButton(position, button, clicktype, modifiers)
 

test/runtests.jl

@@ -237,6 +237,8 @@ end
     @test x+x === UserUnit(0.2+0.2)
     @test x-x === UserUnit(0.0)
     y = UserUnit(-0.3)
+    @test x > y
+    @test y < x
     @test abs(x) === x
     @test abs(y) === UserUnit(0.3)
     @test min(x, y) === y
@@ -249,6 +251,8 @@ end
     @test XY(5, 5) === XY{Int}(5, 5)
     @test XY(5, 5.0) === XY{Float64}(5.0, 5.0)
     @test XY{UserUnit}(5, 5.0) === XY{UserUnit}(5.0, 5.0) === XY{UserUnit}(UserUnit(5), UserUnit(5))
+    @test XY(5.0, 5)+XY(4, 4.1) === XY(9, 9.1)
+    @test XY(5, 5)-XY(4, 4) === XY(1, 1)
 
     @test isa(MouseButton{UserUnit}(), MouseButton{UserUnit})
     @test isa(MouseButton{DeviceUnit}(), MouseButton{DeviceUnit})