Base Subtract operator between Luxor.Point and a Number is incorrect

[j-adel]

When doing a simple math operation between a Point and a Number such as Point(1,1)+10 gets a correct answer. However, subtraction such as 10-Point(1,1) gets Point(-9.0, -9.0). It's worth noting that -Point(1,1)+10 =>Point(9.0, 9.0) and 10+-Point(1,1)=>Point(9.0, 9.0). It's only the case of Number-Point that it fails. I couldn't find the Point type in Cair so I'm not sure where this issue is rooted. I'm really loving the package btw great job! :D

[cormullion]

I’m not sure what it’s even supposed to do 😂

Probably this needs to be looked at

https://github.com/JuliaGraphics/Luxor.jl/blob/d7c261e92b709eaf02020419ecbd8874e934f9fd/src/point.jl#L28

Cairo doesn’t know about Points 😀

[cormullion]

Thanks for the kind words! I might have fixed this now (on master)... 🤞

Hoping to make another release this week...

[j-adel]

Awesome! For the record, I think this worked for me:

function Base.:-(num::Number, p::Point)
    return Point(num - p.x, num - p.y)
end

function Base.:-(p1::Point, num::Number)
    return Point(p1.x - num, p1.y - num)
end

[cormullion]

I think I might just have copy-pasted too carelessly back when I wrote this bit... :)

[j-adel]

Haha yeah I just saw it. Btw this wrapper is pretty much perfect for generative art. I've gotten good results really quickly with it. I hope to make an article guide about it soon :D

[cormullion]

Looking forward to that! It’s mostly designed for that kind of use - parameterized graphic design and similar - so I’m happy that you’re getting some results you like!

[stale[bot]]

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[hyrodium]

Is it reasonable to have a method like +(::Point, ::Number)?

julia> using Luxor

julia> Point(1,2) + 1
Point(2.0, 3.0)

julia> [1,2] + 1
ERROR: MethodError: no method matching +(::Vector{Int64}, ::Int64)
For element-wise addition, use broadcasting with dot syntax: array .+ scalar

I think it would be enough with .+ operator.

julia> Point(1,2) .+ 1
Point(2.0, 3.0)

julia> [1,2] .+ 1
2-element Vector{Int64}:
 2
 3

[cormullion]

It would be a breaking change.

[hyrodium]

Yeah, should we release the breaking change? If so, I can open a PR to deprecate the methods.

[cormullion]

Perhaps the next version of Luxor should be version 4.0, with some breaking changes, supporting only Julia 1.9 and above (thanks to package extensions). It might be good to wait until Julia 1.10 is released first before releasing 4.0 ... 🤔

[hyrodium]

I was planning to release 3.x with deprecated methods (e.g. +(::Point, ::Number)), and then release 4.0 with removing the deprecated methods. However, we have other reasons for the next breaking release, so it would be okay not to release the next 3.x. 🤔