Nice example! Presumably if you wanted to do actual Porter-Duff though, you'd want some arithmetic rather than just comparison.
One observation: you don't actually need the "comparable" constraint on many of the core entities there (e.g. Rect and Op) because they don't actually use any compare operations. The code works just fine if you omit them: https://go2goplay.golang.org/p/dKGOaN_v3He Technically, the "z" argument to Op isn't necessary either AFAICS - you could just use a zero value instead (unless you actually want to be able to have a non-zero "zero" value, I guess). cheers, rog. On Fri, 14 Aug 2020 at 04:37, Beka Westberg <bekawestb...@gmail.com> wrote: > Hello! I just ran into a problem that is solved really nicely with the new > generics proposal and I thought someone might find it interesting :D > > I was trying to implement a library for doing ascii art programmatically. > The main struct is basically an image.Image except it works with bytes > instead of colors. As such you /should/ be able to create functions (like a > flood fill algorithm) that are abstracted over both of these types, but > without "generics" this cannot be done (with compile time type safety). > > I sketched a little project <https://go2goplay.golang.org/p/68KmGdqIVoc> > in the go2go playground that implements generic functions for doing > Porter-Duff > compositions <http://ssp.impulsetrain.com/porterduff.html> on any types > that fulfill the following constraint: > > ``` > type Rect(type T comparable) interface { > At(x, y int) T > Set(x, y int, t T) > } > ``` > > Type defs on lines [8, 13]. Porter-Duff implementation [15, 99] Main [101, > 108] ByteImg implementation [110, 185] > > I liked this example because it requires passing a generic function (the > Porter-Duff func) to another generic function (Merge) :D I hope someone > else finds it interesting as well! > --Beka > > -- > You received this message because you are subscribed to the Google Groups > "golang-nuts" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to golang-nuts+unsubscr...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/golang-nuts/dbc90697-e276-437b-ab39-b52564fc6d5an%40googlegroups.com > <https://groups.google.com/d/msgid/golang-nuts/dbc90697-e276-437b-ab39-b52564fc6d5an%40googlegroups.com?utm_medium=email&utm_source=footer> > . > -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/golang-nuts/CAJhgacjmxWC361xC-W4zTrw%3D6nO-%2BhRi0UVRAWSYKqRBkHfw2w%40mail.gmail.com.
