From b8eea0e7b4908a6f8df5500d3914821bb8247e61 Mon Sep 17 00:00:00 2001
From: TEC <git@tecosaur.net>
Date: Wed, 10 Aug 2022 22:59:19 +0800
Subject: [PATCH] Refactor to avoid stack overflow

---
 pairsurrounding.jl | 25 ++++++++++++-------------
 1 file changed, 12 insertions(+), 13 deletions(-)

diff --git a/pairsurrounding.jl b/pairsurrounding.jl
index f2aa425..f900846 100644
--- a/pairsurrounding.jl
+++ b/pairsurrounding.jl
@@ -95,21 +95,20 @@ end
 
 function growcolour!(cmat::Matrix{Union{Colorant, Missing}}, metric::Colors.DifferenceMetric,
                      refmat::Matrix{<:Colorant}, cnearest::Colorant, safethreshold::Float64,
-                     pos::CartesianIndex{2})
-    # @info "Growing $(pos.I)"
-    surrounding = Ref(pos) .+ CartesianIndex{2}.([(0, 1), (0, -1), (1, 0), (-1, 0)])
-    filter!(s -> all((1,1) .<= s.I .<= size(refmat)), surrounding)
-    reseed = Vector{CartesianIndex{2}}()
-    for spos in surrounding
-        # @info "  @ $(spos.I)"
-        if ismissing(cmat[spos]) && colordiff(cnearest, refmat[spos]; metric) < safethreshold
-            cmat[spos] = cnearest
-            push!(reseed, spos)
+                     initalpos::CartesianIndex{2})
+    seeds = [initalpos]
+    while !isempty(seeds)
+        pos = pop!(seeds)
+        surrounding = Ref(pos) .+ CartesianIndex{2}.([(0, 1), (0, -1), (1, 0), (-1, 0)])
+        filter!(s -> all((1,1) .<= s.I .<= size(refmat)), surrounding)
+        for spos in surrounding
+            if ismissing(cmat[spos]) &&
+                colordiff(cnearest, refmat[spos]; metric) < safethreshold
+                cmat[spos] = cnearest
+                push!(seeds, spos)
+            end
         end
     end
-    for spos in reseed
-        growcolour!(cmat, metric, refmat, cnearest, safethreshold, spos)
-    end
 end
 
 function colour_grid_hsl(xs, ys, saturation=1)