Merge pull request #1704 from mkborregaard/old_spy

Reinstate scatter-based spy implementation; fix #1682

src/recipes.jl

@@ -1024,10 +1024,6 @@ end
     @assert length(g.args) == 1 && typeof(g.args[1]) <: AbstractMatrix
     seriestype := :spy
     mat = g.args[1]
-    if length(unique(mat[mat .!= 0])) < 2
-        legend --> nothing
-        seriescolor --> cgrad([invisible(), fg_color(plotattributes)])
-    end
     n,m = size(mat)
     Plots.SliceIt, 1:m, 1:n, Surface(mat)
 end
@@ -1035,21 +1031,23 @@ end
 @recipe function f(::Type{Val{:spy}}, x,y,z)
     yflip := true
     aspect_ratio := 1
-
     rs, cs, zs = findnz(z.surf)
-    newz = fill(NaN, size(z)...)
-
-    for i in eachindex(zs)
-        newz[rs[i],cs[i]] = zs[i]
+    xlim := ignorenan_extrema(cs)
+    ylim := ignorenan_extrema(rs)
+    if plotattributes[:markershape] == :none
+        markershape := :circle
     end
-
-    seriestype := :heatmap
+    if plotattributes[:markersize] == default(:markersize)
+        markersize := 1
+    end
+    markerstrokewidth := 0
+    marker_z := zs
+    label := ""
+    x := cs
+    y := rs
+    z := nothing
+    seriestype := :scatter
     grid --> false
-    framestyle --> :box
-
-    x := x
-    y := y
-    z := Surface(newz)
     ()
 end