spy recipes

src/recipes.jl

@@ -742,6 +742,43 @@ end
 #         kw...)
 # end
 
+# Only allow matrices through, and make it seriestype :spy so the backend can
+# optionally handle it natively.
+
+@userplot Spy
+
+@recipe function f(g::Spy)
+    @assert length(g.args) == 1 && typeof(g.args[1]) <: AbstractMatrix
+    seriestype := :spy
+    mat = g.args[1]
+    n,m = size(mat)
+    Plots.SliceIt, 1:m, 1:n, Surface(mat)
+end
+
+@recipe function f(::Type{Val{:spy}}, x,y,z)
+    yflip := true
+    aspect_ratio := 1
+    rs, cs, zs = findnz(z.surf)
+    xlim := extrema(cs)
+    ylim := extrema(rs)
+    if d[:markershape] == :none
+        markershape := :circle
+    end
+    if d[:markersize] == default(:markersize)
+        markersize := 1
+    end
+    markerstrokewidth := 0
+    marker_z := zs
+    label := ""
+    x := cs
+    y := rs
+    z := nothing
+    seriestype := :scatter
+    ()
+end
+
+# -------------------------------------------------
+
 "Adds a+bx... straight line over the current plot"
 function abline!(plt::Plot, a, b; kw...)
     plot!(plt, [extrema(plt)...], x -> b + a*x; kw...)