From 755575b98858c1e6a7b87cd180959bd961494b28 Mon Sep 17 00:00:00 2001
From: Simon Christ <SimonChrist@gmx.de>
Date: Mon, 19 Oct 2020 11:16:25 +0200
Subject: [PATCH] add series_projections of contour plots

---
 src/args.jl               |  1 +
 src/backends/pgfplotsx.jl | 34 +++++++++++++++++++++++++++++-----
 src/utils.jl              |  2 +-
 3 files changed, 31 insertions(+), 6 deletions(-)

diff --git a/src/args.jl b/src/args.jl
index b76fe860..7926749c 100644
--- a/src/args.jl
+++ b/src/args.jl
@@ -287,6 +287,7 @@ const _series_defaults = KW(
     :hover              => nothing,  # text to display when hovering over the data points
     :stride             => (1,1),    # array stride for wireframe/surface, the first element is the row stride and the second is the column stride.
     :connections	  => nothing,  # tuple of arrays to specifiy connectivity of a 3d mesh
+    :series_projection  => :none, # allows e.g. projection to planes in a 3D plot 
     :extra_kwargs       => Dict()
 )
 
diff --git a/src/backends/pgfplotsx.jl b/src/backends/pgfplotsx.jl
index d5caf807..a12c1289 100644
--- a/src/backends/pgfplotsx.jl
+++ b/src/backends/pgfplotsx.jl
@@ -202,7 +202,7 @@ function (pgfx_plot::PGFPlotsXPlot)(plt::Plot{PGFPlotsXBackend})
             for series in series_list(sp)
                 if hascolorbar(series)
                     cg = get_colorgradient(series)
-                    cm = pgfx_colormap(get_colorgradient(series))
+                    cm = pgfx_colormap(cg)
                     PGFPlotsX.push_preamble!(
                         pgfx_plot.the_plot,
                         """\\pgfplotsset{
@@ -564,10 +564,34 @@ function pgfx_add_series!(::Val{:filledcontour}, axis, series_opt, series, serie
 end
 
 function pgfx_add_series!(::Val{:contour3d}, axis, series_opt, series, series_func, opt)
-    push!(
-        series_opt,
-        "contour prepared" => PGFPlotsX.Options("labels" => opt[:contour_labels]),
-    )
+    isproj = opt[:series_projection] != :none
+    if isproj
+        proj_letter, lim_value = getproperty(
+            (
+                xy = (:z, zlims(opt[:subplot])[1]),
+                yx = (:z, zlims(opt[:subplot])[2]),
+                yz = (:x, xlims(opt[:subplot])[1]),
+                zy = (:x, xlims(opt[:subplot])[2]),
+                xz = (:y, ylims(opt[:subplot])[1]),
+                zx = (:y, ylims(opt[:subplot])[2]),
+            ),
+            get(opt, :series_projection, :xz),
+        )
+        push!(series_opt,
+              "mesh" => nothing,
+              "mesh/check" => false,
+              "mesh/cols"  => size(opt[:z], 1),
+              "mesh/rows"  => size(opt[:z], 2),
+              "patch type" => "line",
+              "point meta" => "rawz",
+              "$proj_letter filter/.code" => "\\def\\pgfmathresult{$lim_value}"
+              )
+    else
+        push!(
+            series_opt,
+            "contour prepared" => PGFPlotsX.Options("labels" => opt[:contour_labels]),
+        )
+    end
     args = pgfx_series_arguments(series, opt)
     series_plot = series_func(series_opt, PGFPlotsX.Table(Contour.contours(args..., opt[:levels])))
     push!(axis, series_plot)
diff --git a/src/utils.jl b/src/utils.jl
index 81779dd3..6b75182e 100644
--- a/src/utils.jl
+++ b/src/utils.jl
@@ -531,7 +531,7 @@ function get_colorgradient(series::Series)
     st = series[:seriestype]
     if st in (:surface, :heatmap) || isfilledcontour(series)
         series[:fillcolor]
-    elseif st in (:contour, :wireframe)
+    elseif st in (:contour, :wireframe, :contour3d)
         series[:linecolor]
     elseif series[:marker_z] !== nothing
         series[:markercolor]