Merge pull request #3382 from david-macmahon/stepmid-branch

Add support for `seriestype=:stepmid`

src/args.jl

@@ -54,7 +54,7 @@ const _3dTypes = [
     :path3d, :scatter3d, :surface, :wireframe, :contour3d, :volume, :mesh3d
 ]
 const _allTypes = vcat([
-    :none, :line, :path, :steppre, :steppost, :sticks, :scatter,
+    :none, :line, :path, :steppre, :stepmid, :steppost, :sticks, :scatter,
     :heatmap, :hexbin, :barbins, :barhist, :histogram, :scatterbins,
     :scatterhist, :stepbins, :stephist, :bins2d, :histogram2d, :histogram3d,
     :density, :bar, :hline, :vline,
@@ -101,7 +101,7 @@ const _typeAliases = Dict{Symbol,Symbol}(
 add_non_underscore_aliases!(_typeAliases)
 
 const _histogram_like = [:histogram, :barhist, :barbins]
-const _line_like = [:line, :path, :steppre, :steppost]
+const _line_like = [:line, :path, :steppre, :stepmid, :steppost]
 const _surface_like = [:contour, :contourf, :contour3d, :heatmap, :surface, :wireframe, :image]
 
 like_histogram(seriestype::Symbol) = seriestype in _histogram_like

src/axes.jl

@@ -441,7 +441,7 @@ function widen(lmin, lmax, scale = :identity)
 end
 
 # figure out if widening is a good idea.
-const _widen_seriestypes = (:line, :path, :steppre, :steppost, :sticks, :scatter, :barbins, :barhist, :histogram, :scatterbins, :scatterhist, :stepbins, :stephist, :bins2d, :histogram2d, :bar, :shape, :path3d, :scatter3d)
+const _widen_seriestypes = (:line, :path, :steppre, :stepmid, :steppost, :sticks, :scatter, :barbins, :barhist, :histogram, :scatterbins, :scatterhist, :stepbins, :stephist, :bins2d, :histogram2d, :bar, :shape, :path3d, :scatter3d)
 
 function default_should_widen(axis::Axis)
     should_widen = false

src/backends.jl

@@ -555,6 +555,7 @@ const _pyplot_attr = merge_with_base_supported([
 const _pyplot_seriestype = [
     :path,
     :steppre,
+    :stepmid,
     :steppost,
     :shape,
     :straightline,
@@ -636,6 +637,7 @@ const _hdf5_attr = merge_with_base_supported([
 const _hdf5_seriestype = [
     :path,
     :steppre,
+    :stepmid,
     :steppost,
     :shape,
     :straightline,
@@ -707,7 +709,7 @@ const _inspectdr_attr = merge_with_base_supported([
   ])
 const _inspectdr_style = [:auto, :solid, :dash, :dot, :dashdot]
 const _inspectdr_seriestype = [
-        :path, :scatter, :shape, :straightline, #, :steppre, :steppost
+        :path, :scatter, :shape, :straightline, #, :steppre, :stepmid, :steppost
     ]
 #see: _allMarkers, _shape_keys
 const _inspectdr_marker = Symbol[

src/backends/inspectdr.jl

@@ -287,7 +287,7 @@ For st in :shape:
                 color = linecolor, fillcolor = fillcolor
             )
         end
-   elseif st in (:path, :scatter, :straightline) #, :steppre, :steppost)
+   elseif st in (:path, :scatter, :straightline) #, :steppre, :stepmid, :steppost)
         #NOTE: In Plots.jl, :scatter plots have 0-linewidths (I think).
         linewidth = series[:linewidth]
         #More efficient & allows some support for markerstrokewidth:

src/backends/plotly.jl

@@ -789,6 +789,8 @@ function plotly_series_segments(series::Series, plotattributes_base::KW, x, y, z
                 :width => get_linewidth(series, i),
                 :shape => if st == :steppre
                     "vh"
+                elseif st == :stepmid
+                    "hvh"
                 elseif st == :steppost
                     "hv"
                 else

src/backends/pyplot.jl

@@ -152,12 +152,14 @@ end
 
 function py_stepstyle(seriestype::Symbol)
     seriestype == :steppost && return "steps-post"
+    seriestype == :stepmid && return "steps-mid"
     seriestype == :steppre && return "steps-pre"
     return "default"
 end
 
 function py_fillstepstyle(seriestype::Symbol)
     seriestype == :steppost && return "post"
+    seriestype == :stepmid && return "mid"
     seriestype == :steppre && return "pre"
     return nothing
 end
@@ -408,7 +410,7 @@ function py_add_series(plt::Plot{PyPlotBackend}, series::Series)
     # for each plotting command, optionally build and add a series handle to the list
 
     # line plot
-    if st in (:path, :path3d, :steppre, :steppost, :straightline)
+    if st in (:path, :path3d, :steppre, :stepmid, :steppost, :straightline)
         if maximum(series[:linewidth]) > 0
             # TODO: check LineCollection alternative for speed
             # if length(segments) > 1 && (any(typeof(series[attr]) <: AbstractVector for attr in (:fillcolor, :fillalpha)) || series[:fill_z] !== nothing) && !(typeof(series[:linestyle]) <: AbstractVector)
@@ -485,7 +487,7 @@ function py_add_series(plt::Plot{PyPlotBackend}, series::Series)
 
     # add markers?
     if series[:markershape] != :none && st in (
-        :path, :scatter, :path3d, :scatter3d, :steppre, :steppost, :bar
+        :path, :scatter, :path3d, :scatter3d, :steppre, :stepmid, :steppost, :bar
     )
         for segment in series_segments(series, :scatter)
             i, rng = segment.attr_index, segment.range
@@ -1363,7 +1365,7 @@ function py_add_legend(plt::Plot, sp::Subplot, ax)
                             linestyle = py_linestyle(series[:seriestype], get_linestyle(series)),
                             capstyle = "butt"
                         )
-                    elseif series[:seriestype] in (:path, :straightline, :scatter, :steppre, :steppost)
+                    elseif series[:seriestype] in (:path, :straightline, :scatter, :steppre, :stepmid, :steppost)
                         hasline = get_linewidth(series) > 0
                         PyPlot.plt."Line2D"((0, 1),(0,0),
                             color = py_color(single_color(get_linecolor(series, clims)), get_linealpha(series)),

src/examples.jl

@@ -1119,6 +1119,25 @@ const _examples = PlotExample[
             quiver(x,y,z, quiver=(u,v,w))
         end]
     ),
+    PlotExample( # 53
+        "Step Types",
+        "A comparison of the various step-like `seriestype`s",
+        [
+            :(
+              begin
+                  x = 1:5
+                  y = [1, 2, 3, 2, 1]
+                  default(shape=:circle)
+                  plot(
+                       plot(x, y, markershape=:circle, seriestype=:steppre, label="steppre"),
+                       plot(x, y, markershape=:circle, seriestype=:stepmid, label="stepmid"),
+                       plot(x, y, markershape=:circle, seriestype=:steppost, label="steppost"),
+                       layout=(3,1)
+                      )
+              end
+            ),
+        ],
+    ),
 ]
 
 # Some constants for PlotDocs and PlotReferenceImages

src/recipes.jl

@@ -181,33 +181,37 @@ end
 # ---------------------------------------------------------------------------
 # steps
 
-make_steps(x, st) = x
+make_steps(x, st, even) = x
-function make_steps(x::AbstractArray, st)
+function make_steps(x::AbstractArray, st, even)
     n = length(x)
     n == 0 && return zeros(0)
-    newx = zeros(2n - 1)
+    newx = zeros(2n - (even ? 0 : 1))
-    for i = 1:n
+    newx[1] = x[1]
+    for i = 2:n
         idx = 2i - 1
+        if st == :mid
+            newx[idx] = newx[idx-1] = (x[i] + x[i-1]) / 2
+        else
             newx[idx] = x[i]
-        if i > 1
             newx[idx - 1] = x[st == :pre ? i : i - 1]
         end
     end
+    even && (newx[end] = x[end])
     return newx
 end
-make_steps(t::Tuple, st) = Tuple(make_steps(ti, st) for ti in t)
+make_steps(t::Tuple, st, even) = Tuple(make_steps(ti, st, even) for ti in t)
 
 
 @nospecialize
 
 # create a path from steps
 @recipe function f(::Type{Val{:steppre}}, x, y, z)
-    plotattributes[:x] = make_steps(x, :post)
+    plotattributes[:x] = make_steps(x, :post, false)
-    plotattributes[:y] = make_steps(y, :pre)
+    plotattributes[:y] = make_steps(y, :pre, false)
     seriestype := :path
 
     # handle fillrange
-    plotattributes[:fillrange] = make_steps(plotattributes[:fillrange], :pre)
+    plotattributes[:fillrange] = make_steps(plotattributes[:fillrange], :pre, false)
 
     # create a secondary series for the markers
     if plotattributes[:markershape] != :none
@@ -226,13 +230,38 @@ end
 @deps steppre path scatter
 
 # create a path from steps
-@recipe function f(::Type{Val{:steppost}}, x, y, z)
+@recipe function f(::Type{Val{:stepmid}}, x, y, z)
-    plotattributes[:x] = make_steps(x, :pre)
+    plotattributes[:x] = make_steps(x, :mid, true)
-    plotattributes[:y] = make_steps(y, :post)
+    plotattributes[:y] = make_steps(y, :post, true)
     seriestype := :path
 
     # handle fillrange
-    plotattributes[:fillrange] = make_steps(plotattributes[:fillrange], :post)
+    plotattributes[:fillrange] = make_steps(plotattributes[:fillrange], :post, true)
+
+    # create a secondary series for the markers
+    if plotattributes[:markershape] != :none
+        @series begin
+            seriestype := :scatter
+            x := x
+            y := y
+            label := ""
+            primary := false
+            ()
+        end
+        markershape := :none
+    end
+    ()
+end
+@deps stepmid path scatter
+
+# create a path from steps
+@recipe function f(::Type{Val{:steppost}}, x, y, z)
+    plotattributes[:x] = make_steps(x, :pre, false)
+    plotattributes[:y] = make_steps(y, :post, false)
+    seriestype := :path
+
+    # handle fillrange
+    plotattributes[:fillrange] = make_steps(plotattributes[:fillrange], :post, false)
 
     # create a secondary series for the markers
     if plotattributes[:markershape] != :none