Merge pull request #3324 from gustaphe/legendangle

[WIP] position legend at angle

src/Plots.jl

@@ -211,6 +211,7 @@ include("output.jl")
 include("ijulia.jl")
 include("fileio.jl")
 include("init.jl")
+include("legend.jl")
 
 include("backends/plotly.jl")
 include("backends/gr.jl")

src/arg_desc.jl

@@ -90,7 +90,7 @@ const _arg_desc = KW(
 :foreground_color_legend  => "Color Type or `:match` (matches `:foreground_color_subplot`).  Foreground color of the legend.",
 :foreground_color_title   => "Color Type or `:match` (matches `:foreground_color_subplot`). Color of subplot title.",
 :color_palette            => "Vector of colors (cycle through) or color gradient (generate list from gradient) or `:auto` (generate a color list using `Colors.distiguishable_colors` and custom seed colors chosen to contrast with the background).  The color palette is a color list from which series colors are automatically chosen.",
-:legend                   => "Bool (show the legend?) or (x,y) tuple or Symbol (legend position). Bottom left corner of legend is placed at (x,y).  Symbol values: `:none`; `:best`; `:inline`; `:inside`; `:legend`; any valid combination of `:(outer ?)(top/bottom ?)(right/left ?)`, i.e.: `:top`, `:topright`, `:outerleft`, `:outerbottomright` ... (note: only some may be supported in each backend)",
+:legend                   => "Bool (show the legend?) or (x,y) tuple or Symbol (legend position) or angle or (angle,inout) tuple. Bottom left corner of legend is placed at (x,y).  Symbol values: `:none`; `:best`; `:inline`; `:inside`; `:legend`; any valid combination of `:(outer ?)(top/bottom ?)(right/left ?)`, i.e.: `:top`, `:topright`, `:outerleft`, `:outerbottomright` ... (note: only some may be supported in each backend). Legend is positioned at (angle degrees) (so (90,:outer) is roughly equivalent to :outertop), close to the inside of the axes or the outside if inout=:outer.",
 :legendfontfamily         => "String or Symbol. Font family of legend entries.",
 :legendfontsize           => "Integer. Font pointsize of legend entries.",
 :legendfonthalign         => "Symbol. Font horizontal alignment of legend entries: :hcenter, :left, :right or :center",

src/args.jl

@@ -1262,6 +1262,8 @@ end
 convertLegendValue(val::Bool) = val ? :best : :none
 convertLegendValue(val::Nothing) = :none
 convertLegendValue(v::Tuple{S,T}) where {S<:Real, T<:Real} = v
+convertLegendValue(v::Tuple{<:Real,Symbol}) = v
+convertLegendValue(v::Real) = v
 convertLegendValue(v::AbstractArray) = map(convertLegendValue, v)
 
 # -----------------------------------------------------------------------------

src/backends/gr.jl

@@ -1047,7 +1047,24 @@ end
 
 function gr_legend_pos(sp::Subplot, leg, viewport_plotarea)
     s = sp[:legend]
-    typeof(s) <: Symbol || return gr_legend_pos(s, viewport_plotarea)
+    s isa Real && return gr_legend_pos(s, leg, viewport_plotarea)
+    if s isa Tuple{<:Real,Symbol}
+        if s[2] !== :outer
+            return gr_legend_pos(s[1], leg, viewport_plotarea)
+        end
+
+        xaxis, yaxis = sp[:xaxis], sp[:yaxis]
+        xmirror = xaxis[:guide_position] == :top || (xaxis[:guide_position] == :auto && xaxis[:mirror] == true)
+        ymirror = yaxis[:guide_position] == :right || (yaxis[:guide_position] == :auto && yaxis[:mirror] == true)
+        axisclearance = [
+                         !ymirror*gr_axis_width(sp, sp[:yaxis]),
+                         ymirror*gr_axis_width(sp,sp[:yaxis]),
+                         !xmirror*gr_axis_height(sp,sp[:xaxis]),
+                         xmirror*gr_axis_height(sp,sp[:xaxis]),
+                        ]
+        return gr_legend_pos(s[1], leg, viewport_plotarea; axisclearance)
+    end
+    s isa Symbol || return gr_legend_pos(s, viewport_plotarea)
     str = string(s)
     if str == "best"
         str = "topright"
@@ -1081,7 +1098,7 @@ function gr_legend_pos(sp::Subplot, leg, viewport_plotarea)
         end
     elseif occursin("bottom", str)
         if s == :outerbottom
-            ypos = viewport_plotarea[3] - leg.yoffset - leg.h - !xmirror * gr_axis_height(sp, sp[:xaxis])
+            ypos = viewport_plotarea[3] - leg.yoffset  - leg.dy - !xmirror * gr_axis_height(sp, sp[:xaxis])
         else
             ypos = viewport_plotarea[3] + leg.yoffset + leg.h
         end
@@ -1098,6 +1115,27 @@ function gr_legend_pos(v::Tuple{S,T}, viewport_plotarea) where {S<:Real, T<:Real
     (xpos,ypos)
 end
 
+function gr_legend_pos(theta::Real, leg, viewport_plotarea; axisclearance=nothing)
+    xcenter = +(viewport_plotarea[1:2]...)/2
+    ycenter = +(viewport_plotarea[3:4]...)/2
+
+    if isnothing(axisclearance)
+        # Inner
+        # rectangle where the anchor can legally be
+        xmin = viewport_plotarea[1] + leg.xoffset + leg.leftw
+        xmax = viewport_plotarea[2] - leg.xoffset - leg.rightw - leg.textw
+        ymin = viewport_plotarea[3] + leg.yoffset + leg.h
+        ymax = viewport_plotarea[4] - leg.yoffset - leg.dy
+    else
+        # Outer
+        xmin = viewport_plotarea[1] - leg.xoffset - leg.rightw - leg.textw - axisclearance[1]
+        xmax = viewport_plotarea[2] + leg.xoffset + leg.leftw + axisclearance[2]
+        ymin = viewport_plotarea[3] - leg.yoffset - leg.dy - axisclearance[3]
+        ymax = viewport_plotarea[4] + leg.yoffset + leg.h + axisclearance[4]
+    end
+    return legend_pos_from_angle(theta,xmin,xcenter,xmax,ymin,ycenter,ymax)
+end
+
 function gr_get_legend_geometry(viewport_plotarea, sp)
     legendn = 0
     legendw = 0
@@ -1154,12 +1192,28 @@ end
 ## Viewport, window and scale
 
 function gr_update_viewport_legend!(viewport_plotarea, sp, leg)
-    leg_str = string(sp[:legend])
+    s = sp[:legend]
 
     xaxis, yaxis = sp[:xaxis], sp[:yaxis]
     xmirror = xaxis[:guide_position] == :top || (xaxis[:guide_position] == :auto && xaxis[:mirror] == true)
     ymirror = yaxis[:guide_position] == :right || (yaxis[:guide_position] == :auto && yaxis[:mirror] == true)
 
+    if s isa Tuple{<:Real,Symbol}
+        if s[2] === :outer
+            (x,y) = gr_legend_pos(sp, leg, viewport_plotarea) # Dry run, to figure out
+            if x < viewport_plotarea[1]
+                viewport_plotarea[1] += leg.leftw + leg.textw + leg.rightw + leg.xoffset + !ymirror * gr_axis_width(sp, sp[:yaxis])
+            elseif x > viewport_plotarea[2]
+                viewport_plotarea[2] -= leg.leftw + leg.textw + leg.rightw + leg.xoffset
+            end
+            if y < viewport_plotarea[3]
+                viewport_plotarea[3] += leg.h + leg.dy + leg.yoffset + !xmirror * gr_axis_height(sp, sp[:xaxis])
+            elseif y > viewport_plotarea[4]
+                viewport_plotarea[4] -= leg.h + leg.dy + leg.yoffset
+            end
+        end
+    end
+    leg_str = string(s)
     if occursin("outer", leg_str)
         if occursin("right", leg_str)
             viewport_plotarea[2] -= leg.leftw + leg.textw + leg.rightw + leg.xoffset
@@ -1171,7 +1225,7 @@ function gr_update_viewport_legend!(viewport_plotarea, sp, leg)
             viewport_plotarea[3] += leg.h + leg.dy + leg.yoffset + !xmirror * gr_axis_height(sp, sp[:xaxis])
         end
     end
-    if sp[:legend] == :inline
+    if s === :inline
         if sp[:yaxis][:mirror]
             viewport_plotarea[1] += leg.w
         else

src/backends/pgfplotsx.jl

@@ -770,8 +770,26 @@ pgfx_get_legend_pos(k) = get(
     Symbol(k),
     ("at" => string((1.02, 1)), "anchor" => "north west"),
 )
-pgfx_get_legend_pos(t::Tuple) = ("at" => "{$(string(t))}", "anchor" => "north west")
+pgfx_get_legend_pos(t::Tuple{S,T}) where {S<:Real,T<:Real} = ("at" => "{$(string(t))}", "anchor" => "north west")
 pgfx_get_legend_pos(nt::NamedTuple) = ("at" => "{$(string(nt.at))}", "anchor" => string(nt.anchor))
+pgfx_get_legend_pos(theta::Real) = pgfx_get_legend_pos((theta,:inner))
+function pgfx_get_legend_pos(v::Tuple{S,Symbol}) where S <: Real
+    (s,c) = sincosd(v[1])
+    anchors = [
+               "south west" "south" "south east";
+               "west" "center" "east";
+               "north west" "north" "north east";
+              ]
+
+    if v[2] === :inner
+        rect = (0.07,0.5,1.0,0.07,0.52,1.0)
+        anchor = anchors[legend_anchor_index(s),legend_anchor_index(c)]
+    else
+        rect = (-0.15,0.5,1.05,-0.15,0.52,1.1)
+        anchor = anchors[4-legend_anchor_index(s),4-legend_anchor_index(c)]
+    end
+    return ("at"=>"$(string(legend_pos_from_angle(v[1],rect...)))", "anchor"=>anchor)
+end
 
 pgfx_get_colorbar_pos(s) =
     get((left = " left", bottom = " horizontal", top = " horizontal"), s, "")

src/backends/plotly.jl

@@ -384,6 +384,25 @@ end
 
 plotly_legend_pos(v::Tuple{S,T}) where {S<:Real, T<:Real} = (coords=v, xanchor="left", yanchor="top")
 
+plotly_legend_pos(theta::Real) = plotly_legend_pos((theta, :inner))
+
+function plotly_legend_pos(v::Tuple{S,Symbol}) where S<:Real
+    (s,c) = sincosd(v[1])
+    xanchors = ["left", "center", "right"]
+    yanchors = ["bottom", "middle", "top"]
+
+    if v[2] === :inner
+        rect = (0.07,0.5,1.0,0.07,0.52,1.0)
+        xanchor = xanchors[legend_anchor_index(c)]
+        yanchor = yanchors[legend_anchor_index(s)]
+    else
+        rect = (-0.15,0.5,1.05,-0.15,0.52,1.1)
+        xanchor = xanchors[4-legend_anchor_index(c)]
+        yanchor = yanchors[4-legend_anchor_index(s)]
+    end
+    return (coords=legend_pos_from_angle(v[1],rect...), xanchor=xanchor, yanchor=yanchor)
+end
+
 
 function plotly_layout_json(plt::Plot)
     JSON.json(plotly_layout(plt), 4)

src/backends/pyplot.jl

@@ -1309,44 +1309,26 @@ end
 
 # -----------------------------------------------------------------
 
-py_legend_pos(pos::Symbol) = get(
+py_legend_pos(pos::Tuple{S,T}) where {S<:Real,T<:Real} = "lower left"
-    (
+
-        right = "right",
+function py_legend_pos(pos::Tuple{<:Real,Symbol})
-        left = "center left",
+    (s,c) = sincosd(pos[1])
-        top = "upper center",
+    if pos[2] === :outer
-        bottom = "lower center",
+        s = -s
-        bottomleft = "lower left",
+        c = -c
-        bottomright = "lower right",
+    end
-        topright = "upper right",
+    yanchors = ["lower","center","upper"]
-        topleft = "upper left",
+    xanchors = ["left","center","right"]
-        outerright = "center left",
+    return join([yanchors[legend_anchor_index(s)], xanchors[legend_anchor_index(c)]], ' ')
-        outerleft = "right",
+end
-        outertop = "lower center",
+
-        outerbottom = "upper center",
+function py_legend_bbox(pos::Tuple{T,Symbol}) where T<:Real
-        outerbottomleft = "lower right",
+    if pos[2] === :outer
-        outerbottomright = "lower left",
+        return legend_pos_from_angle(pos[1],-0.15,0.5,1.0,-0.15,0.5,1.0)
-        outertopright = "upper left",
+    end
-        outertopleft = "upper right",
+    legend_pos_from_angle(pos[1],0.0,0.5,1.0,0.0,0.5,1.0)
-    ),
+end
-    pos,
-    "best",
-)
-py_legend_pos(pos) = "lower left"
 
-py_legend_bbox(pos::Symbol) = get(
-    (
-        outerright = (1.0, 0.5, 0.0, 0.0),
-        outerleft = (-0.15, 0.5, 0.0, 0.0),
-        outertop = (0.5, 1.0, 0.0, 0.0),
-        outerbottom = (0.5, -0.15, 0.0, 0.0),
-        outerbottomleft = (-0.15, 0.0, 0.0, 0.0),
-        outerbottomright = (1.0, 0.0, 0.0, 0.0),
-        outertopright = (1.0, 1.0, 0.0, 0.0),
-        outertopleft = (-0.15, 1.0, 0.0, 0.0),
-    ),
-    pos,
-    (0.0, 0.0, 1.0, 1.0),
-)
 py_legend_bbox(pos) = pos
 
 function py_add_legend(plt::Plot, sp::Subplot, ax)
@@ -1392,6 +1374,7 @@ function py_add_legend(plt::Plot, sp::Subplot, ax)
 
         # if anything was added, call ax.legend and set the colors
         if !isempty(handles)
+            leg = legend_angle(leg)
             leg = ax."legend"(handles,
                 labels,
                 loc = py_legend_pos(leg),
@@ -1402,7 +1385,7 @@ function py_add_legend(plt::Plot, sp::Subplot, ax)
                 edgecolor = py_color(sp[:foreground_color_legend]),
                 framealpha = alpha(plot_color(sp[:background_color_legend])),
                 fancybox = false,  # makes the legend box square
-                borderpad=0.8      # to match GR legendbox
+                borderpad = 0.8      # to match GR legendbox
             )
             frame = leg."get_frame"()
             frame."set_linewidth"(py_thickness_scale(plt, 1))

src/legend.jl

@@ -0,0 +1,59 @@
+"""
+```julia
+legend_pos_from_angle(theta, xmin, xcenter, xmax, ymin, ycenter, ymax, inout)
+```
+
+Return `(x,y)` at an angle `theta` degrees from
+`(xcenter,ycenter)` on a rectangle defined by (`xmin`,
+`xmax`, `ymin`, `ymax`).
+"""
+function legend_pos_from_angle(theta, xmin, xcenter, xmax, ymin, ycenter, ymax)
+    (s,c) = sincosd(theta)
+    x = c < 0 ? (xmin-xcenter)/c : (xmax-xcenter)/c
+    y = s < 0 ? (ymin-ycenter)/s : (ymax-ycenter)/s
+    A = min(x,y)
+    return (xcenter + A*c, ycenter + A*s)
+end
+
+
+"""
+Split continuous range `[-1,1]` evenly into an integer `[1,2,3]`
+"""
+function legend_anchor_index(x)
+    x<-1//3 && return 1
+    x<1//3 && return 2
+    return 3
+end
+
+"""
+Turn legend argument into a (theta, :inner) or (theta, :outer) tuple.
+For backends where legend position is given in normal coordinates (0,0) -- (1,1),
+so :topleft exactly corresponds to (45, :inner) etc.
+
+If `leg` is a (::Real,::Real) tuple, keep it as is.
+"""
+legend_angle(leg::Real) = (leg,:inner)
+legend_angle(leg::Tuple{S,T}) where {S<:Real,T<:Real} = leg
+legend_angle(leg::Tuple{S,Symbol}) where S<:Real = leg
+legend_angle(leg::Symbol) = get(
+                                (
+                                 topleft            =   (135,:inner),
+                                 top                =   (90, :inner),
+                                 topright           =   (45, :inner),
+                                 left               =   (180,:inner),
+                                 right              =   (0,  :inner),
+                                 bottomleft         =   (225,:inner),
+                                 bottom             =   (270,:inner),
+                                 bottomright        =   (315,:inner),
+                                 outertopleft       =   (135,:outer),
+                                 outertop           =   (90, :outer),
+                                 outertopright      =   (45, :outer),
+                                 outerleft          =   (180,:outer),
+                                 outerright         =   (0,  :outer),
+                                 outerbottomleft    =   (225,:outer),
+                                 outerbottom        =   (270,:outer),
+                                 outerbottomright   =   (315,:outer),
+                                ),
+                                leg,
+                                (45, :inner)
+                               )