:straightline seriestype and gr implementation

src/axes.jl

@@ -287,8 +287,8 @@ end
 
 
 function expand_extrema!(ex::Extrema, v::Number)
-    ex.emin = NaNMath.min(v, ex.emin)
-    ex.emax = NaNMath.max(v, ex.emax)
+    ex.emin = isfinite(v) ? min(v, ex.emin) : ex.emin
+    ex.emax = isfinite(v) ? max(v, ex.emax) : ex.emax
     ex
 end
 
@@ -303,8 +303,8 @@ expand_extrema!(axis::Axis, ::Bool) = axis[:extrema]
 
 function expand_extrema!(axis::Axis, v::Tuple{MIN,MAX}) where {MIN<:Number,MAX<:Number}
     ex = axis[:extrema]
-    ex.emin = NaNMath.min(v[1], ex.emin)
-    ex.emax = NaNMath.max(v[2], ex.emax)
+    ex.emin = isfinite(v[1]) ? min(v[1], ex.emin) : ex.emin
+    ex.emax = isfinite(v[2]) ? max(v[2], ex.emax) : ex.emax
     ex
 end
 function expand_extrema!(axis::Axis, v::AVec{N}) where N<:Number
@@ -326,6 +326,9 @@ function expand_extrema!(sp::Subplot, d::KW)
         else
             letter == :x ? :y : letter == :y ? :x : :z
         end]
+        if letter != :z && d[:seriestype] == :straightline && any(series[:seriestype] != :straightline for series in series_list(sp)) && data[1] != data[2]
+            data = [NaN]
+        end
         axis = sp[Symbol(letter, "axis")]
 
         if isa(data, Volume)

src/backends/gr.jl

@@ -48,7 +48,7 @@ const _gr_attr = merge_with_base_supported([
     :contour_labels,
 ])
 const _gr_seriestype = [
-    :path, :scatter,
+    :path, :scatter, :straightline,
     :heatmap, :pie, :image,
     :contour, :path3d, :scatter3d, :surface, :wireframe,
     :shape
@@ -1014,7 +1014,11 @@ function gr_display(sp::Subplot{GRBackend}, w, h, viewport_canvas)
             x, y = convert_to_polar(x, y, (rmin, rmax))
         end
 
-        if st in (:path, :scatter)
+        if st == :straightline
+            x, y = straightline_data(sp, series)
+        end
+
+        if st in (:path, :scatter, :straightline)
             if length(x) > 1
                 lz = series[:line_z]
                 segments_iterator = if lz != nothing && length(lz) > 1
@@ -1036,7 +1040,7 @@ function gr_display(sp::Subplot{GRBackend}, w, h, viewport_canvas)
                 end
 
                 # draw the line(s)
-                if st == :path
+                if st in (:path, :straightline)
                     for (i, rng) in enumerate(segments_iterator)
                         gr_set_line(series[:linewidth], series[:linestyle], get_linecolor(sp, series, i)) #, series[:linealpha])
                         arrowside = isa(series[:arrow], Arrow) ? series[:arrow].side : :none
@@ -1295,7 +1299,7 @@ function gr_display(sp::Subplot{GRBackend}, w, h, viewport_canvas)
                     st == :shape && gr_polyline(x, y)
                 end
 
-                if st == :path
+                if st in (:path, :straightline)
                     GR.settransparency(gr_alpha(series[:linealpha]))
                     if series[:fillrange] == nothing || series[:ribbon] != nothing
                         GR.polyline([xpos - 0.07, xpos - 0.01], [ypos, ypos])

src/recipes.jl

@@ -79,28 +79,26 @@ function hvline_limits(axis::Axis)
 end
 
 @recipe function f(::Type{Val{:hline}}, x, y, z)
-    xmin, xmax = hvline_limits(plotattributes[:subplot][:xaxis])
     n = length(y)
-    newx = repmat(Float64[xmin, xmax, NaN], n)
+    newx = repmat(Float64[-1, 1, NaN], n)
     newy = vec(Float64[yi for i=1:3,yi=y])
     x := newx
     y := newy
-    seriestype := :path
+    seriestype := :straightline
     ()
 end
-@deps hline path
+@deps hline straightline
 
 @recipe function f(::Type{Val{:vline}}, x, y, z)
-    ymin, ymax = hvline_limits(plotattributes[:subplot][:yaxis])
     n = length(y)
     newx = vec(Float64[yi for i=1:3,yi=y])
-    newy = repmat(Float64[ymin, ymax, NaN], n)
+    newy = repmat(Float64[-1, 1, NaN], n)
     x := newx
     y := newy
-    seriestype := :path
+    seriestype := :straightline
     ()
 end
-@deps vline path
+@deps vline straightline
 
 # ---------------------------------------------------------------------------
 # path and scatter
@@ -999,15 +997,7 @@ end
 # -------------------------------------------------
 
 "Adds a+bx... straight line over the current plot, without changing the axis limits"
-function abline!(plt::Plot, a, b; kw...)
-    xl, yl = xlims(plt), ylims(plt)
-    x1, x2 = max(xl[1], (yl[1] - b)/a), min(xl[2], (yl[2] - b)/a)
-    if x2 > x1
-        plot!(plt, x -> b + a*x, x1, x2; kw...)
-    else
-        nothing
-    end
-end
+abline!(plt::Plot, a, b; kw...) = plot!(plt, [0, 1], [b, b+a]; seriestype = :straightline, kw...)
 
 abline!(args...; kw...) = abline!(current(), args...; kw...)
 

src/utils.jl

@@ -1079,3 +1079,44 @@ function convert_sci_unicode(label::AbstractString)
     end
     label
 end
+
+function straightline_data(sp::Subplot, series::Series)
+    xl, yl = isvertical(series.d) ? (xlims(sp), ylims(sp)) : (ylims(sp), xlims(sp))
+    x, y = series[:x], series[:y]
+    n = length(x)
+    if n == 2
+        return straightline_data(xl, yl, x, y)
+    else
+        k, r = divrem(n, 3)
+        if r == 0
+            xdata, ydata = fill(NaN, n), fill(NaN, n)
+            for i in 1:k
+                inds = (3 * i - 2):(3 * i - 1)
+                xdata[inds], ydata[inds] = straightline_data(xl, yl, x[inds], y[inds])
+            end
+            return xdata, ydata
+        else
+            error("Misformed data. `straightline_data` either accepts vectors of length 2 or 3k. The provided series has length $n")
+        end
+    end
+end
+
+function straightline_data(xl, yl, x, y)
+    if y[1] == y[2]
+        if x[1] == x[2]
+            error("Two identical points cannot be used to describe a straight line.")
+        else
+            return [xl[1], xl[2]], [y[1], y[2]]
+        end
+    elseif x[1] == x[2]
+        return [x[1], x[2]], [yl[1], yl[2]]
+    else
+        # get a and b from the line y = a * x + b through the points given by
+        # the coordinates x and x
+        b = y[1] - (y[1] - y[2]) * x[1] / (x[1] - x[2])
+        a = (y[1] - y[2]) / (x[1] - x[2])
+        # get the data values
+        xdata = [clamp(x[1] + (x[1] - x[2]) * (ylim - y[1]) / (y[1] - y[2]), xl...) for ylim in yl]
+        return xdata, a .* xdata .+ b
+    end
+end