Merge pull request #8 from hdavid16/edge_label_middle

Edge label middle

Author: hdavid16

src/lines.jl

@@ -7,6 +7,22 @@ function midpoint(pt1,pt2)
     return x,y
 end
 
+function interpolate_bezier(x::Vector,t)
+    n = length(x)-1
+    x_loc = sum(binomial(n,i)*(1-t)^(n-i)*t^i*x[i+1][1] for i in 0:n)
+    y_loc = sum(binomial(n,i)*(1-t)^(n-i)*t^i*x[i+1][2] for i in 0:n)
+    return x_loc.value, y_loc.value
+end
+
+interpolate_bezier(x::Compose.CurvePrimitive,t) =
+    interpolate_bezier([x.anchor0, x.ctrl0, x.ctrl1, x.anchor1], t)
+
+function interpolate_line(locs_x,locs_y,i,j,t)
+    x_loc = locs_x[i] + (locs_x[j]-locs_x[i])*t
+    y_loc = locs_y[i] + (locs_y[j]-locs_y[i])*t
+    return x_loc, y_loc
+end
+
 function graphline(edge_list, locs_x, locs_y, nodesize::Vector{T}, arrowlength, angleoffset) where {T<:Real}
     num_edges = length(edge_list)
     lines = Array{Vector{Tuple{Float64,Float64}}}(undef, num_edges)

src/plot.jl

@@ -223,22 +223,6 @@ function gplot(g::AbstractGraph{T},
                      text_locs_y .- nodesize .* (nodelabeldist * sin(nodelabelangleoffset)),
                      map(string, nodelabel), [hcenter], [vcenter])
     end
-    # Create edge labels if provided
-    edgetexts = nothing
-    if !isempty(edgelabel)
-        edge_locs_x = zeros(R1, NE)
-        edge_locs_y = zeros(R2, NE)
-        for (e_idx, e) in enumerate(edges(g))
-            i = src(e)
-            j = dst(e)
-            mid_x = (locs_x[i]+locs_x[j]) / 2.0
-            mid_y = (locs_y[i]+locs_y[j]) / 2.0
-            edge_locs_x[e_idx] = (is_directed(g) ? (mid_x+locs_x[j]) / 2.0 : mid_x) + edgelabeldistx * NODESIZE
-            edge_locs_y[e_idx] = (is_directed(g) ? (mid_y+locs_y[j]) / 2.0 : mid_y) + edgelabeldisty * NODESIZE
-
-        end
-        edgetexts = text(edge_locs_x, edge_locs_y, map(string, edgelabel), [hcenter], [vcenter])
-    end
 
     # Create lines and arrow heads
     lines, larrows = nothing, nothing
@@ -251,6 +235,28 @@ function gplot(g::AbstractGraph{T},
         lines, larrows = build_straight_edges(edges(g), locs_x, locs_y, nodesize, arrowlengthfrac, arrowangleoffset)
     end
 
+    # Create edge labels if provided
+    edgetexts = nothing
+    if !isempty(edgelabel)
+        edge_locs_x = zeros(R1, NE)
+        edge_locs_y = zeros(R2, NE)
+        self_loop_idx = 1
+        for (e_idx, e) in enumerate(edges(g))
+            i, j = src(e), dst(e)
+            if linetype == "curve"
+                mid_x, mid_y = interpolate_bezier(curves.primitives[e_idx], 0.5)
+            elseif src(e) == dst(e)
+                mid_x, mid_y = interpolate_bezier(curves.primitives[self_loop_idx], 0.5)
+                self_loop_idx += 1
+            else
+                mid_x, mid_y = interpolate_line(locs_x,locs_y,i,j,0.5)
+            end
+            edge_locs_x[e_idx] = mid_x + edgelabeldistx * NODESIZE
+            edge_locs_y[e_idx] = mid_y + edgelabeldisty * NODESIZE
+        end
+        edgetexts = text(edge_locs_x, edge_locs_y, map(string, edgelabel), [hcenter], [vcenter])
+    end
+
     # Set plot_size
     if length(plot_size) != 2 || !isa(plot_size[1], Compose.AbsoluteLength) || !isa(plot_size[2], Compose.AbsoluteLength)
         error("`plot_size` must be a Tuple of lengths")