Missing residue handling adjustments

src/ribbon/render.jl

@@ -103,6 +103,7 @@ function render!(
     protein::AbstractVector{Protein.Chain};
     colorscheme::ColorScheme = default_colorscheme,
     color_vectors::AbstractVector{<:AbstractVector{<:RGB}} = [colorscheme[LinRange(0, 1, length(chain))] for chain in protein],
+    missing_residue_color = colorant"gray",
     plots = nothing,
     kwargs...
 )
@@ -121,8 +122,9 @@ function render!(
             # draw lines between start and ends of subchains
             for (i, j) in zip(1:length(subchains)-1, 2:length(subchains))
                 startpoint, endpoint = subchains[i].backbone[end], subchains[j].backbone[begin]
-                xs, ys, zs = [LinRange(startpoint[i], endpoint[i], 16) for i in 1:3]
-                p = linesegments!(container, xs, ys, zs; linewidth=3, color=colorant"white", transparency=true)
+                n_segments = trunc(Int, norm(endpoint - startpoint) / 0.8)
+                xs, ys, zs = [LinRange(startpoint[i], endpoint[i], 2*n_segments) for i in 1:3]
+                p = linesegments!(container, xs, ys, zs; linewidth=2, color=missing_residue_color, transparency=true)
                 !isnothing(plots) && push!(plots, p)
             end
         end

src/ribbon/utils.jl

@@ -25,12 +25,13 @@ function Base.getindex(chain::Protein.Chain, r::UnitRange{<:Integer})
 end
 
 # split a chain into subchains if there is a gap in the residue numbering
-function split_by_resnum(chain::Protein.Chain)
-    split_indices = findall(diff(chain.resnums) .!= 1)
+function split_by_resnum(chain::Protein.Chain, cn_distance_tolerance = 2)
+    resnum_splits = diff(chain.resnums) .!= 1
+    backbone_splits = Protein.carbonyl_nitrogen_distances(chain) .> cn_distance_tolerance
+    split_indices = findall(resnum_splits .| backbone_splits)
     if isempty(split_indices)
         return [chain]
     end
-
     ranges = UnitRange{Int}[]
     start_idx = 0
     for idx in split_indices