Label Font, Arrow Pointing to Node Edge, Plots integration

[willsharpless]

Hi,

This is a sweet package, thanks for your hard work writing it. I had a couple questions/requests about looks,

1. It would be really awesome if the node/edge labels could be LaTeXStrings. The times new roman font for the labels really downgrades the images given that I intend to use these plots for journal figures.

2. Is there a way to make the directed graph arrows point to the surface of nodes? Currently, I see this sloppy behavior where some sizes of nodes overlap with the end of the arrow, and I can't find any kw arg to fix it:
   

3. This package would be much more desireable if graph plots could be integrated into Plots. Maybe there is a way I don't see from the basic usage, but the only way I seem to be able to put these graphs with other plots in Plots.jl is by saving them as images, which feels gratuitous and rigid. I understand this might be a complex suggestion, but it would make a large difference.

Thanks again!

[hdavid16]

Great suggestions:

1. This is an issue with Compose.jl, which is used by both GraphPlot.jl and Gadfly.jl: Support LaTeXStrings.jl GiovineItalia/Gadfly.jl#1094

2. Agreed, this should be fixed and will require editing the logic in graphline and graphcurve so that endx and endy account for the edge linewidth rather than just the nodesize (

   GraphPlot.jl/src/lines.jl

   Line 15 in 52f4aae

   endx = locs_x[j] + nodesize[j]*cos(θ+π)

   )

3. Might be possible since Gadfly is a backend of Plots.jl and it is based on Compose.jl, which is what GraphPlot.jl uses. See Make display in the REPL GiovineItalia/Compose.jl#423

[hdavid16]

@etiennedeg, I thought I'd continue the discussion in #186 (comment) here.

I agree with you on the issue of non-square plots causing problems with the scaling (this still happens when we use triangle arrows instead). However, the arrow head problem persists even with square plots:

---

JuliaGraphs/GraphPlot.jl#master:

using Compose, Graphs, GraphPlot
Compose.set_default_graphic_size(10cm,10cm)
gplot(path_digraph(10),layout=circular_layout)

Makes the plot:

hdavid16/GraphPlot.jl#up:

using Graphs, GaphPlot
gplot(path_digraph(10),layout=circular_layout)

Makes the plot:

Observation:
For square plots, the arrow heads look nicer with triangle arrowheads rather than with angled lines. Since you control the corner of the triangles, you can get a cleaner connection to each vertex. So as long as the plot_size is square (the current default in my PR), the issue here is fixed.

[hdavid16]

@willsharpless ,

If you are still working with plotting graphs, I recommend you try GraphMakie, which addresses your issues:

1. it supports LaTeXStrings without any issue
2. directed graph arrow heads work (just use arrow_shift=:end)
3. Since GraphMakie is part of the Makie ecosystem, you get all the great features of using Makie.

PR #186 would fix #2, but I don't know if this will ever be merged into this package.