Fix Digraph Graphics

[mepland]

• Changed additional hard coded Helvetica to fontname in digraph.
• Added fontname="{fontname}" for digraph edges, now all fonts should be the same.
• Added leading spaces to all_llabel, all_rlabel and root_llabel, root_rlabel.
• Noted that the "  " in edge_label is not doing anything for pdf views, see attached.

dtreeviz_pred_path.pdf

[mepland]

Hmm actually looking at it again, the "Prediction 0" text is in the correct spot on the png I save, but not the pdf, so I think that it is fine. I just changed to two leading spaces to match the other labels. The   character doesn't appear to be doing anything in my testing.

Ideally we would just move the edge label positions in the graph itself, but this doesn't appear possible for graphviz:

• Ref 1
• Ref 2
• Ref 3
• Ref 4 - Note labeldistance only works for headlabel and taillabel, not the midpoint label we use.

[parrt]

Ideally we would just move the edge label positions in the graph itself, but this doesn't appear possible for graphviz:

yeah, I had lots of trouble with positioning...

[parrt]

just ran notebooks. looks fine. thanks!