Lines with label in Plot options syntax

Question

I wrote a little function to add lines with labels to plots. It just creates customized {GridLines -> ..., Epilog -> ...} code:

LastOrEmpty[seq_] := If[Length[seq] > 0, Last[seq], {}];

AddLabel[lab_, pos_] := 
  Inset[Framed[lab, Background -> White, FrameStyle -> None], pos];

AddLines[xs_, ys_, xlvl_, ylvl_] := {
   GridLines -> {LastOrEmpty /@ xs, LastOrEmpty /@ ys},
   Epilog -> Join[
     Table[AddLabel[xs[[i, 1]], {xs[[i, 2]], ylvl}], {i, Length[xs]}],
     Table[AddLabel[ys[[i, 1]], {xlvl, ys[[i, 2]]}], {i, Length[ys]}]
     ] 
   };

But is using a little creepy syntax:

AddLines[
  {label1 -> val1, label2 -> val2, ...}, (* <- vertical lines *)
  {label3 -> val3, label4 -> val4, ...}, (* <- horizontal lines *)
  xlvl, (* <- Horisontal align of labels*)
  ylvl  (* <- Vertical align of labels*)
] // Evaluate

For example:

ParametricPlot[{x1[w], 
   x3[w]}, {w, w1 - 5, w1 + 9},
  AspectRatio -> 1/GoldenRatio,
  AxesOrigin -> {0.10, 0},
  AxesLabel -> {"x1(\[Omega])", "x3(\[Omega])"},
  GridLinesStyle -> Dashed,
  AddLines[
    {T1 -> 0.2},
    {K1 -> 2, Kgr -> 0.52, Baseline -> 1},
    0.59, 2.9] // Evaluate
  ]

Now I would like to write something like:

  Lines -> {
    {T1 -> 0.2},
    {K1 -> 2, Kgr -> 0.52, Baseline -> 1},
    0.59, 2.9}

And at the best I would like to make it to automatically calculate align, i.e. would look like:

  Lines -> {
    {T1 -> 0.2},
    {K1 -> 2, Kgr -> 0.52, Baseline -> 1}}

Have you any idea how to make it?

Answer 1

For example, without modifying your current definitions you can do:

SetAttributes[myPlot, HoldAll];
Options[myPlot] = Join[Options[ParametricPlot], {"Lines" -> ""}];

myPlot[funs_, r_, opts : OptionsPattern[]] :=
    ParametricPlot[funs, r, 
      (Evaluate@Join[FilterRules[{opts}, Options[ParametricPlot]],
                     AddLines[Sequence @@ OptionValue[myPlot, "Lines"]]])];

myPlot[{w, 5 w}, {w, 0, .6}, 
       AspectRatio -> 1/GoldenRatio, AxesOrigin -> {0.10, 0}, 
       AxesLabel -> {"x1(\[Omega])", "x3(\[Omega])"}, GridLinesStyle -> Dashed, 
       "Lines" -> {{T1 -> 0.2}, {K1 -> 2, Kgr -> 0.52, Baseline -> 1}, 0.59, 2.9}]