Support custom line styles in `TTeXDump` as requested...

Support custom line styles in `TTeXDump` as requested [here](https://sft.its.cern.ch/jira/browse/ROOT-8215)

README/ReleaseNotes/v608/index.md

@@ -140,8 +140,8 @@ We added a cache specifically for the fast option of the TTreeCloner to signific
 ## Math Libraries
 
 * Improve thread safety of TMinuit constructor [ROOT-8217]
-* Vc has ben removed from the ROOT sources. If the option 'vc' is enabled, the package will be searched (by default), 
-  alternatively the source tarfile can be downloded and build with the option 'builtin_vc'. 
+* Vc has ben removed from the ROOT sources. If the option 'vc' is enabled, the package will be searched (by default),
+  alternatively the source tarfile can be downloded and build with the option 'builtin_vc'.
 
 ## RooFit Libraries
 
@@ -214,9 +214,10 @@ We added a cache specifically for the fast option of the TTreeCloner to signific
 * New optional parameter "option" in TPad::BuildLegend to set the TLegend option (Georg Troska).
 * TCandle: a new candle plot painter class. It is now used in THistPainter and THStack
   to paint candle plots (Georg Troska).
-* Fix two issues with the fill patterns in `TTextDump` (reported [here](https://sft.its.cern.ch/jira/browse/ROOT-8206)):
+* Fix two issues with the fill patterns in `TTeXDump` (reported [here](https://sft.its.cern.ch/jira/browse/ROOT-8206)):
     - The pattern number 3 was not implemented.
     - Filled area drawn with pattern where surrounded by a solid line.
+* Support custom line styles in `TTeXDump` as requested [here](https://sft.its.cern.ch/jira/browse/ROOT-8215)
 * `TColor::GetFreeColorIndex()` allows to make sure the new color is created with an
   unused color index.
 

graf2d/postscript/src/TTeXDump.cxx

@@ -522,36 +522,34 @@ void TTeXDump::DrawPS(Int_t nn, Double_t *xw, Double_t *yw)
       SetColor(fLineColor);
       PrintStr("@");
       PrintStr("\\draw [c");
-      switch(fLineStyle) {
-      case 1:
-         break;
-      case 2:
-         PrintStr(",dashed");
-         break;
-      case 3:
-         PrintStr(",dotted");
-         break;
-      case 4:
-         PrintStr(",dash pattern=on 2.4pt off 3.2pt on 0.8pt off 3.2pt");
-         break;
-      case 5:
-         PrintStr(",dash pattern=on 4pt off 2.4pt on 0.8pt off 2.4pt");
-         break;
-      case 6:
-         PrintStr(",dash pattern=on 4pt off 2.4pt on 0.8pt off 2.4pt on 0.8pt off 2.4pt on 0.8pt off 2.4pt");
-         break;
-      case 7:
-         PrintStr(",dash pattern=on 4pt off 4pt");
-         break;
-      case 8:
-         PrintStr(",dash pattern=on 4pt off 2.4pt on 0.8pt off 2.4pt on 0.8pt off 2.4pt");
-         break;
-      case 9:
-         PrintStr(",dash pattern=on 16pt off 4pt");
-         break;
-      case 10:
-         PrintStr(",dash pattern=on 16pt off 8pt on 0.8pt off 8pt");
-         break;
+      TString spec = gStyle->GetLineStyleString(fLineStyle);
+      TString tikzSpec;
+      TString stripped = TString{spec.Strip(TString::kBoth)};
+      if (stripped.Length()) {
+         tikzSpec.Append(",dash pattern=");
+         Ssiz_t i{0}, j{0};
+         bool on{true}, iterate{true};
+
+         while (iterate){
+            j = stripped.Index(" ", 1, i, TString::kExact);
+            if (j == kNPOS){
+               iterate = false;
+               j = stripped.Length();
+            }
+
+            if (on) {
+               tikzSpec.Append("on ");
+               on = false;
+            } else {
+               tikzSpec.Append("off ");
+               on = true;
+            }
+            int num = TString{stripped(i, j - i)}.Atoi();
+            float pt = 0.2*num;
+            tikzSpec.Append(TString::Format("%.2fpt ", pt));
+            i = j + 1;
+         }
+         PrintStr(tikzSpec.Data());
       }
       PrintStr(",line width=");
       WriteReal(0.3*fLineScale*fLineWidth, kFALSE);