Introduce compact form for SVG output

In compact form <desc> and <defs> section are excluded.
Also all float values rounded and stored as integer.
Such rounding potentially can have side effects, but let create much smaller files.

Author: linev

graf2d/postscript/inc/TSVG.h

@@ -29,6 +29,7 @@ class TSVG : public TVirtualPS {
 
    static Int_t fgLineJoin;       ///< Appearance of joining lines
    static Int_t fgLineCap;        ///< Appearance of line caps
+   static Bool_t fgCompact;       ///< compact SVG format with integer values and no desc/defs
 
 public:
    TSVG();
@@ -72,6 +73,11 @@ class TSVG : public TVirtualPS {
    void  Text(Double_t, Double_t, const wchar_t *) override {}
    void  TextNDC(Double_t u, Double_t v, const char *string);
    void  TextNDC(Double_t, Double_t, const wchar_t *) {}
+   void  WriteReal(Float_t r, Bool_t space=kTRUE) override;
+
+   static void SetCompact(Bool_t on = kTRUE);
+   static Bool_t IsCompact();
+
    Double_t UtoSVG(Double_t u);
    Double_t VtoSVG(Double_t v);
    Double_t XtoSVG(Double_t x);

graf2d/postscript/src/TSVG.cxx

@@ -16,6 +16,7 @@
 #include <cstdlib>
 #include <cstring>
 #include <cctype>
+#include <cmath>
 #include <fstream>
 
 #include "TROOT.h"
@@ -32,7 +33,7 @@
 
 Int_t TSVG::fgLineJoin = 0;
 Int_t TSVG::fgLineCap  = 0;
-
+Bool_t TSVG::fgCompact = kFALSE;
 
 /** \class TSVG
 \ingroup PS
@@ -1512,6 +1513,9 @@ void TSVG::Initialize()
    PrintStr("@");
    PrintStr("</title>@");
 
+   if (fgCompact)
+      return;
+
    // Description
    PrintStr("<desc>@");
    PrintFast(22,"Creator: ROOT Version ");
@@ -1533,6 +1537,18 @@ void TSVG::Initialize()
 
 }
 
+////////////////////////////////////////////////////////////////////////////////
+/// Write real value into output stream
+/// In compact form only integer value will be written
+
+void TSVG::WriteReal(Float_t r, Bool_t space)
+{
+   if (fgCompact)
+      TVirtualPS::WriteInteger(std::lround(r), space);
+   else
+      TVirtualPS::WriteReal(r, space);
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 /// Move to a new position (ix, iy). The move is done in relative coordinates
 /// which allows to have short numbers which decrease the size of the file.
@@ -2064,3 +2080,22 @@ void TSVG::DrawPS(Int_t, Float_t *, Float_t *)
 {
    Warning("TSVG::DrawPS", "not yet implemented");
 }
+
+////////////////////////////////////////////////////////////////////////////////
+/// Set compact mode for svg output
+/// If enabled - discards creation of <desc> and <defs> section in the SVG file
+/// Also all float values will be rounded to nearest integer values
+/// Produced SVG file potentially can have artifacts but let create much smaller SVG files
+
+void TSVG::SetCompact(Bool_t on)
+{
+   fgCompact = on;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+/// Returns compact mode for svg output
+
+Bool_t TSVG::IsCompact()
+{
+   return fgCompact;
+}