// See www.openfst.org for extensive documentation on this weighted
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// finite-state transducer library.
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//
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// Class to draw a binary FST by producing a text file in dot format, a helper
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// class to fstdraw.cc.
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#ifndef FST_SCRIPT_DRAW_IMPL_H_
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#define FST_SCRIPT_DRAW_IMPL_H_
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#include <ostream>
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#include <sstream>
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#include <string>
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#include <fst/fst.h>
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#include <fst/util.h>
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#include <fst/script/fst-class.h>
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namespace fst {
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// Print a binary FST in GraphViz textual format (helper class for fstdraw.cc).
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// WARNING: Stand-alone use not recommend.
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template <class Arc>
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class FstDrawer {
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public:
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using Label = typename Arc::Label;
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using StateId = typename Arc::StateId;
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using Weight = typename Arc::Weight;
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FstDrawer(const Fst<Arc> &fst, const SymbolTable *isyms,
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const SymbolTable *osyms, const SymbolTable *ssyms, bool accep,
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const string &title, float width, float height, bool portrait,
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bool vertical, float ranksep, float nodesep, int fontsize,
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int precision, const string &float_format, bool show_weight_one)
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: fst_(fst),
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isyms_(isyms),
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osyms_(osyms),
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ssyms_(ssyms),
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accep_(accep && fst.Properties(kAcceptor, true)),
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ostrm_(nullptr),
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title_(title),
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width_(width),
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height_(height),
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portrait_(portrait),
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vertical_(vertical),
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ranksep_(ranksep),
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nodesep_(nodesep),
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fontsize_(fontsize),
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precision_(precision),
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float_format_(float_format),
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show_weight_one_(show_weight_one) {}
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// Draws FST to an output buffer.
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void Draw(std::ostream *strm, const string &dest) {
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ostrm_ = strm;
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SetStreamState(ostrm_);
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dest_ = dest;
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StateId start = fst_.Start();
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if (start == kNoStateId) return;
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PrintString("digraph FST {\n");
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if (vertical_) {
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PrintString("rankdir = BT;\n");
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} else {
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PrintString("rankdir = LR;\n");
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}
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PrintString("size = \"");
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Print(width_);
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PrintString(",");
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Print(height_);
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PrintString("\";\n");
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if (!dest_.empty()) PrintString("label = \"" + title_ + "\";\n");
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PrintString("center = 1;\n");
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if (portrait_) {
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PrintString("orientation = Portrait;\n");
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} else {
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PrintString("orientation = Landscape;\n");
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}
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PrintString("ranksep = \"");
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Print(ranksep_);
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PrintString("\";\n");
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PrintString("nodesep = \"");
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Print(nodesep_);
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PrintString("\";\n");
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// Initial state first.
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DrawState(start);
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for (StateIterator<Fst<Arc>> siter(fst_); !siter.Done(); siter.Next()) {
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const auto s = siter.Value();
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if (s != start) DrawState(s);
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}
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PrintString("}\n");
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}
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private:
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void SetStreamState(std::ostream* strm) const {
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strm->precision(precision_);
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if (float_format_ == "e")
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strm->setf(std::ios_base::scientific, std::ios_base::floatfield);
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if (float_format_ == "f")
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strm->setf(std::ios_base::fixed, std::ios_base::floatfield);
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// O.w. defaults to "g" per standard lib.
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}
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void PrintString(const string &str) const { *ostrm_ << str; }
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// Escapes backslash and double quote if these occur in the string. Dot will
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// not deal gracefully with these if they are not escaped.
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static string Escape(const string &str) {
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string ns;
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for (char c : str) {
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if (c == '\\' || c == '"') ns.push_back('\\');
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ns.push_back(c);
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}
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return ns;
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}
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void PrintId(StateId id, const SymbolTable *syms, const char *name) const {
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if (syms) {
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auto symbol = syms->Find(id);
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if (symbol.empty()) {
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FSTERROR() << "FstDrawer: Integer " << id
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<< " is not mapped to any textual symbol"
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<< ", symbol table = " << syms->Name()
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<< ", destination = " << dest_;
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symbol = "?";
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}
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PrintString(Escape(symbol));
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} else {
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PrintString(std::to_string(id));
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}
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}
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void PrintStateId(StateId s) const { PrintId(s, ssyms_, "state ID"); }
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void PrintILabel(Label label) const {
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PrintId(label, isyms_, "arc input label");
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}
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void PrintOLabel(Label label) const {
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PrintId(label, osyms_, "arc output label");
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}
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void PrintWeight(Weight w) const {
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// Weight may have double quote characters in it, so escape it.
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PrintString(Escape(ToString(w)));
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}
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template <class T>
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void Print(T t) const { *ostrm_ << t; }
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template <class T>
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string ToString(T t) const {
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std::stringstream ss;
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SetStreamState(&ss);
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ss << t;
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return ss.str();
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}
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void DrawState(StateId s) const {
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Print(s);
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PrintString(" [label = \"");
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PrintStateId(s);
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const auto weight = fst_.Final(s);
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if (weight != Weight::Zero()) {
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if (show_weight_one_ || (weight != Weight::One())) {
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PrintString("/");
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PrintWeight(weight);
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}
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PrintString("\", shape = doublecircle,");
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} else {
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PrintString("\", shape = circle,");
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}
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if (s == fst_.Start()) {
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PrintString(" style = bold,");
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} else {
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PrintString(" style = solid,");
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}
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PrintString(" fontsize = ");
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Print(fontsize_);
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PrintString("]\n");
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for (ArcIterator<Fst<Arc>> aiter(fst_, s); !aiter.Done(); aiter.Next()) {
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const auto &arc = aiter.Value();
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PrintString("\t");
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Print(s);
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PrintString(" -> ");
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Print(arc.nextstate);
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PrintString(" [label = \"");
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PrintILabel(arc.ilabel);
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if (!accep_) {
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PrintString(":");
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PrintOLabel(arc.olabel);
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}
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if (show_weight_one_ || (arc.weight != Weight::One())) {
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PrintString("/");
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PrintWeight(arc.weight);
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}
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PrintString("\", fontsize = ");
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Print(fontsize_);
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PrintString("];\n");
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}
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}
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const Fst<Arc> &fst_;
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const SymbolTable *isyms_; // ilabel symbol table.
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const SymbolTable *osyms_; // olabel symbol table.
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const SymbolTable *ssyms_; // slabel symbol table.
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bool accep_; // Print as acceptor when possible.
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std::ostream *ostrm_; // Drawn FST destination.
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string dest_; // Drawn FST destination name.
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string title_;
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float width_;
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float height_;
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bool portrait_;
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bool vertical_;
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float ranksep_;
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float nodesep_;
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int fontsize_;
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int precision_;
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string float_format_;
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bool show_weight_one_;
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FstDrawer(const FstDrawer &) = delete;
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FstDrawer &operator=(const FstDrawer &) = delete;
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};
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} // namespace fst
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#endif // FST_SCRIPT_DRAW_IMPL_H_
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