From d32f71839bc3df81491efa193f76b94e1154ea9e Mon Sep 17 00:00:00 2001
From: Adrian Perez de Castro <aperez@igalia.com>
Date: Mon, 27 May 2013 21:26:57 +0300
Subject: [PATCH v7 6/9] Tagged-PDF: Implement the utils/pdfstructtohtml tool

This adds a new tool "utils/pdfstructtohtml" that uses the document
structure from tagged PDFs to generate an HTML document from it, trying
to preserve as much of the structure and some of the styling in the
output. This serves also as a demonstration of how to use the Attribute
and StructElement classes.
---
 utils/Makefile.am        |   5 +
 utils/pdfstructtohtml.cc | 555 +++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 560 insertions(+)
 create mode 100644 utils/pdfstructtohtml.cc

diff --git a/utils/Makefile.am b/utils/Makefile.am
index 0c95441..137a129 100644
--- a/utils/Makefile.am
+++ b/utils/Makefile.am
@@ -58,6 +58,7 @@ bin_PROGRAMS =					\
 	pdftohtml				\
 	pdfseparate				\
 	pdfunite				\
+	pdfstructtohtml				\
 	$(pdftoppm_binary)			\
 	$(pdftocairo_binary)
 
@@ -131,6 +132,10 @@ pdfunite_SOURCES =				\
 	pdfunite.cc				\
 	$(common)
 
+pdfstructtohtml_SOURCES =			\
+	pdfstructtohtml.cc			\
+	$(common)
+
 # Yay, automake!  It should be able to figure out that it has to dist
 # pdftoppm.1, but nooo.  So we just add it here.
 
diff --git a/utils/pdfstructtohtml.cc b/utils/pdfstructtohtml.cc
new file mode 100644
index 0000000..762f9e1
--- /dev/null
+++ b/utils/pdfstructtohtml.cc
@@ -0,0 +1,555 @@
+//========================================================================
+//
+// pdfstructtohtml.cc
+//
+// Copyright 2013 Igalia S.L.
+//
+//========================================================================
+
+#include "config.h"
+#include <poppler-config.h>
+#include "GlobalParams.h"
+#include "parseargs.h"
+#include "PDFDocFactory.h"
+#include "PDFDoc.h"
+#include "StructElement.h"
+#include "StructTreeRoot.h"
+#include "TextOutputDev.h"
+#include "UnicodeMap.h"
+#include <assert.h>
+#include <string>
+
+
+static void arrayToRGBColor(Object *value, double &r, double &g, double &b)
+{
+  Object obj;
+  r = value->arrayGet(0, &obj)->getNum();
+  g = value->arrayGet(1, &obj)->getNum();
+  b = value->arrayGet(2, &obj)->getNum();
+}
+
+static const char *tagDecideL(const StructElement *elem)
+{
+  const Attribute *attr = elem->findAttribute(Attribute::ListNumbering, gTrue);
+  Object *value = attr ? attr->getValue() : Attribute::getDefaultValue(Attribute::ListNumbering);
+
+  if (value) {
+    if (value->isName("Decimal") ||
+        value->isName("UpperRoman") ||
+	value->isName("LowerRoman") ||
+	value->isName("UpperAlpha") ||
+	value->isName("LowerAlphs"))
+      return "ol";
+  }
+  return "ul";
+}
+
+
+static void attrStyleListNumbering(const StructElement*, Attribute::Type, Object *value, GooString *style)
+{
+  if (value->isName("None"))            style->append("list-style-type: none;");
+  else if (value->isName("Disc"))       style->append("list-style-type: disc");
+  else if (value->isName("Circle"))     style->append("list-style-type: circle;");
+  else if (value->isName("Square"))     style->append("list-style-type: square;");
+  else if (value->isName("Decimal"))    style->append("list-style-type: decimal;");
+  else if (value->isName("UpperRoman")) style->append("list-style-type: upper-roman;");
+  else if (value->isName("LowerRoman")) style->append("list-style-type: lower-roman;");
+  else if (value->isName("UpperAlpha")) style->append("list-style-type: upper-latin;");
+  else if (value->isName("LowerAlphs")) style->append("list-style-type: lower-latin;");
+}
+
+static void attrStyleTextAlign(const StructElement*, Attribute::Type, Object *value, GooString *style)
+{
+  if (value->isName("Justify"))     style->append("text-align: justify;");
+  else if (value->isName("Start"))  style->append("text-align: left;");
+  else if (value->isName("End"))    style->append("text-align: right;");
+  else if (value->isName("Center")) style->append("text-align: center;");
+}
+
+static void attrStyleTextDecoration(const StructElement*, Attribute::Type, Object *value, GooString *style)
+{
+  if (value->isName("Underline"))        style->append("text-decoration: underline;");
+  else if (value->isName("Overline"))    style->append("text-decoration: overline;");
+  else if (value->isName("LineThrough")) style->append("text-decoration: line-through;");
+  else if (value->isName("None"))        style->append("text-decoration: none;");
+}
+
+static void attrColRowSpan(const StructElement*, Attribute::Type type, Object *value, GooString *attrs)
+{
+  if (value->isNum() && value->getNum() > 0.0) {
+    attrs->appendf(" {0:s}span='{1:u}'",
+		   (type == Attribute::RowSpan) ? "row" : "col",
+		   (unsigned) value->getNum());
+  }
+}
+
+static void attrStyleColor(const StructElement*, Attribute::Type type, Object *value, GooString *style)
+{
+  double r, g, b;
+  arrayToRGBColor(value, r, g, b);
+
+  if (type == Attribute::BackgroundColor)
+    style->append("background-");
+  style->appendf("color: rgb({0:u}, {1:u}, {2:u});",
+		 ((Guint) (r * 255)) & 0xFF,
+		 ((Guint) (g * 255)) & 0xFF,
+		 ((Guint) (b * 255)) & 0xFF);
+}
+
+
+typedef void (*TagAttrBuildFunc)(const StructElement*, Attribute::Type, Object*, GooString*);
+
+static const struct AttrMapEntry {
+  Attribute::Type  type;
+  GBool            style;
+  TagAttrBuildFunc buildAttr;
+} attrBuildMap[] = {
+  { Attribute::Color,              gTrue,  attrStyleColor          },
+  { Attribute::BackgroundColor,    gTrue,  attrStyleColor          },
+  { Attribute::ListNumbering,      gTrue,  attrStyleListNumbering  },
+  { Attribute::TextAlign,          gTrue,  attrStyleTextAlign      },
+  { Attribute::TextDecorationType, gTrue,  attrStyleTextDecoration },
+  { Attribute::RowSpan,            gFalse, attrColRowSpan          },
+  { Attribute::ColSpan,            gFalse, attrColRowSpan          },
+};
+
+
+typedef const char* (*TagDecideFunc)(const StructElement*);
+
+static const struct ElementMapEntry {
+  StructElement::Type type;
+  const char         *tagName;
+  TagDecideFunc       tagDecide;
+} elementMap[] = {
+  { StructElement::P,     "p",     NULL },
+  { StructElement::H1,    "h1",    NULL },
+  { StructElement::H2,    "h2",    NULL },
+  { StructElement::H3,    "h3",    NULL },
+  { StructElement::H4,    "h4",    NULL },
+  { StructElement::H5,    "h5",    NULL },
+  { StructElement::H6,    "h6",    NULL },
+  { StructElement::L,     NULL,    tagDecideL },
+  { StructElement::LI,    "li",    NULL },
+  { StructElement::Table, "table", NULL },
+  { StructElement::TR,    "tr",    NULL },
+  { StructElement::TH,    "th",    NULL },
+  { StructElement::TD,    "td",    NULL },
+  { StructElement::TBody, "tbody", NULL },
+  { StructElement::THead, "thead", NULL },
+  { StructElement::Link,  "a",     NULL },
+};
+
+
+static void xmlEscape(FILE *out, const char *str)
+{
+  while (*str) {
+    int ch = *str++;
+    switch (ch) {
+      case '&' : fputs("&amp;",  out); break;
+      case '\'': fputs("&apos;", out); break;
+      case '"' : fputs("&quot;", out); break;
+      case '<' : fputs("&lt;",   out); break;
+      case '>' : fputs("&gt;",   out); break;
+      default  : fputc(ch, out);
+    }
+  }
+}
+
+
+class StructVisitor
+{
+public:
+  StructVisitor(PDFDoc *docA, FILE *output):
+    inTable(gFalse),
+    doc(docA),
+    out(output)
+  {
+    assert(doc);
+    assert(out);
+  }
+
+  GBool process();
+
+private:
+  void start();
+  void finish();
+  void visit(const StructElement *elem);
+  GooString *buildTagAttributes(const StructElement *elem);
+
+  void E(const char *str) { xmlEscape(out, str); }
+  void O(const char *fmt, ...) {
+    va_list args;
+    va_start(args, fmt);
+    vfprintf(out, fmt, args);
+    va_end(args);
+  }
+
+  GBool   inTable;
+  PDFDoc *doc;
+  FILE   *out;
+};
+
+
+class MCOpProcessor {
+public:
+  MCOpProcessor(FILE *output):
+    out(output),
+    map(globalParams->getTextEncoding()),
+    text(),
+    font(),
+    flags(0)
+  {
+    assert(output);
+  }
+
+  ~MCOpProcessor() {
+    emitText();
+    map->decRefCnt();
+  }
+
+  void process(const MCOpArray& ops) {
+    for (MCOpArray::const_iterator i = ops.begin(); i != ops.end(); ++i)
+      process(*i);
+  }
+
+  void process(const MCOp& op) {
+    if (op.type == MCOp::Unichar) {
+      int n = map->mapUnicode(op.unichar, buf, sizeof(buf));
+      text.append(buf, n);
+      return;
+    }
+
+    Guint oldFlags = flags;
+    if (op.type == MCOp::Flags) {
+      if (op.flags & MCOp::FlagFontBold)
+        flags |= FBold;
+      else
+        flags &= ~FBold;
+
+      if (op.flags & MCOp::FlagFontFixed)
+        flags |= FFixed;
+      else
+        flags &= ~FFixed;
+
+      if (op.flags & MCOp::FlagFontItalic)
+        flags |= FItalic;
+      else
+        flags &= ~FItalic;
+    }
+
+    if (op.type == MCOp::FontName) {
+      if (op.value) {
+        flags |= FFont;
+        font.append(op.value);
+      } else {
+        flags &= ~FFont;
+      }
+    }
+
+    if (op.type == MCOp::Color && (color = op.color.rgbPixel()))
+      flags |= FColor;
+    else
+      flags &= ~FColor;
+
+    if (flags != oldFlags)
+      emitText();
+  }
+
+private:
+  enum {
+    FColor   = (1 << 0),
+    FBold    = (1 << 1),
+    FFixed   = (1 << 2),
+    FItalic  = (1 << 3),
+    FFont    = (1 << 4),
+
+    FUseSpan = (FColor | FFont),
+  };
+
+  void E(const char *str) { xmlEscape(out, str); }
+  void O(const char *fmt, ...) {
+    va_list args;
+    va_start(args, fmt);
+    vfprintf(out, fmt, args);
+    va_end(args);
+  }
+
+  void emitText() {
+    if (!flags) {
+      E(text.c_str());
+      text.clear();
+      return;
+    }
+
+    if (flags & FBold) O("<strong>");
+    if (flags & FItalic) O("<em>");
+    if (flags & FFixed) O("<code>");
+
+    if (flags & FUseSpan) {
+      O("<span style='");
+      if (flags & FColor) O(" color: #%x;", color);
+      if (flags & FFont) O(" font-family: \"%s\";", font.c_str());
+      O("'>");
+    }
+
+    E(text.c_str());
+
+    if (flags & FUseSpan)
+      O("</span>");
+
+    if (flags & FFixed) O("</code>");
+    if (flags & FItalic) O("</em>");
+    if (flags & FBold) O("</strong>");
+
+    font.clear();
+    text.clear();
+  }
+
+  FILE *out;
+  UnicodeMap *map;
+  std::string text;
+  std::string font;
+  Guint       flags;
+  char        buf[8];
+  Guint       color;
+};
+
+
+GBool StructVisitor::process()
+{
+  StructTreeRoot *root = doc->getStructTreeRoot();
+  if (!root)
+    return gFalse;
+
+  start();
+  for (unsigned i = 0; i < root->getNumElements(); i++)
+    visit(root->getElement(i));
+  finish();
+
+  return gTrue;
+}
+
+void StructVisitor::start()
+{
+  O("<!DOCTYPE html>\n"
+    "<html>\n"
+    " <head>\n"
+    "  <meta charset='utf-8'>\n");
+
+  Object info;
+  if (doc->getDocInfo(&info)->isDict()) {
+    Object obj;
+    if (info.dictLookup("Title", &obj)->isString()) {
+      O("  <title>"); E(obj.getString()->getCString()); O("</title>\n");
+    }
+  }
+
+  O("  <style type='text/css'>\n"
+    "   * { color: #222; }\n"
+    "   table, tbody, thead, tr { margin: 0; padding: 0; }\n"
+    "   table { border-collapse: collapse; margin: 0 auto; }\n"
+    "   th, td { margin: 0; padding: 0.15em 0.5em; border: 1px solid #aaa; }\n"
+    "   th { background: #eee; }\n"
+    "  </style>\n"
+    " </head>\n"
+    " <body>\n\n");
+}
+
+void StructVisitor::finish()
+{
+  O("\n"
+    " </body>\n"
+    "</html>\n");
+}
+
+
+GooString *StructVisitor::buildTagAttributes(const StructElement *elem)
+{
+  GooString *style = NULL;
+  GooString *attrs = NULL;
+
+  if (elem->getType() == StructElement::Link) {
+    // XXX This is crude, but gets the job done.
+    for (unsigned i = 0; i < elem->getNumElements(); i++) {
+      if (elem->getElement(i)->isObjectRef()) {
+	Ref ref = elem->getElement(i)->getObjectRef();
+	Object value;
+	if (doc->getXRef()->fetch(ref.num, ref.gen, &value)->isDict("Annot")) {
+	  Object action;
+	  if (value.dictLookup("A", &action)->isDict("Action")) {
+	    Object uri;
+	    if (action.dictLookup("URI", &uri)->isString()) {
+	      if (!attrs) attrs = new GooString();
+	      attrs->appendf(" href='{0:s}'", uri.getString());
+	    }
+	    uri.free();
+	  }
+	  action.free();
+	}
+	value.free();
+	break;
+      }
+    }
+  }
+
+  for (unsigned i = 0; i < elem->getNumAttributes(); i++) {
+    const Attribute *attr = elem->getAttribute(i);
+    const AttrMapEntry *entry = NULL;
+    for (unsigned j = 0; j < sizeof(attrBuildMap) / sizeof(attrBuildMap[0]); j++) {
+      if (attrBuildMap[j].type == attr->getType()) {
+	entry = &attrBuildMap[j];
+	break;
+      }
+    }
+    if (entry) {
+      if (entry->style) {
+	if (!style) style = new GooString();
+	(*entry->buildAttr)(elem, attr->getType(), attr->getValue(), style);
+      } else {
+	if (!attrs) attrs = new GooString();
+	(*entry->buildAttr)(elem, attr->getType(), attr->getValue(), attrs);
+      }
+    }
+  }
+
+  if (style) {
+    if (!attrs) attrs = new GooString();
+    attrs->append(" style='");
+    attrs->append(style);
+    attrs->append("'");
+  }
+
+  return attrs;
+}
+
+
+void StructVisitor::visit(const StructElement *elem)
+{
+  if (elem->isContent()) {
+    const GooString *text;
+
+    if ((text = elem->getAltText()) || (text = elem->getActualText()))
+      E(text->getCString());
+    else {
+      const MCOpArray& ops(elem->getMCOps());
+      if (ops.size()) {
+        MCOpProcessor processor(out);
+        processor.process(ops);
+      } else if ((text = elem->getText())) {
+        E(text->getCString());
+        delete text;
+      }
+    }
+  } else {
+    const ElementMapEntry *entry = NULL;
+    for (unsigned i = 0; i < sizeof(elementMap) / sizeof(elementMap[0]); i++)
+      if (elementMap[i].type == elem->getType())
+	entry = &elementMap[i];
+
+    if (entry) {
+      assert(entry->tagName || entry->tagDecide);
+      const char *tag = entry->tagName ? entry->tagName : (*entry->tagDecide)(elem);
+      if (!(inTable && entry->type == StructElement::P)) {
+        GooString *attrs = buildTagAttributes(elem);
+        O("<%s", tag);
+        if (attrs) O("%s", attrs->getCString());
+	delete attrs;
+	O(">");
+      }
+      if (entry->type == StructElement::Table)
+        inTable = gTrue;
+      for (unsigned i = 0; i < elem->getNumElements(); i++)
+	visit(elem->getElement(i));
+      inTable = gFalse;
+      if (!(inTable && entry->type == StructElement::P))
+        O("</%s>\n", tag);
+    } else {
+      for (unsigned i = 0; i < elem->getNumElements(); i++)
+	visit(elem->getElement(i));
+    }
+  }
+}
+
+
+static char ownerPassword[33] = "\001";
+static char userPassword[33]  = "\001";
+static GBool printHelp        = gFalse;
+
+static const ArgDesc argDesc[] = {
+  { "-opw", argString, ownerPassword, sizeof(ownerPassword),
+    "owner password (for encrypted files)" },
+  { "-upw", argString, userPassword, sizeof(userPassword),
+    "user password (for encrypted files)" },
+  { "-h", argFlag, &printHelp, 0,
+    "print usage information" },
+  { "-help", argFlag, &printHelp, 0,
+    "print usage information" },
+  { "--help", argFlag, &printHelp, 0,
+    "print usage information" },
+  { NULL }
+};
+
+int main(int argc, char **argv)
+{
+  PDFDoc *doc;
+  GooString *ownerPW, *userPW, *fileName;
+  GBool ok;
+  int exitCode = 99;
+  StructVisitor *v = NULL;
+  FILE *output = stdout;
+
+  ok = parseArgs(argDesc, &argc, argv);
+  if (!ok || (argc < 2) || (argc > 3) || printHelp) {
+    fprintf(stderr, "pdfstructtohtml version " PACKAGE_VERSION "\n");
+    fprintf(stderr, "%s\n", popplerCopyright);
+    fprintf(stderr, "%s\n", xpdfCopyright);
+    printUsage("pdfstructtohtml", "<PDF-file> [<HTML-file>]", argDesc);
+    if (printHelp)
+      exitCode = EXIT_SUCCESS;
+    goto err0;
+  }
+
+  ownerPW  = (ownerPassword[0] != '\001') ? new GooString(ownerPassword) : NULL;
+  userPW   = (userPassword[0]  != '\001') ? new GooString(userPassword)  : NULL;
+  fileName = new GooString(argv[1]);
+
+  if (fileName->cmp("-") == 0)
+    fileName->Set("fd://0");
+
+  globalParams = new GlobalParams();
+  globalParams->setTextEncoding("UTF-8");
+
+  doc = PDFDocFactory().createPDFDoc(*fileName, ownerPW, userPW);
+  delete ownerPW;
+  delete userPW;
+
+  if (!doc->isOk()) {
+    exitCode = 1;
+    goto err1;
+  }
+
+  if (argc == 3) {
+    if (!(output = fopen(argv[2], "wb"))) {
+      exitCode = 2;
+      goto err1;
+    }
+  }
+
+  v = new StructVisitor(doc, output);
+  v->process();
+
+  if (output != stdout)
+    fclose(output);
+
+  delete v;
+
+err1:
+  delete doc;
+  delete fileName;
+  delete globalParams;
+
+err0:
+  Object::memCheck(stderr);
+  gMemReport(stderr);
+  return exitCode;
+}
-- 
1.8.3.4