Attachment 90249 Details for Bug 64815 – [PATCH v12 01/11] Tagged-PDF: Text content extraction from structure elements

[patch] [PATCH v12 01/11] Tagged-PDF: Text content extraction from structure elements

0001-Tagged-PDF-Text-content-extraction-from-structure-el.patch (text/plain), 14.07 KB, created by Adrian Perez de Castro on 2013-12-04 16:42:19 UTC

(hide)

Description:

Filename:

MIME Type:

Creator: Adrian Perez de Castro

Created: 2013-12-04 16:42:19 UTC

Size: 14.07 KB

patch

obsolete

>From 237385aac41c26322201c691271ecfde86f51696 Mon Sep 17 00:00:00 2001
>From: Adrian Perez de Castro <aperez@igalia.com>
>Date: Tue, 18 Jun 2013 00:35:51 +0300
>Subject: [PATCH v12 01/11] Tagged-PDF: Text content extraction from structure
> elements
>
>Implement StructElement::getText(), by using MCOutputDev. This output device
>captures pieces of text (aka "spans") which have the same attributes into
>a list of TextSpan objects.
>---
> poppler/Makefile.am               |   2 +
> poppler/MarkedContentOutputDev.cc | 216 ++++++++++++++++++++++++++++++++++++++
> poppler/MarkedContentOutputDev.h  | 128 ++++++++++++++++++++++
> poppler/StructElement.cc          |  50 +++++++++
> poppler/StructElement.h           |  28 +++++
> 5 files changed, 424 insertions(+)
> create mode 100644 poppler/MarkedContentOutputDev.cc
> create mode 100644 poppler/MarkedContentOutputDev.h
>
>diff --git a/poppler/Makefile.am b/poppler/Makefile.am
>index 9f90c9d..5f0c795 100644
>--- a/poppler/Makefile.am
>+++ b/poppler/Makefile.am
>@@ -232,6 +232,7 @@ poppler_include_HEADERS =	\
> 	NameToUnicodeTable.h	\
> 	PSOutputDev.h		\
> 	TextOutputDev.h		\
>+	MarkedContentOutputDev.h \
> 	SecurityHandler.h	\
> 	UTF.h			\
> 	UTF8.h			\
>@@ -306,6 +307,7 @@ libpoppler_la_SOURCES =		\
> 	XRef.cc			\
> 	PSOutputDev.cc		\
> 	TextOutputDev.cc	\
>+	MarkedContentOutputDev.cc \
> 	PageLabelInfo.h		\
> 	PageLabelInfo.cc	\
> 	SecurityHandler.cc	\
>diff --git a/poppler/MarkedContentOutputDev.cc b/poppler/MarkedContentOutputDev.cc
>new file mode 100644
>index 0000000..ab27fcd
>--- /dev/null
>+++ b/poppler/MarkedContentOutputDev.cc
>@@ -0,0 +1,216 @@
>+//========================================================================
>+//
>+// MarkedContentOutputDev.cc
>+//
>+// Copyright 2013 Igalia S.L.
>+//
>+//========================================================================
>+
>+#include "MarkedContentOutputDev.h"
>+#include "GlobalParams.h"
>+#include "UnicodeMap.h"
>+#include "GfxState.h"
>+#include "GfxFont.h"
>+#include "Annot.h"
>+#include <vector>
>+
>+
>+MarkedContentOutputDev::MarkedContentOutputDev(int mcidA):
>+  currentFont(NULL),
>+  currentText(NULL),
>+  mcid(mcidA),
>+  pageWidth(0.0),
>+  pageHeight(0.0),
>+  unicodeMap(NULL)
>+{
>+  currentColor.r = currentColor.g = currentColor.b = 0;
>+}
>+
>+
>+MarkedContentOutputDev::~MarkedContentOutputDev()
>+{
>+  if (unicodeMap)
>+    unicodeMap->decRefCnt();
>+  if (currentFont)
>+    currentFont->decRefCnt();
>+  delete currentText;
>+}
>+
>+
>+void MarkedContentOutputDev::endSpan()
>+{
>+  if (currentText && currentText->getLength()) {
>+    // The TextSpan takes ownership of currentText and
>+    // increases the reference count for currentFont.
>+    textSpans.push_back(TextSpan(currentText,
>+                                 currentFont,
>+                                 currentColor));
>+  }
>+  currentText = NULL;
>+}
>+
>+
>+void MarkedContentOutputDev::startPage(int pageNum, GfxState *state, XRef *xref)
>+{
>+  if (state) {
>+    pageWidth  = state->getPageWidth();
>+    pageHeight = state->getPageHeight();
>+  } else {
>+    pageWidth = pageHeight = 0.0;
>+  }
>+}
>+
>+
>+void MarkedContentOutputDev::endPage()
>+{
>+  pageWidth = pageHeight = 0.0;
>+}
>+
>+
>+void MarkedContentOutputDev::beginMarkedContent(char *name, Dict *properties)
>+{
>+  int id = -1;
>+  if (properties)
>+    properties->lookupInt("MCID", NULL, &id);
>+
>+  if (id == -1)
>+    return;
>+
>+  // The stack keep track of MCIDs of nested marked content.
>+  if (inMarkedContent() || id == mcid)
>+    mcidStack.push_back(id);
>+}
>+
>+
>+void MarkedContentOutputDev::endMarkedContent(GfxState *state)
>+{
>+  if (inMarkedContent()) {
>+      mcidStack.pop_back();
>+      // The outer marked content sequence MCID was popped, ensure
>+      // that the last piece of text collected ends up in a TextSpan.
>+      if (!inMarkedContent())
>+        endSpan();
>+  }
>+}
>+
>+
>+bool MarkedContentOutputDev::needFontChange(GfxFont* font) const
>+{
>+  if (currentFont == font)
>+    return gFalse;
>+
>+  if (!currentFont)
>+    return font != NULL && font->isOk();
>+
>+  if (font == NULL)
>+    return gTrue;
>+
>+  // Two non-null valid fonts are the same if they point to the same Ref
>+  if (currentFont->getID()->num == font->getID()->num &&
>+      currentFont->getID()->gen == font->getID()->gen)
>+    return gFalse;
>+
>+  // As a last quick comparison option before falling back on comparing
>+  // the members, check the font tags.
>+  if (font->matches(currentFont->getTag()->getCString()))
>+    return gFalse;
>+
>+  // As a last resort, compare the font names.
>+  return font->getName()->cmp(currentFont->getName()) != 0;
>+}
>+
>+
>+void MarkedContentOutputDev::drawChar(GfxState *state,
>+                                      double xx, double yy,
>+                                      double dx, double dy,
>+                                      double ox, double oy,
>+                                      CharCode c, int nBytes,
>+                                      Unicode *u, int uLen)
>+{
>+  if (!inMarkedContent() || !uLen)
>+    return;
>+
>+
>+  // Color changes are tracked here so the color can be chosen depending on
>+  // the render mode (for mode 1 stroke color is used), so there is no need
>+  // to implement both updateFillColor() and updateStrokeColor().
>+  GBool colorChange = gFalse;
>+  GfxRGB color;
>+  if (state->getRender() == 1)
>+    state->getStrokeRGB(&color);
>+  else
>+    state->getFillRGB(&color);
>+
>+  colorChange = (color.r != currentColor.r ||
>+                 color.g != currentColor.g ||
>+                 color.b != currentColor.b);
>+
>+  // Check also for font changes.
>+  GBool fontChange = needFontChange(state->getFont());
>+
>+  // Save a span with the current changes.
>+  if (colorChange || fontChange) {
>+    endSpan();
>+  }
>+
>+  // Perform the color/font changes.
>+  if (colorChange)
>+    currentColor = color;
>+
>+  if (fontChange) {
>+    if (currentFont != NULL) {
>+      currentFont->decRefCnt();
>+      currentFont = NULL;
>+    }
>+    if (state->getFont() != NULL) {
>+      currentFont = state->getFont();
>+      currentFont->incRefCnt();
>+    }
>+  }
>+
>+
>+  double sp, dx2, dy2, w1, h1, x1, y1;
>+
>+  // Subtract char and word spacing from the (dx,dy) values
>+  sp = state->getCharSpace();
>+  if (c == (CharCode) 0x20)
>+    sp += state->getWordSpace();
>+  state->textTransformDelta(sp * state->getHorizScaling(), 0, &dx2, &dy2);
>+  dx -= dx2;
>+  dy -= dy2;
>+  state->transformDelta(dx, dy, &w1, &h1);
>+  state->transform(xx, yy, &x1, &y1);
>+
>+  // Throw away characters that are not inside the page boundaries.
>+  if (x1 + w1 < 0 || x1 > pageWidth || y1 + h1 < 0 || y1 > pageHeight)
>+    return;
>+
>+  // Make a sanity check on character size. Note: (x != x) <-> isnan(x)
>+  if (x1 != x1 || y1 != y1 || w1 != w1 || h1 != h1)
>+    return;
>+
>+  for (int i = 0; i < uLen; i++) {
>+    // Soft hyphen markers are skipped, as they are invisible unless
>+    // rendering is done to an actual device and the hyphenation hint
>+    // used. MarkedContentOutputDev extracts the *visible* text content.
>+    if (u[i] != 0x00AD) {
>+      // Add the UTF-8 sequence to the current text span.
>+      if (!unicodeMap)
>+        unicodeMap = globalParams->getTextEncoding();
>+
>+      char buf[8];
>+      int n = unicodeMap->mapUnicode(u[i], buf, sizeof(buf));
>+      if (n > 0) {
>+        if (currentText == NULL)
>+          currentText = new GooString();
>+        currentText->append(buf, n);
>+      }
>+    }
>+  }
>+}
>+
>+
>+const TextSpanArray& MarkedContentOutputDev::getTextSpans() const
>+{
>+  return textSpans;
>+}
>diff --git a/poppler/MarkedContentOutputDev.h b/poppler/MarkedContentOutputDev.h
>new file mode 100644
>index 0000000..6decc9b
>--- /dev/null
>+++ b/poppler/MarkedContentOutputDev.h
>@@ -0,0 +1,128 @@
>+//========================================================================
>+//
>+// MarkedContentOutputDev.h
>+//
>+// Copyright 2013 Igalia S.L.
>+//
>+//========================================================================
>+
>+#ifndef MARKEDCONTENTOUTPUTDEV_H
>+#define MARKEDCONTENTOUTPUTDEV_H
>+
>+#include "goo/gtypes.h"
>+#include "goo/gmem.h"
>+#include "OutputDev.h"
>+#include "GfxState.h"
>+#include "GfxFont.h"
>+#include <vector>
>+
>+class Dict;
>+class UnicodeMap;
>+
>+
>+class TextSpan {
>+public:
>+  TextSpan(const TextSpan& other): data(other.data) {
>+    data->refcount++;
>+  }
>+
>+  TextSpan& operator=(const TextSpan& other) {
>+    if (this != &other) {
>+      data = other.data;
>+      data->refcount++;
>+    }
>+    return *this;
>+  }
>+
>+  ~TextSpan() {
>+    if (data && --data->refcount == 0)
>+      delete data;
>+  }
>+
>+  GfxFont* getFont() const { return data->font; }
>+  GooString* getText() const { return data->text; }
>+  GfxRGB& getColor() const { return data->color; }
>+
>+private:
>+  // Note: Takes ownership of strings, increases refcount for font.
>+  TextSpan(GooString *text,
>+           GfxFont *font,
>+           const GfxRGB& color)
>+      : data(new Data) {
>+    data->text = text;
>+    data->font = font;
>+    data->color = color;
>+    if (data->font)
>+      data->font->incRefCnt();
>+  }
>+
>+  struct Data {
>+    GfxFont   *font;
>+    GooString *text;
>+    GfxRGB     color;
>+    unsigned refcount;
>+
>+    Data(): refcount(1) {}
>+
>+    ~Data() {
>+      assert(refcount == 0);
>+      if (font)
>+        font->decRefCnt();
>+      delete text;
>+    }
>+  };
>+
>+  Data *data;
>+
>+  friend class MarkedContentOutputDev;
>+};
>+
>+
>+typedef std::vector<TextSpan> TextSpanArray;
>+
>+
>+class MarkedContentOutputDev: public OutputDev {
>+public:
>+  MarkedContentOutputDev(int mcidA);
>+  virtual ~MarkedContentOutputDev();
>+
>+  virtual GBool isOk() { return gTrue; }
>+  virtual GBool upsideDown() { return gTrue; }
>+  virtual GBool useDrawChar() { return gTrue; }
>+  virtual GBool interpretType3Chars() { return gFalse; }
>+  virtual GBool needNonText() { return gFalse; }
>+  virtual GBool needCharCount() { return gFalse; }
>+
>+  virtual void startPage(int pageNum, GfxState *state, XRef *xref);
>+  virtual void endPage();
>+
>+  virtual void drawChar(GfxState *state,
>+                        double xx, double yy,
>+                        double dx, double dy,
>+                        double ox, double oy,
>+                        CharCode c, int nBytes,
>+                        Unicode *u, int uLen);
>+
>+  virtual void beginMarkedContent(char *name, Dict *properties);
>+  virtual void endMarkedContent(GfxState *state);
>+
>+  const TextSpanArray& getTextSpans() const;
>+
>+private:
>+
>+  void endSpan();
>+  bool inMarkedContent() const { return mcidStack.size() > 0; }
>+  bool needFontChange(GfxFont* font) const;
>+
>+  GfxFont         *currentFont;
>+  GooString       *currentText;
>+  GfxRGB           currentColor;
>+  TextSpanArray    textSpans;
>+  int              mcid;
>+  std::vector<int> mcidStack;
>+  double           pageWidth;
>+  double           pageHeight;
>+  UnicodeMap      *unicodeMap;
>+};
>+
>+#endif /* !MARKEDCONTENTOUTPUTDEV_H */
>diff --git a/poppler/StructElement.cc b/poppler/StructElement.cc
>index 7d893df..3a98658 100644
>--- a/poppler/StructElement.cc
>+++ b/poppler/StructElement.cc
>@@ -14,6 +14,8 @@
> 
> #include "StructElement.h"
> #include "StructTreeRoot.h"
>+#include "GlobalParams.h"
>+#include "UnicodeMap.h"
> #include "PDFDoc.h"
> #include "Dict.h"
> 
>@@ -981,6 +983,54 @@ const Attribute *StructElement::findAttribute(Attribute::Type attributeType, GBo
>   return NULL;
> }
> 
>+GooString* StructElement::appendSubTreeText(GooString *string, GBool recursive) const
>+{
>+  if (isContent() && !isObjectRef()) {
>+    MarkedContentOutputDev mcdev(getMCID());
>+    const TextSpanArray& spans(getTextSpansInternal(mcdev));
>+
>+    if (!string)
>+      string = new GooString();
>+
>+    for (TextSpanArray::const_iterator i = spans.begin(); i != spans.end(); ++i)
>+      string->append(i->getText());
>+
>+    return string;
>+  }
>+
>+  if (!recursive)
>+    return NULL;
>+
>+  // Do a depth-first traversal, to get elements in logical order
>+  if (!string)
>+    string = new GooString();
>+
>+  for (unsigned i = 0; i < getNumElements(); i++)
>+    getElement(i)->appendSubTreeText(string, recursive);
>+
>+  return string;
>+}
>+
>+const TextSpanArray& StructElement::getTextSpansInternal(MarkedContentOutputDev& mcdev) const
>+{
>+  assert(isContent());
>+
>+  int startPage = 0, endPage = 0;
>+
>+  Ref ref;
>+  if (getPageRef(ref)) {
>+    startPage = endPage = treeRoot->getDoc()->findPage(ref.num, ref.gen);
>+  }
>+
>+  if (!(startPage && endPage)) {
>+    startPage = 1;
>+    endPage = treeRoot->getDoc()->getNumPages();
>+  }
>+
>+  treeRoot->getDoc()->displayPages(&mcdev, startPage, endPage, 72.0, 72.0, 0, gTrue, gFalse, gFalse);
>+  return mcdev.getTextSpans();
>+}
>+
> static StructElement::Type roleMapResolve(Dict *roleMap, const char *name, const char *curName, Object *resolved)
> {
>   // Circular reference
>diff --git a/poppler/StructElement.h b/poppler/StructElement.h
>index 00deef4..b9eef8a 100644
>--- a/poppler/StructElement.h
>+++ b/poppler/StructElement.h
>@@ -17,6 +17,7 @@
> 
> #include "goo/gtypes.h"
> #include "goo/GooString.h"
>+#include "MarkedContentOutputDev.h"
> #include "Object.h"
> #include <vector>
> #include <set>
>@@ -218,9 +219,36 @@ public:
>   const GooString *getActualText() const { return isContent() ? NULL : s->actualText; }
>   GooString *getActualText() { return isContent() ? NULL : s->actualText; }
> 
>+  // Content text referenced by the element:
>+  //
>+  // - For MCID reference elements, this is just the text of the
>+  //   corresponding marked content object in the page stream, regardless
>+  //   of the setting of the "recursive" flag.
>+  // - For other elements, if the "recursive" flag is set, the text
>+  //   enclosed by *all* the child MCID reference elements of the subtree
>+  //   is returned. The text is assembled by traversing the leaf MCID
>+  //   reference elements in logical order.
>+  // - In any other case, the function returns NULL.
>+  //
>+  // A new string is returned, and the ownership passed to the caller.
>+  //
>+  GooString *getText(GBool recursive = gTrue) const {
>+    return appendSubTreeText(NULL, recursive);
>+  }
>+
>+  const TextSpanArray getTextSpans() const {
>+    if (!isContent())
>+      return TextSpanArray();
>+    MarkedContentOutputDev mcdev(getMCID());
>+    return getTextSpansInternal(mcdev);
>+  }
>+
>   ~StructElement();
> 
> private:
>+  GooString* appendSubTreeText(GooString *string, GBool recursive) const;
>+  const TextSpanArray& getTextSpansInternal(MarkedContentOutputDev& mcdev) const;
>+
>   typedef std::vector<Attribute*>     AttrPtrArray;
>   typedef std::vector<StructElement*> ElemPtrArray;
> 
>-- 
>1.8.4.2
>

Actions: View | Splinter Review

Attachments on bug 64815: 79990 | 79991 | 80101 | 80407 | 81008 | 81009 | 81010 | 81011 | 81012 | 82286 | 82287 | 82288 | 82289 | 82290 | 86674 | 86675 | 86676 | 86677 | 86678 | 86730 | 87701 | 89046 | 89047 | 89917 | 90249 | 90311

Use of freedesktop.org services, including Bugzilla, is subject to our Code of Conduct. How we collect and use information is described in our Privacy Policy.