textoutputdev.cc

这是一个做pdf阅读器的源代码文件,是大家学习阅读器资料的很好参考

//========================================================================
//
// TextOutputDev.cc
//
// Copyright 1997-2003 Glyph & Cog, LLC
//
//========================================================================

#include <aconf.h>

#ifdef USE_GCC_PRAGMAS
#pragma implementation
#endif

#include <stdio.h>
#include <stdlib.h>
#include <stddef.h>
#include <math.h>
#include <ctype.h>
#ifdef WIN32
#include <fcntl.h> // for O_BINARY
#include <io.h>    // for setmode
#endif
#include "gmem.h"
#include "GString.h"
#include "GList.h"
#include "config.h"
#include "Error.h"
#include "GlobalParams.h"
#include "UnicodeMap.h"
#include "UnicodeTypeTable.h"
#include "GfxState.h"
#include "Link.h"
#include "TextOutputDev.h"

#ifdef MACOS
// needed for setting type/creator of MacOS files
#include "ICSupport.h"
#endif

//------------------------------------------------------------------------
// parameters
//------------------------------------------------------------------------

// Each bucket in a text pool includes baselines within a range of
// this many points.
#define textPoolStep 4

// Inter-character space width which will cause addChar to start a new
// word.
#define minWordBreakSpace 0.1

// Negative inter-character space width, i.e., overlap, which will
// cause addChar to start a new word.
#define minDupBreakOverlap 0.2

// Max distance between baselines of two lines within a block, as a
// fraction of the font size.
#define maxLineSpacingDelta 1.5

// Max difference in primary font sizes on two lines in the same
// block.  Delta1 is used when examining new lines above and below the
// current block; delta2 is used when examining text that overlaps the
// current block; delta3 is used when examining text to the left and
// right of the current block.
#define maxBlockFontSizeDelta1 0.05
#define maxBlockFontSizeDelta2 0.6
#define maxBlockFontSizeDelta3 0.2

// Max difference in font sizes inside a word.
#define maxWordFontSizeDelta 0.05

// Maximum distance between baselines of two words on the same line,
// e.g., distance between subscript or superscript and the primary
// baseline, as a fraction of the font size.
#define maxIntraLineDelta 0.5

// Minimum inter-word spacing, as a fraction of the font size.  (Only
// used for raw ordering.)
#define minWordSpacing 0.15

// Maximum inter-word spacing, as a fraction of the font size.
#define maxWordSpacing 1.5

// Maximum horizontal spacing which will allow a word to be pulled
// into a block.
#define minColSpacing1 0.3

// Minimum spacing between columns, as a fraction of the font size.
#define minColSpacing2 1.0

// Maximum vertical spacing between blocks within a flow, as a
// multiple of the font size.
#define maxBlockSpacing 2.5

// Minimum spacing between characters within a word, as a fraction of
// the font size.
#define minCharSpacing -0.2

// Maximum spacing between characters within a word, as a fraction of
// the font size, when there is no obvious extra-wide character
// spacing.
#define maxCharSpacing 0.03

// When extra-wide character spacing is detected, the inter-character
// space threshold is set to the minimum inter-character space
// multiplied by this constant.
#define maxWideCharSpacingMul 1.3

// Upper limit on spacing between characters in a word.
#define maxWideCharSpacing 0.4

// Max difference in primary,secondary coordinates (as a fraction of
// the font size) allowed for duplicated text (fake boldface, drop
// shadows) which is to be discarded.
#define dupMaxPriDelta 0.1
#define dupMaxSecDelta 0.2

// Max width of underlines (in points).
#define maxUnderlineWidth 3

// Min distance between baseline and underline (in points).
//~ this should be font-size-dependent
#define minUnderlineGap -2

// Max distance between baseline and underline (in points).
//~ this should be font-size-dependent
#define maxUnderlineGap 4

// Max horizontal distance between edge of word and start of underline
// (in points).
//~ this should be font-size-dependent
#define underlineSlack 1

// Max distance between edge of text and edge of link border
#define hyperlinkSlack 2

//------------------------------------------------------------------------
// TextUnderline
//------------------------------------------------------------------------

class TextUnderline {
public:

  TextUnderline(double x0A, double y0A, double x1A, double y1A)
    { x0 = x0A; y0 = y0A; x1 = x1A; y1 = y1A; horiz = y0 == y1; }
  ~TextUnderline() {}

  double x0, y0, x1, y1;
  GBool horiz;
};

//------------------------------------------------------------------------
// TextLink
//------------------------------------------------------------------------

class TextLink {
public:

  TextLink(int xMinA, int yMinA, int xMaxA, int yMaxA, Link *linkA)
    { xMin = xMinA; yMin = yMinA; xMax = xMaxA; yMax = yMaxA; link = linkA; }
  ~TextLink() {}

  int xMin, yMin, xMax, yMax;
  Link *link;
};

//------------------------------------------------------------------------
// TextFontInfo
//------------------------------------------------------------------------

TextFontInfo::TextFontInfo(GfxState *state) {
  gfxFont = state->getFont();
#if TEXTOUT_WORD_LIST
  fontName = (gfxFont && gfxFont->getOrigName())
                 ? gfxFont->getOrigName()->copy()
                 : (GString *)NULL;
  flags = gfxFont ? gfxFont->getFlags() : 0;
#endif
}

TextFontInfo::~TextFontInfo() {
#if TEXTOUT_WORD_LIST
  if (fontName) {
    delete fontName;
  }
#endif
}

GBool TextFontInfo::matches(GfxState *state) {
  return state->getFont() == gfxFont;
}

//------------------------------------------------------------------------
// TextWord
//------------------------------------------------------------------------

TextWord::TextWord(GfxState *state, int rotA, double x0, double y0,
		   int charPosA, TextFontInfo *fontA, double fontSizeA) {
  GfxFont *gfxFont;
  double x, y, ascent, descent;

  rot = rotA;
  charPos = charPosA;
  charLen = 0;
  font = fontA;
  fontSize = fontSizeA;
  state->transform(x0, y0, &x, &y);
  if ((gfxFont = font->gfxFont)) {
    ascent = gfxFont->getAscent() * fontSize;
    descent = gfxFont->getDescent() * fontSize;
  } else {
    // this means that the PDF file draws text without a current font,
    // which should never happen
    ascent = 0.95 * fontSize;
    descent = -0.35 * fontSize;
  }
  switch (rot) {
  case 0:
    yMin = y - ascent;
    yMax = y - descent;
    if (yMin == yMax) {
      // this is a sanity check for a case that shouldn't happen -- but
      // if it does happen, we want to avoid dividing by zero later
      yMin = y;
      yMax = y + 1;
    }
    base = y;
    break;
  case 1:
    xMin = x + descent;
    xMax = x + ascent;
    if (xMin == xMax) {
      // this is a sanity check for a case that shouldn't happen -- but
      // if it does happen, we want to avoid dividing by zero later
      xMin = x;
      xMax = x + 1;
    }
    base = x;
    break;
  case 2:
    yMin = y + descent;
    yMax = y + ascent;
    if (yMin == yMax) {
      // this is a sanity check for a case that shouldn't happen -- but
      // if it does happen, we want to avoid dividing by zero later
      yMin = y;
      yMax = y + 1;
    }
    base = y;
    break;
  case 3:
    xMin = x - ascent;
    xMax = x - descent;
    if (xMin == xMax) {
      // this is a sanity check for a case that shouldn't happen -- but
      // if it does happen, we want to avoid dividing by zero later
      xMin = x;
      xMax = x + 1;
    }
    base = x;
    break;
  }
  text = NULL;
  edge = NULL;
  len = size = 0;
  spaceAfter = gFalse;
  next = NULL;

#if TEXTOUT_WORD_LIST
  GfxRGB rgb;

  if ((state->getRender() & 3) == 1) {
    state->getStrokeRGB(&rgb);
  } else {
    state->getFillRGB(&rgb);
  }
  colorR = colToDbl(rgb.r);
  colorG = colToDbl(rgb.g);
  colorB = colToDbl(rgb.b);
#endif

  underlined = gFalse;
  link = NULL;
}

TextWord::~TextWord() {
  gfree(text);
  gfree(edge);
}

void TextWord::addChar(GfxState *state, double x, double y,
		       double dx, double dy, Unicode u) {
  if (len == size) {
    size += 16;
    text = (Unicode *)greallocn(text, size, sizeof(Unicode));
    edge = (double *)greallocn(edge, size + 1, sizeof(double));
  }
  text[len] = u;
  switch (rot) {
  case 0:
    if (len == 0) {
      xMin = x;
    }
    edge[len] = x;
    xMax = edge[len+1] = x + dx;
    break;
  case 1:
    if (len == 0) {
      yMin = y;
    }
    edge[len] = y;
    yMax = edge[len+1] = y + dy;
    break;
  case 2:
    if (len == 0) {
      xMax = x;
    }
    edge[len] = x;
    xMin = edge[len+1] = x + dx;
    break;
  case 3:
    if (len == 0) {
      yMax = y;
    }
    edge[len] = y;
    yMin = edge[len+1] = y + dy;
    break;
  }
  ++len;
}

void TextWord::merge(TextWord *word) {
  int i;

  if (word->xMin < xMin) {
    xMin = word->xMin;
  }
  if (word->yMin < yMin) {
    yMin = word->yMin;
  }
  if (word->xMax > xMax) {
    xMax = word->xMax;
  }
  if (word->yMax > yMax) {
    yMax = word->yMax;
  }
  if (len + word->len > size) {
    size = len + word->len;
    text = (Unicode *)greallocn(text, size, sizeof(Unicode));
    edge = (double *)greallocn(edge, size + 1, sizeof(double));
  }
  for (i = 0; i < word->len; ++i) {
    text[len + i] = word->text[i];
    edge[len + i] = word->edge[i];
  }
  edge[len + word->len] = word->edge[word->len];
  len += word->len;
  charLen += word->charLen;
}

inline int TextWord::primaryCmp(TextWord *word) {
  double cmp;

  cmp = 0; // make gcc happy
  switch (rot) {
  case 0:
    cmp = xMin - word->xMin;
    break;
  case 1:
    cmp = yMin - word->yMin;
    break;
  case 2:
    cmp = word->xMax - xMax;
    break;
  case 3:
    cmp = word->yMax - yMax;
    break;
  }
  return cmp < 0 ? -1 : cmp > 0 ? 1 : 0;
}

double TextWord::primaryDelta(TextWord *word) {
  double delta;

  delta = 0; // make gcc happy
  switch (rot) {
  case 0:
    delta = word->xMin - xMax;
    break;
  case 1:
    delta = word->yMin - yMax;
    break;
  case 2:
    delta = xMin - word->xMax;
    break;
  case 3:
    delta = yMin - word->yMax;
    break;
  }
  return delta;
}

int TextWord::cmpYX(const void *p1, const void *p2) {
  TextWord *word1 = *(TextWord **)p1;
  TextWord *word2 = *(TextWord **)p2;
  double cmp;

  cmp = word1->yMin - word2->yMin;
  if (cmp == 0) {
    cmp = word1->xMin - word2->xMin;
  }
  return cmp < 0 ? -1 : cmp > 0 ? 1 : 0;
}

#if TEXTOUT_WORD_LIST

GString *TextWord::getText() {
  GString *s;
  UnicodeMap *uMap;
  char buf[8];
  int n, i;

  s = new GString();
  if (!(uMap = globalParams->getTextEncoding())) {
    return s;
  }
  for (i = 0; i < len; ++i) {
    n = uMap->mapUnicode(text[i], buf, sizeof(buf));
    s->append(buf, n);
  }
  uMap->decRefCnt();
  return s;
}

void TextWord::getCharBBox(int charIdx, double *xMinA, double *yMinA,
			   double *xMaxA, double *yMaxA) {
  if (charIdx < 0 || charIdx >= len) {
    return;
  }
  switch (rot) {
  case 0:
    *xMinA = edge[charIdx];
    *xMaxA = edge[charIdx + 1];
    *yMinA = yMin;
    *yMaxA = yMax;
    break;
  case 1:
    *xMinA = xMin;
    *xMaxA = xMax;
    *yMinA = edge[charIdx];
    *yMaxA = edge[charIdx + 1];
    break;
  case 2:
    *xMinA = edge[charIdx + 1];
    *xMaxA = edge[charIdx];
    *yMinA = yMin;
    *yMaxA = yMax;
    break;
  case 3:
    *xMinA = xMin;
    *xMaxA = xMax;
    *yMinA = edge[charIdx + 1];
    *yMaxA = edge[charIdx];
    break;
  }
}

#endif // TEXTOUT_WORD_LIST

//------------------------------------------------------------------------
// TextPool
//------------------------------------------------------------------------

TextPool::TextPool() {
  minBaseIdx = 0;
  maxBaseIdx = -1;
  pool = NULL;
  cursor = NULL;
  cursorBaseIdx = -1;
}

TextPool::~TextPool() {
  int baseIdx;
  TextWord *word, *word2;

  for (baseIdx = minBaseIdx; baseIdx <= maxBaseIdx; ++baseIdx) {
    for (word = pool[baseIdx - minBaseIdx]; word; word = word2) {
      word2 = word->next;
      delete word;
    }
  }
  gfree(pool);
}

int TextPool::getBaseIdx(double base) {
  int baseIdx;

  baseIdx = (int)(base / textPoolStep);
  if (baseIdx < minBaseIdx) {
    return minBaseIdx;
  }
  if (baseIdx > maxBaseIdx) {
    return maxBaseIdx;
  }
  return baseIdx;
}

void TextPool::addWord(TextWord *word) {
  TextWord **newPool;
  int wordBaseIdx, newMinBaseIdx, newMaxBaseIdx, baseIdx;
  TextWord *w0, *w1;