//========================================================================

//

// SplashXPath.cc

//

// Copyright 2003-2013 Glyph & Cog, LLC

//

//========================================================================

#include <aconf.h>

#include <stdlib.h>

#include <string.h>

#if HAVE_STD_SORT

#include <algorithm>

#endif

#include "gmem.h"

#include "gmempp.h"

#include "SplashMath.h"

#include "SplashPath.h"

#include "SplashClip.h"

#include "SplashXPath.h"

//------------------------------------------------------------------------

#define minCosSquaredJoinAngle 0.75

#define maxPointToLineDistanceSquared 0.04

//------------------------------------------------------------------------

struct SplashXPathPoint {

  SplashCoord x, y;

};

struct SplashXPathAdjust {

  int firstPt, lastPt;    // range of points

  GBool vert;     // vertical or horizontal hint

  SplashCoord x0a, x0b,   // hint boundaries

              xma, xmb,

              x1a, x1b;

  SplashCoord x0, x1, xm; // adjusted coordinates

};

//------------------------------------------------------------------------

// Transform a point from user space to device space.

inline void SplashXPath::transform(SplashCoord *matrix,

           SplashCoord xi, SplashCoord yi,

           SplashCoord *xo, SplashCoord *yo) {

  //                          [ m[0] m[1] 0 ]

  // [xo yo 1] = [xi yi 1] *  [ m[2] m[3] 0 ]

  //                          [ m[4] m[5] 1 ]

  *xo = xi * matrix[0] + yi * matrix[2] + matrix[4];

  *yo = xi * matrix[1] + yi * matrix[3] + matrix[5];

}

//------------------------------------------------------------------------

// SplashXPath

//------------------------------------------------------------------------

// SplashXPath segment coords are clipped to +/-maxCoord to avoid

// problems.  The xMin/yMin/xMax/yMax fields are 32-bit integers, so

// coords need to be < 2^31 / aa{Horiz,Vert}.

#define maxCoord 100000000.0

void SplashXPath::clampCoords(SplashCoord *x, SplashCoord *y) {

#if !USE_FIXEDPOINT

  if (*x > maxCoord) {

    *x = maxCoord;

  } else if (*x < -maxCoord) {

    *x = -maxCoord;

  }

  if (*y > maxCoord) {

    *y = maxCoord;

  } else if (*y < -maxCoord) {

    *y = -maxCoord;

  }

#endif

}

SplashXPath::SplashXPath(SplashPath *path, SplashCoord *matrix,

       SplashCoord flatness, GBool closeSubpaths,

       GBool simplify,

       SplashStrokeAdjustMode strokeAdjMode,

       SplashClip *clip) {

  SplashXPathPoint *pts;

  SplashCoord x0, y0, x1, y1, x2, y2, x3, y3, xsp, ysp, t;

  int curSubpath, firstSegInSubpath, i;

  GBool adjusted;

  //--- transform the points

  pts = (SplashXPathPoint *)gmallocn(path->length, sizeof(SplashXPathPoint));

  for (i = 0; i < path->length; ++i) {

    transform(matrix, path->pts[i].x, path->pts[i].y, &pts[i].x, &pts[i].y);

    clampCoords(&pts[i].x, &pts[i].y);

  }

  //--- do stroke adjustment

  if (path->hints) {

    adjusted = strokeAdjust(pts, path->hints, path->hintsLength,

          strokeAdjMode, clip);

  } else {

    adjusted = gFalse;

  }

  //--- construct the segments

  segs = NULL;

  length = size = 0;

  x0 = y0 = xsp = ysp = 0; // make gcc happy

  curSubpath = 0;

  firstSegInSubpath = 0;

  i = 0;

  while (i < path->length) {

    // first point in subpath - skip it

    if (path->flags[i] & splashPathFirst) {

      x0 = pts[i].x;

      y0 = pts[i].y;

      xsp = x0;

      ysp = y0;

      curSubpath = i;

      ++i;

    } else {

      // curve segment

      if (path->flags[i] & splashPathCurve) {

  x1 = pts[i].x;

  y1 = pts[i].y;

  x2 = pts[i+1].x;

  y2 = pts[i+1].y;

  x3 = pts[i+2].x;

  y3 = pts[i+2].y;

  addCurve(x0, y0, x1, y1, x2, y2, x3, y3,

     flatness,

     (path->flags[i-1] & splashPathFirst),

     (path->flags[i+2] & splashPathLast),

     !closeSubpaths &&

       (path->flags[i-1] & splashPathFirst) &&

       !(path->flags[i-1] & splashPathClosed),

     !closeSubpaths &&

       (path->flags[i+2] & splashPathLast) &&

       !(path->flags[i+2] & splashPathClosed));

  x0 = x3;

  y0 = y3;

  i += 3;

      // line segment

      } else {

  x1 = pts[i].x;

  y1 = pts[i].y;

  addSegment(x0, y0, x1, y1);

  x0 = x1;

  y0 = y1;

  ++i;

      }

      // end a subpath

      if (path->flags[i-1] & splashPathLast) {

  if (closeSubpaths &&

      (pts[i-1].x != pts[curSubpath].x ||

       pts[i-1].y != pts[curSubpath].y)) {

    addSegment(x0, y0, xsp, ysp);

  }

  if (simplify && !adjusted) {

    mergeSegments(firstSegInSubpath);

  }

  firstSegInSubpath = length;

      }

    }

  }

  gfree(pts);

  finishSegments();

  //--- check for a rectangle

  isRect = gFalse;

  rectX0 = rectY0 = rectX1 = rectY1 = 0;

  if (length == 4) {

#if HAVE_STD_SORT

    std::sort(segs, segs + length, SplashXPathSeg::cmpY);

#else

    qsort(segs, length, sizeof(SplashXPathSeg), &SplashXPathSeg::cmpY);

#endif

    if (segs[0].y0 == segs[0].y1 &&

  segs[1].x0 == segs[1].x1 &&

  segs[2].x0 == segs[2].x1 &&

  segs[3].y0 == segs[3].y1) {

      isRect = gTrue;

      rectX0 = segs[1].x0;

      rectX1 = segs[2].x0;

      rectY0 = segs[0].y0;

      rectY1 = segs[3].y0;

    } else if (segs[0].x0 == segs[0].x1 &&

         segs[1].y0 == segs[1].y1 &&

         segs[2].x0 == segs[2].x1 &&

         segs[3].y0 == segs[3].y1) {

      isRect = gTrue;

      rectX0 = segs[0].x0;

      rectX1 = segs[2].x0;

      rectY0 = segs[1].y0;

      rectY1 = segs[3].y0;

    } else if (segs[0].x0 == segs[0].x1 &&

         segs[1].x0 == segs[1].x1 &&

         segs[2].y0 == segs[2].y1 &&

         segs[3].y0 == segs[3].y1) {

      isRect = gTrue;

      rectX0 = segs[0].x0;

      rectX1 = segs[1].x0;

      rectY0 = segs[2].y0;

      rectY1 = segs[3].y0;

    }

    if (isRect) {

      if (rectX0 > rectX1) {

  t = rectX0;  rectX0 = rectX1;  rectX1 = t;

      }

      if (rectY0 > rectY1) {

  t = rectY0;  rectY0 = rectY1;  rectY1 = t;

      }

    }

  }

}

GBool SplashXPath::strokeAdjust(SplashXPathPoint *pts,

        SplashPathHint *hints, int nHints,

        SplashStrokeAdjustMode strokeAdjMode,

        SplashClip *clip) {

  SplashXPathAdjust *adjusts, *adjust;

  SplashPathHint *hint;

  SplashCoord x0, y0, x1, y1, x2, y2, x3, y3;

  SplashCoord adj0, adj1, w, d;

  int xi0, xi1;

  int i, j;

  GBool adjusted;

  adjusted = gFalse;

  // With CAD-mode stroke adjustment, and a simple rectangular clip

  // region, stroke-adjusted edges that fall slightly outside the clip

  // region are adjusted back inside the clip region.  This avoids

  // problems with narrow lines in slightly mismatched clip

  // rectangles, which appear to be generated somewhat commonly by

  // buggy CAD software.  (Note: [clip] is NULL when called to build a

  // clip path.)

  GBool clipTweak = clip && clip->getIsSimple() &&

                    strokeAdjMode == splashStrokeAdjustCAD;

  SplashCoord cx0 = 0, cx1 = 0, cy0 = 0, cy1 = 0;

  int cxi0 = 0, cxi1 = 0, cyi0 = 0, cyi1 = 0;

  if (clipTweak) {

    cx0 = clip->getXMin();

    cx1 = clip->getXMax();

    cy0 = clip->getYMin();

    cy1 = clip->getYMax();

    cxi0 = clip->getXMinI(strokeAdjMode);

    cxi1 = clip->getXMaxI(strokeAdjMode);

    cyi0 = clip->getYMinI(strokeAdjMode);

    cyi1 = clip->getYMaxI(strokeAdjMode);

  }

  // set up the stroke adjustment hints

  adjusts = (SplashXPathAdjust *)gmallocn(nHints, sizeof(SplashXPathAdjust));

  for (i = 0; i < nHints; ++i) {

    hint = &hints[i];

    x0 = pts[hint->ctrl0    ].x;    y0 = pts[hint->ctrl0    ].y;

    x1 = pts[hint->ctrl0 + 1].x;    y1 = pts[hint->ctrl0 + 1].y;

    x2 = pts[hint->ctrl1    ].x;    y2 = pts[hint->ctrl1    ].y;

    x3 = pts[hint->ctrl1 + 1].x;    y3 = pts[hint->ctrl1 + 1].y;

    w = -1;

    if (splashAbs(x0 - x1) < 0.01 && splashAbs(x2 - x3) < 0.01) {

      adjusts[i].vert = gTrue;

      adj0 = x0;

      adj1 = x2;

      if (hint->projectingCap) {

  w = splashAbs(y1 - y0);

      }

    } else if (splashAbs(y0 - y1) < 0.01 && splashAbs(y2 - y3) < 0.01) {

      adjusts[i].vert = gFalse;

      adj0 = y0;

      adj1 = y2;

      if (hint->projectingCap) {

  w = splashAbs(x1 - x0);

      }

    } else {

      goto done;

    }

    if (adj0 > adj1) {

      x0 = adj0;

      adj0 = adj1;

      adj1 = x0;

    }

    d = adj1 - adj0;

    if (d > 0.04) {

      d = 0.01;

    } else {

      d *= 0.25;

    }

    adjusts[i].x0a = adj0 - d;

    adjusts[i].x0b = adj0 + d;

    adjusts[i].xma = (SplashCoord)0.5 * (adj0 + adj1) - d;

    adjusts[i].xmb = (SplashCoord)0.5 * (adj0 + adj1) + d;

    adjusts[i].x1a = adj1 - d;

    adjusts[i].x1b = adj1 + d;

    splashStrokeAdjust(adj0, adj1, &xi0, &xi1, strokeAdjMode, w);

    if (clipTweak) {

      SplashCoord c0, c1;

      int ci0, ci1;

      if (adjusts[i].vert) {

  c0 = cx0;

  c1 = cx1;

  ci0 = cxi0;

  ci1 = cxi1;

      } else {

  c0 = cy0;

  c1 = cy1;

  ci0 = cyi0;

  ci1 = cyi1;

      }

      if (adj0 < c0 && c0 < adj1 && adj1 < c1 &&

    adj1 - c0 > (adj1 - adj0) * 0.2 &&

    xi1 <= ci0) {

  xi0 = ci0;

  xi1 = xi0 + 1;

      } else if (c0 < adj0 && adj0 < c1 && c1 < adj1 &&

     c1 - adj0 > (adj1 - adj0) * 0.2 &&

     ci1 < xi0) {

  xi0 = ci1;

  xi1 = ci1 + 1;

      }

    }

    adjusts[i].x0 = (SplashCoord)xi0;

    // the "minus epsilon" thing here is needed when vector

    // antialiasing is turned off -- otherwise stroke adjusted lines

    // will touch an extra pixel on one edge

    adjusts[i].x1 = (SplashCoord)xi1 - 0.001;

    adjusts[i].xm = (SplashCoord)0.5 * (adjusts[i].x0 + adjusts[i].x1);

    adjusts[i].firstPt = hint->firstPt;

    adjusts[i].lastPt = hint->lastPt;

  }

  // perform stroke adjustment

  for (i = 0, adjust = adjusts; i < nHints; ++i, ++adjust) {

    for (j = adjust->firstPt; j <= adjust->lastPt; ++j) {

      if (adjust->vert) {

  x0 = pts[j].x;

  if (x0 > adjust->x0a && x0 < adjust->x0b) {

    pts[j].x = adjust->x0;

  } else if (x0 > adjust->xma && x0 < adjust->xmb) {

    pts[j].x = adjust->xm;

  } else if (x0 > adjust->x1a && x0 < adjust->x1b) {

    pts[j].x = adjust->x1;

  }

      } else {

  y0 = pts[j].y;

  if (y0 > adjust->x0a && y0 < adjust->x0b) {

    pts[j].y = adjust->x0;

  } else if (y0 > adjust->xma && y0 < adjust->xmb) {

    pts[j].y = adjust->xm;

  } else if (y0 > adjust->x1a && y0 < adjust->x1b) {

    pts[j].y = adjust->x1;

  }

      }

    }

  }

  adjusted = gTrue;

 done:

  gfree(adjusts);

  return adjusted;

}

SplashXPath::SplashXPath(SplashXPath *xPath) {

  length = xPath->length;

  size = xPath->size;

  segs = (SplashXPathSeg *)gmallocn(size, sizeof(SplashXPathSeg));

  memcpy(segs, xPath->segs, length * sizeof(SplashXPathSeg));

  xMin = xPath->xMin;

  yMin = xPath->yMin;

  xMax = xPath->xMax;

  yMax = xPath->yMax;

}

SplashXPath::~SplashXPath() {

  gfree(segs);

}

// Add space for <nSegs> more segments

void SplashXPath::grow(int nSegs) {

  if (length + nSegs > size) {

    if (size == 0) {

      size = 32;

    }

    while (size < length + nSegs) {

      size *= 2;

    }

    segs = (SplashXPathSeg *)greallocn(segs, size, sizeof(SplashXPathSeg));

  }

}

void SplashXPath::addCurve(SplashCoord x0, SplashCoord y0,

         SplashCoord x1, SplashCoord y1,

         SplashCoord x2, SplashCoord y2,

         SplashCoord x3, SplashCoord y3,

         SplashCoord flatness,

         GBool first, GBool last, GBool end0, GBool end1) {

  SplashCoord cx[splashMaxCurveSplits + 1][3];

  SplashCoord cy[splashMaxCurveSplits + 1][3];

  int cNext[splashMaxCurveSplits + 1];

  SplashCoord xl0, xl1, xl2, xr0, xr1, xr2, xr3, xx1, xx2, xh;

  SplashCoord yl0, yl1, yl2, yr0, yr1, yr2, yr3, yy1, yy2, yh;

  SplashCoord dx, dy, mx, my, d1, d2, flatness2;

  int p1, p2, p3;

#if USE_FIXEDPOINT

  flatness2 = flatness;

#else

  flatness2 = flatness * flatness;

#endif

  // initial segment

  p1 = 0;

  p2 = splashMaxCurveSplits;

  cx[p1][0] = x0;  cy[p1][0] = y0;

  cx[p1][1] = x1;  cy[p1][1] = y1;

  cx[p1][2] = x2;  cy[p1][2] = y2;

  cx[p2][0] = x3;  cy[p2][0] = y3;

  cNext[p1] = p2;

  while (p1 < splashMaxCurveSplits) {

    // get the next segment

    xl0 = cx[p1][0];  yl0 = cy[p1][0];

    xx1 = cx[p1][1];  yy1 = cy[p1][1];

    xx2 = cx[p1][2];  yy2 = cy[p1][2];

    p2 = cNext[p1];

    xr3 = cx[p2][0];  yr3 = cy[p2][0];

    // compute the distances from the control points to the

    // midpoint of the straight line (this is a bit of a hack, but

    // it's much faster than computing the actual distances to the

    // line)

    mx = (xl0 + xr3) * 0.5;

    my = (yl0 + yr3) * 0.5;

#if USE_FIXEDPOINT

    d1 = splashDist(xx1, yy1, mx, my);

    d2 = splashDist(xx2, yy2, mx, my);

#else

    dx = xx1 - mx;

    dy = yy1 - my;

    d1 = dx*dx + dy*dy;

    dx = xx2 - mx;

    dy = yy2 - my;

    d2 = dx*dx + dy*dy;

#endif

    // if the curve is flat enough, or no more subdivisions are

    // allowed, add the straight line segment

    if (p2 - p1 == 1 || (d1 <= flatness2 && d2 <= flatness2)) {

      addSegment(xl0, yl0, xr3, yr3);

      p1 = p2;

    // otherwise, subdivide the curve

    } else {

      xl1 = (xl0 + xx1) * 0.5;

      yl1 = (yl0 + yy1) * 0.5;

      xh = (xx1 + xx2) * 0.5;

      yh = (yy1 + yy2) * 0.5;

      xl2 = (xl1 + xh) * 0.5;

      yl2 = (yl1 + yh) * 0.5;

      xr2 = (xx2 + xr3) * 0.5;

      yr2 = (yy2 + yr3) * 0.5;

      xr1 = (xh + xr2) * 0.5;

      yr1 = (yh + yr2) * 0.5;

      xr0 = (xl2 + xr1) * 0.5;

      yr0 = (yl2 + yr1) * 0.5;

      // add the new subdivision points

      p3 = (p1 + p2) / 2;

      cx[p1][1] = xl1;  cy[p1][1] = yl1;

      cx[p1][2] = xl2;  cy[p1][2] = yl2;

      cNext[p1] = p3;

      cx[p3][0] = xr0;  cy[p3][0] = yr0;

      cx[p3][1] = xr1;  cy[p3][1] = yr1;

      cx[p3][2] = xr2;  cy[p3][2] = yr2;

      cNext[p3] = p2;

    }

  }

}

void SplashXPath::addSegment(SplashCoord x0, SplashCoord y0,

           SplashCoord x1, SplashCoord y1) {

  grow(1);

  segs[length].x0 = x0;

  segs[length].y0 = y0;

  segs[length].x1 = x1;

  segs[length].y1 = y1;

  ++length;

}

// Returns true if the angle between (x0,y0)-(x1,y1) and

// (x1,y1)-(x2,y2) is close to 180 degrees.

static GBool joinAngleIsFlat(SplashCoord x0, SplashCoord y0,

           SplashCoord x1, SplashCoord y1,

           SplashCoord x2, SplashCoord y2) {

  SplashCoord dx1, dy1, dx2, dy2, d, len1, len2;

  dx1 = x1 - x0;

  dy1 = y1 - y0;

  dx2 = x2 - x1;

  dy2 = y2 - y1;

  d = dx1 * dx2 + dy1 * dy2;

  len1 = dx1 * dx1 + dy1 * dy1;

  len2 = dx2 * dx2 + dy2 * dy2;

  return d > 0 && d * d > len1 * len2 * minCosSquaredJoinAngle;

}

// Returns true if (x1,y1) is sufficiently close to the segment

// (x0,y0)-(x2,y2), looking at the perpendicular point-to-line

// distance.

static GBool pointCloseToSegment(SplashCoord x0, SplashCoord y0,

         SplashCoord x1, SplashCoord y1,

         SplashCoord x2, SplashCoord y2) {

  SplashCoord t1, t2, dx, dy;

  // compute the perpendicular distance from the point to the segment,

  // i.e., the projection of (x0,y0)-(x1,y1) onto a unit normal to the

  // segment (this actually computes the square of the distance)

  dx = x2 - x0;

  dy = y2 - y0;

  t1 = dx*dx + dy*dy;

  if (t1 < 0.0001) {

    // degenerate case: (x0,y0) and (x2,y2) are (nearly) identical --

    // just compute the distance to (x1,y1)

    dx = x0 - x1;

    dy = y0 - y1;

    t2 = dx*dx + dy*dy;

    return t2 < maxPointToLineDistanceSquared;

  }

  t2 = x1 * dy - dx * y1 - x0 * y2 + x2 * y0;

  // actual distance = t2 / sqrt(t1)

  return t2 * t2 < t1 * maxPointToLineDistanceSquared;

}

// Attempt to simplify the path by merging sequences of consecutive

// segments in [first] .. [length]-1.

void SplashXPath::mergeSegments(int first) {

  GBool horiz, vert;

  int in, out, prev, i, j;

  in = out = first;

  while (in < length) {

    // skip zero-length segments

    if (segs[in].x0 == segs[in].x1 && segs[in].y0 == segs[in].y1) {

      ++in;

      continue;

    }

    horiz = segs[in].y0 == segs[in].y1;

    vert = segs[in].x0 == segs[in].x1;

    // check for a sequence of mergeable segments: in .. i

    prev = in;

    for (i = in + 1; i < length; ++i) {

      // skip zero-length segments

      if (segs[i].x0 == segs[i].x1 && segs[i].y0 == segs[i].y1) {

  continue;

      }

      // check for a horizontal or vertical segment

      if ((horiz && segs[in].y0 != segs[in].y1) ||

    (vert && segs[in].x0 != segs[in].x1)) {

  break;

      }

      // check the angle between segs i-1 and i

      // (actually, we compare seg i to the previous non-zero-length

      // segment, which may not be i-1)

      if (!joinAngleIsFlat(segs[prev].x0, segs[prev].y0,

         segs[i].x0, segs[i].y0,

         segs[i].x1, segs[i].y1)) {

  break;

      }

      // check the distances from the ends of segs in .. i-1 to the

      // proposed new segment

      for (j = in; j < i; ++j) {

  if (!pointCloseToSegment(segs[in].x0, segs[in].y0,

         segs[j].x1, segs[j].y1,

         segs[i].x1, segs[i].y1)) {

    break;

  }

      }

      if (j < i) {

  break;

      }

      prev = i;

    }

    // we can merge segs: in .. i-1

    // (this may be the single segment: in)

    segs[out].x0 = segs[in].x0;

    segs[out].y0 = segs[in].y0;

    segs[out].x1 = segs[i-1].x1;

    segs[out].y1 = segs[i-1].y1;

    in = i;

    ++out;

  }

  length = out;

}

void SplashXPath::finishSegments() {

  SplashXPathSeg *seg;

  SplashCoord xMinFP, xMaxFP, yMinFP, yMaxFP, t;

  int i;

  xMinFP = yMinFP = xMaxFP = yMaxFP = 0;

  for (i = 0; i < length; ++i) {

    seg = &segs[i];

    //--- compute the slopes

    if (seg->y0 <= seg->y1) {

      seg->count = 1;

    } else {

      t = seg->x0;  seg->x0 = seg->x1;  seg->x1 = t;

      t = seg->y0;  seg->y0 = seg->y1;  seg->y1 = t;

      seg->count = -1;

    }

#if USE_FIXEDPOINT

    if (seg->y0 == seg->y1 || seg->x0 == seg->x1 ||

  !FixedPoint::divCheck(seg->x1 - seg->x0, seg->y1 - seg->y0,

            &seg->dxdy) ||

  !FixedPoint::divCheck(seg->y1 - seg->y0, seg->x1 - seg->x0,

            &seg->dydx)) {

      seg->dxdy = 0;

      seg->dydx = 0;

    }

#else

    if (splashAbs(seg->y1 - seg->y0) < 1e-200 ||

  splashAbs(seg->x1 - seg->x0) < 1e-200) {

      seg->dxdy = 0;

      seg->dydx = 0;

    } else {

      seg->dxdy = (seg->x1 - seg->x0) / (seg->y1 - seg->y0);

      if (seg->dxdy == 0) {

  seg->dydx = 0;

      } else {

  seg->dydx = 1 / seg->dxdy;

      }

    }

#endif

    //--- update bbox

    if (i == 0) {

      if (seg->x0 <= seg->x1) {

  xMinFP = seg->x0;

  xMaxFP = seg->x1;

      } else {

  xMinFP = seg->x1;

  xMaxFP = seg->x0;

      }

      yMinFP = seg->y0;

      yMaxFP = seg->y1;

    } else {

      if (seg->x0 < xMinFP) {

  xMinFP = seg->x0;

      } else if (seg->x0 > xMaxFP) {

  xMaxFP = seg->x0;

      }

      if (seg->x1 < xMinFP) {

  xMinFP = seg->x1;

      } else if (seg->x1 > xMaxFP) {

  xMaxFP = seg->x1;

      }

      if (seg->y0 < yMinFP) {

  yMinFP = seg->y0;

      }

      if (seg->y1 > yMaxFP) {

  yMaxFP = seg->y1;

      }

    }

  }

  xMin = splashFloor(xMinFP);

  yMin = splashFloor(yMinFP);

  xMax = splashFloor(xMaxFP);

  yMax = splashFloor(yMaxFP);

}