#undef WIN32_LEAN_AND_MEAN
#include <windows.h>
#include <ddk/ntddk.h>
#include <win32k/brush.h>
#include <win32k/dc.h>
#include <win32k/path.h>
#include <win32k/math.h>
#include <win32k/float.h>
#include <win32k/coord.h>
#include <win32k/line.h>

#include <math.h>
#include <float.h>

// #define NDEBUG
#include <win32k/debug1.h>

#define NUM_ENTRIES_INITIAL 16  /* Initial size of points / flags arrays  */
#define GROW_FACTOR_NUMER    2  /* Numerator of grow factor for the array */
#define GROW_FACTOR_DENOM    1  /* Denominator of grow factor             */


static BOOL PATH_PathToRegion(const GdiPath *pPath, INT nPolyFillMode,
   HRGN *pHrgn);
static void   PATH_EmptyPath(GdiPath *pPath);
static BOOL PATH_AddEntry(GdiPath *pPath, const POINT *pPoint,
   BYTE flags);
static BOOL PATH_ReserveEntries(GdiPath *pPath, INT numEntries);
static BOOL PATH_GetPathFromHDC(HDC hdc, GdiPath **ppPath);
static BOOL PATH_DoArcPart(GdiPath *pPath, FLOAT_POINT corners[],
   double angleStart, double angleEnd, BOOL addMoveTo);
static void PATH_ScaleNormalizedPoint(FLOAT_POINT corners[], double x,
   double y, POINT *pPoint);
static void PATH_NormalizePoint(FLOAT_POINT corners[], const FLOAT_POINT
   *pPoint, double *pX, double *pY);

BOOL
STDCALL
W32kAbortPath(HDC  hDC)
{
  UNIMPLEMENTED;
}

BOOL
STDCALL
W32kBeginPath(HDC  hDC)
{
  UNIMPLEMENTED;
}

BOOL
STDCALL
W32kCloseFigure(HDC  hDC)
{
  UNIMPLEMENTED;
}

BOOL
STDCALL
W32kEndPath(HDC  hDC)
{
  UNIMPLEMENTED;
}

BOOL
STDCALL
W32kFillPath(HDC  hDC)
{
  UNIMPLEMENTED;
}

BOOL
STDCALL
W32kFlattenPath(HDC  hDC)
{
  UNIMPLEMENTED;
}


BOOL
STDCALL
W32kGetMiterLimit(HDC  hDC,
                        PFLOAT  Limit)
{
  UNIMPLEMENTED;
}

INT
STDCALL
W32kGetPath(HDC  hDC,
                 LPPOINT  Points,
                 LPBYTE  Types,
                 INT  nSize)
{
  UNIMPLEMENTED;
}

HRGN
STDCALL
W32kPathToRegion(HDC  hDC)
{
  UNIMPLEMENTED;
}

BOOL
STDCALL
W32kSetMiterLimit(HDC  hDC,
                        FLOAT  NewLimit,
                        PFLOAT  OldLimit)
{
  UNIMPLEMENTED;
}

BOOL
STDCALL
W32kStrokeAndFillPath(HDC  hDC)
{
  UNIMPLEMENTED;
}

BOOL
STDCALL
W32kStrokePath(HDC  hDC)
{
  UNIMPLEMENTED;
}

BOOL
STDCALL
W32kWidenPath(HDC  hDC)
{
   UNIMPLEMENTED;
}

/***********************************************************************
 * Exported functions
 */

/* PATH_InitGdiPath
 *
 * Initializes the GdiPath structure.
 */
void PATH_InitGdiPath(GdiPath *pPath)
{
  assert(pPath!=NULL);

  pPath->state=PATH_Null;
  pPath->pPoints=NULL;
  pPath->pFlags=NULL;
  pPath->numEntriesUsed=0;
  pPath->numEntriesAllocated=0;
}

/* PATH_DestroyGdiPath
 *
 * Destroys a GdiPath structure (frees the memory in the arrays).
 */
void PATH_DestroyGdiPath(GdiPath *pPath)
{
  assert(pPath!=NULL);

  ExFreePool(pPath->pPoints);
  ExFreePool(pPath->pFlags);
}

/* PATH_AssignGdiPath
 *
 * Copies the GdiPath structure "pPathSrc" to "pPathDest". A deep copy is
 * performed, i.e. the contents of the pPoints and pFlags arrays are copied,
 * not just the pointers. Since this means that the arrays in pPathDest may
 * need to be resized, pPathDest should have been initialized using
 * PATH_InitGdiPath (in C++, this function would be an assignment operator,
 * not a copy constructor).
 * Returns TRUE if successful, else FALSE.
 */
BOOL PATH_AssignGdiPath(GdiPath *pPathDest, const GdiPath *pPathSrc)
{
  assert(pPathDest!=NULL && pPathSrc!=NULL);

  /* Make sure destination arrays are big enough */
  if(!PATH_ReserveEntries(pPathDest, pPathSrc->numEntriesUsed))
    return FALSE;

  /* Perform the copy operation */
  memcpy(pPathDest->pPoints, pPathSrc->pPoints,
    sizeof(POINT)*pPathSrc->numEntriesUsed);
  memcpy(pPathDest->pFlags, pPathSrc->pFlags,
    sizeof(BYTE)*pPathSrc->numEntriesUsed);

  pPathDest->state=pPathSrc->state;
  pPathDest->numEntriesUsed=pPathSrc->numEntriesUsed;
  pPathDest->newStroke=pPathSrc->newStroke;

  return TRUE;
}

/* PATH_MoveTo
 *
 * Should be called when a MoveTo is performed on a DC that has an
 * open path. This starts a new stroke. Returns TRUE if successful, else
 * FALSE.
 */
BOOL PATH_MoveTo(HDC hdc)
{
  GdiPath *pPath;

  /* Get pointer to path */
  if(!PATH_GetPathFromHDC(hdc, &pPath))
    return FALSE;

  /* Check that path is open */
  if(pPath->state!=PATH_Open)
    /* FIXME: Do we have to call SetLastError? */
    return FALSE;

  /* Start a new stroke */
  pPath->newStroke=TRUE;

  return TRUE;
}

/* PATH_LineTo
 *
 * Should be called when a LineTo is performed on a DC that has an
 * open path. This adds a PT_LINETO entry to the path (and possibly
 * a PT_MOVETO entry, if this is the first LineTo in a stroke).
 * Returns TRUE if successful, else FALSE.
 */
BOOL PATH_LineTo(HDC hdc, INT x, INT y)
{
  GdiPath *pPath;
  POINT point, pointCurPos;

  /* Get pointer to path */
  if(!PATH_GetPathFromHDC(hdc, &pPath))
    return FALSE;

  /* Check that path is open */
  if(pPath->state!=PATH_Open)
    return FALSE;

  /* Convert point to device coordinates */
  point.x=x;
  point.y=y;
  if(!W32kLPtoDP(hdc, &point, 1))
    return FALSE;

  /* Add a PT_MOVETO if necessary */
  if(pPath->newStroke)
  {
    pPath->newStroke=FALSE;
    if(!W32kGetCurrentPositionEx(hdc, &pointCurPos) ||
       !W32kLPtoDP(hdc, &pointCurPos, 1))
      return FALSE;
    if(!PATH_AddEntry(pPath, &pointCurPos, PT_MOVETO))
      return FALSE;
  }

  /* Add a PT_LINETO entry */
  return PATH_AddEntry(pPath, &point, PT_LINETO);
}

/* PATH_Rectangle
 *
 * Should be called when a call to Rectangle is performed on a DC that has
 * an open path. Returns TRUE if successful, else FALSE.
 */
BOOL PATH_Rectangle(HDC hdc, INT x1, INT y1, INT x2, INT y2)
{
  GdiPath *pPath;
  POINT corners[2], pointTemp;
  INT   temp;

  /* Get pointer to path */
  if(!PATH_GetPathFromHDC(hdc, &pPath))
    return FALSE;

  /* Check that path is open */
  if(pPath->state!=PATH_Open)
    return FALSE;

  /* Convert points to device coordinates */
  corners[0].x=x1;
  corners[0].y=y1;
  corners[1].x=x2;
  corners[1].y=y2;
  if(!W32kLPtoDP(hdc, corners, 2))
    return FALSE;

  /* Make sure first corner is top left and second corner is bottom right */
  if(corners[0].x>corners[1].x)
  {
    temp=corners[0].x;
    corners[0].x=corners[1].x;
    corners[1].x=temp;
  }
  if(corners[0].y>corners[1].y)
  {
    temp=corners[0].y;
    corners[0].y=corners[1].y;
    corners[1].y=temp;
  }

  /* In GM_COMPATIBLE, don't include bottom and right edges */
  if(W32kGetGraphicsMode(hdc)==GM_COMPATIBLE)
  {
    corners[1].x--;
    corners[1].y--;
  }

  /* Close any previous figure */
  if(!W32kCloseFigure(hdc))
  {
    /* The W32kCloseFigure call shouldn't have failed */
    assert(FALSE);
    return FALSE;
  }

  /* Add four points to the path */
  pointTemp.x=corners[1].x;
  pointTemp.y=corners[0].y;
  if(!PATH_AddEntry(pPath, &pointTemp, PT_MOVETO))
    return FALSE;
  if(!PATH_AddEntry(pPath, corners, PT_LINETO))
    return FALSE;
  pointTemp.x=corners[0].x;
  pointTemp.y=corners[1].y;
  if(!PATH_AddEntry(pPath, &pointTemp, PT_LINETO))
    return FALSE;
  if(!PATH_AddEntry(pPath, corners+1, PT_LINETO))
    return FALSE;

  /* Close the rectangle figure */
  if(!W32kCloseFigure(hdc))
  {
    /* The W32kCloseFigure call shouldn't have failed */
    assert(FALSE);
    return FALSE;
  }

  return TRUE;
}

/* PATH_Ellipse
 *
 * Should be called when a call to Ellipse is performed on a DC that has
 * an open path. This adds four Bezier splines representing the ellipse
 * to the path. Returns TRUE if successful, else FALSE.
 */
BOOL PATH_Ellipse(HDC hdc, INT x1, INT y1, INT x2, INT y2)
{
  /* TODO: This should probably be revised to call PATH_AngleArc */
  /* (once it exists) */
  return PATH_Arc(hdc, x1, y1, x2, y2, x1, (y1+y2)/2, x1, (y1+y2)/2);
}

/* PATH_Arc
 *
 * Should be called when a call to Arc is performed on a DC that has
 * an open path. This adds up to five Bezier splines representing the arc
 * to the path. Returns TRUE if successful, else FALSE.
 */
BOOL PATH_Arc(HDC hdc, INT x1, INT y1, INT x2, INT y2,
   INT xStart, INT yStart, INT xEnd, INT yEnd)
{
  GdiPath *pPath;
  DC      *pDC;
  double  angleStart, angleEnd, angleStartQuadrant, angleEndQuadrant=0.0;
          /* Initialize angleEndQuadrant to silence gcc's warning */
  double  x, y;
  FLOAT_POINT corners[2], pointStart, pointEnd;
  BOOL    start, end;
  INT     temp;

  /* FIXME: This function should check for all possible error returns */
  /* FIXME: Do we have to respect newStroke? */

  /* Get pointer to DC */
  pDC=DC_HandleToPtr(hdc);
  if(pDC==NULL)
    return FALSE;

  /* Get pointer to path */
  if(!PATH_GetPathFromHDC(hdc, &pPath)){
	DC_ReleasePtr( hdc );
    return FALSE;
  }

  /* Check that path is open */
  if(pPath->state!=PATH_Open){
	DC_ReleasePtr( hdc );
    return FALSE;
  }

  /* FIXME: Do we have to close the current figure? */

  /* Check for zero height / width */
  /* FIXME: Only in GM_COMPATIBLE? */
  if(x1==x2 || y1==y2){
	DC_ReleasePtr( hdc );
    return TRUE;
  }

  /* Convert points to device coordinates */
  corners[0].x=(FLOAT)x1;
  corners[0].y=(FLOAT)y1;
  corners[1].x=(FLOAT)x2;
  corners[1].y=(FLOAT)y2;
  pointStart.x=(FLOAT)xStart;
  pointStart.y=(FLOAT)yStart;
  pointEnd.x=(FLOAT)xEnd;
  pointEnd.y=(FLOAT)yEnd;
  INTERNAL_LPTODP_FLOAT(pDC, corners);
  INTERNAL_LPTODP_FLOAT(pDC, corners+1);
  INTERNAL_LPTODP_FLOAT(pDC, &pointStart);
  INTERNAL_LPTODP_FLOAT(pDC, &pointEnd);

  /* Make sure first corner is top left and second corner is bottom right */
  if(corners[0].x>corners[1].x)
  {
    temp=corners[0].x;
    corners[0].x=corners[1].x;
    corners[1].x=temp;
  }
  if(corners[0].y>corners[1].y)
  {
    temp=corners[0].y;
    corners[0].y=corners[1].y;
    corners[1].y=temp;
  }

  /* Compute start and end angle */
  PATH_NormalizePoint(corners, &pointStart, &x, &y);
  angleStart=atan2(y, x);
  PATH_NormalizePoint(corners, &pointEnd, &x, &y);
  angleEnd=atan2(y, x);

  /* Make sure the end angle is "on the right side" of the start angle */
  if(W32kGetArcDirection(hdc)==AD_CLOCKWISE)
  {
    if(angleEnd<=angleStart)
    {
      angleEnd+=2*M_PI;
      assert(angleEnd>=angleStart);
    }
  }
  else
  {
    if(angleEnd>=angleStart)
    {
      angleEnd-=2*M_PI;
      assert(angleEnd<=angleStart);
    }
  }

  /* In GM_COMPATIBLE, don't include bottom and right edges */
  if(W32kGetGraphicsMode(hdc)==GM_COMPATIBLE)
  {
    corners[1].x--;
    corners[1].y--;
  }

  /* Add the arc to the path with one Bezier spline per quadrant that the
   * arc spans */
  start=TRUE;
  end=FALSE;
  do
  {
    /* Determine the start and end angles for this quadrant */
    if(start)
    {
      angleStartQuadrant=angleStart;
      if(W32kGetArcDirection(hdc)==AD_CLOCKWISE)
        angleEndQuadrant=(floor(angleStart/M_PI_2)+1.0)*M_PI_2;
      else
        angleEndQuadrant=(ceil(angleStart/M_PI_2)-1.0)*M_PI_2;
    }
    else
    {
      angleStartQuadrant=angleEndQuadrant;
      if(W32kGetArcDirection(hdc)==AD_CLOCKWISE)
        angleEndQuadrant+=M_PI_2;
      else
        angleEndQuadrant-=M_PI_2;
    }

    /* Have we reached the last part of the arc? */
    if((W32kGetArcDirection(hdc)==AD_CLOCKWISE &&
        angleEnd<angleEndQuadrant) ||
        (W32kGetArcDirection(hdc)==AD_COUNTERCLOCKWISE &&
        angleEnd>angleEndQuadrant))
    {
      /* Adjust the end angle for this quadrant */
     angleEndQuadrant=angleEnd;
     end=TRUE;
    }

    /* Add the Bezier spline to the path */
    PATH_DoArcPart(pPath, corners, angleStartQuadrant, angleEndQuadrant, start);
    start=FALSE;
  }  while(!end);

  DC_ReleasePtr( hdc );
  return TRUE;
}

BOOL PATH_PolyBezierTo(HDC hdc, const POINT *pts, DWORD cbPoints)
{
  GdiPath *pPath;
  POINT pt;
  INT i;

  if(!PATH_GetPathFromHDC(hdc, &pPath))
    return FALSE;

  /* Check that path is open */
  if(pPath->state!=PATH_Open)
    return FALSE;

  /* Add a PT_MOVETO if necessary */
  if(pPath->newStroke)
  {
    pPath->newStroke=FALSE;
    if(!W32kGetCurrentPositionEx(hdc, &pt) ||
       !W32kLPtoDP(hdc, &pt, 1))
        return FALSE;
    if(!PATH_AddEntry(pPath, &pt, PT_MOVETO))
        return FALSE;
  }

  for(i = 0; i < cbPoints; i++) {
    pt = pts[i];
    if(!W32kLPtoDP(hdc, &pt, 1))
      return FALSE;
    PATH_AddEntry(pPath, &pt, PT_BEZIERTO);
  }
  return TRUE;
}

BOOL PATH_PolyBezier(HDC hdc, const POINT *pts, DWORD cbPoints)
{
  GdiPath *pPath;
  POINT   pt;
  INT     i;

  if(!PATH_GetPathFromHDC(hdc, &pPath))
    return FALSE;

   /* Check that path is open */
  if(pPath->state!=PATH_Open)
    return FALSE;

  for(i = 0; i < cbPoints; i++) {
    pt = pts[i];
    if(!W32kLPtoDP(hdc, &pt, 1))
      return FALSE;
    PATH_AddEntry(pPath, &pt, (i == 0) ? PT_MOVETO : PT_BEZIERTO);
  }
  return TRUE;
}

BOOL PATH_Polyline(HDC hdc, const POINT *pts, DWORD cbPoints)
{
  GdiPath *pPath;
  POINT   pt;
  INT     i;

  if(!PATH_GetPathFromHDC(hdc, &pPath))
    return FALSE;

  /* Check that path is open */
  if(pPath->state!=PATH_Open)
    return FALSE;

  for(i = 0; i < cbPoints; i++) {
    pt = pts[i];
    if(!W32kLPtoDP(hdc, &pt, 1))
      return FALSE;
    PATH_AddEntry(pPath, &pt, (i == 0) ? PT_MOVETO : PT_LINETO);
  }
  return TRUE;
}

BOOL PATH_PolylineTo(HDC hdc, const POINT *pts, DWORD cbPoints)
{
  GdiPath *pPath;
  POINT   pt;
  INT     i;

  if(!PATH_GetPathFromHDC(hdc, &pPath))
    return FALSE;

  /* Check that path is open */
  if(pPath->state!=PATH_Open)
    return FALSE;

  /* Add a PT_MOVETO if necessary */
  if(pPath->newStroke)
  {
    pPath->newStroke=FALSE;
    if(!W32kGetCurrentPositionEx(hdc, &pt) ||
       !W32kLPtoDP(hdc, &pt, 1))
      return FALSE;
    if(!PATH_AddEntry(pPath, &pt, PT_MOVETO))
      return FALSE;
  }

  for(i = 0; i < cbPoints; i++) {
    pt = pts[i];
    if(!W32kLPtoDP(hdc, &pt, 1))
      return FALSE;
    PATH_AddEntry(pPath, &pt, PT_LINETO);
  }

  return TRUE;
}


BOOL PATH_Polygon(HDC hdc, const POINT *pts, DWORD cbPoints)
{
  GdiPath *pPath;
  POINT   pt;
  INT     i;

  if(!PATH_GetPathFromHDC(hdc, &pPath))
    return FALSE;

  /* Check that path is open */
  if(pPath->state!=PATH_Open)
    return FALSE;

  for(i = 0; i < cbPoints; i++) {
    pt = pts[i];
    if(!W32kLPtoDP(hdc, &pt, 1))
      return FALSE;
    PATH_AddEntry(pPath, &pt, (i == 0) ? PT_MOVETO :
      ((i == cbPoints-1) ? PT_LINETO | PT_CLOSEFIGURE :
      PT_LINETO));
  }
  return TRUE;
}

BOOL PATH_PolyPolygon( HDC hdc, const POINT* pts, const INT* counts,
		       UINT polygons )
{
  GdiPath *pPath;
  POINT   pt, startpt;
  INT     poly, point, i;

  if(!PATH_GetPathFromHDC(hdc, &pPath))
    return FALSE;

  /* Check that path is open */
  if(pPath->state!=PATH_Open)
    return FALSE;

  for(i = 0, poly = 0; poly < polygons; poly++) {
    for(point = 0; point < counts[poly]; point++, i++) {
      pt = pts[i];
      if(!W32kLPtoDP(hdc, &pt, 1))
         return FALSE;
      if(point == 0) startpt = pt;
        PATH_AddEntry(pPath, &pt, (point == 0) ? PT_MOVETO : PT_LINETO);
    }
    /* win98 adds an extra line to close the figure for some reason */
    PATH_AddEntry(pPath, &startpt, PT_LINETO | PT_CLOSEFIGURE);
  }
  return TRUE;
}

BOOL PATH_PolyPolyline( HDC hdc, const POINT* pts, const DWORD* counts,
			DWORD polylines )
{
  GdiPath *pPath;
  POINT   pt;
  INT     poly, point, i;

  if(!PATH_GetPathFromHDC(hdc, &pPath))
    return FALSE;

  /* Check that path is open */
  if(pPath->state!=PATH_Open)
    return FALSE;

  for(i = 0, poly = 0; poly < polylines; poly++) {
    for(point = 0; point < counts[poly]; point++, i++) {
      pt = pts[i];
      if(!W32kLPtoDP(hdc, &pt, 1))
        return FALSE;
      PATH_AddEntry(pPath, &pt, (point == 0) ? PT_MOVETO : PT_LINETO);
    }
  }
  return TRUE;
}

/***********************************************************************
 * Internal functions
 */


/* PATH_AddFlatBezier
 *
 */
static BOOL PATH_AddFlatBezier(GdiPath *pPath, POINT *pt, BOOL closed)
{
  POINT *pts;
  INT no, i;

  pts = GDI_Bezier( pt, 4, &no );
  if(!pts) return FALSE;

  for(i = 1; i < no; i++)
    PATH_AddEntry(pPath, &pts[i],  (i == no-1 && closed) ? PT_LINETO | PT_CLOSEFIGURE : PT_LINETO);

  ExFreePool(pts);
  return TRUE;
}

/* PATH_FlattenPath
 *
 * Replaces Beziers with line segments
 *
 */
static BOOL PATH_FlattenPath(GdiPath *pPath)
{
  GdiPath newPath;
  INT srcpt;

  memset(&newPath, 0, sizeof(newPath));
  newPath.state = PATH_Open;
  for(srcpt = 0; srcpt < pPath->numEntriesUsed; srcpt++) {
    switch(pPath->pFlags[srcpt] & ~PT_CLOSEFIGURE) {
      case PT_MOVETO:
      case PT_LINETO:
        PATH_AddEntry(&newPath, &pPath->pPoints[srcpt], pPath->pFlags[srcpt]);
        break;
      case PT_BEZIERTO:
        PATH_AddFlatBezier(&newPath, &pPath->pPoints[srcpt-1], pPath->pFlags[srcpt+2] & PT_CLOSEFIGURE);
        srcpt += 2;
        break;
    }
  }
  newPath.state = PATH_Closed;
  PATH_AssignGdiPath(pPath, &newPath);
  PATH_EmptyPath(&newPath);
  return TRUE;
}

/* PATH_PathToRegion
 *
 * Creates a region from the specified path using the specified polygon
 * filling mode. The path is left unchanged. A handle to the region that
 * was created is stored in *pHrgn. If successful, TRUE is returned; if an
 * error occurs, SetLastError is called with the appropriate value and
 * FALSE is returned.
 */
static BOOL PATH_PathToRegion(const GdiPath *pPath, INT nPolyFillMode,
   HRGN *pHrgn)
{
  int    numStrokes, iStroke, i;
  INT  *pNumPointsInStroke;
  HRGN hrgn;

  assert(pPath!=NULL);
  assert(pHrgn!=NULL);

  PATH_FlattenPath(pPath);

  /* FIXME: What happens when number of points is zero? */

  /* First pass: Find out how many strokes there are in the path */
  /* FIXME: We could eliminate this with some bookkeeping in GdiPath */
  numStrokes=0;
  for(i=0; i<pPath->numEntriesUsed; i++)
    if((pPath->pFlags[i] & ~PT_CLOSEFIGURE) == PT_MOVETO)
      numStrokes++;

  /* Allocate memory for number-of-points-in-stroke array */
  pNumPointsInStroke=(int *)ExAllocatePool(NonPagedPool, sizeof(int) * numStrokes);
  if(!pNumPointsInStroke)
  {
//    SetLastError(ERROR_NOT_ENOUGH_MEMORY);
    return FALSE;
  }

  /* Second pass: remember number of points in each polygon */
  iStroke=-1;  /* Will get incremented to 0 at beginning of first stroke */
  for(i=0; i<pPath->numEntriesUsed; i++)
  {
    /* Is this the beginning of a new stroke? */
    if((pPath->pFlags[i] & ~PT_CLOSEFIGURE) == PT_MOVETO)
    {
      iStroke++;
      pNumPointsInStroke[iStroke]=0;
    }

    pNumPointsInStroke[iStroke]++;
  }

  /* Create a region from the strokes */
/*  hrgn=CreatePolyPolygonRgn(pPath->pPoints, pNumPointsInStroke,
    numStrokes, nPolyFillMode); FIXME: reinclude when region code implemented */
  if(hrgn==(HRGN)0)
  {
//    SetLastError(ERROR_NOT_ENOUGH_MEMORY);
    return FALSE;
  }

  /* Free memory for number-of-points-in-stroke array */
  ExFreePool(pNumPointsInStroke);

  /* Success! */
  *pHrgn=hrgn;
  return TRUE;
}

/* PATH_EmptyPath
 *
 * Removes all entries from the path and sets the path state to PATH_Null.
 */
static void PATH_EmptyPath(GdiPath *pPath)
{
  assert(pPath!=NULL);

  pPath->state=PATH_Null;
  pPath->numEntriesUsed=0;
}

/* PATH_AddEntry
 *
 * Adds an entry to the path. For "flags", pass either PT_MOVETO, PT_LINETO
 * or PT_BEZIERTO, optionally ORed with PT_CLOSEFIGURE. Returns TRUE if
 * successful, FALSE otherwise (e.g. if not enough memory was available).
 */
BOOL PATH_AddEntry(GdiPath *pPath, const POINT *pPoint, BYTE flags)
{
  assert(pPath!=NULL);

  /* FIXME: If newStroke is true, perhaps we want to check that we're
   * getting a PT_MOVETO
   */

  /* Check that path is open */
  if(pPath->state!=PATH_Open)
    return FALSE;

  /* Reserve enough memory for an extra path entry */
  if(!PATH_ReserveEntries(pPath, pPath->numEntriesUsed+1))
    return FALSE;

  /* Store information in path entry */
  pPath->pPoints[pPath->numEntriesUsed]=*pPoint;
  pPath->pFlags[pPath->numEntriesUsed]=flags;

  /* If this is PT_CLOSEFIGURE, we have to start a new stroke next time */
  if((flags & PT_CLOSEFIGURE) == PT_CLOSEFIGURE)
    pPath->newStroke=TRUE;

  /* Increment entry count */
  pPath->numEntriesUsed++;

  return TRUE;
}

/* PATH_ReserveEntries
 *
 * Ensures that at least "numEntries" entries (for points and flags) have
 * been allocated; allocates larger arrays and copies the existing entries
 * to those arrays, if necessary. Returns TRUE if successful, else FALSE.
 */
static BOOL PATH_ReserveEntries(GdiPath *pPath, INT numEntries)
{
  INT   numEntriesToAllocate;
  POINT *pPointsNew;
  BYTE    *pFlagsNew;

  assert(pPath!=NULL);
  assert(numEntries>=0);

  /* Do we have to allocate more memory? */
  if(numEntries > pPath->numEntriesAllocated)
  {
    /* Find number of entries to allocate. We let the size of the array
     * grow exponentially, since that will guarantee linear time
     * complexity. */
    if(pPath->numEntriesAllocated)
    {
      numEntriesToAllocate=pPath->numEntriesAllocated;
      while(numEntriesToAllocate<numEntries)
        numEntriesToAllocate=numEntriesToAllocate*GROW_FACTOR_NUMER/GROW_FACTOR_DENOM;
    } else
       numEntriesToAllocate=numEntries;

    /* Allocate new arrays */
    pPointsNew=(POINT *)ExAllocatePool(NonPagedPool, numEntriesToAllocate * sizeof(POINT));
    if(!pPointsNew)
      return FALSE;
    pFlagsNew=(BYTE *)ExAllocatePool(NonPagedPool, numEntriesToAllocate * sizeof(BYTE));
    if(!pFlagsNew)
    {
      ExFreePool(pPointsNew);
      return FALSE;
    }

    /* Copy old arrays to new arrays and discard old arrays */
    if(pPath->pPoints)
    {
      assert(pPath->pFlags);

      memcpy(pPointsNew, pPath->pPoints, sizeof(POINT)*pPath->numEntriesUsed);
      memcpy(pFlagsNew, pPath->pFlags, sizeof(BYTE)*pPath->numEntriesUsed);

      ExFreePool(pPath->pPoints);
      ExFreePool(pPath->pFlags);
    }
    pPath->pPoints=pPointsNew;
    pPath->pFlags=pFlagsNew;
    pPath->numEntriesAllocated=numEntriesToAllocate;
  }

  return TRUE;
}

/* PATH_GetPathFromHDC
 *
 * Retrieves a pointer to the GdiPath structure contained in an HDC and
 * places it in *ppPath. TRUE is returned if successful, FALSE otherwise.
 */
static BOOL PATH_GetPathFromHDC(HDC hdc, GdiPath **ppPath)
{
  DC *pDC;

  pDC=DC_HandleToPtr(hdc);
  if(pDC)
  {
    *ppPath=&pDC->w.path;
	DC_ReleasePtr( hdc );
    return TRUE;
  }
  return FALSE;
}

/* PATH_DoArcPart
 *
 * Creates a Bezier spline that corresponds to part of an arc and appends the
 * corresponding points to the path. The start and end angles are passed in
 * "angleStart" and "angleEnd"; these angles should span a quarter circle
 * at most. If "addMoveTo" is true, a PT_MOVETO entry for the first control
 * point is added to the path; otherwise, it is assumed that the current
 * position is equal to the first control point.
 */
static BOOL PATH_DoArcPart(GdiPath *pPath, FLOAT_POINT corners[],
   double angleStart, double angleEnd, BOOL addMoveTo)
{
  double  halfAngle, a;
  double  xNorm[4], yNorm[4];
  POINT point;
  int i;

  assert(fabs(angleEnd-angleStart)<=M_PI_2);

  /* FIXME: Is there an easier way of computing this? */

  /* Compute control points */
  halfAngle=(angleEnd-angleStart)/2.0;
  if(fabs(halfAngle)>1e-8)
  {
    a=4.0/3.0*(1-cos(halfAngle))/sin(halfAngle);
    xNorm[0]=cos(angleStart);
    yNorm[0]=sin(angleStart);
    xNorm[1]=xNorm[0] - a*yNorm[0];
    yNorm[1]=yNorm[0] + a*xNorm[0];
    xNorm[3]=cos(angleEnd);
    yNorm[3]=sin(angleEnd);
    xNorm[2]=xNorm[3] + a*yNorm[3];
    yNorm[2]=yNorm[3] - a*xNorm[3];
  } else
    for(i=0; i<4; i++)
    {
      xNorm[i]=cos(angleStart);
      yNorm[i]=sin(angleStart);
    }

  /* Add starting point to path if desired */
  if(addMoveTo)
  {
    PATH_ScaleNormalizedPoint(corners, xNorm[0], yNorm[0], &point);
    if(!PATH_AddEntry(pPath, &point, PT_MOVETO))
      return FALSE;
  }

  /* Add remaining control points */
  for(i=1; i<4; i++)
  {
    PATH_ScaleNormalizedPoint(corners, xNorm[i], yNorm[i], &point);
    if(!PATH_AddEntry(pPath, &point, PT_BEZIERTO))
      return FALSE;
  }

  return TRUE;
}

/* PATH_ScaleNormalizedPoint
 *
 * Scales a normalized point (x, y) with respect to the box whose corners are
 * passed in "corners". The point is stored in "*pPoint". The normalized
 * coordinates (-1.0, -1.0) correspond to corners[0], the coordinates
 * (1.0, 1.0) correspond to corners[1].
 */
static void PATH_ScaleNormalizedPoint(FLOAT_POINT corners[], double x,
   double y, POINT *pPoint)
{
  pPoint->x=GDI_ROUND( (double)corners[0].x + (double)(corners[1].x-corners[0].x)*0.5*(x+1.0) );
  pPoint->y=GDI_ROUND( (double)corners[0].y + (double)(corners[1].y-corners[0].y)*0.5*(y+1.0) );
}

/* PATH_NormalizePoint
 *
 * Normalizes a point with respect to the box whose corners are passed in
 * corners. The normalized coordinates are stored in *pX and *pY.
 */
static void PATH_NormalizePoint(FLOAT_POINT corners[],
   const FLOAT_POINT *pPoint,
   double *pX, double *pY)
{
  *pX=(double)(pPoint->x-corners[0].x)/(double)(corners[1].x-corners[0].x) * 2.0 - 1.0;
  *pY=(double)(pPoint->y-corners[0].y)/(double)(corners[1].y-corners[0].y) * 2.0 - 1.0;
}
