graphics/path.c

   1 /*
   2  * Graphics paths (BeginPath, EndPath etc.)
   3  *
   4  * Copyright 1997, 1998 Martin Boehme
   5  */
   6
   7 #include <assert.h>
   8 #include <malloc.h>
   9 #include <math.h>
  10
  11 #include "windows.h"
  12 #include "winerror.h"
  13
  14 #include "dc.h"
  15 #include "debug.h"
  16 #include "path.h"
  17
  18 /* Notes on the implementation
  19  *
  20  * The implementation is based on dynamically resizable arrays of points and
  21  * flags. I dithered for a bit before deciding on this implementation, and
  22  * I had even done a bit of work on a linked list version before switching
  23  * to arrays. It's a bit of a tradeoff. When you use linked lists, the
  24  * implementation of FlattenPath is easier, because you can rip the
  25  * PT_BEZIERTO entries out of the middle of the list and link the
  26  * corresponding PT_LINETO entries in. However, when you use arrays,
  27  * PathToRegion becomes easier, since you can essentially just pass your array
  28  * of points to CreatePolyPolygonRgn. Also, if I'd used linked lists, I would
  29  * have had the extra effort of creating a chunk-based allocation scheme
  30  * in order to use memory effectively. That's why I finally decided to use
  31  * arrays. Note by the way that the array based implementation has the same
  32  * linear time complexity that linked lists would have since the arrays grow
  33  * exponentially.
  34  *
  35  * The points are stored in the path in device coordinates. This is
  36  * consistent with the way Windows does things (for instance, see the Win32
  37  * SDK documentation for GetPath).
  38  *
  39  * The word "stroke" appears in several places (e.g. in the flag
  40  * GdiPath.newStroke). A stroke consists of a PT_MOVETO followed by one or
  41  * more PT_LINETOs or PT_BEZIERTOs, up to, but not including, the next
  42  * PT_MOVETO. Note that this is not the same as the definition of a figure;
  43  * a figure can contain several strokes.
  44  *
  45  * I modified the drawing functions (MoveTo, LineTo etc.) to test whether
  46  * the path is open and to call the corresponding function in path.c if this
  47  * is the case. A more elegant approach would be to modify the function
  48  * pointers in the DC_FUNCTIONS structure; however, this would be a lot more
  49  * complex. Also, the performance degradation caused by my approach in the
  50  * case where no path is open is so small that it cannot be measured.
  51  *
  52  * Martin Boehme
  53  */
  54
  55 /* FIXME: A lot of stuff isn't implemented yet. There is much more to come. */
  56
  57 #define NUM_ENTRIES_INITIAL 16  /* Initial size of points / flags arrays  */
  58 #define GROW_FACTOR_NUMER    2  /* Numerator of grow factor for the array */
  59 #define GROW_FACTOR_DENOM    1  /* Denominator of grow factor             */
  60
  61
  62 static BOOL32 PATH_PathToRegion(const GdiPath *pPath, INT32 nPolyFillMode,
  63    HRGN32 *pHrgn);
  64 static void   PATH_EmptyPath(GdiPath *pPath);
  65 static BOOL32 PATH_AddEntry(GdiPath *pPath, const POINT32 *pPoint,
  66    BYTE flags);
  67 static BOOL32 PATH_ReserveEntries(GdiPath *pPath, INT32 numEntries);
  68 static BOOL32 PATH_GetPathFromHDC(HDC32 hdc, GdiPath **ppPath);
  69 static BOOL32 PATH_DoArcPart(GdiPath *pPath, FLOAT_POINT corners[],
  70    double angleStart, double angleEnd, BOOL32 addMoveTo);
  71 static void PATH_ScaleNormalizedPoint(FLOAT_POINT corners[], double x,
  72    double y, POINT32 *pPoint);
  73 static void PATH_NormalizePoint(FLOAT_POINT corners[], const FLOAT_POINT
  74    *pPoint, double *pX, double *pY);
  75
  76
  77 /***********************************************************************
  78  *           BeginPath16    (GDI.512)
  79  */
  80 BOOL16 WINAPI BeginPath16(HDC16 hdc)
  81 {
  82    return (BOOL16)BeginPath32((HDC32)hdc);
  83 }
  84
  85
  86 /***********************************************************************
  87  *           BeginPath32    (GDI32.9)
  88  */
  89 BOOL32 WINAPI BeginPath32(HDC32 hdc)
  90 {
  91    GdiPath *pPath;
  92
  93    /* Get pointer to path */
  94    if(!PATH_GetPathFromHDC(hdc, &pPath))
  95    {
  96       SetLastError(ERROR_INVALID_HANDLE);
  97       return FALSE;
  98    }
  99
 100    /* If path is already open, do nothing */
 101    if(pPath->state==PATH_Open)
 102       return TRUE;
 103
 104    /* Make sure that path is empty */
 105    PATH_EmptyPath(pPath);
 106
 107    /* Initialize variables for new path */
 108    pPath->newStroke=TRUE;
 109    pPath->state=PATH_Open;
 110
 111    return TRUE;
 112 }
 113
 114
 115 /***********************************************************************
 116  *           EndPath16    (GDI.514)
 117  */
 118 BOOL16 WINAPI EndPath16(HDC16 hdc)
 119 {
 120    return (BOOL16)EndPath32((HDC32)hdc);
 121 }
 122
 123
 124 /***********************************************************************
 125  *           EndPath32    (GDI32.78)
 126  */
 127 BOOL32 WINAPI EndPath32(HDC32 hdc)
 128 {
 129    GdiPath *pPath;
 130
 131    /* Get pointer to path */
 132    if(!PATH_GetPathFromHDC(hdc, &pPath))
 133    {
 134       SetLastError(ERROR_INVALID_HANDLE);
 135       return FALSE;
 136    }
 137
 138    /* Check that path is currently being constructed */
 139    if(pPath->state!=PATH_Open)
 140    {
 141       SetLastError(ERROR_CAN_NOT_COMPLETE);
 142       return FALSE;
 143    }
 144
 145    /* Set flag to indicate that path is finished */
 146    pPath->state=PATH_Closed;
 147
 148    return TRUE;
 149 }
 150
 151
 152 /***********************************************************************
 153  *           AbortPath16    (GDI.511)
 154  */
 155 BOOL16 WINAPI AbortPath16(HDC16 hdc)
 156 {
 157    return (BOOL16)AbortPath32((HDC32)hdc);
 158 }
 159
 160
 161 /******************************************************************************
 162  * AbortPath32 [GDI32.1]
 163  * Closes and discards paths from device context
 164  *
 165  * NOTES
 166  *    Check that SetLastError is being called correctly
 167  *
 168  * PARAMS
 169  *    hdc [I] Handle to device context
 170  *
 171  * RETURNS STD
 172  */
 173 BOOL32 WINAPI AbortPath32( HDC32 hdc )
 174 {
 175    GdiPath *pPath;
 176
 177    /* Get pointer to path */
 178    if(!PATH_GetPathFromHDC(hdc, &pPath))
 179    {
 180       SetLastError(ERROR_INVALID_PARAMETER);
 181       return FALSE;
 182    }
 183
 184    /* Remove all entries from the path */
 185    PATH_EmptyPath(pPath);
 186
 187    return TRUE;
 188 }
 189
 190
 191 /***********************************************************************
 192  *           CloseFigure16    (GDI.513)
 193  */
 194 BOOL16 WINAPI CloseFigure16(HDC16 hdc)
 195 {
 196    return (BOOL16)CloseFigure32((HDC32)hdc);
 197 }
 198
 199
 200 /***********************************************************************
 201  *           CloseFigure32    (GDI32.16)
 202  *
 203  * FIXME: Check that SetLastError is being called correctly
 204  */
 205 BOOL32 WINAPI CloseFigure32(HDC32 hdc)
 206 {
 207    GdiPath *pPath;
 208
 209    /* Get pointer to path */
 210    if(!PATH_GetPathFromHDC(hdc, &pPath))
 211    {
 212       SetLastError(ERROR_INVALID_PARAMETER);
 213       return FALSE;
 214    }
 215
 216    /* Check that path is open */
 217    if(pPath->state!=PATH_Open)
 218    {
 219       SetLastError(ERROR_CAN_NOT_COMPLETE);
 220       return FALSE;
 221    }
 222
 223    /* FIXME: Shouldn't we draw a line to the beginning of the figure? */
 224
 225    /* Set PT_CLOSEFIGURE on the last entry and start a new stroke */
 226    if(pPath->numEntriesUsed)
 227    {
 228       pPath->pFlags[pPath->numEntriesUsed-1]|=PT_CLOSEFIGURE;
 229       pPath->newStroke=TRUE;
 230    }
 231
 232    return TRUE;
 233 }
 234
 235
 236 /***********************************************************************
 237  *           GetPath16    (GDI.517)
 238  */
 239 INT16 WINAPI GetPath16(HDC16 hdc, LPPOINT16 pPoints, LPBYTE pTypes,
 240    INT16 nSize)
 241 {
 242    FIXME(gdi, "(%d,%p,%p): stub\n",hdc,pPoints,pTypes);
 243
 244    return 0;
 245 }
 246
 247
 248 /***********************************************************************
 249  *           GetPath32    (GDI32.210)
 250  */
 251 INT32 WINAPI GetPath32(HDC32 hdc, LPPOINT32 pPoints, LPBYTE pTypes,
 252    INT32 nSize)
 253 {
 254    GdiPath *pPath;
 255
 256    /* Get pointer to path */
 257    if(!PATH_GetPathFromHDC(hdc, &pPath))
 258    {
 259       SetLastError(ERROR_INVALID_PARAMETER);
 260       return -1;
 261    }
 262
 263    /* Check that path is closed */
 264    if(pPath->state!=PATH_Closed)
 265    {
 266       SetLastError(ERROR_CAN_NOT_COMPLETE);
 267       return -1;
 268    }
 269
 270    if(nSize==0)
 271       return pPath->numEntriesUsed;
 272    else if(nSize<pPath->numEntriesUsed)
 273    {
 274       SetLastError(ERROR_INVALID_PARAMETER);
 275       return -1;
 276    }
 277    else
 278    {
 279       memcpy(pPoints, pPath->pPoints, sizeof(POINT32)*pPath->numEntriesUsed);
 280       memcpy(pTypes, pPath->pFlags, sizeof(BYTE)*pPath->numEntriesUsed);
 281
 282       /* Convert the points to logical coordinates */
 283       if(!DPtoLP32(hdc, pPoints, pPath->numEntriesUsed))
 284       {
 285          /* FIXME: Is this the correct value? */
 286          SetLastError(ERROR_CAN_NOT_COMPLETE);
 287          return -1;
 288       }
 289
 290       return pPath->numEntriesUsed;
 291    }
 292 }
 293
 294
 295 /***********************************************************************
 296  *           PathToRegion32    (GDI32.261)
 297  *
 298  * FIXME
 299  *   Check that SetLastError is being called correctly
 300  *
 301  * The documentation does not state this explicitly, but a test under Windows
 302  * shows that the region which is returned should be in device coordinates.
 303  */
 304 HRGN32 WINAPI PathToRegion32(HDC32 hdc)
 305 {
 306    GdiPath *pPath;
 307    HRGN32  hrgnRval;
 308
 309    /* Get pointer to path */
 310    if(!PATH_GetPathFromHDC(hdc, &pPath))
 311    {
 312       SetLastError(ERROR_INVALID_PARAMETER);
 313       return 0;
 314    }
 315
 316    /* Check that path is closed */
 317    if(pPath->state!=PATH_Closed)
 318    {
 319       SetLastError(ERROR_CAN_NOT_COMPLETE);
 320       return 0;
 321    }
 322
 323    /* FIXME: Should we empty the path even if conversion failed? */
 324    if(PATH_PathToRegion(pPath, GetPolyFillMode32(hdc), &hrgnRval))
 325       PATH_EmptyPath(pPath);
 326    else
 327       hrgnRval=0;
 328
 329    return hrgnRval;
 330 }
 331
 332
 333 /***********************************************************************
 334  *           FillPath32    (GDI32.100)
 335  *
 336  * FIXME
 337  *    Check that SetLastError is being called correctly
 338  */
 339 BOOL32 WINAPI FillPath32(HDC32 hdc)
 340 {
 341    GdiPath *pPath;
 342    INT32   mapMode, graphicsMode;
 343    SIZE32  ptViewportExt, ptWindowExt;
 344    POINT32 ptViewportOrg, ptWindowOrg;
 345    XFORM   xform;
 346    HRGN32  hrgn;
 347
 348    /* Get pointer to path */
 349    if(!PATH_GetPathFromHDC(hdc, &pPath))
 350    {
 351       SetLastError(ERROR_INVALID_PARAMETER);
 352       return FALSE;
 353    }
 354
 355    /* Check that path is closed */
 356    if(pPath->state!=PATH_Closed)
 357    {
 358       SetLastError(ERROR_CAN_NOT_COMPLETE);
 359       return FALSE;
 360    }
 361
 362    /* Construct a region from the path and fill it */
 363    if(PATH_PathToRegion(pPath, GetPolyFillMode32(hdc), &hrgn))
 364    {
 365       /* Since PaintRgn interprets the region as being in logical coordinates
 366        * but the points we store for the path are already in device
 367        * coordinates, we have to set the mapping mode to MM_TEXT temporarily.
 368        * Using SaveDC to save information about the mapping mode / world
 369        * transform would be easier but would require more overhead, especially
 370        * now that SaveDC saves the current path.
 371        */
 372
 373       /* Save the information about the old mapping mode */
 374       mapMode=GetMapMode32(hdc);
 375       GetViewportExtEx32(hdc, &ptViewportExt);
 376       GetViewportOrgEx32(hdc, &ptViewportOrg);
 377       GetWindowExtEx32(hdc, &ptWindowExt);
 378       GetWindowOrgEx32(hdc, &ptWindowOrg);
 379
 380       /* Save world transform
 381        * NB: The Windows documentation on world transforms would lead one to
 382        * believe that this has to be done only in GM_ADVANCED; however, my
 383        * tests show that resetting the graphics mode to GM_COMPATIBLE does
 384        * not reset the world transform.
 385        */
 386       GetWorldTransform(hdc, &xform);
 387
 388       /* Set MM_TEXT */
 389       SetMapMode32(hdc, MM_TEXT);
 390
 391       /* Paint the region */
 392       PaintRgn32(hdc, hrgn);
 393
 394       /* Restore the old mapping mode */
 395       SetMapMode32(hdc, mapMode);
 396       SetViewportExtEx32(hdc, ptViewportExt.cx, ptViewportExt.cy, NULL);
 397       SetViewportOrgEx32(hdc, ptViewportOrg.x, ptViewportOrg.y, NULL);
 398       SetWindowExtEx32(hdc, ptWindowExt.cx, ptWindowExt.cy, NULL);
 399       SetWindowOrgEx32(hdc, ptWindowOrg.x, ptWindowOrg.y, NULL);
 400
 401       /* Go to GM_ADVANCED temporarily to restore the world transform */
 402       graphicsMode=GetGraphicsMode(hdc);
 403       SetGraphicsMode(hdc, GM_ADVANCED);
 404       SetWorldTransform(hdc, &xform);
 405       SetGraphicsMode(hdc, graphicsMode);
 406
 407       /* Empty the path */
 408       PATH_EmptyPath(pPath);
 409       return TRUE;
 410    }
 411    else
 412    {
 413       /* FIXME: Should the path be emptied even if conversion failed? */
 414       /* PATH_EmptyPath(pPath); */
 415       return FALSE;
 416    }
 417 }
 418
 419
 420 /***********************************************************************
 421  *           SelectClipPath32    (GDI32.296)
 422  * FIXME
 423  *  Check that SetLastError is being called correctly
 424  */
 425 BOOL32 WINAPI SelectClipPath32(HDC32 hdc, INT32 iMode)
 426 {
 427    GdiPath *pPath;
 428    HRGN32  hrgnPath;
 429    BOOL32  success;
 430
 431    /* Get pointer to path */
 432    if(!PATH_GetPathFromHDC(hdc, &pPath))
 433    {
 434       SetLastError(ERROR_INVALID_PARAMETER);
 435       return FALSE;
 436    }
 437
 438    /* Check that path is closed */
 439    if(pPath->state!=PATH_Closed)
 440    {
 441       SetLastError(ERROR_CAN_NOT_COMPLETE);
 442       return FALSE;
 443    }
 444
 445    /* Construct a region from the path */
 446    if(PATH_PathToRegion(pPath, GetPolyFillMode32(hdc), &hrgnPath))
 447    {
 448       success = ExtSelectClipRgn( hdc, hrgnPath, iMode ) != ERROR;
 449       DeleteObject32(hrgnPath);
 450
 451       /* Empty the path */
 452       if(success)
 453          PATH_EmptyPath(pPath);
 454       /* FIXME: Should this function delete the path even if it failed? */
 455
 456       return success;
 457    }
 458    else
 459       return FALSE;
 460 }
 461
 462
 463 /***********************************************************************
 464  * Exported functions
 465  */
 466
 467 /* PATH_InitGdiPath
 468  *
 469  * Initializes the GdiPath structure.
 470  */
 471 void PATH_InitGdiPath(GdiPath *pPath)
 472 {
 473    assert(pPath!=NULL);
 474
 475    pPath->state=PATH_Null;
 476    pPath->pPoints=NULL;
 477    pPath->pFlags=NULL;
 478    pPath->numEntriesUsed=0;
 479    pPath->numEntriesAllocated=0;
 480 }
 481
 482 /* PATH_DestroyGdiPath
 483  *
 484  * Destroys a GdiPath structure (frees the memory in the arrays).
 485  */
 486 void PATH_DestroyGdiPath(GdiPath *pPath)
 487 {
 488    assert(pPath!=NULL);
 489
 490    free(pPath->pPoints);
 491    free(pPath->pFlags);
 492 }
 493
 494 /* PATH_AssignGdiPath
 495  *
 496  * Copies the GdiPath structure "pPathSrc" to "pPathDest". A deep copy is
 497  * performed, i.e. the contents of the pPoints and pFlags arrays are copied,
 498  * not just the pointers. Since this means that the arrays in pPathDest may
 499  * need to be resized, pPathDest should have been initialized using
 500  * PATH_InitGdiPath (in C++, this function would be an assignment operator,
 501  * not a copy constructor).
 502  * Returns TRUE if successful, else FALSE.
 503  */
 504 BOOL32 PATH_AssignGdiPath(GdiPath *pPathDest, const GdiPath *pPathSrc)
 505 {
 506    assert(pPathDest!=NULL && pPathSrc!=NULL);
 507
 508    /* Make sure destination arrays are big enough */
 509    if(!PATH_ReserveEntries(pPathDest, pPathSrc->numEntriesUsed))
 510       return FALSE;
 511
 512    /* Perform the copy operation */
 513    memcpy(pPathDest->pPoints, pPathSrc->pPoints,
 514       sizeof(POINT32)*pPathSrc->numEntriesUsed);
 515    memcpy(pPathDest->pFlags, pPathSrc->pFlags,
 516       sizeof(INT32)*pPathSrc->numEntriesUsed);
 517    pPathDest->state=pPathSrc->state;
 518    pPathDest->numEntriesUsed=pPathSrc->numEntriesUsed;
 519    pPathDest->newStroke=pPathSrc->newStroke;
 520
 521    return TRUE;
 522 }
 523
 524 /* PATH_MoveTo
 525  *
 526  * Should be called when a MoveTo is performed on a DC that has an
 527  * open path. This starts a new stroke. Returns TRUE if successful, else
 528  * FALSE.
 529  */
 530 BOOL32 PATH_MoveTo(HDC32 hdc)
 531 {
 532    GdiPath *pPath;
 533
 534    /* Get pointer to path */
 535    if(!PATH_GetPathFromHDC(hdc, &pPath))
 536       return FALSE;
 537
 538    /* Check that path is open */
 539    if(pPath->state!=PATH_Open)
 540       /* FIXME: Do we have to call SetLastError? */
 541       return FALSE;
 542
 543    /* Start a new stroke */
 544    pPath->newStroke=TRUE;
 545
 546    return TRUE;
 547 }
 548
 549 /* PATH_LineTo
 550  *
 551  * Should be called when a LineTo is performed on a DC that has an
 552  * open path. This adds a PT_LINETO entry to the path (and possibly
 553  * a PT_MOVETO entry, if this is the first LineTo in a stroke).
 554  * Returns TRUE if successful, else FALSE.
 555  */
 556 BOOL32 PATH_LineTo(HDC32 hdc, INT32 x, INT32 y)
 557 {
 558    GdiPath *pPath;
 559    POINT32 point, pointCurPos;
 560
 561    /* Get pointer to path */
 562    if(!PATH_GetPathFromHDC(hdc, &pPath))
 563       return FALSE;
 564
 565    /* Check that path is open */
 566    if(pPath->state!=PATH_Open)
 567       return FALSE;
 568
 569    /* Convert point to device coordinates */
 570    point.x=x;
 571    point.y=y;
 572    if(!LPtoDP32(hdc, &point, 1))
 573       return FALSE;
 574
 575    /* Add a PT_MOVETO if necessary */
 576    if(pPath->newStroke)
 577    {
 578       pPath->newStroke=FALSE;
 579       if(!GetCurrentPositionEx32(hdc, &pointCurPos) ||
 580          !LPtoDP32(hdc, &pointCurPos, 1))
 581          return FALSE;
 582       if(!PATH_AddEntry(pPath, &pointCurPos, PT_MOVETO))
 583          return FALSE;
 584    }
 585
 586    /* Add a PT_LINETO entry */
 587    return PATH_AddEntry(pPath, &point, PT_LINETO);
 588 }
 589
 590 /* PATH_Rectangle
 591  *
 592  * Should be called when a call to Rectangle is performed on a DC that has
 593  * an open path. Returns TRUE if successful, else FALSE.
 594  */
 595 BOOL32 PATH_Rectangle(HDC32 hdc, INT32 x1, INT32 y1, INT32 x2, INT32 y2)
 596 {
 597    GdiPath *pPath;
 598    POINT32 corners[2], pointTemp;
 599    INT32   temp;
 600
 601    /* Get pointer to path */
 602    if(!PATH_GetPathFromHDC(hdc, &pPath))
 603       return FALSE;
 604
 605    /* Check that path is open */
 606    if(pPath->state!=PATH_Open)
 607       return FALSE;
 608
 609    /* Convert points to device coordinates */
 610    corners[0].x=x1;
 611    corners[0].y=y1;
 612    corners[1].x=x2;
 613    corners[1].y=y2;
 614    if(!LPtoDP32(hdc, corners, 2))
 615       return FALSE;
 616
 617    /* Make sure first corner is top left and second corner is bottom right */
 618    if(corners[0].x>corners[1].x)
 619    {
 620       temp=corners[0].x;
 621       corners[0].x=corners[1].x;
 622       corners[1].x=temp;
 623    }
 624    if(corners[0].y>corners[1].y)
 625    {
 626       temp=corners[0].y;
 627       corners[0].y=corners[1].y;
 628       corners[1].y=temp;
 629    }
 630
 631    /* In GM_COMPATIBLE, don't include bottom and right edges */
 632    if(GetGraphicsMode(hdc)==GM_COMPATIBLE)
 633    {
 634       corners[1].x--;
 635       corners[1].y--;
 636    }
 637
 638    /* Close any previous figure */
 639    if(!CloseFigure32(hdc))
 640    {
 641       /* The CloseFigure call shouldn't have failed */
 642       assert(FALSE);
 643       return FALSE;
 644    }
 645
 646    /* Add four points to the path */
 647    pointTemp.x=corners[1].x;
 648    pointTemp.y=corners[0].y;
 649    if(!PATH_AddEntry(pPath, &pointTemp, PT_MOVETO))
 650       return FALSE;
 651    if(!PATH_AddEntry(pPath, corners, PT_LINETO))
 652       return FALSE;
 653    pointTemp.x=corners[0].x;
 654    pointTemp.y=corners[1].y;
 655    if(!PATH_AddEntry(pPath, &pointTemp, PT_LINETO))
 656       return FALSE;
 657    if(!PATH_AddEntry(pPath, corners+1, PT_LINETO))
 658       return FALSE;
 659
 660    /* Close the rectangle figure */
 661    if(!CloseFigure32(hdc))
 662    {
 663       /* The CloseFigure call shouldn't have failed */
 664       assert(FALSE);
 665       return FALSE;
 666    }
 667
 668    return TRUE;
 669 }
 670
 671 /* PATH_Ellipse
 672  *
 673  * Should be called when a call to Ellipse is performed on a DC that has
 674  * an open path. This adds four Bezier splines representing the ellipse
 675  * to the path. Returns TRUE if successful, else FALSE.
 676  */
 677 BOOL32 PATH_Ellipse(HDC32 hdc, INT32 x1, INT32 y1, INT32 x2, INT32 y2)
 678 {
 679    /* TODO: This should probably be revised to call PATH_AngleArc */
 680    /* (once it exists) */
 681    return PATH_Arc(hdc, x1, y1, x2, y2, x1, (y1+y2)/2, x1, (y1+y2)/2);
 682 }
 683
 684 /* PATH_Arc
 685  *
 686  * Should be called when a call to Arc is performed on a DC that has
 687  * an open path. This adds up to five Bezier splines representing the arc
 688  * to the path. Returns TRUE if successful, else FALSE.
 689  */
 690 BOOL32 PATH_Arc(HDC32 hdc, INT32 x1, INT32 y1, INT32 x2, INT32 y2,
 691    INT32 xStart, INT32 yStart, INT32 xEnd, INT32 yEnd)
 692 {
 693    GdiPath     *pPath;
 694    DC          *pDC;
 695    double      angleStart, angleEnd, angleStartQuadrant, angleEndQuadrant=0.0;
 696                /* Initialize angleEndQuadrant to silence gcc's warning */
 697    double      x, y;
 698    FLOAT_POINT corners[2], pointStart, pointEnd;
 699    BOOL32      start, end;
 700    INT32       temp;
 701
 702    /* FIXME: This function should check for all possible error returns */
 703    /* FIXME: Do we have to respect newStroke? */
 704
 705    /* Get pointer to DC */
 706    pDC=DC_GetDCPtr(hdc);
 707    if(pDC==NULL)
 708       return FALSE;
 709
 710    /* Get pointer to path */
 711    if(!PATH_GetPathFromHDC(hdc, &pPath))
 712       return FALSE;
 713
 714    /* Check that path is open */
 715    if(pPath->state!=PATH_Open)
 716       return FALSE;
 717
 718    /* FIXME: Do we have to close the current figure? */
 719
 720    /* Check for zero height / width */
 721    /* FIXME: Only in GM_COMPATIBLE? */
 722    if(x1==x2 || y1==y2)
 723       return TRUE;
 724
 725    /* Convert points to device coordinates */
 726    corners[0].x=(FLOAT)x1;
 727    corners[0].y=(FLOAT)y1;
 728    corners[1].x=(FLOAT)x2;
 729    corners[1].y=(FLOAT)y2;
 730    pointStart.x=(FLOAT)xStart;
 731    pointStart.y=(FLOAT)yStart;
 732    pointEnd.x=(FLOAT)xEnd;
 733    pointEnd.y=(FLOAT)yEnd;
 734    INTERNAL_LPTODP_FLOAT(pDC, corners);
 735    INTERNAL_LPTODP_FLOAT(pDC, corners+1);
 736    INTERNAL_LPTODP_FLOAT(pDC, &pointStart);
 737    INTERNAL_LPTODP_FLOAT(pDC, &pointEnd);
 738
 739    /* Make sure first corner is top left and second corner is bottom right */
 740    if(corners[0].x>corners[1].x)
 741    {
 742       temp=corners[0].x;
 743       corners[0].x=corners[1].x;
 744       corners[1].x=temp;
 745    }
 746    if(corners[0].y>corners[1].y)
 747    {
 748       temp=corners[0].y;
 749       corners[0].y=corners[1].y;
 750       corners[1].y=temp;
 751    }
 752
 753    /* Compute start and end angle */
 754    PATH_NormalizePoint(corners, &pointStart, &x, &y);
 755    angleStart=atan2(y, x);
 756    PATH_NormalizePoint(corners, &pointEnd, &x, &y);
 757    angleEnd=atan2(y, x);
 758
 759    /* Make sure the end angle is "on the right side" of the start angle */
 760    if(GetArcDirection32(hdc)==AD_CLOCKWISE)
 761    {
 762       if(angleEnd<=angleStart)
 763       {
 764          angleEnd+=2*M_PI;
 765          assert(angleEnd>=angleStart);
 766       }
 767    }
 768    else
 769    {
 770       if(angleEnd>=angleStart)
 771       {
 772          angleEnd-=2*M_PI;
 773          assert(angleEnd<=angleStart);
 774       }
 775    }
 776
 777    /* In GM_COMPATIBLE, don't include bottom and right edges */
 778    if(GetGraphicsMode(hdc)==GM_COMPATIBLE)
 779    {
 780       corners[1].x--;
 781       corners[1].y--;
 782    }
 783
 784    /* Add the arc to the path with one Bezier spline per quadrant that the
 785     * arc spans */
 786    start=TRUE;
 787    end=FALSE;
 788    do
 789    {
 790       /* Determine the start and end angles for this quadrant */
 791       if(start)
 792       {
 793          angleStartQuadrant=angleStart;
 794          if(GetArcDirection32(hdc)==AD_CLOCKWISE)
 795             angleEndQuadrant=(floor(angleStart/M_PI_2)+1.0)*M_PI_2;
 796          else
 797             angleEndQuadrant=(ceil(angleStart/M_PI_2)-1.0)*M_PI_2;
 798       }
 799       else
 800       {
 801          angleStartQuadrant=angleEndQuadrant;
 802          if(GetArcDirection32(hdc)==AD_CLOCKWISE)
 803             angleEndQuadrant+=M_PI_2;
 804          else
 805             angleEndQuadrant-=M_PI_2;
 806       }
 807
 808       /* Have we reached the last part of the arc? */
 809       if((GetArcDirection32(hdc)==AD_CLOCKWISE &&
 810          angleEnd<angleEndQuadrant) ||
 811          (GetArcDirection32(hdc)==AD_COUNTERCLOCKWISE &&
 812          angleEnd>angleEndQuadrant))
 813       {
 814          /* Adjust the end angle for this quadrant */
 815          angleEndQuadrant=angleEnd;
 816          end=TRUE;
 817       }
 818
 819       /* Add the Bezier spline to the path */
 820       PATH_DoArcPart(pPath, corners, angleStartQuadrant, angleEndQuadrant,
 821          start);
 822       start=FALSE;
 823    }  while(!end);
 824
 825    return TRUE;
 826 }
 827
 828 /***********************************************************************
 829  * Internal functions
 830  */
 831
 832 /* PATH_PathToRegion
 833  *
 834  * Creates a region from the specified path using the specified polygon
 835  * filling mode. The path is left unchanged. A handle to the region that
 836  * was created is stored in *pHrgn. If successful, TRUE is returned; if an
 837  * error occurs, SetLastError is called with the appropriate value and
 838  * FALSE is returned.
 839  */
 840 static BOOL32 PATH_PathToRegion(const GdiPath *pPath, INT32 nPolyFillMode,
 841    HRGN32 *pHrgn)
 842 {
 843    int    numStrokes, iStroke, i;
 844    INT32  *pNumPointsInStroke;
 845    HRGN32 hrgn;
 846
 847    assert(pPath!=NULL);
 848    assert(pHrgn!=NULL);
 849
 850    /* FIXME: What happens when number of points is zero? */
 851
 852    /* First pass: Find out how many strokes there are in the path */
 853    /* FIXME: We could eliminate this with some bookkeeping in GdiPath */
 854    numStrokes=0;
 855    for(i=0; i<pPath->numEntriesUsed; i++)
 856       if((pPath->pFlags[i] & ~PT_CLOSEFIGURE) == PT_MOVETO)
 857          numStrokes++;
 858
 859    /* Allocate memory for number-of-points-in-stroke array */
 860    pNumPointsInStroke=(int *)malloc(sizeof(int)*numStrokes);
 861    if(!pNumPointsInStroke)
 862    {
 863       SetLastError(ERROR_NOT_ENOUGH_MEMORY);
 864       return FALSE;
 865    }
 866
 867    /* Second pass: remember number of points in each polygon */
 868    iStroke=-1;  /* Will get incremented to 0 at beginning of first stroke */
 869    for(i=0; i<pPath->numEntriesUsed; i++)
 870    {
 871       /* Is this the beginning of a new stroke? */
 872       if((pPath->pFlags[i] & ~PT_CLOSEFIGURE) == PT_MOVETO)
 873       {
 874          iStroke++;
 875          pNumPointsInStroke[iStroke]=0;
 876       }
 877
 878       pNumPointsInStroke[iStroke]++;
 879    }
 880
 881    /* Create a region from the strokes */
 882    hrgn=CreatePolyPolygonRgn32(pPath->pPoints, pNumPointsInStroke,
 883       numStrokes, nPolyFillMode);
 884    if(hrgn==(HRGN32)0)
 885    {
 886       SetLastError(ERROR_NOT_ENOUGH_MEMORY);
 887       return FALSE;
 888    }
 889
 890    /* Free memory for number-of-points-in-stroke array */
 891    free(pNumPointsInStroke);
 892
 893    /* Success! */
 894    *pHrgn=hrgn;
 895    return TRUE;
 896 }
 897
 898 /* PATH_EmptyPath
 899  *
 900  * Removes all entries from the path and sets the path state to PATH_Null.
 901  */
 902 static void PATH_EmptyPath(GdiPath *pPath)
 903 {
 904    assert(pPath!=NULL);
 905
 906    pPath->state=PATH_Null;
 907    pPath->numEntriesUsed=0;
 908 }
 909
 910 /* PATH_AddEntry
 911  *
 912  * Adds an entry to the path. For "flags", pass either PT_MOVETO, PT_LINETO
 913  * or PT_BEZIERTO, optionally ORed with PT_CLOSEFIGURE. Returns TRUE if
 914  * successful, FALSE otherwise (e.g. if not enough memory was available).
 915  */
 916 BOOL32 PATH_AddEntry(GdiPath *pPath, const POINT32 *pPoint, BYTE flags)
 917 {
 918    assert(pPath!=NULL);
 919
 920    /* FIXME: If newStroke is true, perhaps we want to check that we're
 921     * getting a PT_MOVETO
 922     */
 923
 924    /* Check that path is open */
 925    if(pPath->state!=PATH_Open)
 926       return FALSE;
 927
 928    /* Reserve enough memory for an extra path entry */
 929    if(!PATH_ReserveEntries(pPath, pPath->numEntriesUsed+1))
 930       return FALSE;
 931
 932    /* Store information in path entry */
 933    pPath->pPoints[pPath->numEntriesUsed]=*pPoint;
 934    pPath->pFlags[pPath->numEntriesUsed]=flags;
 935
 936    /* If this is PT_CLOSEFIGURE, we have to start a new stroke next time */
 937    if((flags & PT_CLOSEFIGURE) == PT_CLOSEFIGURE)
 938       pPath->newStroke=TRUE;
 939
 940    /* Increment entry count */
 941    pPath->numEntriesUsed++;
 942
 943    return TRUE;
 944 }
 945
 946 /* PATH_ReserveEntries
 947  *
 948  * Ensures that at least "numEntries" entries (for points and flags) have
 949  * been allocated; allocates larger arrays and copies the existing entries
 950  * to those arrays, if necessary. Returns TRUE if successful, else FALSE.
 951  */
 952 static BOOL32 PATH_ReserveEntries(GdiPath *pPath, INT32 numEntries)
 953 {
 954    INT32   numEntriesToAllocate;
 955    POINT32 *pPointsNew;
 956    BYTE    *pFlagsNew;
 957
 958    assert(pPath!=NULL);
 959    assert(numEntries>=0);
 960
 961    /* Do we have to allocate more memory? */
 962    if(numEntries > pPath->numEntriesAllocated)
 963    {
 964       /* Find number of entries to allocate. We let the size of the array
 965        * grow exponentially, since that will guarantee linear time
 966        * complexity. */
 967       if(pPath->numEntriesAllocated)
 968       {
 969          numEntriesToAllocate=pPath->numEntriesAllocated;
 970          while(numEntriesToAllocate<numEntries)
 971             numEntriesToAllocate=numEntriesToAllocate*GROW_FACTOR_NUMER/
 972                GROW_FACTOR_DENOM;
 973       }
 974       else
 975          numEntriesToAllocate=NUM_ENTRIES_INITIAL;
 976
 977       /* Allocate new arrays */
 978       pPointsNew=(POINT32 *)malloc(numEntriesToAllocate * sizeof(POINT32));
 979       if(!pPointsNew)
 980          return FALSE;
 981       pFlagsNew=(BYTE *)malloc(numEntriesToAllocate * sizeof(BYTE));
 982       if(!pFlagsNew)
 983       {
 984          free(pPointsNew);
 985          return FALSE;
 986       }
 987
 988       /* Copy old arrays to new arrays and discard old arrays */
 989       if(pPath->pPoints)
 990       {
 991          assert(pPath->pFlags);
 992
 993          memcpy(pPointsNew, pPath->pPoints,
 994              sizeof(POINT32)*pPath->numEntriesUsed);
 995          memcpy(pFlagsNew, pPath->pFlags,
 996              sizeof(BYTE)*pPath->numEntriesUsed);
 997
 998          free(pPath->pPoints);
 999          free(pPath->pFlags);
1000       }
1001       pPath->pPoints=pPointsNew;
1002       pPath->pFlags=pFlagsNew;
1003       pPath->numEntriesAllocated=numEntriesToAllocate;
1004    }
1005
1006    return TRUE;
1007 }
1008
1009 /* PATH_GetPathFromHDC
1010  *
1011  * Retrieves a pointer to the GdiPath structure contained in an HDC and
1012  * places it in *ppPath. TRUE is returned if successful, FALSE otherwise.
1013  */
1014 static BOOL32 PATH_GetPathFromHDC(HDC32 hdc, GdiPath **ppPath)
1015 {
1016    DC *pDC;
1017
1018    pDC=DC_GetDCPtr(hdc);
1019    if(pDC)
1020    {
1021       *ppPath=&pDC->w.path;
1022       return TRUE;
1023    }
1024    else
1025       return FALSE;
1026 }
1027
1028 /* PATH_DoArcPart
1029  *
1030  * Creates a Bezier spline that corresponds to part of an arc and appends the
1031  * corresponding points to the path. The start and end angles are passed in
1032  * "angleStart" and "angleEnd"; these angles should span a quarter circle
1033  * at most. If "addMoveTo" is true, a PT_MOVETO entry for the first control
1034  * point is added to the path; otherwise, it is assumed that the current
1035  * position is equal to the first control point.
1036  */
1037 static BOOL32 PATH_DoArcPart(GdiPath *pPath, FLOAT_POINT corners[],
1038    double angleStart, double angleEnd, BOOL32 addMoveTo)
1039 {
1040    double  halfAngle, a;
1041    double  xNorm[4], yNorm[4];
1042    POINT32 point;
1043    int     i;
1044
1045    assert(fabs(angleEnd-angleStart)<=M_PI_2);
1046
1047    /* FIXME: Is there an easier way of computing this? */
1048
1049    /* Compute control points */
1050    halfAngle=(angleEnd-angleStart)/2.0;
1051    if(fabs(halfAngle)>1e-8)
1052    {
1053       a=4.0/3.0*(1-cos(halfAngle))/sin(halfAngle);
1054       xNorm[0]=cos(angleStart);
1055       yNorm[0]=sin(angleStart);
1056       xNorm[1]=xNorm[0] - a*yNorm[0];
1057       yNorm[1]=yNorm[0] + a*xNorm[0];
1058       xNorm[3]=cos(angleEnd);
1059       yNorm[3]=sin(angleEnd);
1060       xNorm[2]=xNorm[3] + a*yNorm[3];
1061       yNorm[2]=yNorm[3] - a*xNorm[3];
1062    }
1063    else
1064       for(i=0; i<4; i++)
1065       {
1066          xNorm[i]=cos(angleStart);
1067          yNorm[i]=sin(angleStart);
1068       }
1069
1070    /* Add starting point to path if desired */
1071    if(addMoveTo)
1072    {
1073       PATH_ScaleNormalizedPoint(corners, xNorm[0], yNorm[0], &point);
1074       if(!PATH_AddEntry(pPath, &point, PT_MOVETO))
1075          return FALSE;
1076    }
1077
1078    /* Add remaining control points */
1079    for(i=1; i<4; i++)
1080    {
1081       PATH_ScaleNormalizedPoint(corners, xNorm[i], yNorm[i], &point);
1082       if(!PATH_AddEntry(pPath, &point, PT_BEZIERTO))
1083          return FALSE;
1084    }
1085
1086    return TRUE;
1087 }
1088
1089 /* PATH_ScaleNormalizedPoint
1090  *
1091  * Scales a normalized point (x, y) with respect to the box whose corners are
1092  * passed in "corners". The point is stored in "*pPoint". The normalized
1093  * coordinates (-1.0, -1.0) correspond to corners[0], the coordinates
1094  * (1.0, 1.0) correspond to corners[1].
1095  */
1096 static void PATH_ScaleNormalizedPoint(FLOAT_POINT corners[], double x,
1097    double y, POINT32 *pPoint)
1098 {
1099    pPoint->x=GDI_ROUND( (double)corners[0].x +
1100       (double)(corners[1].x-corners[0].x)*0.5*(x+1.0) );
1101    pPoint->y=GDI_ROUND( (double)corners[0].y +
1102       (double)(corners[1].y-corners[0].y)*0.5*(y+1.0) );
1103 }
1104
1105 /* PATH_NormalizePoint
1106  *
1107  * Normalizes a point with respect to the box whose corners are passed in
1108  * "corners". The normalized coordinates are stored in "*pX" and "*pY".
1109  */
1110 static void PATH_NormalizePoint(FLOAT_POINT corners[],
1111    const FLOAT_POINT *pPoint,
1112    double *pX, double *pY)
1113 {
1114    *pX=(double)(pPoint->x-corners[0].x)/(double)(corners[1].x-corners[0].x) *
1115       2.0 - 1.0;
1116    *pY=(double)(pPoint->y-corners[0].y)/(double)(corners[1].y-corners[0].y) *
1117       2.0 - 1.0;
1118 }
1119
1120 /*******************************************************************
1121  *      FlattenPath32 [GDI32.103]
1122  *
1123  *
1124  */
1125 BOOL32 WINAPI FlattenPath32(HDC32 hdc)
1126 {
1127         FIXME(gdi, "FlattenPath, stub\n");
1128         return 0;
1129 }
1130
1131 /*******************************************************************
1132  *      StrokeAndFillPath [GDI32.352]
1133  *
1134  *
1135  */
1136 BOOL32 WINAPI StrokeAndFillPath32(HDC32 hdc)
1137 {
1138         FIXME(gdi, "StrokeAndFillPath, stub\n");
1139         return 0;
1140 }
1141
1142 /*******************************************************************
1143  *      StrokePath [GDI32.353]
1144  *
1145  *
1146  */
1147 BOOL32 WINAPI StrokePath32(HDC32 hdc)
1148 {
1149         FIXME(gdi, "StrokePath, stub\n");
1150         return 0;
1151 }
1152
1153 /*******************************************************************
1154  *      WidenPath [GDI32.360]
1155  *
1156  *
1157  */
1158 BOOL32 WINAPI WidenPath32(HDC32 hdc)
1159 {
1160         FIXME(gdi, "WidenPath, stub\n");
1161         return 0;
1162 }
1163