src/common/dcbase.cpp

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        common/dcbase.cpp
   3 // Purpose:     generic methods of the wxDC Class
   4 // Author:      Vadim Zeitlin
   5 // Modified by:
   6 // Created:     05/25/99
   7 // RCS-ID:      $Id$
   8 // Copyright:   (c) wxWidgets team
   9 // Licence:     wxWindows licence
  10 /////////////////////////////////////////////////////////////////////////////
  11
  12 // ============================================================================
  13 // declarations
  14 // ============================================================================
  15
  16 #if defined(__GNUG__) && !defined(NO_GCC_PRAGMA)
  17     #pragma implementation "dcbase.h"
  18 #endif
  19
  20 // ----------------------------------------------------------------------------
  21 // headers
  22 // ----------------------------------------------------------------------------
  23
  24 // For compilers that support precompilation, includes "wx.h".
  25 #include "wx/wxprec.h"
  26
  27 #ifdef __BORLANDC__
  28     #pragma hdrstop
  29 #endif
  30
  31 #include "wx/dc.h"
  32
  33 #include <math.h>
  34
  35 // bool wxDCBase::sm_cacheing = false;
  36
  37 // ============================================================================
  38 // implementation
  39 // ============================================================================
  40
  41 // ----------------------------------------------------------------------------
  42 // special symbols
  43 // ----------------------------------------------------------------------------
  44
  45 void wxDCBase::DoDrawCheckMark(wxCoord x1, wxCoord y1,
  46                                wxCoord width, wxCoord height)
  47 {
  48     wxCHECK_RET( Ok(), wxT("invalid window dc") );
  49
  50     wxCoord x2 = x1 + width,
  51             y2 = y1 + height;
  52
  53     // this is to yield width of 3 for width == height == 10
  54     SetPen(wxPen(GetTextForeground(), (width + height + 1) / 7, wxSOLID));
  55
  56     // we're drawing a scaled version of wx/generic/tick.xpm here
  57     wxCoord x3 = x1 + (4*width) / 10,   // x of the tick bottom
  58             y3 = y1 + height / 2;       // y of the left tick branch
  59     DoDrawLine(x1, y3, x3, y2);
  60     DoDrawLine(x3, y2, x2, y1);
  61
  62     CalcBoundingBox(x1, y1);
  63     CalcBoundingBox(x2, y2);
  64 }
  65
  66 // ----------------------------------------------------------------------------
  67 // line/polygons
  68 // ----------------------------------------------------------------------------
  69
  70 void wxDCBase::DrawLines(const wxList *list, wxCoord xoffset, wxCoord yoffset)
  71 {
  72     int n = list->GetCount();
  73     wxPoint *points = new wxPoint[n];
  74
  75     int i = 0;
  76     for ( wxList::compatibility_iterator node = list->GetFirst(); node; node = node->GetNext(), i++ )
  77     {
  78         wxPoint *point = (wxPoint *)node->GetData();
  79         points[i].x = point->x;
  80         points[i].y = point->y;
  81     }
  82
  83     DoDrawLines(n, points, xoffset, yoffset);
  84
  85     delete [] points;
  86 }
  87
  88
  89 void wxDCBase::DrawPolygon(const wxList *list,
  90                            wxCoord xoffset, wxCoord yoffset,
  91                            int fillStyle)
  92 {
  93     int n = list->GetCount();
  94     wxPoint *points = new wxPoint[n];
  95
  96     int i = 0;
  97     for ( wxList::compatibility_iterator node = list->GetFirst(); node; node = node->GetNext(), i++ )
  98     {
  99         wxPoint *point = (wxPoint *)node->GetData();
 100         points[i].x = point->x;
 101         points[i].y = point->y;
 102     }
 103
 104     DoDrawPolygon(n, points, xoffset, yoffset, fillStyle);
 105
 106     delete [] points;
 107 }
 108
 109 void
 110 wxDCBase::DoDrawPolyPolygon(int n,
 111                             int count[],
 112                             wxPoint points[],
 113                             wxCoord xoffset, wxCoord yoffset,
 114                             int fillStyle)
 115 {
 116     if ( n == 1 )
 117     {
 118         DoDrawPolygon(count[0], points, xoffset, yoffset, fillStyle);
 119         return;
 120     }
 121
 122     int      i, j, lastOfs;
 123     wxPoint* pts;
 124     wxPen    pen;
 125
 126     for (i = j = lastOfs = 0; i < n; i++)
 127     {
 128         lastOfs = j;
 129         j      += count[i];
 130     }
 131     pts = new wxPoint[j+n-1];
 132     for (i = 0; i < j; i++)
 133         pts[i] = points[i];
 134     for (i = 2; i <= n; i++)
 135     {
 136         lastOfs -= count[n-i];
 137         pts[j++] = pts[lastOfs];
 138     }
 139
 140     pen = GetPen();
 141     SetPen(wxPen(*wxBLACK, 0, wxTRANSPARENT));
 142     DoDrawPolygon(j, pts, xoffset, yoffset, fillStyle);
 143     SetPen(pen);
 144     for (i = j = 0; i < n; i++)
 145     {
 146         DoDrawLines(count[i], pts+j, xoffset, yoffset);
 147         j += count[i];
 148     }
 149     delete[] pts;
 150 }
 151
 152 // ----------------------------------------------------------------------------
 153 // splines
 154 // ----------------------------------------------------------------------------
 155
 156 #if wxUSE_SPLINES
 157
 158 // TODO: this API needs fixing (wxPointList, why (!const) "wxList *"?)
 159 void wxDCBase::DrawSpline(wxCoord x1, wxCoord y1, wxCoord x2, wxCoord y2, wxCoord x3, wxCoord y3)
 160 {
 161     wxList point_list;
 162
 163     wxPoint *point1 = new wxPoint;
 164     point1->x = x1; point1->y = y1;
 165     point_list.Append((wxObject*)point1);
 166
 167     wxPoint *point2 = new wxPoint;
 168     point2->x = x2; point2->y = y2;
 169     point_list.Append((wxObject*)point2);
 170
 171     wxPoint *point3 = new wxPoint;
 172     point3->x = x3; point3->y = y3;
 173     point_list.Append((wxObject*)point3);
 174
 175     DrawSpline(&point_list);
 176
 177     for( wxList::compatibility_iterator node = point_list.GetFirst(); node; node = node->GetNext() )
 178     {
 179         wxPoint *p = (wxPoint *)node->GetData();
 180         delete p;
 181     }
 182 }
 183
 184 void wxDCBase::DrawSpline(int n, wxPoint points[])
 185 {
 186     wxList list;
 187     for (int i =0; i < n; i++)
 188     {
 189         list.Append((wxObject*)&points[i]);
 190     }
 191
 192     DrawSpline(&list);
 193 }
 194
 195 // ----------------------------------- spline code ----------------------------------------
 196
 197 void wx_quadratic_spline(double a1, double b1, double a2, double b2,
 198                          double a3, double b3, double a4, double b4);
 199 void wx_clear_stack();
 200 int wx_spline_pop(double *x1, double *y1, double *x2, double *y2, double *x3,
 201         double *y3, double *x4, double *y4);
 202 void wx_spline_push(double x1, double y1, double x2, double y2, double x3, double y3,
 203           double x4, double y4);
 204 static bool wx_spline_add_point(double x, double y);
 205 static void wx_spline_draw_point_array(wxDCBase *dc);
 206
 207 wxList wx_spline_point_list;
 208
 209 #define                half(z1, z2)        ((z1+z2)/2.0)
 210 #define                THRESHOLD        5
 211
 212 /* iterative version */
 213
 214 void wx_quadratic_spline(double a1, double b1, double a2, double b2, double a3, double b3, double a4,
 215                  double b4)
 216 {
 217     register double  xmid, ymid;
 218     double           x1, y1, x2, y2, x3, y3, x4, y4;
 219
 220     wx_clear_stack();
 221     wx_spline_push(a1, b1, a2, b2, a3, b3, a4, b4);
 222
 223     while (wx_spline_pop(&x1, &y1, &x2, &y2, &x3, &y3, &x4, &y4)) {
 224         xmid = (double)half(x2, x3);
 225         ymid = (double)half(y2, y3);
 226         if (fabs(x1 - xmid) < THRESHOLD && fabs(y1 - ymid) < THRESHOLD &&
 227             fabs(xmid - x4) < THRESHOLD && fabs(ymid - y4) < THRESHOLD) {
 228             wx_spline_add_point( x1, y1 );
 229             wx_spline_add_point( xmid, ymid );
 230         } else {
 231             wx_spline_push(xmid, ymid, (double)half(xmid, x3), (double)half(ymid, y3),
 232                  (double)half(x3, x4), (double)half(y3, y4), x4, y4);
 233             wx_spline_push(x1, y1, (double)half(x1, x2), (double)half(y1, y2),
 234                  (double)half(x2, xmid), (double)half(y2, ymid), xmid, ymid);
 235         }
 236     }
 237 }
 238
 239 /* utilities used by spline drawing routines */
 240
 241 typedef struct wx_spline_stack_struct {
 242     double           x1, y1, x2, y2, x3, y3, x4, y4;
 243 } Stack;
 244
 245 #define         SPLINE_STACK_DEPTH             20
 246 static Stack    wx_spline_stack[SPLINE_STACK_DEPTH];
 247 static Stack   *wx_stack_top;
 248 static int      wx_stack_count;
 249
 250 void wx_clear_stack()
 251 {
 252     wx_stack_top = wx_spline_stack;
 253     wx_stack_count = 0;
 254 }
 255
 256 void wx_spline_push(double x1, double y1, double x2, double y2, double x3, double y3, double x4, double y4)
 257 {
 258     wx_stack_top->x1 = x1;
 259     wx_stack_top->y1 = y1;
 260     wx_stack_top->x2 = x2;
 261     wx_stack_top->y2 = y2;
 262     wx_stack_top->x3 = x3;
 263     wx_stack_top->y3 = y3;
 264     wx_stack_top->x4 = x4;
 265     wx_stack_top->y4 = y4;
 266     wx_stack_top++;
 267     wx_stack_count++;
 268 }
 269
 270 int wx_spline_pop(double *x1, double *y1, double *x2, double *y2,
 271                   double *x3, double *y3, double *x4, double *y4)
 272 {
 273     if (wx_stack_count == 0)
 274         return (0);
 275     wx_stack_top--;
 276     wx_stack_count--;
 277     *x1 = wx_stack_top->x1;
 278     *y1 = wx_stack_top->y1;
 279     *x2 = wx_stack_top->x2;
 280     *y2 = wx_stack_top->y2;
 281     *x3 = wx_stack_top->x3;
 282     *y3 = wx_stack_top->y3;
 283     *x4 = wx_stack_top->x4;
 284     *y4 = wx_stack_top->y4;
 285     return (1);
 286 }
 287
 288 static bool wx_spline_add_point(double x, double y)
 289 {
 290   wxPoint *point = new wxPoint ;
 291   point->x = (int) x;
 292   point->y = (int) y;
 293   wx_spline_point_list.Append((wxObject*)point);
 294   return true;
 295 }
 296
 297 static void wx_spline_draw_point_array(wxDCBase *dc)
 298 {
 299   dc->DrawLines(&wx_spline_point_list, 0, 0 );
 300   wxList::compatibility_iterator node = wx_spline_point_list.GetFirst();
 301   while (node)
 302   {
 303     wxPoint *point = (wxPoint *)node->GetData();
 304     delete point;
 305     wx_spline_point_list.Erase(node);
 306     node = wx_spline_point_list.GetFirst();
 307   }
 308 }
 309
 310 void wxDCBase::DoDrawSpline( wxList *points )
 311 {
 312     wxCHECK_RET( Ok(), wxT("invalid window dc") );
 313
 314     wxPoint *p;
 315     double           cx1, cy1, cx2, cy2, cx3, cy3, cx4, cy4;
 316     double           x1, y1, x2, y2;
 317
 318     wxList::compatibility_iterator node = points->GetFirst();
 319     p = (wxPoint *)node->GetData();
 320
 321     x1 = p->x;
 322     y1 = p->y;
 323
 324     node = node->GetNext();
 325     p = (wxPoint *)node->GetData();
 326
 327     x2 = p->x;
 328     y2 = p->y;
 329     cx1 = (double)((x1 + x2) / 2);
 330     cy1 = (double)((y1 + y2) / 2);
 331     cx2 = (double)((cx1 + x2) / 2);
 332     cy2 = (double)((cy1 + y2) / 2);
 333
 334     wx_spline_add_point(x1, y1);
 335
 336     while ((node = node->GetNext())
 337 #if !wxUSE_STL
 338            != NULL
 339 #endif // !wxUSE_STL
 340           )
 341     {
 342         p = (wxPoint *)node->GetData();
 343         x1 = x2;
 344         y1 = y2;
 345         x2 = p->x;
 346         y2 = p->y;
 347         cx4 = (double)(x1 + x2) / 2;
 348         cy4 = (double)(y1 + y2) / 2;
 349         cx3 = (double)(x1 + cx4) / 2;
 350         cy3 = (double)(y1 + cy4) / 2;
 351
 352         wx_quadratic_spline(cx1, cy1, cx2, cy2, cx3, cy3, cx4, cy4);
 353
 354         cx1 = cx4;
 355         cy1 = cy4;
 356         cx2 = (double)(cx1 + x2) / 2;
 357         cy2 = (double)(cy1 + y2) / 2;
 358     }
 359
 360     wx_spline_add_point( cx1, cy1 );
 361     wx_spline_add_point( x2, y2 );
 362
 363     wx_spline_draw_point_array( this );
 364 }
 365
 366 #endif // wxUSE_SPLINES
 367
 368 // ----------------------------------------------------------------------------
 369 // Partial Text Extents
 370 // ----------------------------------------------------------------------------
 371
 372
 373 // Each element of the widths array will be the width of the string up to and
 374 // including the coresponding character in text.  This is the generic
 375 // implementation, the port-specific classes should do this with native APIs
 376 // if available and if faster.  Note: pango_layout_index_to_pos is much slower
 377 // than calling GetTextExtent!!
 378
 379 #define FWC_SIZE 256
 380
 381 class FontWidthCache
 382 {
 383 public:
 384     FontWidthCache() : m_scaleX(1), m_widths(NULL) { }
 385     ~FontWidthCache() { delete []m_widths; }
 386
 387     void Reset()
 388     {
 389         if (!m_widths)
 390             m_widths = new int[FWC_SIZE];
 391
 392         memset(m_widths, 0, sizeof(int)*FWC_SIZE);
 393     }
 394
 395     wxFont m_font;
 396     double m_scaleX;
 397     int *m_widths;
 398 };
 399
 400 static FontWidthCache s_fontWidthCache;
 401
 402 bool wxDCBase::DoGetPartialTextExtents(const wxString& text, wxArrayInt& widths) const
 403 {
 404     int totalWidth = 0;
 405
 406     size_t i, len = text.Length();
 407     widths.Empty();
 408     widths.Add(0, len);
 409     int w, h;
 410
 411     // reset the cache if font or horizontal scale have changed
 412     if (!s_fontWidthCache.m_widths ||
 413         (s_fontWidthCache.m_scaleX != m_scaleX) ||
 414         (s_fontWidthCache.m_font != GetFont()))
 415     {
 416         s_fontWidthCache.Reset();
 417         s_fontWidthCache.m_font = GetFont();
 418         s_fontWidthCache.m_scaleX = m_scaleX;
 419     }
 420
 421     // Calculate the position of each character based on the widths of
 422     // the previous characters
 423     for (i=0; i<len; i++)
 424     {
 425         const wxChar c = text[i];
 426         unsigned int c_int = (unsigned int)c;
 427
 428         if ((c_int < FWC_SIZE) && (s_fontWidthCache.m_widths[c_int] != 0))
 429         {
 430             w = s_fontWidthCache.m_widths[c_int];
 431         }
 432         else
 433         {
 434             GetTextExtent(c, &w, &h);
 435             if (c_int < FWC_SIZE)
 436                 s_fontWidthCache.m_widths[c_int] = w;
 437         }
 438
 439         totalWidth += w;
 440         widths[i] = totalWidth;
 441     }
 442
 443     return true;
 444 }
 445
 446
 447 // ----------------------------------------------------------------------------
 448 // enhanced text drawing
 449 // ----------------------------------------------------------------------------
 450
 451 void wxDCBase::GetMultiLineTextExtent(const wxString& text,
 452                                       wxCoord *x,
 453                                       wxCoord *y,
 454                                       wxCoord *h,
 455                                       wxFont *font)
 456 {
 457     wxCoord widthTextMax = 0, widthLine,
 458             heightTextTotal = 0, heightLineDefault = 0, heightLine = 0;
 459
 460     wxString curLine;
 461     for ( const wxChar *pc = text; ; pc++ )
 462     {
 463         if ( *pc == _T('\n') || *pc == _T('\0') )
 464         {
 465             if ( curLine.empty() )
 466             {
 467                 // we can't use GetTextExtent - it will return 0 for both width
 468                 // and height and an empty line should count in height
 469                 // calculation
 470
 471                 // assume that this line has the same height as the previous
 472                 // one
 473                 if ( !heightLineDefault )
 474                     heightLineDefault = heightLine;
 475
 476                 if ( !heightLineDefault )
 477                 {
 478                     // but we don't know it yet - choose something reasonable
 479                     GetTextExtent(_T("W"), NULL, &heightLineDefault,
 480                                   NULL, NULL, font);
 481                 }
 482
 483                 heightTextTotal += heightLineDefault;
 484             }
 485             else
 486             {
 487                 GetTextExtent(curLine, &widthLine, &heightLine,
 488                               NULL, NULL, font);
 489                 if ( widthLine > widthTextMax )
 490                     widthTextMax = widthLine;
 491                 heightTextTotal += heightLine;
 492             }
 493
 494             if ( *pc == _T('\n') )
 495             {
 496                curLine.clear();
 497             }
 498             else
 499             {
 500                // the end of string
 501                break;
 502             }
 503         }
 504         else
 505         {
 506             curLine += *pc;
 507         }
 508     }
 509
 510     if ( x )
 511         *x = widthTextMax;
 512     if ( y )
 513         *y = heightTextTotal;
 514     if ( h )
 515         *h = heightLine;
 516 }
 517
 518 void wxDCBase::DrawLabel(const wxString& text,
 519                          const wxBitmap& bitmap,
 520                          const wxRect& rect,
 521                          int alignment,
 522                          int indexAccel,
 523                          wxRect *rectBounding)
 524 {
 525     // find the text position
 526     wxCoord widthText, heightText, heightLine;
 527     GetMultiLineTextExtent(text, &widthText, &heightText, &heightLine);
 528
 529     wxCoord width, height;
 530     if ( bitmap.Ok() )
 531     {
 532         width = widthText + bitmap.GetWidth();
 533         height = bitmap.GetHeight();
 534     }
 535     else // no bitmap
 536     {
 537         width = widthText;
 538         height = heightText;
 539     }
 540
 541     wxCoord x, y;
 542     if ( alignment & wxALIGN_RIGHT )
 543     {
 544         x = rect.GetRight() - width;
 545     }
 546     else if ( alignment & wxALIGN_CENTRE_HORIZONTAL )
 547     {
 548         x = (rect.GetLeft() + rect.GetRight() + 1 - width) / 2;
 549     }
 550     else // alignment & wxALIGN_LEFT
 551     {
 552         x = rect.GetLeft();
 553     }
 554
 555     if ( alignment & wxALIGN_BOTTOM )
 556     {
 557         y = rect.GetBottom() - height;
 558     }
 559     else if ( alignment & wxALIGN_CENTRE_VERTICAL )
 560     {
 561         y = (rect.GetTop() + rect.GetBottom() + 1 - height) / 2;
 562     }
 563     else // alignment & wxALIGN_TOP
 564     {
 565         y = rect.GetTop();
 566     }
 567
 568     // draw the bitmap first
 569     wxCoord x0 = x,
 570             y0 = y,
 571             width0 = width;
 572     if ( bitmap.Ok() )
 573     {
 574         DrawBitmap(bitmap, x, y, true /* use mask */);
 575
 576         wxCoord offset = bitmap.GetWidth() + 4;
 577         x += offset;
 578         width -= offset;
 579
 580         y += (height - heightText) / 2;
 581     }
 582
 583     // we will draw the underscore under the accel char later
 584     wxCoord startUnderscore = 0,
 585             endUnderscore = 0,
 586             yUnderscore = 0;
 587
 588     // split the string into lines and draw each of them separately
 589     wxString curLine;
 590     for ( const wxChar *pc = text; ; pc++ )
 591     {
 592         if ( *pc == _T('\n') || *pc == _T('\0') )
 593         {
 594             int xRealStart = x; // init it here to avoid compielr warnings
 595
 596             if ( !curLine.empty() )
 597             {
 598                 // NB: can't test for !(alignment & wxALIGN_LEFT) because
 599                 //     wxALIGN_LEFT is 0
 600                 if ( alignment & (wxALIGN_RIGHT | wxALIGN_CENTRE_HORIZONTAL) )
 601                 {
 602                     wxCoord widthLine;
 603                     GetTextExtent(curLine, &widthLine, NULL);
 604
 605                     if ( alignment & wxALIGN_RIGHT )
 606                     {
 607                         xRealStart += width - widthLine;
 608                     }
 609                     else // if ( alignment & wxALIGN_CENTRE_HORIZONTAL )
 610                     {
 611                         xRealStart += (width - widthLine) / 2;
 612                     }
 613                 }
 614                 //else: left aligned, nothing to do
 615
 616                 DrawText(curLine, xRealStart, y);
 617             }
 618
 619             y += heightLine;
 620
 621             // do we have underscore in this line? we can check yUnderscore
 622             // because it is set below to just y + heightLine if we do
 623             if ( y == yUnderscore )
 624             {
 625                 // adjust the horz positions to account for the shift
 626                 startUnderscore += xRealStart;
 627                 endUnderscore += xRealStart;
 628             }
 629
 630             if ( *pc == _T('\0') )
 631                 break;
 632
 633             curLine.clear();
 634         }
 635         else // not end of line
 636         {
 637             if ( pc - text.c_str() == indexAccel )
 638             {
 639                 // remeber to draw underscore here
 640                 GetTextExtent(curLine, &startUnderscore, NULL);
 641                 curLine += *pc;
 642                 GetTextExtent(curLine, &endUnderscore, NULL);
 643
 644                 yUnderscore = y + heightLine;
 645             }
 646             else
 647             {
 648                 curLine += *pc;
 649             }
 650         }
 651     }
 652
 653     // draw the underscore if found
 654     if ( startUnderscore != endUnderscore )
 655     {
 656         // it should be of the same colour as text
 657         SetPen(wxPen(GetTextForeground(), 0, wxSOLID));
 658
 659         yUnderscore--;
 660
 661         DrawLine(startUnderscore, yUnderscore, endUnderscore, yUnderscore);
 662     }
 663
 664     // return bounding rect if requested
 665     if ( rectBounding )
 666     {
 667         *rectBounding = wxRect(x, y - heightText, widthText, heightText);
 668     }
 669
 670     CalcBoundingBox(x0, y0);
 671     CalcBoundingBox(x0 + width0, y0 + height);
 672 }
 673
 674 /*
 675 Notes for wxWidgets DrawEllipticArcRot(...)
 676
 677 wxDCBase::DrawEllipticArcRot(...) draws a rotated elliptic arc or an ellipse.
 678 It uses wxDCBase::CalculateEllipticPoints(...) and wxDCBase::Rotate(...),
 679 which are also new.
 680
 681 All methods are generic, so they can be implemented in wxDCBase.
 682 DoDrawEllipticArcRot(...) is virtual, so it can be called from deeper
 683 methods like (WinCE) wxDC::DoDrawArc(...).
 684
 685 CalculateEllipticPoints(...) fills a given list of wxPoints with some points
 686 of an elliptic arc. The algorithm is pixel-based: In every row (in flat
 687 parts) or every column (in steep parts) only one pixel is calculated.
 688 Trigonometric calculation (sin, cos, tan, atan) is only done if the
 689 starting angle is not equal to the ending angle. The calculation of the
 690 pixels is done using simple arithmetic only and should perform not too
 691 bad even on devices without floating point processor. I didn't test this yet.
 692
 693 Rotate(...) rotates a list of point pixel-based, you will see rounding errors.
 694 For instance: an ellipse rotated 180 degrees is drawn
 695 slightly different from the original.
 696
 697 The points are then moved to an array and used to draw a polyline and/or polygon
 698 (with center added, the pie).
 699 The result looks quite similar to the native ellipse, only e few pixels differ.
 700
 701 The performance on a desktop system (Athlon 1800, WinXP) is about 7 times
 702 slower as DrawEllipse(...), which calls the native API.
 703 An rotated ellipse outside the clipping region takes nearly the same time,
 704 while an native ellipse outside takes nearly no time to draw.
 705
 706 If you draw an arc with this new method, you will see the starting and ending angles
 707 are calculated properly.
 708 If you use DrawEllipticArc(...), you will see they are only correct for circles
 709 and not properly calculated for ellipses.
 710
 711 Peter Lenhard
 712 p.lenhard@t-online.de
 713 */
 714
 715 #ifdef __WXWINCE__
 716 void wxDCBase::DoDrawEllipticArcRot( wxCoord x, wxCoord y,
 717                                      wxCoord w, wxCoord h,
 718                                      double sa, double ea, double angle )
 719 {
 720     wxList list;
 721
 722     CalculateEllipticPoints( &list, x, y, w, h, sa, ea );
 723     Rotate( &list, angle, wxPoint( x+w/2, y+h/2 ) );
 724
 725     // Add center (for polygon/pie)
 726     list.Append( (wxObject*) new wxPoint( x+w/2, y+h/2 ) );
 727
 728     // copy list into array and delete list elements
 729     int n = list.Number();
 730     wxPoint *points = new wxPoint[n];
 731     int i = 0;
 732     wxNode* node = 0;
 733     for ( node = list.First(); node; node = node->Next(), i++ )
 734     {
 735         wxPoint *point = (wxPoint *)node->Data();
 736         points[i].x = point->x;
 737         points[i].y = point->y;
 738         delete point;
 739     }
 740
 741     // first draw the pie without pen, if necessary
 742     if( GetBrush() != *wxTRANSPARENT_BRUSH )
 743     {
 744         wxPen tempPen( GetPen() );
 745         SetPen( *wxTRANSPARENT_PEN );
 746         DoDrawPolygon( n, points, 0, 0 );
 747         SetPen( tempPen );
 748     }
 749
 750     // then draw the arc without brush, if necessary
 751     if( GetPen() != *wxTRANSPARENT_PEN )
 752     {
 753         // without center
 754         DoDrawLines( n-1, points, 0, 0 );
 755     }
 756
 757     delete [] points;
 758
 759 } // DrawEllipticArcRot
 760
 761 void wxDCBase::Rotate( wxList* points, double angle, wxPoint center )
 762 {
 763     if( angle != 0.0 )
 764     {
 765         double pi(3.1415926536);
 766         double dSinA = -sin(angle*2.0*pi/360.0);
 767         double dCosA = cos(angle*2.0*pi/360.0);
 768         for ( wxNode* node = points->First(); node; node = node->Next() )
 769         {
 770             wxPoint* point = (wxPoint*)node->Data();
 771
 772             // transform coordinates, if necessary
 773             if( center.x ) point->x -= center.x;
 774             if( center.y ) point->y -= center.y;
 775
 776             // calculate rotation, rounding simply by implicit cast to integer
 777             int xTemp = point->x * dCosA - point->y * dSinA;
 778             point->y = point->x * dSinA + point->y * dCosA;
 779             point->x = xTemp;
 780
 781             // back transform coordinates, if necessary
 782             if( center.x ) point->x += center.x;
 783             if( center.y ) point->y += center.y;
 784         }
 785     }
 786 }
 787
 788 void wxDCBase::CalculateEllipticPoints( wxList* points,
 789                                         wxCoord xStart, wxCoord yStart,
 790                                         wxCoord w, wxCoord h,
 791                                         double sa, double ea )
 792 {
 793     double pi = 3.1415926535;
 794     double sar = 0;
 795     double ear = 0;
 796     int xsa = 0;
 797     int ysa = 0;
 798     int xea = 0;
 799     int yea = 0;
 800     int sq = 0;
 801     int eq = 0;
 802     bool bUseAngles = false;
 803     if( w<0 ) w = -w;
 804     if( h<0 ) h = -h;
 805     // half-axes
 806     wxCoord a = w/2;
 807     wxCoord b = h/2;
 808     // decrement 1 pixel if ellipse is smaller than 2*a, 2*b
 809     int decrX = 0;
 810     if( 2*a == w ) decrX = 1;
 811     int decrY = 0;
 812     if( 2*b == h ) decrY = 1;
 813     // center
 814     wxCoord xCenter = xStart + a;
 815     wxCoord yCenter = yStart + b;
 816     // calculate data for start and end, if necessary
 817     if( sa != ea )
 818     {
 819         bUseAngles = true;
 820         // normalisation of angles
 821         while( sa<0 ) sa += 360;
 822         while( ea<0 ) ea += 360;
 823         while( sa>=360 ) sa -= 360;
 824         while( ea>=360 ) ea -= 360;
 825         // calculate quadrant numbers
 826         if( sa > 270 ) sq = 3;
 827         else if( sa > 180 ) sq = 2;
 828         else if( sa > 90 ) sq = 1;
 829         if( ea > 270 ) eq = 3;
 830         else if( ea > 180 ) eq = 2;
 831         else if( ea > 90 ) eq = 1;
 832         sar = sa * pi / 180.0;
 833         ear = ea * pi / 180.0;
 834         // correct angle circle -> ellipse
 835         sar = atan( -a/(double)b * tan( sar ) );
 836         if ( sq == 1 || sq == 2 ) sar += pi;
 837         ear = atan( -a/(double)b * tan( ear ) );
 838         if ( eq == 1 || eq == 2 ) ear += pi;
 839         // coordinates of points
 840         xsa = xCenter + a * cos( sar );
 841         if( sq == 0 || sq == 3 ) xsa -= decrX;
 842         ysa = yCenter + b * sin( sar );
 843         if( sq == 2 || sq == 3 ) ysa -= decrY;
 844         xea = xCenter + a * cos( ear );
 845         if( eq == 0 || eq == 3 ) xea -= decrX;
 846         yea = yCenter + b * sin( ear );
 847         if( eq == 2 || eq == 3 ) yea -= decrY;
 848     } // if iUseAngles
 849     // calculate c1 = b^2, c2 = b^2/a^2 with a = w/2, b = h/2
 850     double c1 = b * b;
 851     double c2 = 2.0 / w;
 852     c2 *= c2;
 853     c2 *= c1;
 854     wxCoord x = 0;
 855     wxCoord y = b;
 856     long x2 = 1;
 857     long y2 = y*y;
 858     long y2_old = 0;
 859     long y_old = 0;
 860     // Lists for quadrant 1 to 4
 861     wxList pointsarray[4];
 862     // Calculate points for first quadrant and set in all quadrants
 863     for( x = 0; x <= a; ++x )
 864     {
 865         x2 = x2+x+x-1;
 866         y2_old = y2;
 867         y_old = y;
 868         bool bNewPoint = false;
 869         while( y2 > c1 - c2 * x2 && y > 0 )
 870         {
 871             bNewPoint = true;
 872             y2 = y2-y-y+1;
 873             --y;
 874         }
 875         // old y now to big: set point with old y, old x
 876         if( bNewPoint && x>1)
 877         {
 878             int x1 = x - 1;
 879             // remove points on the same line
 880             pointsarray[0].Insert( (wxObject*) new wxPoint( xCenter + x1 - decrX, yCenter - y_old ) );
 881             pointsarray[1].Append( (wxObject*) new wxPoint( xCenter - x1, yCenter - y_old ) );
 882             pointsarray[2].Insert( (wxObject*) new wxPoint( xCenter - x1, yCenter + y_old - decrY ) );
 883             pointsarray[3].Append( (wxObject*) new wxPoint( xCenter + x1 - decrX, yCenter + y_old - decrY ) );
 884         } // set point
 885     } // calculate point
 886
 887     // Starting and/or ending points for the quadrants, first quadrant gets both.
 888     pointsarray[0].Insert( (wxObject*) new wxPoint( xCenter + a - decrX, yCenter ) );
 889     pointsarray[0].Append( (wxObject*) new wxPoint( xCenter, yCenter - b ) );
 890     pointsarray[1].Append( (wxObject*) new wxPoint( xCenter - a, yCenter ) );
 891     pointsarray[2].Append( (wxObject*) new wxPoint( xCenter, yCenter + b - decrY ) );
 892     pointsarray[3].Append( (wxObject*) new wxPoint( xCenter + a - decrX, yCenter ) );
 893
 894     // copy quadrants in original list
 895     if( bUseAngles )
 896     {
 897         // Copy the right part of the points in the lists
 898         // and delete the wxPoints, because they do not leave this method.
 899         points->Append( (wxObject*) new wxPoint( xsa, ysa ) );
 900         int q = sq;
 901         bool bStarted = false;
 902         bool bReady = false;
 903         bool bForceTurn = ( sq == eq && sa > ea );
 904         while( !bReady )
 905         {
 906             for( wxNode *node = pointsarray[q].First(); node; node = node->Next() )
 907             {
 908                 // once: go to starting point in start quadrant
 909                 if( !bStarted &&
 910                     (
 911                       ( (wxPoint*) node->Data() )->x < xsa+1 && q <= 1
 912                       ||
 913                       ( (wxPoint*) node->Data() )->x > xsa-1 && q >= 2
 914                     )
 915                   )
 916                 {
 917                     bStarted = true;
 918                 }
 919
 920                 // copy point, if not at ending point
 921                 if( bStarted )
 922                 {
 923                     if( q != eq || bForceTurn
 924                         ||
 925                         ( (wxPoint*) node->Data() )->x > xea+1 && q <= 1
 926                         ||
 927                         ( (wxPoint*) node->Data() )->x < xea-1 && q >= 2
 928                       )
 929                     {
 930                         // copy point
 931                         wxPoint* pPoint = new wxPoint( *((wxPoint*) node->Data() ) );
 932                         points->Append( (wxObject*) pPoint );
 933                     }
 934                     else if( q == eq && !bForceTurn || ( (wxPoint*) node->Data() )->x == xea)
 935                     {
 936                         bReady = true;
 937                     }
 938                 }
 939             } // for node
 940             ++q;
 941             if( q > 3 ) q = 0;
 942             bForceTurn = false;
 943             bStarted = true;
 944         } // while not bReady
 945         points->Append( (wxObject*) new wxPoint( xea, yea ) );
 946
 947         // delete points
 948         for( q = 0; q < 4; ++q )
 949         {
 950             for( wxNode *node = pointsarray[q].First(); node; node = node->Next() )
 951             {
 952                 wxPoint *p = (wxPoint *)node->Data();
 953                 delete p;
 954             }
 955         }
 956     }
 957     else
 958     {
 959         // copy whole ellipse, wxPoints will be deleted outside
 960         for( wxNode *node = pointsarray[0].First(); node; node = node->Next() )
 961         {
 962             wxObject *p = node->Data();
 963             points->Append( p );
 964         }
 965         for( node = pointsarray[1].First(); node; node = node->Next() )
 966         {
 967             wxObject *p = node->Data();
 968             points->Append( p );
 969         }
 970         for( node = pointsarray[2].First(); node; node = node->Next() )
 971         {
 972             wxObject *p = node->Data();
 973             points->Append( p );
 974         }
 975         for( node = pointsarray[3].First(); node; node = node->Next() )
 976         {
 977             wxObject *p = node->Data();
 978             points->Append( p );
 979         }
 980     } // not iUseAngles
 981 } // CalculateEllipticPoints
 982
 983 #endif
 984