contrib/src/ogl/ogldiag.cpp

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        ogldiag.cpp
   3 // Purpose:     wxDiagram
   4 // Author:      Julian Smart
   5 // Modified by:
   6 // Created:     12/07/98
   7 // RCS-ID:      $Id$
   8 // Copyright:   (c) Julian Smart
   9 // Licence:     wxWindows licence
  10 /////////////////////////////////////////////////////////////////////////////
  11
  12 #ifdef __GNUG__
  13 #pragma implementation "ogldiag.h"
  14 #endif
  15
  16 // For compilers that support precompilation, includes "wx.h".
  17 #include "wx/wxprec.h"
  18
  19 #ifdef __BORLANDC__
  20 #pragma hdrstop
  21 #endif
  22
  23 #ifndef WX_PRECOMP
  24 #include <wx/wx.h>
  25 #endif
  26
  27 #if wxUSE_PROLOGIO
  28 #include <wx/deprecated/wxexpr.h>
  29 #endif
  30
  31 #ifdef new
  32 #undef new
  33 #endif
  34
  35 #include <ctype.h>
  36 #include <math.h>
  37 #include <stdlib.h>
  38
  39 #include "wx/ogl/ogl.h"
  40
  41
  42 IMPLEMENT_DYNAMIC_CLASS(wxDiagram, wxObject)
  43
  44 // Object canvas
  45 wxDiagram::wxDiagram()
  46 {
  47   m_diagramCanvas = NULL;
  48   m_quickEditMode = FALSE;
  49   m_snapToGrid = TRUE;
  50   m_gridSpacing = 5.0;
  51   m_shapeList = new wxList;
  52   m_mouseTolerance = DEFAULT_MOUSE_TOLERANCE;
  53 }
  54
  55 wxDiagram::~wxDiagram()
  56 {
  57   if (m_shapeList)
  58     delete m_shapeList;
  59 }
  60
  61 void wxDiagram::SetSnapToGrid(bool snap)
  62 {
  63   m_snapToGrid = snap;
  64 }
  65
  66 void wxDiagram::SetGridSpacing(double spacing)
  67 {
  68   m_gridSpacing = spacing;
  69 }
  70
  71 void wxDiagram::Snap(double *x, double *y)
  72 {
  73   if (m_snapToGrid)
  74   {
  75     *x = m_gridSpacing * ((int)(*x/m_gridSpacing + 0.5));
  76     *y = m_gridSpacing * ((int)(*y/m_gridSpacing + 0.5));
  77   }
  78 }
  79
  80
  81 void wxDiagram::Redraw(wxDC& dc)
  82 {
  83   if (m_shapeList)
  84   {
  85     if (GetCanvas())
  86       GetCanvas()->SetCursor(* wxHOURGLASS_CURSOR);
  87     wxNode *current = m_shapeList->GetFirst();
  88
  89     while (current)
  90     {
  91       wxShape *object = (wxShape *)current->GetData();
  92       if (!object->GetParent())
  93         object->Draw(dc);
  94
  95       current = current->GetNext();
  96     }
  97     if (GetCanvas())
  98       GetCanvas()->SetCursor(* wxSTANDARD_CURSOR);
  99   }
 100 }
 101
 102 void wxDiagram::Clear(wxDC& dc)
 103 {
 104   dc.Clear();
 105 }
 106
 107 // Insert object after addAfter, or at end of list.
 108 void wxDiagram::AddShape(wxShape *object, wxShape *addAfter)
 109 {
 110   wxNode *nodeAfter = NULL;
 111   if (addAfter)
 112     nodeAfter = m_shapeList->Member(addAfter);
 113
 114   if (!m_shapeList->Member(object))
 115   {
 116     if (nodeAfter)
 117     {
 118       if (nodeAfter->GetNext())
 119         m_shapeList->Insert(nodeAfter->GetNext(), object);
 120       else
 121         m_shapeList->Append(object);
 122     }
 123     else
 124       m_shapeList->Append(object);
 125     object->SetCanvas(GetCanvas());
 126   }
 127 }
 128
 129 void wxDiagram::InsertShape(wxShape *object)
 130 {
 131   m_shapeList->Insert(object);
 132   object->SetCanvas(GetCanvas());
 133 }
 134
 135 void wxDiagram::RemoveShape(wxShape *object)
 136 {
 137   m_shapeList->DeleteObject(object);
 138 }
 139
 140 // Should this delete the actual objects too? I think not.
 141 void wxDiagram::RemoveAllShapes()
 142 {
 143   m_shapeList->Clear();
 144 }
 145
 146 void wxDiagram::DeleteAllShapes()
 147 {
 148   wxNode *node = m_shapeList->GetFirst();
 149   while (node)
 150   {
 151     wxShape *shape = (wxShape *)node->GetData();
 152     if (!shape->GetParent())
 153     {
 154       RemoveShape(shape);
 155       delete shape;
 156       node = m_shapeList->GetFirst();
 157     }
 158     else
 159       node = node->GetNext();
 160   }
 161 }
 162
 163 void wxDiagram::ShowAll(bool show)
 164 {
 165   wxNode *current = m_shapeList->GetFirst();
 166
 167   while (current)
 168   {
 169     wxShape *object = (wxShape *)current->GetData();
 170     object->Show(show);
 171
 172     current = current->GetNext();
 173   }
 174 }
 175
 176 void wxDiagram::DrawOutline(wxDC& dc, double x1, double y1, double x2, double y2)
 177 {
 178   wxPen dottedPen(wxColour(0, 0, 0), 1, wxDOT);
 179   dc.SetPen(dottedPen);
 180   dc.SetBrush((* wxTRANSPARENT_BRUSH));
 181
 182   wxPoint points[5];
 183
 184   points[0].x = (int) x1;
 185   points[0].y = (int) y1;
 186
 187   points[1].x = (int) x2;
 188   points[1].y = (int) y1;
 189
 190   points[2].x = (int) x2;
 191   points[2].y = (int) y2;
 192
 193   points[3].x = (int) x1;
 194   points[3].y = (int) y2;
 195
 196   points[4].x = (int) x1;
 197   points[4].y = (int) y1;
 198   dc.DrawLines(5, points);
 199 }
 200
 201 // Make sure all text that should be centred, is centred.
 202 void wxDiagram::RecentreAll(wxDC& dc)
 203 {
 204   wxNode *object_node = m_shapeList->GetFirst();
 205   while (object_node)
 206   {
 207     wxShape *obj = (wxShape *)object_node->GetData();
 208     obj->Recentre(dc);
 209     object_node = object_node->GetNext();
 210   }
 211 }
 212
 213 // Input/output
 214 #if wxUSE_PROLOGIO
 215 bool wxDiagram::SaveFile(const wxString& filename)
 216 {
 217   wxBeginBusyCursor();
 218
 219   wxExprDatabase *database = new wxExprDatabase;
 220
 221   // First write the diagram type
 222   wxExpr *header = new wxExpr(_T("diagram"));
 223   OnHeaderSave(*database, *header);
 224
 225   database->Append(header);
 226
 227   wxNode *node = m_shapeList->GetFirst();
 228   while (node)
 229   {
 230     wxShape *shape = (wxShape *)node->GetData();
 231
 232     if (!shape->IsKindOf(CLASSINFO(wxControlPoint)))
 233     {
 234       wxExpr *expr;
 235       if (shape->IsKindOf(CLASSINFO(wxLineShape)))
 236         expr = new wxExpr(_T("line"));
 237        else
 238         expr = new wxExpr(_T("shape"));
 239
 240       OnShapeSave(*database, *shape, *expr);
 241     }
 242     node = node->GetNext();
 243   }
 244   OnDatabaseSave(*database);
 245
 246   wxString tempFile;
 247   wxGetTempFileName(wxT("diag"), tempFile);
 248   FILE* file = fopen(tempFile.mb_str(wxConvFile), "w");
 249   if (! file)
 250   {
 251     wxEndBusyCursor();
 252     delete database;
 253     return FALSE;
 254   }
 255
 256   database->Write(file);
 257   fclose(file);
 258   delete database;
 259
 260 /*
 261   // Save backup
 262   if (FileExists(filename))
 263   {
 264     char buf[400];
 265 #ifdef __X__
 266     sprintf(buf, "%s.bak", filename);
 267 #endif
 268 #ifdef __WXMSW__
 269     sprintf(buf, "_diagram.bak");
 270 #endif
 271     if (FileExists(buf)) wxRemoveFile(buf);
 272     if (!wxRenameFile(filename, buf))
 273     {
 274       wxCopyFile(filename, buf);
 275       wxRemoveFile(filename);
 276     }
 277   }
 278 */
 279
 280   // Copy the temporary file to the correct filename
 281   if (!wxRenameFile(tempFile, filename))
 282   {
 283     wxCopyFile(tempFile, filename);
 284     wxRemoveFile(tempFile);
 285   }
 286
 287   wxEndBusyCursor();
 288   return TRUE;
 289 }
 290
 291 bool wxDiagram::LoadFile(const wxString& filename)
 292 {
 293   wxBeginBusyCursor();
 294
 295   wxExprDatabase database(wxExprInteger, _T("id"));
 296   if (!database.Read(filename))
 297   {
 298     wxEndBusyCursor();
 299     return FALSE;
 300   }
 301
 302   DeleteAllShapes();
 303
 304   database.BeginFind();
 305   wxExpr *header = database.FindClauseByFunctor(_T("diagram"));
 306
 307   if (header)
 308     OnHeaderLoad(database, *header);
 309
 310   // Scan through all clauses and register the ids
 311   wxNode *node = database.GetFirst();
 312   while (node)
 313   {
 314     wxExpr *clause = (wxExpr *)node->GetData();
 315     long id = -1;
 316     clause->GetAttributeValue(_T("id"), id);
 317     wxRegisterId(id);
 318     node = node->GetNext();
 319   }
 320
 321   ReadNodes(database);
 322   ReadContainerGeometry(database);
 323   ReadLines(database);
 324
 325   OnDatabaseLoad(database);
 326
 327   wxEndBusyCursor();
 328
 329   return TRUE;
 330 }
 331
 332 void wxDiagram::ReadNodes(wxExprDatabase& database)
 333 {
 334   // Find and create the node images
 335   database.BeginFind();
 336   wxExpr *clause = database.FindClauseByFunctor(_T("shape"));
 337   while (clause)
 338   {
 339     wxChar *type = NULL;
 340     long parentId = -1;
 341
 342     clause->AssignAttributeValue(wxT("type"), &type);
 343     clause->AssignAttributeValue(wxT("parent"), &parentId);
 344     wxClassInfo *classInfo = wxClassInfo::FindClass(type);
 345     if (classInfo)
 346     {
 347       wxShape *shape = (wxShape *)classInfo->CreateObject();
 348       OnShapeLoad(database, *shape, *clause);
 349
 350       shape->SetCanvas(GetCanvas());
 351       shape->Show(TRUE);
 352
 353       m_shapeList->Append(shape);
 354
 355       // If child of composite, link up
 356       if (parentId > -1)
 357       {
 358         wxExpr *parentExpr = database.HashFind(_T("shape"), parentId);
 359         if (parentExpr && parentExpr->GetClientData())
 360         {
 361           wxShape *parent = (wxShape *)parentExpr->GetClientData();
 362           shape->SetParent(parent);
 363           parent->GetChildren().Append(shape);
 364         }
 365       }
 366
 367       clause->SetClientData(shape);
 368     }
 369     if (type)
 370       delete[] type;
 371
 372     clause = database.FindClauseByFunctor(_T("shape"));
 373   }
 374   return;
 375 }
 376
 377 void wxDiagram::ReadLines(wxExprDatabase& database)
 378 {
 379   database.BeginFind();
 380   wxExpr *clause = database.FindClauseByFunctor(_T("line"));
 381   while (clause)
 382   {
 383     wxString type;
 384     long parentId = -1;
 385
 386     clause->GetAttributeValue(_T("type"), type);
 387     clause->GetAttributeValue(_T("parent"), parentId);
 388     wxClassInfo *classInfo = wxClassInfo::FindClass(type);
 389     if (classInfo)
 390     {
 391       wxLineShape *shape = (wxLineShape *)classInfo->CreateObject();
 392       shape->Show(TRUE);
 393
 394       OnShapeLoad(database, *shape, *clause);
 395       shape->SetCanvas(GetCanvas());
 396
 397       long image_to = -1; long image_from = -1;
 398       clause->GetAttributeValue(_T("to"), image_to);
 399       clause->GetAttributeValue(_T("from"), image_from);
 400
 401       wxExpr *image_to_expr = database.HashFind(_T("shape"), image_to);
 402
 403       if (!image_to_expr)
 404       {
 405         // Error
 406       }
 407       wxExpr *image_from_expr = database.HashFind(_T("shape"), image_from);
 408
 409       if (!image_from_expr)
 410       {
 411         // Error
 412       }
 413
 414       if (image_to_expr && image_from_expr)
 415       {
 416         wxShape *image_to_object = (wxShape *)image_to_expr->GetClientData();
 417         wxShape *image_from_object = (wxShape *)image_from_expr->GetClientData();
 418
 419         if (image_to_object && image_from_object)
 420         {
 421           image_from_object->AddLine(shape, image_to_object, shape->GetAttachmentFrom(), shape->GetAttachmentTo());
 422         }
 423       }
 424       clause->SetClientData(shape);
 425
 426       m_shapeList->Append(shape);
 427     }
 428
 429     clause = database.FindClauseByFunctor(_T("line"));
 430   }
 431 }
 432
 433 // Containers have divisions that reference adjoining divisions,
 434 // so we need a separate pass to link everything up.
 435 // Also used by Symbol Library.
 436 void wxDiagram::ReadContainerGeometry(wxExprDatabase& database)
 437 {
 438   database.BeginFind();
 439   wxExpr *clause = database.FindClauseByFunctor(_T("shape"));
 440   while (clause)
 441   {
 442     wxShape *image = (wxShape *)clause->GetClientData();
 443     if (image && image->IsKindOf(CLASSINFO(wxCompositeShape)))
 444     {
 445       wxCompositeShape *composite = (wxCompositeShape *)image;
 446       wxExpr *divisionExpr = NULL;
 447
 448       // Find the list of divisions in the composite
 449       clause->GetAttributeValue(_T("divisions"), &divisionExpr);
 450       if (divisionExpr)
 451       {
 452         int i = 0;
 453         wxExpr *idExpr = divisionExpr->Nth(i);
 454         while (idExpr)
 455         {
 456           long divisionId = idExpr->IntegerValue();
 457           wxExpr *childExpr = database.HashFind(_T("shape"), divisionId);
 458           if (childExpr && childExpr->GetClientData())
 459           {
 460             wxDivisionShape *child = (wxDivisionShape *)childExpr->GetClientData();
 461             composite->GetDivisions().Append(child);
 462
 463             // Find the adjoining shapes
 464             long leftSideId = -1;
 465             long topSideId = -1;
 466             long rightSideId = -1;
 467             long bottomSideId = -1;
 468             childExpr->GetAttributeValue(_T("left_side"), leftSideId);
 469             childExpr->GetAttributeValue(_T("top_side"), topSideId);
 470             childExpr->GetAttributeValue(_T("right_side"), rightSideId);
 471             childExpr->GetAttributeValue(_T("bottom_side"), bottomSideId);
 472             if (leftSideId > -1)
 473             {
 474               wxExpr *leftExpr = database.HashFind(_T("shape"), leftSideId);
 475               if (leftExpr && leftExpr->GetClientData())
 476               {
 477                 wxDivisionShape *leftSide = (wxDivisionShape *)leftExpr->GetClientData();
 478                 child->SetLeftSide(leftSide);
 479               }
 480             }
 481             if (topSideId > -1)
 482             {
 483               wxExpr *topExpr = database.HashFind(_T("shape"), topSideId);
 484               if (topExpr && topExpr->GetClientData())
 485               {
 486                 wxDivisionShape *topSide = (wxDivisionShape *)topExpr->GetClientData();
 487                 child->SetTopSide(topSide);
 488               }
 489             }
 490             if (rightSideId > -1)
 491             {
 492               wxExpr *rightExpr = database.HashFind(_T("shape"), rightSideId);
 493               if (rightExpr && rightExpr->GetClientData())
 494               {
 495                 wxDivisionShape *rightSide = (wxDivisionShape *)rightExpr->GetClientData();
 496                 child->SetRightSide(rightSide);
 497               }
 498             }
 499             if (bottomSideId > -1)
 500             {
 501               wxExpr *bottomExpr = database.HashFind(_T("shape"), bottomSideId);
 502               if (bottomExpr && bottomExpr->GetClientData())
 503               {
 504                 wxDivisionShape *bottomSide = (wxDivisionShape *)bottomExpr->GetClientData();
 505                 child->SetBottomSide(bottomSide);
 506               }
 507             }
 508           }
 509           i ++;
 510           idExpr = divisionExpr->Nth(i);
 511         }
 512       }
 513     }
 514
 515     clause = database.FindClauseByFunctor(_T("shape"));
 516   }
 517 }
 518
 519 // Allow for modifying file
 520 bool wxDiagram::OnDatabaseLoad(wxExprDatabase& WXUNUSED(db))
 521 {
 522   return TRUE;
 523 }
 524
 525 bool wxDiagram::OnDatabaseSave(wxExprDatabase& WXUNUSED(db))
 526 {
 527   return TRUE;
 528 }
 529
 530 bool wxDiagram::OnShapeSave(wxExprDatabase& db, wxShape& shape, wxExpr& expr)
 531 {
 532   shape.WriteAttributes(&expr);
 533   db.Append(&expr);
 534
 535   if (shape.IsKindOf(CLASSINFO(wxCompositeShape)))
 536   {
 537     wxNode *node = shape.GetChildren().GetFirst();
 538     while (node)
 539     {
 540       wxShape *childShape = (wxShape *)node->GetData();
 541       wxExpr *childExpr = new wxExpr(_T("shape"));
 542       OnShapeSave(db, *childShape, *childExpr);
 543       node = node->GetNext();
 544     }
 545   }
 546
 547   return TRUE;
 548 }
 549
 550 bool wxDiagram::OnShapeLoad(wxExprDatabase& WXUNUSED(db), wxShape& shape, wxExpr& expr)
 551 {
 552   shape.ReadAttributes(&expr);
 553   return TRUE;
 554 }
 555
 556 bool wxDiagram::OnHeaderSave(wxExprDatabase& WXUNUSED(db), wxExpr& WXUNUSED(expr))
 557 {
 558   return TRUE;
 559 }
 560
 561 bool wxDiagram::OnHeaderLoad(wxExprDatabase& WXUNUSED(db), wxExpr& WXUNUSED(expr))
 562 {
 563   return TRUE;
 564 }
 565
 566 #endif
 567
 568 void wxDiagram::SetCanvas(wxShapeCanvas *can)
 569 {
 570   m_diagramCanvas = can;
 571 }
 572
 573 // Find a shape by its id
 574 wxShape* wxDiagram::FindShape(long id) const
 575 {
 576     wxNode* node = GetShapeList()->GetFirst();
 577     while (node)
 578     {
 579         wxShape* shape = (wxShape*) node->GetData();
 580         if (shape->GetId() == id)
 581             return shape;
 582         node = node->GetNext();
 583     }
 584     return NULL;
 585 }
 586
 587
 588 //// Crossings classes
 589
 590 wxLineCrossings::wxLineCrossings()
 591 {
 592 }
 593
 594 wxLineCrossings::~wxLineCrossings()
 595 {
 596     ClearCrossings();
 597 }
 598
 599 void wxLineCrossings::FindCrossings(wxDiagram& diagram)
 600 {
 601     ClearCrossings();
 602     wxNode* node1 = diagram.GetShapeList()->GetFirst();
 603     while (node1)
 604     {
 605         wxShape* shape1 = (wxShape*) node1->GetData();
 606         if (shape1->IsKindOf(CLASSINFO(wxLineShape)))
 607         {
 608             wxLineShape* lineShape1 = (wxLineShape*) shape1;
 609             // Iterate through the segments
 610             wxList* pts1 = lineShape1->GetLineControlPoints();
 611             size_t i;
 612             for (i = 0; i < (pts1->GetCount() - 1); i++)
 613             {
 614                 wxRealPoint* pt1_a = (wxRealPoint*) (pts1->Item(i)->GetData());
 615                 wxRealPoint* pt1_b = (wxRealPoint*) (pts1->Item(i+1)->GetData());
 616
 617                 // Now we iterate through the segments again
 618
 619                 wxNode* node2 = diagram.GetShapeList()->GetFirst();
 620                 while (node2)
 621                 {
 622                     wxShape* shape2 = (wxShape*) node2->GetData();
 623
 624                     // Assume that the same line doesn't cross itself
 625                     if (shape2->IsKindOf(CLASSINFO(wxLineShape)) && (shape1 != shape2))
 626                     {
 627                         wxLineShape* lineShape2 = (wxLineShape*) shape2;
 628                         // Iterate through the segments
 629                         wxList* pts2 = lineShape2->GetLineControlPoints();
 630                         int j;
 631                         for (j = 0; j < (int) (pts2->GetCount() - 1); j++)
 632                         {
 633                             wxRealPoint* pt2_a = (wxRealPoint*) (pts2->Item(j)->GetData());
 634                             wxRealPoint* pt2_b = (wxRealPoint*) (pts2->Item(j+1)->GetData());
 635
 636                             // Now let's see if these two segments cross.
 637                             double ratio1, ratio2;
 638                             oglCheckLineIntersection(pt1_a->x, pt1_a->y, pt1_b->x, pt1_b->y,
 639                                pt2_a->x, pt2_a->y, pt2_b->x, pt2_b->y,
 640                              & ratio1, & ratio2);
 641
 642                             if ((ratio1 < 1.0) && (ratio1 > -1.0))
 643                             {
 644                                 // Intersection!
 645                                 wxLineCrossing* crossing = new wxLineCrossing;
 646                                 crossing->m_intersect.x = (pt1_a->x + (pt1_b->x - pt1_a->x)*ratio1);
 647                                 crossing->m_intersect.y = (pt1_a->y + (pt1_b->y - pt1_a->y)*ratio1);
 648
 649                                 crossing->m_pt1 = * pt1_a;
 650                                 crossing->m_pt2 = * pt1_b;
 651                                 crossing->m_pt3 = * pt2_a;
 652                                 crossing->m_pt4 = * pt2_b;
 653
 654                                 crossing->m_lineShape1 = lineShape1;
 655                                 crossing->m_lineShape2 = lineShape2;
 656
 657                                 m_crossings.Append(crossing);
 658                             }
 659                         }
 660                     }
 661                     node2 = node2->GetNext();
 662                 }
 663             }
 664         }
 665
 666         node1 = node1->GetNext();
 667     }
 668 }
 669
 670 void wxLineCrossings::DrawCrossings(wxDiagram& WXUNUSED(diagram), wxDC& dc)
 671 {
 672     dc.SetBrush(*wxTRANSPARENT_BRUSH);
 673
 674     long arcWidth = 8;
 675
 676     wxNode* node = m_crossings.GetFirst();
 677     while (node)
 678     {
 679         wxLineCrossing* crossing = (wxLineCrossing*) node->GetData();
 680 //        dc.DrawEllipse((long) (crossing->m_intersect.x - (arcWidth/2.0) + 0.5), (long) (crossing->m_intersect.y - (arcWidth/2.0) + 0.5),
 681 //           arcWidth, arcWidth);
 682
 683
 684         // Let's do some geometry to find the points on either end of the arc.
 685 /*
 686
 687 (x1, y1)
 688     |\
 689     | \
 690     |  \
 691     |   \
 692     |    \
 693     |    |\ c    c1
 694     |  a | \
 695          |  \
 696     |     -  x <-- centre of arc
 697  a1 |     b  |\
 698     |        | \ c2
 699     |     a2 |  \
 700     |         -  \
 701     |         b2  \
 702     |              \
 703     |_______________\ (x2, y2)
 704           b1
 705
 706 */
 707
 708         double a1 = wxMax(crossing->m_pt1.y, crossing->m_pt2.y) - wxMin(crossing->m_pt1.y, crossing->m_pt2.y) ;
 709         double b1 = wxMax(crossing->m_pt1.x, crossing->m_pt2.x) - wxMin(crossing->m_pt1.x, crossing->m_pt2.x) ;
 710         double c1 = sqrt( (a1*a1) + (b1*b1) );
 711
 712         double c = arcWidth / 2.0;
 713         double a = c * a1/c1 ;
 714         double b = c * b1/c1 ;
 715
 716         // I'm not sure this is right, since we don't know which direction we should be going in - need
 717         // to know which way the line slopes and choose the sign appropriately.
 718         double arcX1 = crossing->m_intersect.x - b;
 719         double arcY1 = crossing->m_intersect.y - a;
 720
 721         double arcX2 = crossing->m_intersect.x + b;
 722         double arcY2 = crossing->m_intersect.y + a;
 723
 724         dc.SetPen(*wxBLACK_PEN);
 725         dc.DrawArc( (long) arcX1, (long) arcY1, (long) arcX2, (long) arcY2,
 726             (long) crossing->m_intersect.x, (long) crossing->m_intersect.y);
 727
 728         dc.SetPen(*wxWHITE_PEN);
 729         dc.DrawLine( (long) arcX1, (long) arcY1, (long) arcX2, (long) arcY2 );
 730
 731         node = node->GetNext();
 732     }
 733 }
 734
 735 void wxLineCrossings::ClearCrossings()
 736 {
 737     wxNode* node = m_crossings.GetFirst();
 738     while (node)
 739     {
 740         wxLineCrossing* crossing = (wxLineCrossing*) node->GetData();
 741         delete crossing;
 742         node = node->GetNext();
 743     }
 744     m_crossings.Clear();
 745 }
 746