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 #include <wx/wxexpr.h>
  28
  29 #if wxUSE_IOSTREAMH
  30 #include <iostream.h>
  31 #include <fstream.h>
  32 #else
  33 #include <iostream>
  34 #include <fstream>
  35 #ifdef _MSC_VER
  36 //using namespace std;
  37 #endif
  38 #endif
  39
  40 #include <ctype.h>
  41 #include <math.h>
  42 #include <stdlib.h>
  43
  44 #include <wx/ogl/basic.h>
  45 #include <wx/ogl/basicp.h>
  46 #include <wx/ogl/canvas.h>
  47 #include <wx/ogl/ogldiag.h>
  48 #include <wx/ogl/lines.h>
  49 #include <wx/ogl/composit.h>
  50 #include <wx/ogl/misc.h>
  51
  52 IMPLEMENT_DYNAMIC_CLASS(wxDiagram, wxObject)
  53
  54 // Object canvas
  55 wxDiagram::wxDiagram()
  56 {
  57   m_diagramCanvas = NULL;
  58   m_quickEditMode = FALSE;
  59   m_snapToGrid = TRUE;
  60   m_gridSpacing = 5.0;
  61   m_shapeList = new wxList;
  62   m_mouseTolerance = DEFAULT_MOUSE_TOLERANCE;
  63 }
  64
  65 wxDiagram::~wxDiagram()
  66 {
  67   if (m_shapeList)
  68     delete m_shapeList;
  69 }
  70
  71 void wxDiagram::SetSnapToGrid(bool snap)
  72 {
  73   m_snapToGrid = snap;
  74 }
  75
  76 void wxDiagram::SetGridSpacing(double spacing)
  77 {
  78   m_gridSpacing = spacing;
  79 }
  80
  81 void wxDiagram::Snap(double *x, double *y)
  82 {
  83   if (m_snapToGrid)
  84   {
  85     *x = m_gridSpacing * ((int)(*x/m_gridSpacing + 0.5));
  86     *y = m_gridSpacing * ((int)(*y/m_gridSpacing + 0.5));
  87   }
  88 }
  89
  90
  91 void wxDiagram::Redraw(wxDC& dc)
  92 {
  93   if (m_shapeList)
  94   {
  95     if (GetCanvas())
  96       GetCanvas()->SetCursor(* wxHOURGLASS_CURSOR);
  97     wxNode *current = m_shapeList->First();
  98
  99     while (current)
 100     {
 101       wxShape *object = (wxShape *)current->Data();
 102       if (!object->GetParent())
 103         object->Draw(dc);
 104
 105       current = current->Next();
 106     }
 107     if (GetCanvas())
 108       GetCanvas()->SetCursor(* wxSTANDARD_CURSOR);
 109   }
 110 }
 111
 112 void wxDiagram::Clear(wxDC& dc)
 113 {
 114   dc.Clear();
 115 }
 116
 117 // Insert object after addAfter, or at end of list.
 118 void wxDiagram::AddShape(wxShape *object, wxShape *addAfter)
 119 {
 120   wxNode *nodeAfter = NULL;
 121   if (addAfter)
 122     nodeAfter = m_shapeList->Member(addAfter);
 123
 124   if (!m_shapeList->Member(object))
 125   {
 126     if (nodeAfter)
 127     {
 128       if (nodeAfter->Next())
 129         m_shapeList->Insert(nodeAfter->Next(), object);
 130       else
 131         m_shapeList->Append(object);
 132     }
 133     else
 134       m_shapeList->Append(object);
 135     object->SetCanvas(GetCanvas());
 136   }
 137 }
 138
 139 void wxDiagram::InsertShape(wxShape *object)
 140 {
 141   m_shapeList->Insert(object);
 142   object->SetCanvas(GetCanvas());
 143 }
 144
 145 void wxDiagram::RemoveShape(wxShape *object)
 146 {
 147   m_shapeList->DeleteObject(object);
 148 }
 149
 150 // Should this delete the actual objects too? I think not.
 151 void wxDiagram::RemoveAllShapes()
 152 {
 153   m_shapeList->Clear();
 154 }
 155
 156 void wxDiagram::DeleteAllShapes()
 157 {
 158   wxNode *node = m_shapeList->First();
 159   while (node)
 160   {
 161     wxShape *shape = (wxShape *)node->Data();
 162     if (!shape->GetParent())
 163     {
 164       RemoveShape(shape);
 165       delete shape;
 166       node = m_shapeList->First();
 167     }
 168     else
 169       node = node->Next();
 170   }
 171 }
 172
 173 void wxDiagram::ShowAll(bool show)
 174 {
 175   wxNode *current = m_shapeList->First();
 176
 177   while (current)
 178   {
 179     wxShape *object = (wxShape *)current->Data();
 180     object->Show(show);
 181
 182     current = current->Next();
 183   }
 184 }
 185
 186 void wxDiagram::DrawOutline(wxDC& dc, double x1, double y1, double x2, double y2)
 187 {
 188   wxPen dottedPen(wxColour(0, 0, 0), 1, wxDOT);
 189   dc.SetPen(dottedPen);
 190   dc.SetBrush((* wxTRANSPARENT_BRUSH));
 191
 192   wxPoint points[5];
 193
 194   points[0].x = (int) x1;
 195   points[0].y = (int) y1;
 196
 197   points[1].x = (int) x2;
 198   points[1].y = (int) y1;
 199
 200   points[2].x = (int) x2;
 201   points[2].y = (int) y2;
 202
 203   points[3].x = (int) x1;
 204   points[3].y = (int) y2;
 205
 206   points[4].x = (int) x1;
 207   points[4].y = (int) y1;
 208   dc.DrawLines(5, points);
 209 }
 210
 211 // Make sure all text that should be centred, is centred.
 212 void wxDiagram::RecentreAll(wxDC& dc)
 213 {
 214   wxNode *object_node = m_shapeList->First();
 215   while (object_node)
 216   {
 217     wxShape *obj = (wxShape *)object_node->Data();
 218     obj->Recentre(dc);
 219     object_node = object_node->Next();
 220   }
 221 }
 222
 223 // Input/output
 224 #ifdef PROLOGIO
 225 bool wxDiagram::SaveFile(const wxString& filename)
 226 {
 227   wxBeginBusyCursor();
 228
 229   wxExprDatabase *database = new wxExprDatabase;
 230
 231   // First write the diagram type
 232   wxExpr *header = new wxExpr("diagram");
 233   OnHeaderSave(*database, *header);
 234
 235   database->Append(header);
 236
 237   wxNode *node = m_shapeList->First();
 238   while (node)
 239   {
 240     wxShape *shape = (wxShape *)node->Data();
 241
 242     if (!shape->IsKindOf(CLASSINFO(wxControlPoint)))
 243     {
 244       wxExpr *expr = NULL;
 245       if (shape->IsKindOf(CLASSINFO(wxLineShape)))
 246         expr = new wxExpr("line");
 247        else
 248         expr = new wxExpr("shape");
 249
 250       OnShapeSave(*database, *shape, *expr);
 251     }
 252     node = node->Next();
 253   }
 254   OnDatabaseSave(*database);
 255
 256   char tempFile[400];
 257   wxGetTempFileName("diag", tempFile);
 258   FILE* file = fopen(tempFile, "w");
 259   if (! file)
 260   {
 261     wxEndBusyCursor();
 262     delete database;
 263     return FALSE;
 264   }
 265
 266   database->Write(file);
 267   fclose(file);
 268   delete database;
 269
 270 /*
 271   // Save backup
 272   if (FileExists(filename))
 273   {
 274     char buf[400];
 275 #ifdef __X__
 276     sprintf(buf, "%s.bak", filename);
 277 #endif
 278 #ifdef __WXMSW__
 279     sprintf(buf, "_diagram.bak");
 280 #endif
 281     if (FileExists(buf)) wxRemoveFile(buf);
 282     if (!wxRenameFile(filename, buf))
 283     {
 284       wxCopyFile(filename, buf);
 285       wxRemoveFile(filename);
 286     }
 287   }
 288 */
 289
 290   // Copy the temporary file to the correct filename
 291   if (!wxRenameFile(tempFile, filename))
 292   {
 293     wxCopyFile(tempFile, filename);
 294     wxRemoveFile(tempFile);
 295   }
 296
 297   wxEndBusyCursor();
 298   return TRUE;
 299 }
 300
 301 bool wxDiagram::LoadFile(const wxString& filename)
 302 {
 303   wxBeginBusyCursor();
 304
 305   wxExprDatabase database(wxExprInteger, "id");
 306   if (!database.Read(filename))
 307   {
 308     wxEndBusyCursor();
 309     return FALSE;
 310   }
 311
 312   DeleteAllShapes();
 313
 314   database.BeginFind();
 315   wxExpr *header = database.FindClauseByFunctor("diagram");
 316
 317   if (header)
 318     OnHeaderLoad(database, *header);
 319
 320   // Scan through all clauses and register the ids
 321   wxNode *node = database.First();
 322   while (node)
 323   {
 324     wxExpr *clause = (wxExpr *)node->Data();
 325     long id = -1;
 326     clause->GetAttributeValue("id", id);
 327     wxRegisterId(id);
 328     node = node->Next();
 329   }
 330
 331   ReadNodes(database);
 332   ReadContainerGeometry(database);
 333   ReadLines(database);
 334
 335   OnDatabaseLoad(database);
 336
 337   wxEndBusyCursor();
 338
 339   return TRUE;
 340 }
 341
 342 void wxDiagram::ReadNodes(wxExprDatabase& database)
 343 {
 344   // Find and create the node images
 345   database.BeginFind();
 346   wxExpr *clause = database.FindClauseByFunctor("shape");
 347   while (clause)
 348   {
 349     char *type = NULL;
 350     long parentId = -1;
 351
 352     clause->AssignAttributeValue("type", &type);
 353     clause->AssignAttributeValue("parent", &parentId);
 354     wxClassInfo *classInfo = wxClassInfo::FindClass(type);
 355     if (classInfo)
 356     {
 357       wxShape *shape = (wxShape *)classInfo->CreateObject();
 358       OnShapeLoad(database, *shape, *clause);
 359
 360       shape->SetCanvas(GetCanvas());
 361       shape->Show(TRUE);
 362
 363       m_shapeList->Append(shape);
 364
 365       // If child of composite, link up
 366       if (parentId > -1)
 367       {
 368         wxExpr *parentExpr = database.HashFind("shape", parentId);
 369         if (parentExpr && parentExpr->GetClientData())
 370         {
 371           wxShape *parent = (wxShape *)parentExpr->GetClientData();
 372           shape->SetParent(parent);
 373           parent->GetChildren().Append(shape);
 374         }
 375       }
 376
 377       clause->SetClientData(shape);
 378     }
 379     if (type)
 380       delete[] type;
 381
 382     clause = database.FindClauseByFunctor("shape");
 383   }
 384   return;
 385 }
 386
 387 void wxDiagram::ReadLines(wxExprDatabase& database)
 388 {
 389   database.BeginFind();
 390   wxExpr *clause = database.FindClauseByFunctor("line");
 391   while (clause)
 392   {
 393     wxString type("");
 394     long parentId = -1;
 395
 396     clause->GetAttributeValue("type", type);
 397     clause->GetAttributeValue("parent", parentId);
 398     wxClassInfo *classInfo = wxClassInfo::FindClass((char*) (const char*) type);
 399     if (classInfo)
 400     {
 401       wxLineShape *shape = (wxLineShape *)classInfo->CreateObject();
 402       shape->Show(TRUE);
 403
 404       OnShapeLoad(database, *shape, *clause);
 405       shape->SetCanvas(GetCanvas());
 406
 407       long image_to = -1; long image_from = -1;
 408       clause->GetAttributeValue("to", image_to);
 409       clause->GetAttributeValue("from", image_from);
 410
 411       wxExpr *image_to_expr = database.HashFind("shape", image_to);
 412
 413       if (!image_to_expr)
 414       {
 415         // Error
 416       }
 417       wxExpr *image_from_expr = database.HashFind("shape", image_from);
 418
 419       if (!image_from_expr)
 420       {
 421         // Error
 422       }
 423
 424       if (image_to_expr && image_from_expr)
 425       {
 426         wxShape *image_to_object = (wxShape *)image_to_expr->GetClientData();
 427         wxShape *image_from_object = (wxShape *)image_from_expr->GetClientData();
 428
 429         if (image_to_object && image_from_object)
 430         {
 431           image_from_object->AddLine(shape, image_to_object, shape->GetAttachmentFrom(), shape->GetAttachmentTo());
 432         }
 433       }
 434       clause->SetClientData(shape);
 435
 436       m_shapeList->Append(shape);
 437     }
 438
 439     clause = database.FindClauseByFunctor("line");
 440   }
 441 }
 442
 443 // Containers have divisions that reference adjoining divisions,
 444 // so we need a separate pass to link everything up.
 445 // Also used by Symbol Library.
 446 void wxDiagram::ReadContainerGeometry(wxExprDatabase& database)
 447 {
 448   database.BeginFind();
 449   wxExpr *clause = database.FindClauseByFunctor("shape");
 450   while (clause)
 451   {
 452     wxShape *image = (wxShape *)clause->GetClientData();
 453     if (image && image->IsKindOf(CLASSINFO(wxCompositeShape)))
 454     {
 455       wxCompositeShape *composite = (wxCompositeShape *)image;
 456       wxExpr *divisionExpr = NULL;
 457
 458       // Find the list of divisions in the composite
 459       clause->GetAttributeValue("divisions", &divisionExpr);
 460       if (divisionExpr)
 461       {
 462         int i = 0;
 463         wxExpr *idExpr = divisionExpr->Nth(i);
 464         while (idExpr)
 465         {
 466           long divisionId = idExpr->IntegerValue();
 467           wxExpr *childExpr = database.HashFind("shape", divisionId);
 468           if (childExpr && childExpr->GetClientData())
 469           {
 470             wxDivisionShape *child = (wxDivisionShape *)childExpr->GetClientData();
 471             composite->GetDivisions().Append(child);
 472
 473             // Find the adjoining shapes
 474             long leftSideId = -1;
 475             long topSideId = -1;
 476             long rightSideId = -1;
 477             long bottomSideId = -1;
 478             childExpr->GetAttributeValue("left_side", leftSideId);
 479             childExpr->GetAttributeValue("top_side", topSideId);
 480             childExpr->GetAttributeValue("right_side", rightSideId);
 481             childExpr->GetAttributeValue("bottom_side", bottomSideId);
 482             if (leftSideId > -1)
 483             {
 484               wxExpr *leftExpr = database.HashFind("shape", leftSideId);
 485               if (leftExpr && leftExpr->GetClientData())
 486               {
 487                 wxDivisionShape *leftSide = (wxDivisionShape *)leftExpr->GetClientData();
 488                 child->SetLeftSide(leftSide);
 489               }
 490             }
 491             if (topSideId > -1)
 492             {
 493               wxExpr *topExpr = database.HashFind("shape", topSideId);
 494               if (topExpr && topExpr->GetClientData())
 495               {
 496                 wxDivisionShape *topSide = (wxDivisionShape *)topExpr->GetClientData();
 497                 child->SetTopSide(topSide);
 498               }
 499             }
 500             if (rightSideId > -1)
 501             {
 502               wxExpr *rightExpr = database.HashFind("shape", rightSideId);
 503               if (rightExpr && rightExpr->GetClientData())
 504               {
 505                 wxDivisionShape *rightSide = (wxDivisionShape *)rightExpr->GetClientData();
 506                 child->SetRightSide(rightSide);
 507               }
 508             }
 509             if (bottomSideId > -1)
 510             {
 511               wxExpr *bottomExpr = database.HashFind("shape", bottomSideId);
 512               if (bottomExpr && bottomExpr->GetClientData())
 513               {
 514                 wxDivisionShape *bottomSide = (wxDivisionShape *)bottomExpr->GetClientData();
 515                 child->SetBottomSide(bottomSide);
 516               }
 517             }
 518           }
 519           i ++;
 520           idExpr = divisionExpr->Nth(i);
 521         }
 522       }
 523     }
 524
 525     clause = database.FindClauseByFunctor("shape");
 526   }
 527 }
 528
 529 // Allow for modifying file
 530 bool wxDiagram::OnDatabaseLoad(wxExprDatabase& db)
 531 {
 532   return TRUE;
 533 }
 534
 535 bool wxDiagram::OnDatabaseSave(wxExprDatabase& db)
 536 {
 537   return TRUE;
 538 }
 539
 540 bool wxDiagram::OnShapeSave(wxExprDatabase& db, wxShape& shape, wxExpr& expr)
 541 {
 542   shape.WriteAttributes(&expr);
 543   db.Append(&expr);
 544
 545   if (shape.IsKindOf(CLASSINFO(wxCompositeShape)))
 546   {
 547     wxNode *node = shape.GetChildren().First();
 548     while (node)
 549     {
 550       wxShape *childShape = (wxShape *)node->Data();
 551       wxExpr *childExpr = new wxExpr("shape");
 552       OnShapeSave(db, *childShape, *childExpr);
 553       node = node->Next();
 554     }
 555   }
 556
 557   return TRUE;
 558 }
 559
 560 bool wxDiagram::OnShapeLoad(wxExprDatabase& db, wxShape& shape, wxExpr& expr)
 561 {
 562   shape.ReadAttributes(&expr);
 563   return TRUE;
 564 }
 565
 566 bool wxDiagram::OnHeaderSave(wxExprDatabase& db, wxExpr& expr)
 567 {
 568   return TRUE;
 569 }
 570
 571 bool wxDiagram::OnHeaderLoad(wxExprDatabase& db, wxExpr& expr)
 572 {
 573   return TRUE;
 574 }
 575
 576 #endif
 577
 578 void wxDiagram::SetCanvas(wxShapeCanvas *can)
 579 {
 580   m_diagramCanvas = can;
 581 }
 582
 583 // Find a shape by its id
 584 wxShape* wxDiagram::FindShape(long id) const
 585 {
 586     wxNode* node = GetShapeList()->First();
 587     while (node)
 588     {
 589         wxShape* shape = (wxShape*) node->Data();
 590         if (shape->GetId() == id)
 591             return shape;
 592         node = node->Next();
 593     }
 594     return NULL;
 595 }
 596
 597
 598 //// Crossings classes
 599
 600 wxLineCrossings::wxLineCrossings()
 601 {
 602 }
 603
 604 wxLineCrossings::~wxLineCrossings()
 605 {
 606     ClearCrossings();
 607 }
 608
 609 void wxLineCrossings::FindCrossings(wxDiagram& diagram)
 610 {
 611     ClearCrossings();
 612     wxNode* node1 = diagram.GetShapeList()->First();
 613     while (node1)
 614     {
 615         wxShape* shape1 = (wxShape*) node1->Data();
 616         if (shape1->IsKindOf(CLASSINFO(wxLineShape)))
 617         {
 618             wxLineShape* lineShape1 = (wxLineShape*) shape1;
 619             // Iterate through the segments
 620             wxList* pts1 = lineShape1->GetLineControlPoints();
 621             int i;
 622             for (i = 0; i < (pts1->Number() - 1); i++)
 623             {
 624                 wxRealPoint* pt1_a = (wxRealPoint*) (pts1->Nth(i)->Data());
 625                 wxRealPoint* pt1_b = (wxRealPoint*) (pts1->Nth(i+1)->Data());
 626
 627                 // Now we iterate through the segments again
 628
 629                 wxNode* node2 = diagram.GetShapeList()->First();
 630                 while (node2)
 631                 {
 632                     wxShape* shape2 = (wxShape*) node2->Data();
 633
 634                     // Assume that the same line doesn't cross itself
 635                     if (shape2->IsKindOf(CLASSINFO(wxLineShape)) && (shape1 != shape2))
 636                     {
 637                         wxLineShape* lineShape2 = (wxLineShape*) shape2;
 638                         // Iterate through the segments
 639                         wxList* pts2 = lineShape2->GetLineControlPoints();
 640                         int j;
 641                         for (j = 0; j < (pts2->Number() - 1); j++)
 642                         {
 643                             wxRealPoint* pt2_a = (wxRealPoint*) (pts2->Nth(j)->Data());
 644                             wxRealPoint* pt2_b = (wxRealPoint*) (pts2->Nth(j+1)->Data());
 645
 646                             // Now let's see if these two segments cross.
 647                             double ratio1, ratio2;
 648                             oglCheckLineIntersection(pt1_a->x, pt1_a->y, pt1_b->x, pt1_b->y,
 649                                pt2_a->x, pt2_a->y, pt2_b->x, pt2_b->y,
 650                              & ratio1, & ratio2);
 651
 652                             if ((ratio1 < 1.0) && (ratio1 > -1.0))
 653                             {
 654                                 // Intersection!
 655                                 wxLineCrossing* crossing = new wxLineCrossing;
 656                                 crossing->m_intersect.x = (pt1_a->x + (pt1_b->x - pt1_a->x)*ratio1);
 657                                 crossing->m_intersect.y = (pt1_a->y + (pt1_b->y - pt1_a->y)*ratio1);
 658
 659                                 crossing->m_pt1 = * pt1_a;
 660                                 crossing->m_pt2 = * pt1_b;
 661                                 crossing->m_pt3 = * pt2_a;
 662                                 crossing->m_pt4 = * pt2_b;
 663
 664                                 crossing->m_lineShape1 = lineShape1;
 665                                 crossing->m_lineShape2 = lineShape2;
 666
 667                                 m_crossings.Append(crossing);
 668                             }
 669                         }
 670                     }
 671                     node2 = node2->Next();
 672                 }
 673             }
 674         }
 675
 676         node1 = node1->Next();
 677     }
 678 }
 679
 680 void wxLineCrossings::DrawCrossings(wxDiagram& diagram, wxDC& dc)
 681 {
 682     dc.SetBrush(*wxTRANSPARENT_BRUSH);
 683
 684     long arcWidth = 8;
 685
 686     wxNode* node = m_crossings.First();
 687     while (node)
 688     {
 689         wxLineCrossing* crossing = (wxLineCrossing*) node->Data();
 690 //        dc.DrawEllipse((long) (crossing->m_intersect.x - (arcWidth/2.0) + 0.5), (long) (crossing->m_intersect.y - (arcWidth/2.0) + 0.5),
 691 //           arcWidth, arcWidth);
 692
 693
 694         // Let's do some geometry to find the points on either end of the arc.
 695 /*
 696
 697 (x1, y1)
 698     |\
 699     | \
 700     |  \
 701     |   \
 702     |    \
 703     |    |\ c    c1
 704     |  a | \
 705          |  \
 706     |     -  x <-- centre of arc
 707  a1 |     b  |\
 708     |        | \ c2
 709     |     a2 |  \
 710     |         -  \
 711     |         b2  \
 712     |              \
 713     |_______________\ (x2, y2)
 714           b1
 715
 716 */
 717
 718         double a1 = wxMax(crossing->m_pt1.y, crossing->m_pt2.y) - wxMin(crossing->m_pt1.y, crossing->m_pt2.y) ;
 719         double b1 = wxMax(crossing->m_pt1.x, crossing->m_pt2.x) - wxMin(crossing->m_pt1.x, crossing->m_pt2.x) ;
 720         double c1 = sqrt( (a1*a1) + (b1*b1) );
 721
 722         double c = arcWidth / 2.0;
 723         double a = c * a1/c1 ;
 724         double b = c * b1/c1 ;
 725
 726         // I'm not sure this is right, since we don't know which direction we should be going in - need
 727         // to know which way the line slopes and choose the sign appropriately.
 728         double arcX1 = crossing->m_intersect.x - b;
 729         double arcY1 = crossing->m_intersect.y - a;
 730
 731         double arcX2 = crossing->m_intersect.x + b;
 732         double arcY2 = crossing->m_intersect.y + a;
 733
 734         dc.SetPen(*wxBLACK_PEN);
 735         dc.DrawArc( (long) arcX1, (long) arcY1, (long) arcX2, (long) arcY2,
 736             (long) crossing->m_intersect.x, (long) crossing->m_intersect.y);
 737
 738         dc.SetPen(*wxWHITE_PEN);
 739         dc.DrawLine( (long) arcX1, (long) arcY1, (long) arcX2, (long) arcY2 );
 740
 741         node = node->Next();
 742     }
 743 }
 744
 745 void wxLineCrossings::ClearCrossings()
 746 {
 747     wxNode* node = m_crossings.First();
 748     while (node)
 749     {
 750         wxLineCrossing* crossing = (wxLineCrossing*) node->Data();
 751         delete crossing;
 752         node = node->Next();
 753     }
 754     m_crossings.Clear();
 755 }
 756