src/cocoa/dc.mm

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        src/cocoa/dc.mm
   3 // Purpose:     wxDC
   4 // Author:      David Elliott
   5 // Modified by:
   6 // Created:     2003/04/01
   7 // RCS-ID:      $Id$
   8 // Copyright:   (c) 2003 David Elliott
   9 // Licence:     wxWidgets licence
  10 /////////////////////////////////////////////////////////////////////////////
  11
  12 #include "wx/wxprec.h"
  13 #ifndef WX_PRECOMP
  14     #include "wx/log.h"
  15     #include "wx/dc.h"
  16 #endif //WX_PRECOMP
  17
  18 #include "wx/cocoa/autorelease.h"
  19 #include "wx/cocoa/string.h"
  20
  21 #import <AppKit/NSBezierPath.h>
  22 #import <AppKit/NSTextStorage.h>
  23 #import <AppKit/NSLayoutManager.h>
  24 #import <AppKit/NSTextContainer.h>
  25 #import <AppKit/NSGraphicsContext.h>
  26 #import <AppKit/NSAffineTransform.h>
  27 #import <AppKit/NSColor.h>
  28 #import <AppKit/NSTypesetter.h>
  29 #import <AppKit/NSImage.h>
  30
  31 #include "wx/listimpl.cpp"
  32 WX_DEFINE_LIST(wxCocoaDCStack);
  33
  34 IMPLEMENT_ABSTRACT_CLASS(wxDC, wxObject)
  35 WX_NSTextStorage wxDC::sm_cocoaNSTextStorage = nil;
  36 WX_NSLayoutManager wxDC::sm_cocoaNSLayoutManager = nil;
  37 WX_NSTextContainer wxDC::sm_cocoaNSTextContainer = nil;
  38 wxCocoaDCStack wxDC::sm_cocoaDCStack;
  39
  40 inline void CocoaSetPenForNSBezierPath(wxPen &pen, NSBezierPath *bezpath)
  41 {
  42     [pen.GetNSColor() set];
  43     const float *pattern;
  44     [bezpath setLineDash:pattern count:pen.GetCocoaLineDash(&pattern) phase:0.0];
  45     [bezpath setLineWidth:pen.GetWidth()];
  46     switch(pen.GetJoin())
  47     {
  48     case wxJOIN_BEVEL:
  49         [bezpath setLineJoinStyle:NSBevelLineJoinStyle];
  50         break;
  51     case wxJOIN_ROUND:
  52         [bezpath setLineJoinStyle:NSRoundLineJoinStyle];
  53         break;
  54     case wxJOIN_MITER:
  55         [bezpath setLineJoinStyle:NSMiterLineJoinStyle];
  56         break;
  57     }
  58     switch(pen.GetCap())
  59     {
  60     case wxCAP_ROUND:
  61         [bezpath setLineCapStyle:NSRoundLineCapStyle];
  62         break;
  63     case wxCAP_PROJECTING:
  64         [bezpath setLineCapStyle:NSSquareLineCapStyle];
  65         break;
  66     case wxCAP_BUTT:
  67         [bezpath setLineCapStyle:NSButtLineCapStyle];
  68         break;
  69     }
  70 }
  71
  72 void wxDC::CocoaInitializeTextSystem()
  73 {
  74     wxASSERT_MSG(!sm_cocoaNSTextStorage && !sm_cocoaNSLayoutManager && !sm_cocoaNSTextContainer,wxT("Text system already initalized!  BAD PROGRAMMER!"));
  75
  76     sm_cocoaNSTextStorage = [[NSTextStorage alloc] init];
  77
  78     sm_cocoaNSLayoutManager = [[NSLayoutManager alloc] init];
  79     [sm_cocoaNSTextStorage addLayoutManager:sm_cocoaNSLayoutManager];
  80     // NSTextStorage retains NSLayoutManager, but so do we
  81     // [sm_cocoaNSLayoutManager release]; [sm_cocoaNSLayoutManager retain];
  82
  83     // NOTE:  initWithContainerSize is the designated initializer, but the
  84     // Apple CircleView sample gets away with just calling init, which
  85     // is all we really need for our purposes.
  86     sm_cocoaNSTextContainer = [[NSTextContainer alloc] init];
  87     [sm_cocoaNSLayoutManager addTextContainer:sm_cocoaNSTextContainer];
  88     // NSLayoutManager retains NSTextContainer, but so do we
  89     // [sm_cocoaNSTextContainer release]; [sm_cocoaNSTextContainer retain];
  90 }
  91
  92 void wxDC::CocoaShutdownTextSystem()
  93 {
  94     [sm_cocoaNSTextContainer release]; sm_cocoaNSTextContainer = nil;
  95     [sm_cocoaNSLayoutManager release]; sm_cocoaNSLayoutManager = nil;
  96     [sm_cocoaNSTextStorage release]; sm_cocoaNSTextStorage = nil;
  97 }
  98
  99 void wxDC::CocoaUnwindStackAndLoseFocus()
 100 {
 101     wxCocoaDCStack::compatibility_iterator ourNode=sm_cocoaDCStack.Find(this);
 102     if(ourNode)
 103     {
 104         wxCocoaDCStack::compatibility_iterator node=sm_cocoaDCStack.GetFirst();
 105         for(;node!=ourNode; node=sm_cocoaDCStack.GetFirst())
 106         {
 107             wxDC *dc = node->GetData();
 108             wxASSERT(dc);
 109             wxASSERT(dc!=this);
 110             if(!dc->CocoaUnlockFocus())
 111             {
 112                 wxFAIL_MSG(wxT("Unable to unlock focus on higher-level DC!"));
 113             }
 114             sm_cocoaDCStack.Erase(node);
 115         }
 116         wxASSERT(node==ourNode);
 117         wxASSERT(ourNode->GetData() == this);
 118         ourNode->GetData()->CocoaUnlockFocus();
 119         sm_cocoaDCStack.Erase(ourNode);
 120     }
 121 }
 122
 123 bool wxDC::CocoaUnwindStackAndTakeFocus()
 124 {
 125     wxCocoaDCStack::compatibility_iterator node=sm_cocoaDCStack.GetFirst();
 126     for(;node;node = sm_cocoaDCStack.GetFirst())
 127     {
 128         wxDC *dc = node->GetData();
 129         wxASSERT(dc);
 130         // If we're on the stack, then it's unwound enough and we have focus
 131         if(dc==this)
 132             return true;
 133         // If unable to unlockFocus (e.g. wxPaintDC) stop here
 134         if(!dc->CocoaUnlockFocus())
 135             break;
 136         sm_cocoaDCStack.Erase(node);
 137     }
 138     return CocoaLockFocus();
 139 }
 140
 141 wxDC::wxDC(void)
 142 {
 143     m_cocoaWxToBoundsTransform = nil;
 144     m_pen = *wxBLACK_PEN;
 145 }
 146
 147 wxDC::~wxDC(void)
 148 {
 149 }
 150
 151 bool wxDC::CocoaLockFocus()
 152 {
 153     return false;
 154 }
 155
 156 bool wxDC::CocoaUnlockFocus()
 157 {
 158     return false;
 159 }
 160
 161 /*static*/ WX_NSAffineTransform wxDC::CocoaGetWxToBoundsTransform(bool isFlipped, float height)
 162 {
 163     NSAffineTransform *transform = nil;
 164     // This transform flips the graphics since wxDC uses top-left origin
 165     if(!isFlipped)
 166     {
 167         // The transform is auto released
 168         transform = [NSAffineTransform transform];
 169         /*  x' = 1x + 0y + 0
 170             y' = 0x + -1y + window's height
 171         */
 172         NSAffineTransformStruct matrix = {
 173             1,  0
 174         ,   0, -1
 175         ,   0, height
 176         };
 177         [transform setTransformStruct: matrix];
 178     }
 179     return transform;
 180 }
 181
 182 void wxDC::CocoaApplyTransformations()
 183 {
 184     [m_cocoaWxToBoundsTransform concat];
 185     // TODO: Apply device/logical/user position/scaling transformations
 186 }
 187
 188 void wxDC::DoDrawRectangle(wxCoord x, wxCoord y, wxCoord width, wxCoord height)
 189 {
 190     wxAutoNSAutoreleasePool pool;
 191     if(!CocoaTakeFocus()) return;
 192     NSBezierPath *bezpath = [NSBezierPath bezierPathWithRect:NSMakeRect(x,y,width,height)];
 193     CocoaSetPenForNSBezierPath(m_pen,bezpath);
 194     [bezpath stroke];
 195     [m_brush.GetNSColor() set];
 196     [bezpath fill];
 197 }
 198
 199 void wxDC::DoDrawLine(wxCoord x1, wxCoord y1, wxCoord x2, wxCoord y2)
 200 {
 201     wxAutoNSAutoreleasePool pool;
 202     if(!CocoaTakeFocus()) return;
 203     NSBezierPath *bezpath = [NSBezierPath bezierPath];
 204     [bezpath moveToPoint:NSMakePoint(x1,y1)];
 205     [bezpath lineToPoint:NSMakePoint(x2,y2)];
 206
 207     CocoaSetPenForNSBezierPath(m_pen,bezpath);
 208     [bezpath stroke];
 209 }
 210
 211 void wxDC::DoGetTextExtent(const wxString& text, wxCoord *x, wxCoord *y, wxCoord *descent, wxCoord *externalLeading, wxFont *theFont) const
 212 {
 213     wxAutoNSAutoreleasePool pool;
 214 // FIXME: Cache this so it can be used for DoDrawText
 215     wxASSERT_MSG(sm_cocoaNSTextStorage && sm_cocoaNSLayoutManager && sm_cocoaNSTextContainer, wxT("Text system has not been initialized.  BAD PROGRAMMER!"));
 216     NSAttributedString *attributedString = [[NSAttributedString alloc]
 217             initWithString:wxNSStringWithWxString(text.c_str())];
 218     [sm_cocoaNSTextStorage setAttributedString:attributedString];
 219     [attributedString release];
 220
 221     NSRange glyphRange = [sm_cocoaNSLayoutManager glyphRangeForTextContainer:sm_cocoaNSTextContainer];
 222     NSRect usedRect = [sm_cocoaNSLayoutManager usedRectForTextContainer:sm_cocoaNSTextContainer];
 223     if(x)
 224         *x=(int)usedRect.size.width;
 225     if(y)
 226         *y=(int)usedRect.size.height;
 227     if(descent)
 228         *descent=0;
 229     if(externalLeading)
 230         *externalLeading=0;
 231 }
 232
 233 void wxDC::DoDrawText(const wxString& text, wxCoord x, wxCoord y)
 234 {
 235     wxAutoNSAutoreleasePool pool;
 236     if(!CocoaTakeFocus()) return;
 237     wxASSERT_MSG(sm_cocoaNSTextStorage && sm_cocoaNSLayoutManager && sm_cocoaNSTextContainer, wxT("Text system has not been initialized.  BAD PROGRAMMER!"));
 238     NSAttributedString *attributedString = [[NSAttributedString alloc]
 239             initWithString:wxNSStringWithWxString(text.c_str())];
 240     [sm_cocoaNSTextStorage setAttributedString:attributedString];
 241     [attributedString release];
 242
 243     // Set the color (and later font) attributes
 244     NSColor *fgColor = m_textForegroundColour.GetNSColor();
 245     NSColor *bgColor = m_textBackgroundColour.GetNSColor();
 246     if(!fgColor)
 247         fgColor = [NSColor clearColor];
 248     if(!bgColor)
 249         bgColor = [NSColor clearColor];
 250     NSDictionary *attrDict = [[NSDictionary alloc] initWithObjectsAndKeys:
 251             fgColor, NSForegroundColorAttributeName,
 252             bgColor, NSBackgroundColorAttributeName,
 253             nil];
 254     [sm_cocoaNSTextStorage addAttributes: attrDict range:NSMakeRange(0,[sm_cocoaNSTextStorage length])];
 255     [attrDict release];
 256
 257     NSRange glyphRange = [sm_cocoaNSLayoutManager glyphRangeForTextContainer:sm_cocoaNSTextContainer];
 258     NSRect usedRect = [sm_cocoaNSLayoutManager usedRectForTextContainer:sm_cocoaNSTextContainer];
 259     // NOTE: We'll crash trying to get the location of glyphAtIndex:0 if
 260     // there is no length or we don't start at zero
 261     if(!glyphRange.length)
 262         return;
 263     wxASSERT_MSG(glyphRange.location==0,wxT("glyphRange must begin at zero"));
 264
 265     NSAffineTransform *transform = [NSAffineTransform transform];
 266     [transform translateXBy:x yBy:y];
 267
 268     NSAffineTransform *flipTransform = [NSAffineTransform transform];
 269     /*  x' = 1x + 0y + 0
 270         y' = 0x + -1y + window's height
 271     */
 272     NSAffineTransformStruct matrix = {
 273         1,  0
 274     ,   0, -1
 275     ,   0, usedRect.size.height
 276     };
 277     [flipTransform setTransformStruct: matrix];
 278
 279     NSGraphicsContext *context = [NSGraphicsContext currentContext];
 280     [context saveGraphicsState];
 281     [transform concat];
 282     [flipTransform concat];
 283     #if 0
 284     // Draw+fill a rectangle so we can see where the shit is supposed to be.
 285     wxLogTrace(wxTRACE_COCOA,wxT("(%f,%f) (%fx%f)"),usedRect.origin.x,usedRect.origin.y,usedRect.size.width,usedRect.size.height);
 286     NSBezierPath *bezpath = [NSBezierPath bezierPathWithRect:NSMakeRect(0,0,usedRect.size.width,usedRect.size.height)];
 287     [[NSColor blackColor] set];
 288     [bezpath stroke];
 289     [[NSColor blueColor] set];
 290     [bezpath fill];
 291     #endif
 292
 293     NSPoint layoutLocation = [sm_cocoaNSLayoutManager locationForGlyphAtIndex:0];
 294     layoutLocation.x = 0.0;
 295     layoutLocation.y *= -1.0;
 296     layoutLocation.y += [[sm_cocoaNSLayoutManager typesetter] baselineOffsetInLayoutManager:sm_cocoaNSLayoutManager glyphIndex:0];
 297     if(m_backgroundMode==wxSOLID)
 298         [sm_cocoaNSLayoutManager drawBackgroundForGlyphRange:glyphRange  atPoint:NSZeroPoint];
 299     [sm_cocoaNSLayoutManager drawGlyphsForGlyphRange:glyphRange  atPoint:layoutLocation];
 300
 301     [context restoreGraphicsState];
 302 }
 303
 304 // wxDCBase functions
 305 int wxDCBase::DeviceToLogicalX(int x) const
 306 {
 307     return x;
 308 }
 309
 310 int wxDCBase::DeviceToLogicalY(int y) const
 311 {
 312     return y;
 313 }
 314
 315 int wxDCBase::DeviceToLogicalXRel(int x) const
 316 {
 317     return x;
 318 }
 319
 320 int wxDCBase::DeviceToLogicalYRel(int y) const
 321 {
 322     return y;
 323 }
 324
 325 int wxDCBase::LogicalToDeviceX(int x) const
 326 {
 327     return x;
 328 }
 329
 330 int wxDCBase::LogicalToDeviceY(int y) const
 331 {
 332     return y;
 333 }
 334
 335 int wxDCBase::LogicalToDeviceXRel(int x) const
 336 {
 337     return x;
 338 }
 339
 340 int wxDCBase::LogicalToDeviceYRel(int y) const
 341 {
 342     return y;
 343 }
 344
 345 ///////////////////////////////////////////////////////////////////////////
 346 // cut here, the rest is stubs
 347 ///////////////////////////////////////////////////////////////////////////
 348
 349 //-----------------------------------------------------------------------------
 350 // constants
 351 //-----------------------------------------------------------------------------
 352
 353 #define mm2inches               0.0393700787402
 354 #define inches2mm               25.4
 355 #define mm2twips                56.6929133859
 356 #define twips2mm                0.0176388888889
 357 #define mm2pt                   2.83464566929
 358 #define pt2mm                   0.352777777778
 359
 360 //-----------------------------------------------------------------------------
 361 // wxDC
 362 //-----------------------------------------------------------------------------
 363
 364 void wxDC::DoDrawIcon( const wxIcon &WXUNUSED(icon), int WXUNUSED(x), int WXUNUSED(y) )
 365 {
 366 };
 367
 368 void wxDC::DoDrawPoint( int x, int y )
 369 {
 370 };
 371
 372 void wxDC::DoDrawPolygon( int, wxPoint *, int, int, int)
 373 {
 374 };
 375
 376 void wxDC::DoDrawLines( int, wxPoint *, int, int )
 377 {
 378 }
 379
 380 int wxDC::GetDepth() const
 381 {
 382     return 0;
 383 }
 384
 385 wxSize wxDC::GetPPI() const
 386 {
 387     return wxSize(0,0);
 388 }
 389
 390 bool wxDC::CanGetTextExtent() const
 391 {
 392     return false;
 393 }
 394
 395 wxCoord wxDC::GetCharHeight() const
 396 {
 397     return 0;
 398 }
 399
 400 wxCoord wxDC::GetCharWidth() const
 401 {
 402     return 0;
 403 }
 404
 405 bool wxDC::CanDrawBitmap() const
 406 {
 407     return true;
 408 }
 409
 410 bool wxDC::DoGetPixel(wxCoord x, wxCoord y, wxColour *col) const
 411 {
 412     return false;
 413 }
 414
 415 void wxDC::DoDrawArc(wxCoord x1, wxCoord y1, wxCoord x2, wxCoord y2, wxCoord xc, wxCoord yc)
 416 {
 417 }
 418
 419 void wxDC::SetPen(const wxPen& pen)
 420 {
 421     m_pen = pen;
 422 }
 423
 424 void wxDC::SetBrush(const wxBrush& brush)
 425 {
 426     m_brush = brush;
 427 }
 428
 429 void wxDC::DoSetClippingRegionAsRegion(const wxRegion& region)
 430 {
 431 }
 432
 433 void wxDC::DoSetClippingRegion(wxCoord x, wxCoord y, wxCoord width, wxCoord height)
 434 {
 435 }
 436
 437 void wxDC::DestroyClippingRegion()
 438 {
 439 }
 440
 441 void wxDC::DoDrawRoundedRectangle(wxCoord x, wxCoord y, wxCoord width, wxCoord height, double radius)
 442 {
 443 }
 444
 445 void wxDC::DoDrawRotatedText(const wxString& text, wxCoord x, wxCoord y, double angle)
 446 {
 447 }
 448
 449 void wxDC::DoDrawEllipticArc(wxCoord x, wxCoord y, wxCoord w, wxCoord h, double sa, double ea)
 450 {
 451 }
 452
 453 void wxDC::DoDrawEllipse(wxCoord x, wxCoord y, wxCoord width, wxCoord height)
 454 {
 455 }
 456
 457 void wxDC::DoDrawBitmap(const wxBitmap &bmp, wxCoord x, wxCoord y, bool useMask)
 458 {
 459     wxAutoNSAutoreleasePool pool;
 460     if(!CocoaTakeFocus()) return;
 461     if(!bmp.Ok())
 462         return;
 463
 464 #if 0
 465     // Draw a rect so we can see where it's supposed to be
 466     wxLogTrace(wxTRACE_COCOA,wxT("image at (%d,%d) size %dx%d"),x,y,bmp.GetWidth(),bmp.GetHeight());
 467     NSBezierPath *bezpath = [NSBezierPath bezierPathWithRect:NSMakeRect(x,y,bmp.GetWidth(),bmp.GetHeight())];
 468     [[NSColor blackColor] set];
 469     [bezpath stroke];
 470     [[NSColor blueColor] set];
 471     [bezpath fill];
 472 #endif // 0
 473
 474     NSAffineTransform *transform = [NSAffineTransform transform];
 475     [transform translateXBy:x yBy:y];
 476
 477     NSAffineTransform *flipTransform = [NSAffineTransform transform];
 478     /*  x' = 1x + 0y + 0
 479         y' = 0x + -1y + window's height
 480     */
 481     NSAffineTransformStruct matrix = {
 482         1,  0
 483     ,   0, -1
 484     ,   0, bmp.GetHeight()
 485     };
 486     [flipTransform setTransformStruct: matrix];
 487
 488     NSGraphicsContext *context = [NSGraphicsContext currentContext];
 489     [context saveGraphicsState];
 490     [transform concat];
 491     [flipTransform concat];
 492
 493     NSImage *nsimage = [bmp.GetNSImage(useMask) retain];
 494
 495     [nsimage drawAtPoint: NSMakePoint(0,0)
 496         fromRect: NSMakeRect(0.0,0.0,bmp.GetWidth(),bmp.GetHeight())
 497         operation: NSCompositeSourceOver
 498         fraction: 1.0];
 499
 500     [nsimage release];
 501     [context restoreGraphicsState];
 502 }
 503
 504 bool wxDC::DoFloodFill(wxCoord x, wxCoord y, const wxColour& col, int style)
 505 {
 506     return false;
 507 }
 508
 509 void wxDC::DoCrossHair(wxCoord x, wxCoord y)
 510 {
 511 }
 512
 513
 514 bool wxDC::DoBlit(wxCoord xdest, wxCoord ydest, wxCoord width, wxCoord height, wxDC *source, wxCoord xsrc, wxCoord ysrc, int rop, bool useMask , wxCoord xsrcMask, wxCoord ysrcMask)
 515 {
 516     if(!CocoaTakeFocus()) return false;
 517     if(!source) return false;
 518     return source->CocoaDoBlitOnFocusedDC(xdest,ydest,width,height,
 519         xsrc, ysrc, rop, useMask, xsrcMask, ysrcMask);
 520 }
 521
 522 bool wxDC::CocoaDoBlitOnFocusedDC(wxCoord xdest, wxCoord ydest,
 523     wxCoord width, wxCoord height, wxCoord xsrc, wxCoord ysrc,
 524     int logicalFunc, bool useMask, wxCoord xsrcMask, wxCoord ysrcMask)
 525 {
 526     return false;
 527 }
 528
 529 void wxDC::DoGetSize( int* width, int* height ) const
 530 {
 531   *width = m_maxX-m_minX;
 532   *height = m_maxY-m_minY;
 533 };
 534
 535 void wxDC::DoGetSizeMM( int* width, int* height ) const
 536 {
 537   int w = 0;
 538   int h = 0;
 539   GetSize( &w, &h );
 540 };
 541
 542 void wxDC::SetTextForeground( const wxColour &col )
 543 {
 544   if (!Ok()) return;
 545   m_textForegroundColour = col;
 546 };
 547
 548 void wxDC::SetTextBackground( const wxColour &col )
 549 {
 550   if (!Ok()) return;
 551   m_textBackgroundColour = col;
 552 };
 553
 554 void wxDC::Clear()
 555 {
 556 }
 557
 558 void wxDC::SetBackground(const wxBrush& brush)
 559 {
 560     m_backgroundBrush = brush;
 561 }
 562
 563 void wxDC::SetPalette(const wxPalette&)
 564 {
 565 }
 566
 567 void wxDC::SetLogicalFunction(int)
 568 {
 569 }
 570
 571
 572 void wxDC::SetMapMode( int mode )
 573 {
 574   switch (mode)
 575   {
 576     case wxMM_TWIPS:
 577       break;
 578     case wxMM_POINTS:
 579       break;
 580     case wxMM_METRIC:
 581       break;
 582     case wxMM_LOMETRIC:
 583       break;
 584     default:
 585     case wxMM_TEXT:
 586       SetLogicalScale( 1.0, 1.0 );
 587       break;
 588   };
 589   if (mode != wxMM_TEXT)
 590   {
 591   };
 592 };
 593
 594 void wxDC::SetUserScale( double x, double y )
 595 {
 596   // allow negative ? -> no
 597   m_userScaleX = x;
 598   m_userScaleY = y;
 599   ComputeScaleAndOrigin();
 600 };
 601
 602 void wxDC::SetLogicalScale( double x, double y )
 603 {
 604   // allow negative ?
 605   m_logicalScaleX = x;
 606   m_logicalScaleY = y;
 607   ComputeScaleAndOrigin();
 608 };
 609
 610 void wxDC::SetLogicalOrigin( wxCoord x, wxCoord y )
 611 {
 612   m_logicalOriginX = x * m_signX;   // is this still correct ?
 613   m_logicalOriginY = y * m_signY;
 614   ComputeScaleAndOrigin();
 615 };
 616
 617 void wxDC::SetDeviceOrigin( wxCoord x, wxCoord y )
 618 {
 619   ComputeScaleAndOrigin();
 620 };
 621
 622 void wxDC::SetAxisOrientation( bool xLeftRight, bool yBottomUp )
 623 {
 624   m_signX = (xLeftRight ?  1 : -1);
 625   m_signY = (yBottomUp  ? -1 :  1);
 626   ComputeScaleAndOrigin();
 627 };
 628
 629 void wxDC::ComputeScaleAndOrigin(void)
 630 {
 631   // CMB: copy scale to see if it changes
 632   double origScaleX = m_scaleX;
 633   double origScaleY = m_scaleY;
 634
 635   m_scaleX = m_logicalScaleX * m_userScaleX;
 636   m_scaleY = m_logicalScaleY * m_userScaleY;
 637
 638   // CMB: if scale has changed call SetPen to recalulate the line width
 639   if (m_scaleX != origScaleX || m_scaleY != origScaleY)
 640   {
 641     // this is a bit artificial, but we need to force wxDC to think
 642     // the pen has changed
 643     const wxPen* pen = & GetPen();
 644     wxPen tempPen;
 645     m_pen = tempPen;
 646     SetPen(* pen);
 647   }
 648 };
 649