interface/wx/dc.h

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        dc.h
   3 // Purpose:     interface of wxDC
   4 // Author:      wxWidgets team
   5 // RCS-ID:      $Id$
   6 // Licence:     wxWindows license
   7 /////////////////////////////////////////////////////////////////////////////
   8
   9 /**
  10     @class wxDC
  11
  12     A wxDC is a @e "device context" onto which graphics and text can be drawn.
  13     It is intended to represent different output devices and offers a common
  14     abstract API for drawing on any of them.
  15
  16     wxWidgets offers an alternative drawing API based on the modern drawing
  17     backends GDI+, CoreGraphics and Cairo. See wxGraphicsContext, wxGraphicsRenderer
  18     and related classes. There is also a wxGCDC linking the APIs by offering
  19     the wxDC API ontop of a wxGraphicsContext.
  20
  21     wxDC is an abstract base class and cannot be created directly.
  22     Use wxPaintDC, wxClientDC, wxWindowDC, wxScreenDC, wxMemoryDC or
  23     wxPrinterDC. Notice that device contexts which are associated with windows
  24     (i.e. wxClientDC, wxWindowDC and wxPaintDC) use the window font and colours
  25     by default (starting with wxWidgets 2.9.0) but the other device context
  26     classes use system-default values so you always must set the appropriate
  27     fonts and colours before using them.
  28
  29     In addition to the versions of the methods documented below, there
  30     are also versions which accept single wxPoint parameter instead
  31     of the two wxCoord ones or wxPoint and wxSize instead of the four
  32     wxCoord parameters.
  33
  34     Beginning with wxWidgets 2.9.0 the entire wxDC code has been
  35     reorganized. All platform dependent code (actually all drawing code)
  36     has been moved into backend classes which derive from a common
  37     wxDCImpl class. The user-visible classes such as wxClientDC and
  38     wxPaintDC merely forward all calls to the backend implementation.
  39
  40     On Mac OS X colours with alpha channel are supported. Instances wxPen
  41     or wxBrush that are built from wxColour use the colour's alpha values
  42     when stroking or filling.
  43
  44     @library{wxcore}
  45     @category{dc,gdi}
  46
  47     @see @ref overview_dc, wxGraphicsContext
  48
  49     @todo Precise definition of default/initial state.
  50     @todo Pixelwise definition of operations (e.g. last point of a line not
  51           drawn).
  52     @todo Coordinates: state clearly which type of coordinates are returned by
  53           the various Get*Point() or similar functions - often they are client
  54           coordinates but not always.
  55 */
  56 class wxDC : public wxObject
  57 {
  58 public:
  59     /**
  60         Copy from a source DC to this DC, specifying the destination
  61         coordinates, size of area to copy, source DC, source coordinates,
  62         logical function, whether to use a bitmap mask, and mask source
  63         position.
  64
  65         @param xdest
  66             Destination device context x position.
  67         @param ydest
  68             Destination device context y position.
  69         @param width
  70             Width of source area to be copied.
  71         @param height
  72             Height of source area to be copied.
  73         @param source
  74             Source device context.
  75         @param xsrc
  76             Source device context x position.
  77         @param ysrc
  78             Source device context y position.
  79         @param logicalFunc
  80             Logical function to use, see SetLogicalFunction().
  81         @param useMask
  82             If @true, Blit does a transparent blit using the mask that is
  83             associated with the bitmap selected into the source device context.
  84             The Windows implementation does the following if MaskBlt cannot be
  85             used:
  86             <ol>
  87             <li>Creates a temporary bitmap and copies the destination area into
  88                 it.</li>
  89             <li>Copies the source area into the temporary bitmap using the
  90                 specified logical function.</li>
  91             <li>Sets the masked area in the temporary bitmap to BLACK by ANDing
  92                 the mask bitmap with the temp bitmap with the foreground colour
  93                 set to WHITE and the bg colour set to BLACK.</li>
  94             <li>Sets the unmasked area in the destination area to BLACK by
  95                 ANDing the mask bitmap with the destination area with the
  96                 foreground colour set to BLACK and the background colour set to
  97                 WHITE.</li>
  98             <li>ORs the temporary bitmap with the destination area.</li>
  99             <li>Deletes the temporary bitmap.</li>
 100             </ol>
 101             This sequence of operations ensures that the source's transparent
 102             area need not be black, and logical functions are supported.
 103             @n @b Note: on Windows, blitting with masks can be speeded up
 104             considerably by compiling wxWidgets with the wxUSE_DC_CACHE option
 105             enabled. You can also influence whether MaskBlt or the explicit
 106             mask blitting code above is used, by using wxSystemOptions and
 107             setting the @c no-maskblt option to 1.
 108         @param xsrcMask
 109             Source x position on the mask. If both xsrcMask and ysrcMask are
 110             -1, xsrc and ysrc will be assumed for the mask source position.
 111             Currently only implemented on Windows.
 112         @param ysrcMask
 113             Source y position on the mask. If both xsrcMask and ysrcMask are
 114             -1, xsrc and ysrc will be assumed for the mask source position.
 115             Currently only implemented on Windows.
 116
 117         @remarks There is partial support for Blit() in wxPostScriptDC, under X.
 118
 119         @see StretchBlit(), wxMemoryDC, wxBitmap, wxMask
 120     */
 121     bool Blit(wxCoord xdest, wxCoord ydest, wxCoord width,
 122               wxCoord height, wxDC* source, wxCoord xsrc, wxCoord ysrc,
 123               int logicalFunc = wxCOPY, bool useMask = false,
 124               wxCoord xsrcMask = -1, wxCoord ysrcMask = -1);
 125
 126     /**
 127         Adds the specified point to the bounding box which can be retrieved
 128         with MinX(), MaxX() and MinY(), MaxY() functions.
 129
 130         @see ResetBoundingBox()
 131     */
 132     void CalcBoundingBox(wxCoord x, wxCoord y);
 133
 134     /**
 135         Clears the device context using the current background brush.
 136     */
 137     void Clear();
 138
 139     /**
 140         Performs all necessary computations for given platform and context type
 141         after each change of scale and origin parameters. Usually called
 142         automatically internally after such changes.
 143     */
 144     virtual void ComputeScaleAndOrigin();
 145
 146     /**
 147         Displays a cross hair using the current pen. This is a vertical and
 148         horizontal line the height and width of the window, centred on the
 149         given point.
 150     */
 151     void CrossHair(wxCoord x, wxCoord y);
 152
 153     /**
 154         Destroys the current clipping region so that none of the DC is clipped.
 155
 156         @see SetClippingRegion()
 157     */
 158     void DestroyClippingRegion();
 159
 160     /**
 161         Convert device X coordinate to logical coordinate, using the current
 162         mapping mode.
 163     */
 164     virtual wxCoord DeviceToLogicalX(wxCoord x);
 165
 166     /**
 167         Convert device X coordinate to relative logical coordinate, using the
 168         current mapping mode but ignoring the x axis orientation. Use this
 169         function for converting a width, for example.
 170     */
 171     virtual wxCoord DeviceToLogicalXRel(wxCoord x);
 172
 173     /**
 174         Converts device Y coordinate to logical coordinate, using the current
 175         mapping mode.
 176     */
 177     virtual wxCoord DeviceToLogicalY(wxCoord y);
 178
 179     /**
 180         Convert device Y coordinate to relative logical coordinate, using the
 181         current mapping mode but ignoring the y axis orientation. Use this
 182         function for converting a height, for example.
 183     */
 184     virtual wxCoord DeviceToLogicalYRel(wxCoord y);
 185
 186     /**
 187         Draws an arc of a circle, centred on (@a xc, @a yc), with starting
 188         point (@a x1, @a y1) and ending at (@a x2, @a y2). The current pen is
 189         used for the outline and the current brush for filling the shape.
 190
 191         The arc is drawn in a counter-clockwise direction from the start point
 192         to the end point.
 193     */
 194     void DrawArc(wxCoord x1, wxCoord y1, wxCoord x2, wxCoord y2,
 195                   wxCoord xc, wxCoord yc);
 196
 197     /**
 198         Draw a bitmap on the device context at the specified point. If
 199         @a transparent is @true and the bitmap has a transparency mask, the
 200         bitmap will be drawn transparently.
 201
 202         When drawing a mono-bitmap, the current text foreground colour will be
 203         used to draw the foreground of the bitmap (all bits set to 1), and the
 204         current text background colour to draw the background (all bits set to
 205         0).
 206
 207         @see SetTextForeground(), SetTextBackground(), wxMemoryDC
 208     */
 209     void DrawBitmap(const wxBitmap& bitmap, wxCoord x, wxCoord y,
 210                      bool transparent);
 211
 212     //@{
 213     /**
 214         Draws a check mark inside the given rectangle.
 215     */
 216     void DrawCheckMark(wxCoord x, wxCoord y, wxCoord width, wxCoord height);
 217     void DrawCheckMark(const wxRect& rect);
 218     //@}
 219
 220     //@{
 221     /**
 222         Draws a circle with the given centre and radius.
 223
 224         @see DrawEllipse()
 225     */
 226     void DrawCircle(wxCoord x, wxCoord y, wxCoord radius);
 227     void DrawCircle(const wxPoint& pt, wxCoord radius);
 228     //@}
 229
 230     //@{
 231     /**
 232         Draws an ellipse contained in the rectangle specified either with the
 233         given top left corner and the given size or directly. The current pen
 234         is used for the outline and the current brush for filling the shape.
 235
 236         @see DrawCircle()
 237     */
 238     void DrawEllipse(wxCoord x, wxCoord y, wxCoord width, wxCoord height);
 239     void DrawEllipse(const wxPoint& pt, const wxSize& size);
 240     void DrawEllipse(const wxRect& rect);
 241     //@}
 242
 243     /**
 244         Draws an arc of an ellipse. The current pen is used for drawing the arc
 245         and the current brush is used for drawing the pie.
 246
 247         @a x and @a y specify the x and y coordinates of the upper-left corner
 248         of the rectangle that contains the ellipse.
 249
 250         @a width and @a height specify the width and height of the rectangle
 251         that contains the ellipse.
 252
 253         @a start and @a end specify the start and end of the arc relative to
 254         the three-o'clock position from the center of the rectangle. Angles are
 255         specified in degrees (360 is a complete circle). Positive values mean
 256         counter-clockwise motion. If @a start is equal to @e end, a complete
 257         ellipse will be drawn.
 258     */
 259     void DrawEllipticArc(wxCoord x, wxCoord y, wxCoord width, wxCoord height,
 260                           double start, double end);
 261
 262     /**
 263         Draw an icon on the display (does nothing if the device context is
 264         PostScript). This can be the simplest way of drawing bitmaps on a
 265         window.
 266     */
 267     void DrawIcon(const wxIcon& icon, wxCoord x, wxCoord y);
 268
 269     //@{
 270     /**
 271         Draw optional bitmap and the text into the given rectangle and aligns
 272         it as specified by alignment parameter; it also will emphasize the
 273         character with the given index if it is != -1 and return the bounding
 274         rectangle if required.
 275     */
 276     virtual void DrawLabel(const wxString& text, const wxBitmap& image,
 277                            const wxRect& rect,
 278                            int alignment = wxALIGN_LEFT | wxALIGN_TOP,
 279                            int indexAccel = -1, wxRect* rectBounding = NULL);
 280     void DrawLabel(const wxString& text, const wxRect& rect,
 281                    int alignment = wxALIGN_LEFT | wxALIGN_TOP,
 282                    int indexAccel = -1);
 283     //@}
 284
 285     /**
 286         Draws a line from the first point to the second. The current pen is
 287         used for drawing the line. Note that the point (@a x2, @a y2) is not
 288         part of the line and is not drawn by this function (this is consistent
 289         with the behaviour of many other toolkits).
 290     */
 291     void DrawLine(wxCoord x1, wxCoord y1, wxCoord x2, wxCoord y2);
 292
 293     /**
 294         Draws lines using an array of points of size @a n adding the optional
 295         offset coordinate. The current pen is used for drawing the lines.
 296
 297         @beginWxPythonOnly
 298         The wxPython version of this method accepts a Python list of wxPoint
 299         objects.
 300         @endWxPythonOnly
 301     */
 302     void DrawLines(int n, wxPoint points[], wxCoord xoffset = 0,
 303                    wxCoord yoffset = 0);
 304     /**
 305         This method uses a list of wxPoints, adding the optional offset
 306         coordinate. The programmer is responsible for deleting the list of
 307         points.
 308
 309         @beginWxPythonOnly
 310         The wxPython version of this method accepts a Python list of wxPoint
 311         objects.
 312         @endWxPythonOnly
 313     */
 314     void DrawLines(const wxPointList* points,
 315                    wxCoord xoffset = 0, wxCoord yoffset = 0);
 316
 317     /**
 318         Draws a point using the color of the current pen. Note that the other
 319         properties of the pen are not used, such as width.
 320     */
 321     void DrawPoint(wxCoord x, wxCoord y);
 322
 323     /**
 324         Draws a filled polygon using an array of points of size @a n, adding
 325         the optional offset coordinate. The first and last points are
 326         automatically closed.
 327
 328         The last argument specifies the fill rule: @b wxODDEVEN_RULE (the
 329         default) or @b wxWINDING_RULE.
 330
 331         The current pen is used for drawing the outline, and the current brush
 332         for filling the shape. Using a transparent brush suppresses filling.
 333     */
 334     void DrawPolygon(int n, wxPoint points[], wxCoord xoffset = 0,
 335                      wxCoord yoffset = 0, int fill_style = wxODDEVEN_RULE);
 336     /**
 337         This method draws a filled polygon using a list of wxPoints, adding the
 338         optional offset coordinate. The first and last points are automatically
 339         closed.
 340
 341         The last argument specifies the fill rule: @b wxODDEVEN_RULE (the
 342         default) or @b wxWINDING_RULE.
 343
 344         The current pen is used for drawing the outline, and the current brush
 345         for filling the shape. Using a transparent brush suppresses filling.
 346
 347         The programmer is responsible for deleting the list of points.
 348
 349         @beginWxPythonOnly
 350         The wxPython version of this method accepts a Python list of wxPoint
 351         objects.
 352         @endWxPythonOnly
 353     */
 354     void DrawPolygon(const wxPointList* points,
 355                      wxCoord xoffset = 0, wxCoord yoffset = 0,
 356                      int fill_style = wxODDEVEN_RULE);
 357
 358     /**
 359         Draws two or more filled polygons using an array of @a points, adding
 360         the optional offset coordinates.
 361
 362         Notice that for the platforms providing a native implementation of this
 363         function (Windows and PostScript-based wxDC currently), this is more
 364         efficient than using DrawPolygon() in a loop.
 365
 366         @a n specifies the number of polygons to draw, the array @e count of
 367         size @a n specifies the number of points in each of the polygons in the
 368         @a points array.
 369
 370         The last argument specifies the fill rule: @b wxODDEVEN_RULE (the
 371         default) or @b wxWINDING_RULE.
 372
 373         The current pen is used for drawing the outline, and the current brush
 374         for filling the shape. Using a transparent brush suppresses filling.
 375
 376         The polygons maybe disjoint or overlapping. Each polygon specified in a
 377         call to DrawPolyPolygon() must be closed. Unlike polygons created by
 378         the DrawPolygon() member function, the polygons created by this
 379         method are not closed automatically.
 380
 381         @beginWxPythonOnly
 382         Not implemented yet.
 383         @endWxPythonOnly
 384     */
 385     void DrawPolyPolygon(int n, int count[], wxPoint points[],
 386                          wxCoord xoffset = 0, wxCoord yoffset = 0,
 387                          int fill_style = wxODDEVEN_RULE);
 388
 389     /**
 390         Draws a rectangle with the given top left corner, and with the given
 391         size.  The current pen is used for the outline and the current brush
 392         for filling the shape.
 393     */
 394     void DrawRectangle(wxCoord x, wxCoord y, wxCoord width, wxCoord height);
 395
 396     /**
 397         Draws the text rotated by @a angle degrees.
 398
 399         @note Under Win9x only TrueType fonts can be drawn by this function. In
 400               particular, a font different from @c wxNORMAL_FONT should be used
 401               as the latter is not a TrueType font. @c wxSWISS_FONT is an
 402               example of a font which is.
 403
 404         @see DrawText()
 405     */
 406     void DrawRotatedText(const wxString& text, wxCoord x, wxCoord y,
 407                          double angle);
 408
 409     /**
 410         Draws a rectangle with the given top left corner, and with the given
 411         size. The corners are quarter-circles using the given radius. The
 412         current pen is used for the outline and the current brush for filling
 413         the shape.
 414
 415         If @a radius is positive, the value is assumed to be the radius of the
 416         rounded corner. If @a radius is negative, the absolute value is assumed
 417         to be the @e proportion of the smallest dimension of the rectangle.
 418         This means that the corner can be a sensible size relative to the size
 419         of the rectangle, and also avoids the strange effects X produces when
 420         the corners are too big for the rectangle.
 421     */
 422     void DrawRoundedRectangle(wxCoord x, wxCoord y, wxCoord width,
 423                               wxCoord height, double radius);
 424
 425     //@{
 426     /**
 427         Draws a spline between all given points using the current pen.
 428
 429         @beginWxPythonOnly
 430         The wxPython version of this method accepts a Python list of wxPoint
 431         objects.
 432         @endWxPythonOnly
 433     */
 434     void DrawSpline(int n, wxPoint points[]);
 435     void DrawSpline(const wxPointList* points);
 436     void DrawSpline(wxCoord x1, wxCoord y1, wxCoord x2, wxCoord y2,
 437                     wxCoord x3, wxCoord y3);
 438     //@}
 439
 440     /**
 441         Draws a text string at the specified point, using the current text
 442         font, and the current text foreground and background colours.
 443
 444         The coordinates refer to the top-left corner of the rectangle bounding
 445         the string. See GetTextExtent() for how to get the dimensions of a text
 446         string, which can be used to position the text more precisely.
 447
 448         @note Under wxGTK, the current
 449               @ref GetLogicalFunction() "logical function" is used by this
 450               function but it is ignored by wxMSW. Thus, you should avoid using
 451               logical functions with this function in portable programs.
 452     */
 453     void DrawText(const wxString& text, wxCoord x, wxCoord y);
 454
 455     /**
 456         Ends a document (only relevant when outputting to a printer).
 457     */
 458     void EndDoc();
 459
 460     /**
 461         Ends a document page (only relevant when outputting to a printer).
 462     */
 463     void EndPage();
 464
 465     /**
 466         Flood fills the device context starting from the given point, using
 467         the current brush colour, and using a style:
 468
 469         - wxFLOOD_SURFACE: The flooding occurs until a colour other than the
 470           given colour is encountered.
 471         - wxFLOOD_BORDER: The area to be flooded is bounded by the given
 472           colour.
 473
 474         @return @false if the operation failed.
 475
 476         @note The present implementation for non-Windows platforms may fail to
 477               find colour borders if the pixels do not match the colour
 478               exactly. However the function will still return @true.
 479     */
 480     bool FloodFill(wxCoord x, wxCoord y, const wxColour& colour,
 481                    int style = wxFLOOD_SURFACE);
 482
 483     /**
 484         Gets the brush used for painting the background.
 485
 486         @see wxDC::SetBackground()
 487     */
 488     const wxBrush GetBackground() const;
 489
 490     /**
 491         Returns the current background mode: @c wxSOLID or @c wxTRANSPARENT.
 492
 493         @see SetBackgroundMode()
 494     */
 495     int GetBackgroundMode() const;
 496
 497     /**
 498         Gets the current brush.
 499
 500         @see wxDC::SetBrush()
 501     */
 502     const wxBrush GetBrush() const;
 503
 504     /**
 505         Gets the character height of the currently set font.
 506     */
 507     wxCoord GetCharHeight();
 508
 509     /**
 510         Gets the average character width of the currently set font.
 511     */
 512     wxCoord GetCharWidth();
 513
 514     /**
 515         Gets the rectangle surrounding the current clipping region.
 516
 517         @beginWxPythonOnly
 518         No arguments are required and the four values defining the rectangle
 519         are returned as a tuple.
 520         @endWxPythonOnly
 521     */
 522     void GetClippingBox(wxCoord x, wxCoord y, wxCoord width, wxCoord height);
 523
 524     /**
 525         Returns the depth (number of bits/pixel) of this DC.
 526
 527         @see wxDisplayDepth()
 528     */
 529     int GetDepth() const;
 530
 531     /**
 532         Gets the current font. Notice that even although each device context
 533         object has some default font after creation, this method would return a
 534         wxNullFont initially and only after calling SetFont() a valid font is
 535         returned.
 536     */
 537     const wxFont GetFont() const;
 538
 539     /**
 540         Gets the current layout direction of the device context. On platforms
 541         where RTL layout is supported, the return value will either be
 542         @c wxLayout_LeftToRight or @c wxLayout_RightToLeft. If RTL layout is
 543         not supported, the return value will be @c wxLayout_Default.
 544
 545         @see SetLayoutDirection()
 546     */
 547     wxLayoutDirection GetLayoutDirection() const;
 548
 549     /**
 550         Gets the current logical function.
 551
 552         @see SetLogicalFunction()
 553     */
 554     int GetLogicalFunction();
 555
 556     /**
 557         Gets the mapping mode for the device context.
 558
 559         @see SetMapMode()
 560     */
 561     int GetMapMode();
 562
 563     /**
 564         Gets the dimensions of the string using the currently selected font.
 565         @a string is the text string to measure, @e heightLine, if non @NULL,
 566         is where to store the height of a single line.
 567
 568         The text extent is set in the given @a w and @a h pointers.
 569
 570         If the optional parameter @a font is specified and valid, then it is
 571         used for the text extent calculation, otherwise the currently selected
 572         font is used.
 573
 574         @note This function works with both single-line and multi-line strings.
 575
 576         @see wxFont, SetFont(), GetPartialTextExtents(), GetTextExtent()
 577     */
 578     void GetMultiLineTextExtent(const wxString& string, wxCoord* w,
 579                                 wxCoord* h,
 580                                 wxCoord* heightLine = NULL,
 581                                 wxFont* font = NULL) const;
 582     /**
 583         Gets the dimensions of the string using the currently selected font.
 584         @a string is the text string to measure, @e heightLine, if non @NULL,
 585         is where to store the height of a single line.
 586
 587         @return The text extent as a wxSize object.
 588
 589         @note This function works with both single-line and multi-line strings.
 590
 591         @see wxFont, SetFont(), GetPartialTextExtents(), GetTextExtent()
 592     */
 593     const wxSize GetMultiLineTextExtent(const wxString& string) const;
 594
 595     /**
 596         Fills the @a widths array with the widths from the beginning of @a text
 597         to the corresponding character of @a text. The generic version simply
 598         builds a running total of the widths of each character using
 599         GetTextExtent(), however if the various platforms have a native API
 600         function that is faster or more accurate than the generic
 601         implementation then it should be used instead.
 602
 603         @beginWxPythonOnly
 604         This method only takes the @a text parameter and returns a Python list
 605         of integers.
 606         @endWxPythonOnly
 607
 608         @see GetMultiLineTextExtent(), GetTextExtent()
 609     */
 610     bool GetPartialTextExtents(const wxString& text,
 611                                wxArrayInt& widths) const;
 612
 613     /**
 614         Gets the current pen.
 615
 616         @see SetPen()
 617     */
 618     const wxPen GetPen() const;
 619
 620     /**
 621         Gets in @a colour the colour at the specified location. Not available
 622         for wxPostScriptDC or wxMetafileDC.
 623
 624         @note Setting a pixel can be done using DrawPoint().
 625
 626         @beginWxPythonOnly
 627         The wxColour value is returned and is not required as a parameter.
 628         @endWxPythonOnly
 629     */
 630     bool GetPixel(wxCoord x, wxCoord y, wxColour* colour);
 631
 632     /**
 633         Returns the resolution of the device in pixels per inch.
 634     */
 635     wxSize GetPPI() const;
 636
 637     //@{
 638     /**
 639         This gets the horizontal and vertical resolution in device units. It
 640         can be used to scale graphics to fit the page.
 641
 642         For example, if @e maxX and @e maxY represent the maximum horizontal
 643         and vertical 'pixel' values used in your application, the following
 644         code will scale the graphic to fit on the printer page:
 645
 646         @code
 647         wxCoord w, h;
 648         dc.GetSize(&w, &h);
 649         double scaleX = (double)(maxX / w);
 650         double scaleY = (double)(maxY / h);
 651         dc.SetUserScale(min(scaleX, scaleY),min(scaleX, scaleY));
 652         @endcode
 653
 654         @beginWxPythonOnly
 655         In place of a single overloaded method name, wxPython implements the
 656         following methods:
 657         - GetSize() - Returns a wxSize.
 658         - GetSizeWH() - Returns a 2-tuple (width, height).
 659         @endWxPythonOnly
 660     */
 661     void GetSize(wxCoord* width, wxCoord* height) const;
 662     const wxSize GetSize() const;
 663     //@}
 664
 665     //@{
 666     /**
 667         Returns the horizontal and vertical resolution in millimetres.
 668     */
 669     void GetSizeMM(wxCoord* width, wxCoord* height) const;
 670     const wxSize GetSizeMM() const;
 671     //@}
 672
 673     /**
 674         Gets the current text background colour.
 675
 676         @see SetTextBackground()
 677     */
 678     const wxColour GetTextBackground() const;
 679
 680     //@{
 681     /**
 682         Gets the dimensions of the string using the currently selected font.
 683         @a string is the text string to measure, @a descent is the dimension
 684         from the baseline of the font to the bottom of the descender, and
 685         @a externalLeading is any extra vertical space added to the font by the
 686         font designer (usually is zero).
 687
 688         The text extent is returned in @a w and @a h pointers or as a wxSize
 689         object depending on which version of this function is used.
 690
 691         If the optional parameter @a font is specified and valid, then it is
 692         used for the text extent calculation. Otherwise the currently selected
 693         font is.
 694
 695         @note This function only works with single-line strings.
 696
 697         @beginWxPythonOnly
 698         The following methods are implemented in wxPython:
 699         - GetTextExtent(string) - Returns a 2-tuple, (width, height).
 700         - GetFullTextExtent(string, font=NULL) -
 701             Returns a 4-tuple, (width, height, descent, externalLeading).
 702         @endWxPythonOnly
 703
 704         @see wxFont, SetFont(), GetPartialTextExtents(),
 705              GetMultiLineTextExtent()
 706     */
 707     void GetTextExtent(const wxString& string, wxCoord* w, wxCoord* h,
 708                        wxCoord* descent = NULL,
 709                        wxCoord* externalLeading = NULL,
 710                        const wxFont* font = NULL) const;
 711     const wxSize  GetTextExtent(const wxString& string) const;
 712     //@}
 713
 714     /**
 715         Gets the current text foreground colour.
 716
 717         @see SetTextForeground()
 718     */
 719     const wxColour GetTextForeground() const;
 720
 721     /**
 722         Gets the current user scale factor.
 723
 724         @see SetUserScale()
 725     */
 726     void GetUserScale(double x, double y);
 727
 728     //@{
 729     /**
 730         Fill the area specified by rect with a radial gradient, starting from
 731         @a initialColour at the centre of the circle and fading to
 732         @a destColour on the circle outside.
 733
 734         @a circleCenter are the relative coordinates of centre of the circle in
 735         the specified @e rect. If not specified, the circle is placed at the
 736         centre of rect.
 737
 738         @note Currently this function is very slow, don't use it for real-time
 739               drawing.
 740     */
 741     void GradientFillConcentric(const wxRect& rect,
 742                                 const wxColour& initialColour,
 743                                 const wxColour& destColour);
 744     void GradientFillConcentric(const wxRect& rect,
 745                                 const wxColour& initialColour,
 746                                 const wxColour& destColour,
 747                                 const wxPoint& circleCenter);
 748     //@}
 749
 750     /**
 751         Fill the area specified by @a rect with a linear gradient, starting
 752         from @a initialColour and eventually fading to @e destColour. The
 753         @a nDirection specifies the direction of the colour change, default is
 754         to use @a initialColour on the left part of the rectangle and
 755         @a destColour on the right one.
 756     */
 757     void GradientFillLinear(const wxRect& rect,
 758                             const wxColour& initialColour,
 759                             const wxColour& destColour,
 760                             wxDirection nDirection = wxEAST);
 761
 762     /**
 763         Returns @true if the DC is ok to use.
 764     */
 765     bool Ok();
 766
 767     /**
 768         Converts logical X coordinate to device coordinate, using the current
 769         mapping mode.
 770     */
 771     virtual wxCoord LogicalToDeviceX(wxCoord x);
 772
 773     /**
 774         Converts logical X coordinate to relative device coordinate, using the
 775         current mapping mode but ignoring the x axis orientation. Use this for
 776         converting a width, for example.
 777     */
 778     virtual wxCoord LogicalToDeviceXRel(wxCoord x);
 779
 780     /**
 781         Converts logical Y coordinate to device coordinate, using the current
 782         mapping mode.
 783     */
 784     virtual wxCoord LogicalToDeviceY(wxCoord y);
 785
 786     /**
 787         Converts logical Y coordinate to relative device coordinate, using the
 788         current mapping mode but ignoring the y axis orientation. Use this for
 789         converting a height, for example.
 790     */
 791     virtual wxCoord LogicalToDeviceYRel(wxCoord y);
 792
 793     /**
 794         Gets the maximum horizontal extent used in drawing commands so far.
 795     */
 796     wxCoord MaxX();
 797
 798     /**
 799         Gets the maximum vertical extent used in drawing commands so far.
 800     */
 801     wxCoord MaxY();
 802
 803     /**
 804         Gets the minimum horizontal extent used in drawing commands so far.
 805     */
 806     wxCoord MinX();
 807
 808     /**
 809         Gets the minimum vertical extent used in drawing commands so far.
 810     */
 811     wxCoord MinY();
 812
 813     /**
 814         Resets the bounding box: after a call to this function, the bounding
 815         box doesn't contain anything.
 816
 817         @see CalcBoundingBox()
 818     */
 819     void ResetBoundingBox();
 820
 821     /**
 822         Sets the x and y axis orientation (i.e., the direction from lowest to
 823         highest values on the axis). The default orientation is x axis from
 824         left to right and y axis from top down.
 825
 826         @param xLeftRight
 827             True to set the x axis orientation to the natural left to right
 828             orientation, @false to invert it.
 829         @param yBottomUp
 830             True to set the y axis orientation to the natural bottom up
 831             orientation, @false to invert it.
 832     */
 833     void SetAxisOrientation(bool xLeftRight, bool yBottomUp);
 834
 835     /**
 836         Sets the current background brush for the DC.
 837     */
 838     void SetBackground(const wxBrush& brush);
 839
 840     /**
 841         @a mode may be one of wxSOLID and wxTRANSPARENT. This setting
 842         determines whether text will be drawn with a background colour or not.
 843     */
 844     void SetBackgroundMode(int mode);
 845
 846     /**
 847         Sets the current brush for the DC.
 848
 849         If the argument is wxNullBrush, the current brush is selected out of
 850         the device context (leaving wxDC without any valid brush), allowing the
 851         current brush to be destroyed safely.
 852
 853         @see wxBrush, wxMemoryDC (for the interpretation of colours when
 854              drawing into a monochrome bitmap)
 855     */
 856     void SetBrush(const wxBrush& brush);
 857
 858     //@{
 859     /**
 860         Sets the clipping region for this device context to the intersection of
 861         the given region described by the parameters of this method and the
 862         previously set clipping region. You should call DestroyClippingRegion()
 863         if you want to set the clipping region exactly to the region specified.
 864
 865         The clipping region is an area to which drawing is restricted. Possible
 866         uses for the clipping region are for clipping text or for speeding up
 867         window redraws when only a known area of the screen is damaged.
 868
 869         @see DestroyClippingRegion(), wxRegion
 870     */
 871     void SetClippingRegion(wxCoord x, wxCoord y, wxCoord width,
 872                            wxCoord height);
 873     void SetClippingRegion(const wxPoint& pt, const wxSize& sz);
 874     void SetClippingRegion(const wxRect& rect);
 875     //@}
 876
 877     /**
 878         Sets the clipping region for this device context.
 879
 880         Unlike SetClippingRegion(), this function works with physical
 881         coordinates and not with the logical ones.
 882      */
 883     void SetDeviceClippingRegion(const wxRegion& region);
 884
 885     /**
 886         Sets the device origin (i.e., the origin in pixels after scaling has
 887         been applied). This function may be useful in Windows printing
 888         operations for placing a graphic on a page.
 889     */
 890     void SetDeviceOrigin(wxCoord x, wxCoord y);
 891
 892     /**
 893         Sets the current font for the DC. It must be a valid font, in
 894         particular you should not pass wxNullFont to this method.
 895
 896         @see wxFont
 897     */
 898     void SetFont(const wxFont& font);
 899
 900     /**
 901         Sets the current layout direction for the device context. @a dir may be
 902         either @c wxLayout_Default, @c wxLayout_LeftToRight or
 903         @c wxLayout_RightToLeft.
 904
 905         @see GetLayoutDirection()
 906     */
 907     void SetLayoutDirection(wxLayoutDirection dir);
 908
 909     /**
 910         Sets the current logical function for the device context. This
 911         determines how a source pixel (from a pen or brush colour, or source
 912         device context if using Blit()) combines with a destination pixel in
 913         the current device context.
 914
 915         The possible values and their meaning in terms of source and
 916         destination pixel values are as follows:
 917
 918         @verbatim
 919         wxAND           src AND dst
 920         wxAND_INVERT    (NOT src) AND dst
 921         wxAND_REVERSE   src AND (NOT dst)
 922         wxCLEAR         0
 923         wxCOPY          src
 924         wxEQUIV         (NOT src) XOR dst
 925         wxINVERT        NOT dst
 926         wxNAND          (NOT src) OR (NOT dst)
 927         wxNOR           (NOT src) AND (NOT dst)
 928         wxNO_OP         dst
 929         wxOR            src OR dst
 930         wxOR_INVERT     (NOT src) OR dst
 931         wxOR_REVERSE    src OR (NOT dst)
 932         wxSET           1
 933         wxSRC_INVERT    NOT src
 934         wxXOR           src XOR dst
 935         @endverbatim
 936
 937         The default is wxCOPY, which simply draws with the current colour. The
 938         others combine the current colour and the background using a logical
 939         operation. wxINVERT is commonly used for drawing rubber bands or moving
 940         outlines, since drawing twice reverts to the original colour.
 941     */
 942     void SetLogicalFunction(int function);
 943
 944     /**
 945         The mapping mode of the device context defines the unit of measurement
 946         used to convert logical units to device units. Note that in X, text
 947         drawing isn't handled consistently with the mapping mode; a font is
 948         always specified in point size. However, setting the user scale (see
 949         SetUserScale()) scales the text appropriately. In Windows, scalable
 950         TrueType fonts are always used; in X, results depend on availability of
 951         fonts, but usually a reasonable match is found.
 952
 953         The coordinate origin is always at the top left of the screen/printer.
 954
 955         Drawing to a Windows printer device context uses the current mapping
 956         mode, but mapping mode is currently ignored for PostScript output.
 957
 958         The mapping mode can be one of the following:
 959         - wxMM_TWIPS: Each logical unit is 1/20 of a point, or 1/1440 of an
 960           inch.
 961         - wxMM_POINTS: Each logical unit is a point, or 1/72 of an inch.
 962         - wxMM_METRIC: Each logical unit is 1 mm.
 963         - wxMM_LOMETRIC: Each logical unit is 1/10 of a mm.
 964         - wxMM_TEXT: Each logical unit is 1 device pixel.
 965     */
 966     void SetMapMode(int mode);
 967
 968     /**
 969         If this is a window DC or memory DC, assigns the given palette to the
 970         window or bitmap associated with the DC. If the argument is
 971         wxNullPalette, the current palette is selected out of the device
 972         context, and the original palette restored.
 973
 974         @see wxPalette
 975     */
 976     void SetPalette(const wxPalette& palette);
 977
 978     /**
 979         Sets the current pen for the DC. If the argument is wxNullPen, the
 980         current pen is selected out of the device context (leaving wxDC without
 981         any valid pen), allowing the current brush to be destroyed safely.
 982
 983         @see wxMemoryDC for the interpretation of colours when drawing into a
 984              monochrome bitmap.
 985     */
 986     void SetPen(const wxPen& pen);
 987
 988     /**
 989         Sets the current text background colour for the DC.
 990     */
 991     void SetTextBackground(const wxColour& colour);
 992
 993     /**
 994         Sets the current text foreground colour for the DC.
 995
 996         @see wxMemoryDC for the interpretation of colours when drawing into a
 997              monochrome bitmap.
 998     */
 999     void SetTextForeground(const wxColour& colour);
1000
1001     /**
1002         Sets the user scaling factor, useful for applications which require
1003         'zooming'.
1004     */
1005     void SetUserScale(double xScale, double yScale);
1006
1007     /**
1008         Starts a document (only relevant when outputting to a printer).
1009         @a message is a message to show while printing.
1010     */
1011     bool StartDoc(const wxString& message);
1012
1013     /**
1014         Starts a document page (only relevant when outputting to a printer).
1015     */
1016     bool StartPage();
1017
1018     /**
1019         Copy from a source DC to this DC, specifying the destination
1020         coordinates, destination size, source DC, source coordinates, size of
1021         source area to copy, logical function, whether to use a bitmap mask,
1022         and mask source position.
1023
1024         @param xdest
1025             Destination device context x position.
1026         @param ydest
1027             Destination device context y position.
1028         @param dstWidth
1029             Width of destination area.
1030         @param dstHeight
1031             Height of destination area.
1032         @param source
1033             Source device context.
1034         @param xsrc
1035             Source device context x position.
1036         @param ysrc
1037             Source device context y position.
1038         @param srcWidth
1039             Width of source area to be copied.
1040         @param srcHeight
1041             Height of source area to be copied.
1042         @param logicalFunc
1043             Logical function to use, see SetLogicalFunction().
1044         @param useMask
1045             If @true, Blit does a transparent blit using the mask that is
1046             associated with the bitmap selected into the source device context.
1047             The Windows implementation does the following if MaskBlt cannot be
1048             used:
1049             <ol>
1050             <li>Creates a temporary bitmap and copies the destination area into
1051                 it.</li>
1052             <li>Copies the source area into the temporary bitmap using the
1053                 specified logical function.</li>
1054             <li>Sets the masked area in the temporary bitmap to BLACK by ANDing
1055                 the mask bitmap with the temp bitmap with the foreground colour
1056                 set to WHITE and the bg colour set to BLACK.</li>
1057             <li>Sets the unmasked area in the destination area to BLACK by
1058                 ANDing the mask bitmap with the destination area with the
1059                 foreground colour set to BLACK and the background colour set to
1060                 WHITE.</li>
1061             <li>ORs the temporary bitmap with the destination area.</li>
1062             <li>Deletes the temporary bitmap.</li>
1063             </ol>
1064             This sequence of operations ensures that the source's transparent
1065             area need not be black, and logical functions are supported.
1066             @n @b Note: on Windows, blitting with masks can be speeded up
1067             considerably by compiling wxWidgets with the wxUSE_DC_CACHE option
1068             enabled. You can also influence whether MaskBlt or the explicit
1069             mask blitting code above is used, by using wxSystemOptions and
1070             setting the @c no-maskblt option to 1.
1071         @param xsrcMask
1072             Source x position on the mask. If both xsrcMask and ysrcMask are
1073             -1, xsrc and ysrc will be assumed for the mask source position.
1074             Currently only implemented on Windows.
1075         @param ysrcMask
1076             Source y position on the mask. If both xsrcMask and ysrcMask are
1077             -1, xsrc and ysrc will be assumed for the mask source position.
1078             Currently only implemented on Windows.
1079
1080         There is partial support for Blit() in wxPostScriptDC, under X.
1081
1082         StretchBlit() is only implemented under wxMAC and wxMSW.
1083
1084         See wxMemoryDC for typical usage.
1085
1086         @since 2.9.0
1087
1088         @see Blit(), wxMemoryDC, wxBitmap, wxMask
1089     */
1090     bool StretchBlit(wxCoord xdest, wxCoord ydest,
1091                      wxCoord dstWidth, wxCoord dstHeight,
1092                      wxDC* source, wxCoord xsrc, wxCoord ysrc,
1093                      wxCoord srcWidth, wxCoord srcHeight,
1094                      int logicalFunc = wxCOPY,
1095                      bool useMask = false,
1096                      wxCoord xsrcMask = -1, wxCoord ysrcMask = -1);
1097 };
1098
1099
1100
1101 /**
1102     @class wxDCClipper
1103
1104     wxDCClipper is a small helper class for setting a clipping region on a wxDC
1105     and unsetting it automatically. An object of wxDCClipper class is typically
1106     created on the stack so that it is automatically destroyed when the object
1107     goes out of scope. A typical usage example:
1108
1109     @code
1110     void MyFunction(wxDC& dc)
1111     {
1112         wxDCClipper clip(dc, rect);
1113         // ... drawing functions here are affected by clipping rect ...
1114     }
1115
1116     void OtherFunction()
1117     {
1118         wxDC dc;
1119         MyFunction(dc);
1120         // ... drawing functions here are not affected by clipping rect ...
1121     }
1122     @endcode
1123
1124     @library{wxcore}
1125     @category{gdi}
1126
1127     @see wxDC::SetClippingRegion()
1128 */
1129 class wxDCClipper
1130 {
1131 public:
1132     //@{
1133     /**
1134         Sets the clipping region to the specified region/coordinates.
1135
1136         The clipping region is automatically unset when this object is destroyed.
1137     */
1138     wxDCClipper(wxDC& dc, const wxRegion& r);
1139     wxDCClipper(wxDC& dc, const wxRect& rect);
1140     wxDCClipper(wxDC& dc, int x, int y, int w, int h);
1141     //@}
1142 };
1143