1 /////////////////////////////////////////////////////////////////////////////
3 // Purpose: interface of wxDC
4 // Author: wxWidgets team
6 // Licence: wxWindows licence
7 /////////////////////////////////////////////////////////////////////////////
11 Logical raster operations which can be used with wxDC::SetLogicalFunction
12 and some other wxDC functions (e.g. wxDC::Blit and wxDC::StretchBlit).
14 The description of the values below refer to how a generic @e src source pixel
15 and the corresponding @e dst destination pixel gets combined together to produce
16 the final pixel. E.g. @c wxCLEAR and @c wxSET completely ignore the source
17 and the destination pixel and always put zeroes or ones in the final surface.
19 enum wxRasterOperationMode
22 wxXOR
, //!< @e src XOR @e dst
23 wxINVERT
, //!< NOT @e dst
24 wxOR_REVERSE
, //!< @e src OR (NOT @e dst)
25 wxAND_REVERSE
, //!< @e src AND (NOT @e dst)
27 wxAND
, //!< @e src AND @e dst
28 wxAND_INVERT
, //!< (NOT @e src) AND @e dst
30 wxNOR
, //!< (NOT @e src) AND (NOT @e dst)
31 wxEQUIV
, //!< (NOT @e src) XOR @e dst
32 wxSRC_INVERT
, //!< (NOT @e src)
33 wxOR_INVERT
, //!< (NOT @e src) OR @e dst
34 wxNAND
, //!< (NOT @e src) OR (NOT @e dst)
35 wxOR
, //!< @e src OR @e dst
40 Flood styles used by wxDC::FloodFill.
44 /** The flooding occurs until a colour other than the given colour is encountered. */
47 /** The area to be flooded is bounded by the given colour. */
52 The mapping used to transform @e logical units to @e device units.
58 Each logical unit is 1 device pixel.
59 This is the default mapping mode for all wxDC-derived classes.
63 /** Each logical unit is 1 millimeter. */
66 /** Each logical unit is 1/10 of a millimeter. */
70 Each logical unit is 1/20 of a @e "printer point", or 1/1440 of an inch
71 (also known as "twip"). Equivalent to about 17.64 micrometers.
76 Each logical unit is a @e "printer point" i.e. 1/72 of an inch.
77 Equivalent to about 353 micrometers.
83 Simple collection of various font metrics.
85 This object is returned by wxDC::GetFontMetrics().
94 /// Constructor initializes all fields to 0.
97 int height
, ///< Total character height.
98 ascent
, ///< Part of the height above the baseline.
99 descent
, ///< Part of the height below the baseline.
100 internalLeading
, ///< Intra-line spacing.
101 externalLeading
, ///< Inter-line spacing.
102 averageWidth
; ///< Average font width, a.k.a. "x-width".
109 A wxDC is a @e "device context" onto which graphics and text can be drawn.
110 It is intended to represent different output devices and offers a common
111 abstract API for drawing on any of them.
113 wxWidgets offers an alternative drawing API based on the modern drawing
114 backends GDI+, CoreGraphics and Cairo. See wxGraphicsContext, wxGraphicsRenderer
115 and related classes. There is also a wxGCDC linking the APIs by offering
116 the wxDC API on top of a wxGraphicsContext.
118 wxDC is an abstract base class and cannot be created directly.
119 Use wxPaintDC, wxClientDC, wxWindowDC, wxScreenDC, wxMemoryDC or
120 wxPrinterDC. Notice that device contexts which are associated with windows
121 (i.e. wxClientDC, wxWindowDC and wxPaintDC) use the window font and colours
122 by default (starting with wxWidgets 2.9.0) but the other device context
123 classes use system-default values so you always must set the appropriate
124 fonts and colours before using them.
126 In addition to the versions of the methods documented below, there
127 are also versions which accept single wxPoint parameter instead
128 of the two wxCoord ones or wxPoint and wxSize instead of the four
131 Beginning with wxWidgets 2.9.0 the entire wxDC code has been
132 reorganized. All platform dependent code (actually all drawing code)
133 has been moved into backend classes which derive from a common
134 wxDCImpl class. The user-visible classes such as wxClientDC and
135 wxPaintDC merely forward all calls to the backend implementation.
138 @section dc_units Device and logical units
140 In the wxDC context there is a distinction between @e logical units and @e device units.
142 @b Device units are the units native to the particular device; e.g. for a screen,
143 a device unit is a @e pixel. For a printer, the device unit is defined by the
144 resolution of the printer (usually given in @c DPI: dot-per-inch).
146 All wxDC functions use instead @b logical units, unless where explicitly
147 stated. Logical units are arbitrary units mapped to device units using
148 the current mapping mode (see wxDC::SetMapMode).
150 This mechanism allows to reuse the same code which prints on e.g. a window
151 on the screen to print on e.g. a paper.
154 @section dc_alpha_support Support for Transparency / Alpha Channel
156 In general wxDC methods don't support alpha transparency and the alpha
157 component of wxColour is simply ignored and you need to use wxGraphicsContext
158 for full transparency support. There are, however, a few exceptions: first,
159 under Mac OS X colours with alpha channel are supported in all the normal
160 wxDC-derived classes as they use wxGraphicsContext internally. Second,
161 under all platforms wxSVGFileDC also fully supports alpha channel. In both
162 of these cases the instances of wxPen or wxBrush that are built from
163 wxColour use the colour's alpha values when stroking or filling.
166 @section Support for Transformation Matrix
168 On some platforms (currently only under MSW and only on Windows NT, i.e.
169 not Windows 9x/ME, systems) wxDC has support for applying an arbitrary
170 affine transformation matrix to its coordinate system. Call
171 CanUseTransformMatrix() to check if this support is available and then call
172 SetTransformMatrix() if it is. If the transformation matrix is not
173 supported, SetTransformMatrix() always simply returns false and doesn't do
180 @see @ref overview_dc, wxGraphicsContext, wxDCFontChanger, wxDCTextColourChanger,
181 wxDCPenChanger, wxDCBrushChanger, wxDCClipper
183 @todo Precise definition of default/initial state.
184 @todo Pixelwise definition of operations (e.g. last point of a line not
187 class wxDC
: public wxObject
191 @name Coordinate conversion functions
196 Convert @e device X coordinate to logical coordinate, using the current
197 mapping mode, user scale factor, device origin and axis orientation.
199 wxCoord
DeviceToLogicalX(wxCoord x
) const;
202 Convert @e device X coordinate to relative logical coordinate, using the
203 current mapping mode and user scale factor but ignoring the
204 axis orientation. Use this for converting a width, for example.
206 wxCoord
DeviceToLogicalXRel(wxCoord x
) const;
209 Converts @e device Y coordinate to logical coordinate, using the current
210 mapping mode, user scale factor, device origin and axis orientation.
212 wxCoord
DeviceToLogicalY(wxCoord y
) const;
215 Convert @e device Y coordinate to relative logical coordinate, using the
216 current mapping mode and user scale factor but ignoring the
217 axis orientation. Use this for converting a height, for example.
219 wxCoord
DeviceToLogicalYRel(wxCoord y
) const;
222 Converts logical X coordinate to device coordinate, using the current
223 mapping mode, user scale factor, device origin and axis orientation.
225 wxCoord
LogicalToDeviceX(wxCoord x
) const;
228 Converts logical X coordinate to relative device coordinate, using the
229 current mapping mode and user scale factor but ignoring the
230 axis orientation. Use this for converting a width, for example.
232 wxCoord
LogicalToDeviceXRel(wxCoord x
) const;
235 Converts logical Y coordinate to device coordinate, using the current
236 mapping mode, user scale factor, device origin and axis orientation.
238 wxCoord
LogicalToDeviceY(wxCoord y
) const;
241 Converts logical Y coordinate to relative device coordinate, using the
242 current mapping mode and user scale factor but ignoring the
243 axis orientation. Use this for converting a height, for example.
245 wxCoord
LogicalToDeviceYRel(wxCoord y
) const;
252 @name Drawing functions
257 Clears the device context using the current background brush.
262 Draws an arc of a circle, centred on (@a xc, @a yc), with starting
263 point (@a xStart, @a yStart) and ending at (@a xEnd, @a yEnd).
264 The current pen is used for the outline and the current brush for
267 The arc is drawn in a counter-clockwise direction from the start point
270 void DrawArc(wxCoord xStart
, wxCoord yStart
, wxCoord xEnd
, wxCoord yEnd
,
271 wxCoord xc
, wxCoord yc
);
276 void DrawArc(const wxPoint
& ptStart
, const wxPoint
& ptEnd
, const wxPoint
& centre
);
279 Draw a bitmap on the device context at the specified point. If
280 @a transparent is @true and the bitmap has a transparency mask, the
281 bitmap will be drawn transparently.
283 When drawing a mono-bitmap, the current text foreground colour will be
284 used to draw the foreground of the bitmap (all bits set to 1), and the
285 current text background colour to draw the background (all bits set to
288 @see SetTextForeground(), SetTextBackground(), wxMemoryDC
290 void DrawBitmap(const wxBitmap
& bitmap
, wxCoord x
, wxCoord y
,
291 bool useMask
= false);
296 void DrawBitmap(const wxBitmap
&bmp
, const wxPoint
& pt
,
297 bool useMask
= false);
300 Draws a check mark inside the given rectangle.
302 void DrawCheckMark(wxCoord x
, wxCoord y
, wxCoord width
, wxCoord height
);
307 void DrawCheckMark(const wxRect
& rect
);
310 Draws a circle with the given centre and radius.
314 void DrawCircle(wxCoord x
, wxCoord y
, wxCoord radius
);
319 void DrawCircle(const wxPoint
& pt
, wxCoord radius
);
322 Draws an ellipse contained in the rectangle specified either with the
323 given top left corner and the given size or directly. The current pen
324 is used for the outline and the current brush for filling the shape.
328 void DrawEllipse(wxCoord x
, wxCoord y
, wxCoord width
, wxCoord height
);
333 void DrawEllipse(const wxPoint
& pt
, const wxSize
& size
);
338 void DrawEllipse(const wxRect
& rect
);
341 Draws an arc of an ellipse. The current pen is used for drawing the arc
342 and the current brush is used for drawing the pie.
344 @a x and @a y specify the x and y coordinates of the upper-left corner
345 of the rectangle that contains the ellipse.
347 @a width and @a height specify the width and height of the rectangle
348 that contains the ellipse.
350 @a start and @a end specify the start and end of the arc relative to
351 the three-o'clock position from the center of the rectangle. Angles are
352 specified in degrees (360 is a complete circle). Positive values mean
353 counter-clockwise motion. If @a start is equal to @e end, a complete
354 ellipse will be drawn.
356 void DrawEllipticArc(wxCoord x
, wxCoord y
, wxCoord width
, wxCoord height
,
357 double start
, double end
);
362 void DrawEllipticArc(const wxPoint
& pt
, const wxSize
& sz
,
363 double sa
, double ea
);
366 Draw an icon on the display (does nothing if the device context is
367 PostScript). This can be the simplest way of drawing bitmaps on a
370 void DrawIcon(const wxIcon
& icon
, wxCoord x
, wxCoord y
);
375 void DrawIcon(const wxIcon
& icon
, const wxPoint
& pt
);
378 Draw optional bitmap and the text into the given rectangle and aligns
379 it as specified by alignment parameter; it also will emphasize the
380 character with the given index if it is != -1 and return the bounding
381 rectangle if required.
383 void DrawLabel(const wxString
& text
, const wxBitmap
& bitmap
,
385 int alignment
= wxALIGN_LEFT
| wxALIGN_TOP
,
386 int indexAccel
= -1, wxRect
* rectBounding
= NULL
);
391 void DrawLabel(const wxString
& text
, const wxRect
& rect
,
392 int alignment
= wxALIGN_LEFT
| wxALIGN_TOP
,
393 int indexAccel
= -1);
396 Draws a line from the first point to the second. The current pen is
397 used for drawing the line. Note that the point (@a x2, @a y2) is not
398 part of the line and is not drawn by this function (this is consistent
399 with the behaviour of many other toolkits).
401 void DrawLine(wxCoord x1
, wxCoord y1
, wxCoord x2
, wxCoord y2
);
406 void DrawLine(const wxPoint
& pt1
, const wxPoint
& pt2
);
409 Draws lines using an array of points of size @a n adding the optional
410 offset coordinate. The current pen is used for drawing the lines.
413 Not supported by wxPerl.
416 void DrawLines(int n
, wxPoint points
[], wxCoord xoffset
= 0,
417 wxCoord yoffset
= 0);
419 This method uses a list of wxPoints, adding the optional offset
420 coordinate. The programmer is responsible for deleting the list of
424 The wxPerl version of this method accepts
425 as its first parameter a reference to an array
429 void DrawLines(const wxPointList
* points
,
430 wxCoord xoffset
= 0, wxCoord yoffset
= 0);
433 Draws a point using the color of the current pen. Note that the other
434 properties of the pen are not used, such as width.
436 void DrawPoint(wxCoord x
, wxCoord y
);
441 void DrawPoint(const wxPoint
& pt
);
444 Draws a filled polygon using an array of points of size @a n, adding
445 the optional offset coordinate. The first and last points are
446 automatically closed.
448 The last argument specifies the fill rule: @b wxODDEVEN_RULE (the
449 default) or @b wxWINDING_RULE.
451 The current pen is used for drawing the outline, and the current brush
452 for filling the shape. Using a transparent brush suppresses filling.
455 Not supported by wxPerl.
458 void DrawPolygon(int n
, wxPoint points
[], wxCoord xoffset
= 0,
460 wxPolygonFillMode fill_style
= wxODDEVEN_RULE
);
462 This method draws a filled polygon using a list of wxPoints, adding the
463 optional offset coordinate. The first and last points are automatically
466 The last argument specifies the fill rule: @b wxODDEVEN_RULE (the
467 default) or @b wxWINDING_RULE.
469 The current pen is used for drawing the outline, and the current brush
470 for filling the shape. Using a transparent brush suppresses filling.
472 The programmer is responsible for deleting the list of points.
475 The wxPerl version of this method accepts
476 as its first parameter a reference to an array
480 void DrawPolygon(const wxPointList
* points
,
481 wxCoord xoffset
= 0, wxCoord yoffset
= 0,
482 wxPolygonFillMode fill_style
= wxODDEVEN_RULE
);
485 Draws two or more filled polygons using an array of @a points, adding
486 the optional offset coordinates.
488 Notice that for the platforms providing a native implementation of this
489 function (Windows and PostScript-based wxDC currently), this is more
490 efficient than using DrawPolygon() in a loop.
492 @a n specifies the number of polygons to draw, the array @e count of
493 size @a n specifies the number of points in each of the polygons in the
496 The last argument specifies the fill rule: @b wxODDEVEN_RULE (the
497 default) or @b wxWINDING_RULE.
499 The current pen is used for drawing the outline, and the current brush
500 for filling the shape. Using a transparent brush suppresses filling.
502 The polygons maybe disjoint or overlapping. Each polygon specified in a
503 call to DrawPolyPolygon() must be closed. Unlike polygons created by
504 the DrawPolygon() member function, the polygons created by this
505 method are not closed automatically.
507 void DrawPolyPolygon(int n
, int count
[], wxPoint points
[],
508 wxCoord xoffset
= 0, wxCoord yoffset
= 0,
509 wxPolygonFillMode fill_style
= wxODDEVEN_RULE
);
512 Draws a rectangle with the given top left corner, and with the given
513 size. The current pen is used for the outline and the current brush
514 for filling the shape.
516 void DrawRectangle(wxCoord x
, wxCoord y
, wxCoord width
, wxCoord height
);
521 void DrawRectangle(const wxPoint
& pt
, const wxSize
& sz
);
526 void DrawRectangle(const wxRect
& rect
);
529 Draws the text rotated by @a angle degrees
530 (positive angles are counterclockwise; the full angle is 360 degrees).
532 @note Under Win9x only TrueType fonts can be drawn by this function. In
533 particular, a font different from @c wxNORMAL_FONT should be used
534 as the latter is not a TrueType font. @c wxSWISS_FONT is an
535 example of a font which is.
539 void DrawRotatedText(const wxString
& text
, wxCoord x
, wxCoord y
,
545 void DrawRotatedText(const wxString
& text
, const wxPoint
& point
,
549 Draws a rectangle with the given top left corner, and with the given
550 size. The corners are quarter-circles using the given radius. The
551 current pen is used for the outline and the current brush for filling
554 If @a radius is positive, the value is assumed to be the radius of the
555 rounded corner. If @a radius is negative, the absolute value is assumed
556 to be the @e proportion of the smallest dimension of the rectangle.
557 This means that the corner can be a sensible size relative to the size
558 of the rectangle, and also avoids the strange effects X produces when
559 the corners are too big for the rectangle.
561 void DrawRoundedRectangle(wxCoord x
, wxCoord y
, wxCoord width
,
562 wxCoord height
, double radius
);
567 void DrawRoundedRectangle(const wxPoint
& pt
, const wxSize
& sz
,
573 void DrawRoundedRectangle(const wxRect
& rect
, double radius
);
576 Draws a spline between all given points using the current pen.
579 Not supported by wxPerl.
582 void DrawSpline(int n
, wxPoint points
[]);
589 The wxPerl version of this method accepts
590 as its first parameter a reference to an array
594 void DrawSpline(const wxPointList
* points
);
601 Not supported by wxPerl.
604 void DrawSpline(wxCoord x1
, wxCoord y1
, wxCoord x2
, wxCoord y2
,
605 wxCoord x3
, wxCoord y3
);
608 Draws a text string at the specified point, using the current text
609 font, and the current text foreground and background colours.
611 The coordinates refer to the top-left corner of the rectangle bounding
612 the string. See GetTextExtent() for how to get the dimensions of a text
613 string, which can be used to position the text more precisely and
614 DrawLabel() if you need to align the string differently.
616 Starting from wxWidgets 2.9.2 @a text parameter can be a multi-line
617 string, i.e. contain new line characters, and will be rendered
620 @note The current @ref GetLogicalFunction() "logical function" is
621 ignored by this function.
623 void DrawText(const wxString
& text
, wxCoord x
, wxCoord y
);
628 void DrawText(const wxString
& text
, const wxPoint
& pt
);
631 Fill the area specified by rect with a radial gradient, starting from
632 @a initialColour at the centre of the circle and fading to
633 @a destColour on the circle outside.
635 The circle is placed at the centre of @a rect.
637 @note Currently this function is very slow, don't use it for real-time
640 void GradientFillConcentric(const wxRect
& rect
,
641 const wxColour
& initialColour
,
642 const wxColour
& destColour
);
645 Fill the area specified by rect with a radial gradient, starting from
646 @a initialColour at the centre of the circle and fading to
647 @a destColour on the circle outside.
649 @a circleCenter are the relative coordinates of centre of the circle in
650 the specified @a rect.
652 @note Currently this function is very slow, don't use it for real-time
655 void GradientFillConcentric(const wxRect
& rect
,
656 const wxColour
& initialColour
,
657 const wxColour
& destColour
,
658 const wxPoint
& circleCenter
);
661 Fill the area specified by @a rect with a linear gradient, starting
662 from @a initialColour and eventually fading to @e destColour.
664 The @a nDirection specifies the direction of the colour change, default is
665 to use @a initialColour on the left part of the rectangle and
666 @a destColour on the right one.
668 void GradientFillLinear(const wxRect
& rect
, const wxColour
& initialColour
,
669 const wxColour
& destColour
,
670 wxDirection nDirection
= wxRIGHT
);
673 Flood fills the device context starting from the given point, using
674 the current brush colour, and using a style:
676 - wxFLOOD_SURFACE: The flooding occurs until a colour other than the
677 given colour is encountered.
678 - wxFLOOD_BORDER: The area to be flooded is bounded by the given
681 @return @false if the operation failed.
683 @note The present implementation for non-Windows platforms may fail to
684 find colour borders if the pixels do not match the colour
685 exactly. However the function will still return @true.
687 @note This method shouldn't be used with wxPaintDC under non-Windows
688 platforms as it uses GetPixel() internally and this may give
689 wrong results, notably in wxGTK. If you need to flood fill
690 wxPaintDC, create a temporary wxMemoryDC, flood fill it and then
691 blit it to, or draw as a bitmap on, wxPaintDC. See the example of
692 doing this in the drawing sample and wxBufferedPaintDC class.
694 bool FloodFill(wxCoord x
, wxCoord y
, const wxColour
& colour
,
695 wxFloodFillStyle style
= wxFLOOD_SURFACE
);
700 bool FloodFill(const wxPoint
& pt
, const wxColour
& col
,
701 wxFloodFillStyle style
= wxFLOOD_SURFACE
);
704 Displays a cross hair using the current pen. This is a vertical and
705 horizontal line the height and width of the window, centred on the
708 void CrossHair(wxCoord x
, wxCoord y
);
713 void CrossHair(const wxPoint
& pt
);
719 @name Clipping region functions
724 Destroys the current clipping region so that none of the DC is clipped.
726 @see SetClippingRegion()
728 void DestroyClippingRegion();
731 Gets the rectangle surrounding the current clipping region.
733 void GetClippingBox(wxCoord
*x
, wxCoord
*y
, wxCoord
*width
, wxCoord
*height
) const;
736 Sets the clipping region for this device context to the intersection of
737 the given region described by the parameters of this method and the
738 previously set clipping region.
740 The clipping region is an area to which drawing is restricted. Possible
741 uses for the clipping region are for clipping text or for speeding up
742 window redraws when only a known area of the screen is damaged.
744 Notice that you need to call DestroyClippingRegion() if you want to set
745 the clipping region exactly to the region specified.
747 Also note that if the clipping region is empty, any previously set
748 clipping region is destroyed, i.e. it is equivalent to calling
749 DestroyClippingRegion(), and not to clipping out all drawing on the DC
750 as might be expected.
752 @see DestroyClippingRegion(), wxRegion
754 void SetClippingRegion(wxCoord x
, wxCoord y
, wxCoord width
, wxCoord height
);
759 void SetClippingRegion(const wxPoint
& pt
, const wxSize
& sz
);
764 void SetClippingRegion(const wxRect
& rect
);
767 Sets the clipping region for this device context.
769 Unlike SetClippingRegion(), this function works with physical
770 coordinates and not with the logical ones.
772 void SetDeviceClippingRegion(const wxRegion
& region
);
778 @name Text/character extent functions
783 Gets the character height of the currently set font.
785 wxCoord
GetCharHeight() const;
788 Gets the average character width of the currently set font.
790 wxCoord
GetCharWidth() const;
793 Returns the various font characteristics.
795 This method allows to retrieve some of the font characteristics not
796 returned by GetTextExtent(), notably internal leading and average
799 Currently this method returns correct results only under wxMSW, in the
800 other ports the internal leading will always be 0 and the average
801 character width will be computed as the width of the character 'x'.
805 wxFontMetrics
GetFontMetrics() const;
808 Gets the dimensions of the string using the currently selected font.
809 @a string is the text string to measure, @e heightLine, if non @NULL,
810 is where to store the height of a single line.
812 The text extent is set in the given @a w and @a h pointers.
814 If the optional parameter @a font is specified and valid, then it is
815 used for the text extent calculation, otherwise the currently selected
818 @note This function works with both single-line and multi-line strings.
821 In wxPerl this method is implemented as
822 GetMultiLineTextExtent(string, font = undef) returning a
823 3-element list (width, height, line_height)
826 @see wxFont, SetFont(), GetPartialTextExtents(), GetTextExtent()
828 void GetMultiLineTextExtent(const wxString
& string
, wxCoord
* w
,
830 wxCoord
* heightLine
= NULL
,
831 const wxFont
* font
= NULL
) const;
833 Gets the dimensions of the string using the currently selected font.
834 @a string is the text string to measure, @e heightLine, if non @NULL,
835 is where to store the height of a single line.
837 @return The text extent as a wxSize object.
839 @note This function works with both single-line and multi-line strings.
842 Not supported by wxPerl.
845 @see wxFont, SetFont(), GetPartialTextExtents(), GetTextExtent()
847 wxSize
GetMultiLineTextExtent(const wxString
& string
) const;
850 Fills the @a widths array with the widths from the beginning of @a text
851 to the corresponding character of @a text. The generic version simply
852 builds a running total of the widths of each character using
853 GetTextExtent(), however if the various platforms have a native API
854 function that is faster or more accurate than the generic
855 implementation then it should be used instead.
858 In wxPerl this method only takes the @a text parameter and
859 returns the widths as a list of integers.
862 @see GetMultiLineTextExtent(), GetTextExtent()
864 bool GetPartialTextExtents(const wxString
& text
,
865 wxArrayInt
& widths
) const;
868 Gets the dimensions of the string using the currently selected font.
869 @a string is the text string to measure, @a descent is the dimension
870 from the baseline of the font to the bottom of the descender, and
871 @a externalLeading is any extra vertical space added to the font by the
872 font designer (usually is zero).
874 The text extent is returned in @a w and @a h pointers or as a wxSize
875 object depending on which version of this function is used.
877 If the optional parameter @a font is specified and valid, then it is
878 used for the text extent calculation. Otherwise the currently selected
881 @note This function only works with single-line strings.
884 In wxPerl this method is implemented as GetTextExtent(string,
885 font = undef) returning a 4-element list (width, height,
886 descent, externalLeading)
889 @see wxFont, SetFont(), GetPartialTextExtents(),
890 GetMultiLineTextExtent()
892 void GetTextExtent(const wxString
& string
, wxCoord
* w
, wxCoord
* h
,
893 wxCoord
* descent
= NULL
,
894 wxCoord
* externalLeading
= NULL
,
895 const wxFont
* font
= NULL
) const;
902 Not supported by wxPerl.
905 wxSize
GetTextExtent(const wxString
& string
) const;
911 @name Text properties functions
916 Returns the current background mode: @c wxSOLID or @c wxTRANSPARENT.
918 @see SetBackgroundMode()
920 int GetBackgroundMode() const;
923 Gets the current font.
925 Notice that even although each device context object has some default font
926 after creation, this method would return a ::wxNullFont initially and only
927 after calling SetFont() a valid font is returned.
929 const wxFont
& GetFont() const;
932 Gets the current layout direction of the device context. On platforms
933 where RTL layout is supported, the return value will either be
934 @c wxLayout_LeftToRight or @c wxLayout_RightToLeft. If RTL layout is
935 not supported, the return value will be @c wxLayout_Default.
937 @see SetLayoutDirection()
939 wxLayoutDirection
GetLayoutDirection() const;
942 Gets the current text background colour.
944 @see SetTextBackground()
946 const wxColour
& GetTextBackground() const;
949 Gets the current text foreground colour.
951 @see SetTextForeground()
953 const wxColour
& GetTextForeground() const;
956 @a mode may be one of @c wxSOLID and @c wxTRANSPARENT.
958 This setting determines whether text will be drawn with a background
961 void SetBackgroundMode(int mode
);
964 Sets the current font for the DC.
966 If the argument is ::wxNullFont (or another invalid font; see wxFont::IsOk),
967 the current font is selected out of the device context (leaving wxDC without
968 any valid font), allowing the current font to be destroyed safely.
972 void SetFont(const wxFont
& font
);
975 Sets the current text background colour for the DC.
977 void SetTextBackground(const wxColour
& colour
);
980 Sets the current text foreground colour for the DC.
982 @see wxMemoryDC for the interpretation of colours when drawing into a
985 void SetTextForeground(const wxColour
& colour
);
988 Sets the current layout direction for the device context.
991 May be either @c wxLayout_Default, @c wxLayout_LeftToRight or
992 @c wxLayout_RightToLeft.
994 @see GetLayoutDirection()
996 void SetLayoutDirection(wxLayoutDirection dir
);
1002 @name Bounding box functions
1007 Adds the specified point to the bounding box which can be retrieved
1008 with MinX(), MaxX() and MinY(), MaxY() functions.
1010 @see ResetBoundingBox()
1012 void CalcBoundingBox(wxCoord x
, wxCoord y
);
1015 Gets the maximum horizontal extent used in drawing commands so far.
1017 wxCoord
MaxX() const;
1020 Gets the maximum vertical extent used in drawing commands so far.
1022 wxCoord
MaxY() const;
1025 Gets the minimum horizontal extent used in drawing commands so far.
1027 wxCoord
MinX() const;
1030 Gets the minimum vertical extent used in drawing commands so far.
1032 wxCoord
MinY() const;
1035 Resets the bounding box: after a call to this function, the bounding
1036 box doesn't contain anything.
1038 @see CalcBoundingBox()
1040 void ResetBoundingBox();
1046 @name Page and document start/end functions
1051 Starts a document (only relevant when outputting to a printer).
1052 @a message is a message to show while printing.
1054 bool StartDoc(const wxString
& message
);
1057 Starts a document page (only relevant when outputting to a printer).
1062 Ends a document (only relevant when outputting to a printer).
1067 Ends a document page (only relevant when outputting to a printer).
1075 @name Bit-Block Transfer operations (blit)
1080 Copy from a source DC to this DC.
1082 With this method you can specify the destination coordinates and the
1083 size of area to copy which will be the same for both the source and
1084 target DCs. If you need to apply scaling while copying, use
1087 Notice that source DC coordinates @a xsrc and @a ysrc are interpreted
1088 using the current source DC coordinate system, i.e. the scale, origin
1089 position and axis directions are taken into account when transforming
1090 them to physical (pixel) coordinates.
1093 Destination device context x position.
1095 Destination device context y position.
1097 Width of source area to be copied.
1099 Height of source area to be copied.
1101 Source device context.
1103 Source device context x position.
1105 Source device context y position.
1107 Logical function to use, see SetLogicalFunction().
1109 If @true, Blit does a transparent blit using the mask that is
1110 associated with the bitmap selected into the source device context.
1111 The Windows implementation does the following if MaskBlt cannot be
1114 <li>Creates a temporary bitmap and copies the destination area into
1116 <li>Copies the source area into the temporary bitmap using the
1117 specified logical function.</li>
1118 <li>Sets the masked area in the temporary bitmap to BLACK by ANDing
1119 the mask bitmap with the temp bitmap with the foreground colour
1120 set to WHITE and the bg colour set to BLACK.</li>
1121 <li>Sets the unmasked area in the destination area to BLACK by
1122 ANDing the mask bitmap with the destination area with the
1123 foreground colour set to BLACK and the background colour set to
1125 <li>ORs the temporary bitmap with the destination area.</li>
1126 <li>Deletes the temporary bitmap.</li>
1128 This sequence of operations ensures that the source's transparent
1129 area need not be black, and logical functions are supported.
1130 @n @b Note: on Windows, blitting with masks can be speeded up
1131 considerably by compiling wxWidgets with the wxUSE_DC_CACHEING option
1132 enabled. You can also influence whether MaskBlt or the explicit
1133 mask blitting code above is used, by using wxSystemOptions and
1134 setting the @c no-maskblt option to 1.
1136 Source x position on the mask. If both xsrcMask and ysrcMask are
1137 @c -1, xsrc and ysrc will be assumed for the mask source position.
1138 Currently only implemented on Windows.
1140 Source y position on the mask. If both xsrcMask and ysrcMask are
1141 @c -1, xsrc and ysrc will be assumed for the mask source position.
1142 Currently only implemented on Windows.
1144 @remarks There is partial support for Blit() in wxPostScriptDC, under X.
1146 @see StretchBlit(), wxMemoryDC, wxBitmap, wxMask
1148 bool Blit(wxCoord xdest
, wxCoord ydest
, wxCoord width
,
1149 wxCoord height
, wxDC
* source
, wxCoord xsrc
, wxCoord ysrc
,
1150 wxRasterOperationMode logicalFunc
= wxCOPY
, bool useMask
= false,
1151 wxCoord xsrcMask
= wxDefaultCoord
, wxCoord ysrcMask
= wxDefaultCoord
);
1154 Copy from a source DC to this DC possibly changing the scale.
1156 Unlike Blit(), this method allows to specify different source and
1157 destination region sizes, meaning that it can stretch or shrink it
1158 while copying. The same can be achieved by changing the scale of the
1159 source or target DC but calling this method is simpler and can also be
1160 more efficient if the platform provides a native implementation of it.
1162 The meaning of its other parameters is the same as with Blit(), in
1163 particular all source coordinates are interpreted using the source DC
1164 coordinate system, i.e. are affected by its scale, origin translation
1168 Destination device context x position.
1170 Destination device context y position.
1172 Width of destination area.
1174 Height of destination area.
1176 Source device context.
1178 Source device context x position.
1180 Source device context y position.
1182 Width of source area to be copied.
1184 Height of source area to be copied.
1186 Logical function to use, see SetLogicalFunction().
1188 If @true, Blit does a transparent blit using the mask that is
1189 associated with the bitmap selected into the source device context.
1190 The Windows implementation does the following if MaskBlt cannot be
1193 <li>Creates a temporary bitmap and copies the destination area into
1195 <li>Copies the source area into the temporary bitmap using the
1196 specified logical function.</li>
1197 <li>Sets the masked area in the temporary bitmap to BLACK by ANDing
1198 the mask bitmap with the temp bitmap with the foreground colour
1199 set to WHITE and the bg colour set to BLACK.</li>
1200 <li>Sets the unmasked area in the destination area to BLACK by
1201 ANDing the mask bitmap with the destination area with the
1202 foreground colour set to BLACK and the background colour set to
1204 <li>ORs the temporary bitmap with the destination area.</li>
1205 <li>Deletes the temporary bitmap.</li>
1207 This sequence of operations ensures that the source's transparent
1208 area need not be black, and logical functions are supported.
1209 @n @b Note: on Windows, blitting with masks can be speeded up
1210 considerably by compiling wxWidgets with the wxUSE_DC_CACHEING option
1211 enabled. You can also influence whether MaskBlt or the explicit
1212 mask blitting code above is used, by using wxSystemOptions and
1213 setting the @c no-maskblt option to 1.
1215 Source x position on the mask. If both xsrcMask and ysrcMask are
1216 wxDefaultCoord, @a xsrc and @a ysrc will be assumed for the mask
1217 source position. Currently only implemented on Windows.
1219 Source y position on the mask. If both xsrcMask and ysrcMask are
1220 wxDefaultCoord, @a xsrc and @a ysrc will be assumed for the mask
1221 source position. Currently only implemented on Windows.
1223 There is partial support for Blit() in wxPostScriptDC, under X.
1225 See wxMemoryDC for typical usage.
1229 @see Blit(), wxMemoryDC, wxBitmap, wxMask
1231 bool StretchBlit(wxCoord xdest
, wxCoord ydest
,
1232 wxCoord dstWidth
, wxCoord dstHeight
,
1233 wxDC
* source
, wxCoord xsrc
, wxCoord ysrc
,
1234 wxCoord srcWidth
, wxCoord srcHeight
,
1235 wxRasterOperationMode logicalFunc
= wxCOPY
,
1236 bool useMask
= false,
1237 wxCoord xsrcMask
= wxDefaultCoord
,
1238 wxCoord ysrcMask
= wxDefaultCoord
);
1243 @name Background/foreground brush and pen
1248 Gets the brush used for painting the background.
1250 @see wxDC::SetBackground()
1252 const wxBrush
& GetBackground() const;
1255 Gets the current brush.
1257 @see wxDC::SetBrush()
1259 const wxBrush
& GetBrush() const;
1262 Gets the current pen.
1266 const wxPen
& GetPen() const;
1269 Sets the current background brush for the DC.
1271 void SetBackground(const wxBrush
& brush
);
1274 Sets the current brush for the DC.
1276 If the argument is ::wxNullBrush (or another invalid brush; see wxBrush::IsOk),
1277 the current brush is selected out of the device context (leaving wxDC without
1278 any valid brush), allowing the current brush to be destroyed safely.
1280 @see wxBrush, wxMemoryDC (for the interpretation of colours when
1281 drawing into a monochrome bitmap)
1283 void SetBrush(const wxBrush
& brush
);
1286 Sets the current pen for the DC.
1288 If the argument is ::wxNullPen (or another invalid pen; see wxPen::IsOk),
1289 the current pen is selected out of the device context (leaving wxDC without any
1290 valid pen), allowing the current pen to be destroyed safely.
1292 @see wxMemoryDC for the interpretation of colours when drawing into a
1295 void SetPen(const wxPen
& pen
);
1301 Copy attributes from another DC.
1303 The copied attributes currently are:
1305 - Text foreground and background colours
1310 A valid (i.e. its IsOk() must return @true) source device context.
1312 void CopyAttributes(const wxDC
& dc
);
1315 Returns the depth (number of bits/pixel) of this DC.
1317 @see wxDisplayDepth()
1319 int GetDepth() const;
1322 Returns the current device origin.
1324 @see SetDeviceOrigin()
1326 wxPoint
GetDeviceOrigin() const;
1329 Gets the current logical function.
1331 @see SetLogicalFunction()
1333 wxRasterOperationMode
GetLogicalFunction() const;
1336 Gets the current mapping mode for the device context.
1340 wxMappingMode
GetMapMode() const;
1343 Gets in @a colour the colour at the specified location. Not available
1344 for wxPostScriptDC or wxMetafileDC.
1346 @note Setting a pixel can be done using DrawPoint().
1348 @note This method shouldn't be used with wxPaintDC as accessing the DC
1349 while drawing can result in unexpected results, notably in wxGTK.
1351 bool GetPixel(wxCoord x
, wxCoord y
, wxColour
* colour
) const;
1354 Returns the resolution of the device in pixels per inch.
1356 wxSize
GetPPI() const;
1359 Gets the horizontal and vertical extent of this device context in @e device units.
1360 It can be used to scale graphics to fit the page.
1362 For example, if @e maxX and @e maxY represent the maximum horizontal
1363 and vertical 'pixel' values used in your application, the following
1364 code will scale the graphic to fit on the printer page:
1369 double scaleX = (double)(maxX / w);
1370 double scaleY = (double)(maxY / h);
1371 dc.SetUserScale(min(scaleX, scaleY),min(scaleX, scaleY));
1375 In wxPerl there are two methods instead of a single overloaded
1377 - GetSize(): returns a Wx::Size object.
1378 - GetSizeWH(): returns a 2-element list (width, height).
1381 void GetSize(wxCoord
* width
, wxCoord
* height
) const;
1386 wxSize
GetSize() const;
1389 Returns the horizontal and vertical resolution in millimetres.
1391 void GetSizeMM(wxCoord
* width
, wxCoord
* height
) const;
1396 wxSize
GetSizeMM() const;
1399 Gets the current user scale factor.
1402 In wxPerl this method takes no arguments and return a two
1403 element array (x, y).
1408 void GetUserScale(double* x
, double* y
) const;
1411 Returns @true if the DC is ok to use.
1416 Sets the x and y axis orientation (i.e., the direction from lowest to
1417 highest values on the axis). The default orientation is x axis from
1418 left to right and y axis from top down.
1421 True to set the x axis orientation to the natural left to right
1422 orientation, @false to invert it.
1424 True to set the y axis orientation to the natural bottom up
1425 orientation, @false to invert it.
1427 void SetAxisOrientation(bool xLeftRight
, bool yBottomUp
);
1430 Sets the device origin (i.e., the origin in pixels after scaling has
1431 been applied). This function may be useful in Windows printing
1432 operations for placing a graphic on a page.
1434 void SetDeviceOrigin(wxCoord x
, wxCoord y
);
1437 Sets the current logical function for the device context.
1438 It determines how a @e source pixel (from a pen or brush colour, or source
1439 device context if using Blit()) combines with a @e destination pixel in
1440 the current device context.
1441 Text drawing is not affected by this function.
1443 See ::wxRasterOperationMode enumeration values for more info.
1445 The default is @c wxCOPY, which simply draws with the current colour.
1446 The others combine the current colour and the background using a logical
1447 operation. @c wxINVERT is commonly used for drawing rubber bands or moving
1448 outlines, since drawing twice reverts to the original colour.
1450 void SetLogicalFunction(wxRasterOperationMode function
);
1453 The mapping mode of the device context defines the unit of measurement
1454 used to convert @e logical units to @e device units.
1456 Note that in X, text drawing isn't handled consistently with the mapping mode;
1457 a font is always specified in point size. However, setting the user scale (see
1458 SetUserScale()) scales the text appropriately. In Windows, scalable
1459 TrueType fonts are always used; in X, results depend on availability of
1460 fonts, but usually a reasonable match is found.
1462 The coordinate origin is always at the top left of the screen/printer.
1464 Drawing to a Windows printer device context uses the current mapping
1465 mode, but mapping mode is currently ignored for PostScript output.
1467 void SetMapMode(wxMappingMode mode
);
1470 If this is a window DC or memory DC, assigns the given palette to the
1471 window or bitmap associated with the DC. If the argument is
1472 ::wxNullPalette, the current palette is selected out of the device
1473 context, and the original palette restored.
1477 void SetPalette(const wxPalette
& palette
);
1480 Sets the user scaling factor, useful for applications which require
1483 void SetUserScale(double xScale
, double yScale
);
1487 @name Transformation matrix
1489 See the notes about the availability of these functions in the class
1495 Check if the use of transformation matrix is supported by the current
1498 Currently this function always returns @false for non-MSW platforms and
1499 may return @false for old (Windows 9x/ME) Windows systems. Normally
1500 support for the transformation matrix is always available in any
1501 relatively recent Windows versions.
1505 bool CanUseTransformMatrix() const;
1508 Set the transformation matrix.
1510 If transformation matrix is supported on the current system, the
1511 specified @a matrix will be used to transform between wxDC and physical
1512 coordinates. Otherwise the function returns @false and doesn't change
1513 the coordinate mapping.
1517 bool SetTransformMatrix(const wxAffineMatrix2D
& matrix
);
1520 Return the transformation matrix used by this device context.
1522 By default the transformation matrix is the identity matrix.
1526 wxAffineMatrix2D
GetTransformMatrix() const;
1529 Revert the transformation matrix to identity matrix.
1533 void ResetTransformMatrix();
1538 void SetLogicalScale(double x
, double y
);
1539 void GetLogicalScale(double *x
, double *y
) const;
1540 void SetLogicalOrigin(wxCoord x
, wxCoord y
);
1541 void GetLogicalOrigin(wxCoord
*x
, wxCoord
*y
) const;
1542 wxPoint
GetLogicalOrigin() const;
1551 wxDCClipper is a helper class for setting a clipping region on a wxDC
1552 during its lifetime.
1554 An object of wxDCClipper class is typically created on the stack so that it
1555 is automatically destroyed when the object goes out of scope. A typical
1559 void MyFunction(wxDC& dc)
1561 wxDCClipper clip(dc, rect);
1562 // ... drawing functions here are affected by clipping rect ...
1565 void OtherFunction()
1569 // ... drawing functions here are not affected by clipping rect ...
1573 @note Unlike other similar classes such as wxDCFontChanger, wxDCClipper
1574 currently doesn't restore the previously active clipping region when it
1575 is destroyed but simply resets clipping on the associated wxDC. This
1576 may be changed in the future wxWidgets versions but has to be taken
1577 into account explicitly in the current one.
1582 @see wxDC::SetClippingRegion(), wxDCFontChanger, wxDCTextColourChanger, wxDCPenChanger,
1590 Sets the clipping region to the specified region/coordinates.
1592 The clipping region is automatically unset when this object is destroyed.
1594 wxDCClipper(wxDC
& dc
, const wxRegion
& region
);
1595 wxDCClipper(wxDC
& dc
, const wxRect
& rect
);
1596 wxDCClipper(wxDC
& dc
, wxCoord x
, wxCoord y
, wxCoord w
, wxCoord h
);
1600 Destroys the clipping region associated with the DC passed to the ctor.
1607 @class wxDCBrushChanger
1609 wxDCBrushChanger is a small helper class for setting a brush on a wxDC
1610 and unsetting it automatically in the destructor, restoring the previous one.
1615 @see wxDC::SetBrush(), wxDCFontChanger, wxDCTextColourChanger, wxDCPenChanger,
1618 class wxDCBrushChanger
1622 Sets @a brush on the given @a dc, storing the old one.
1625 The DC where the brush must be temporary set.
1629 wxDCBrushChanger(wxDC
& dc
, const wxBrush
& brush
);
1632 Restores the brush originally selected in the DC passed to the ctor.
1634 ~wxDCBrushChanger();
1639 @class wxDCPenChanger
1641 wxDCPenChanger is a small helper class for setting a pen on a wxDC
1642 and unsetting it automatically in the destructor, restoring the previous one.
1647 @see wxDC::SetPen(), wxDCFontChanger, wxDCTextColourChanger, wxDCBrushChanger,
1650 class wxDCPenChanger
1654 Sets @a pen on the given @a dc, storing the old one.
1657 The DC where the pen must be temporary set.
1661 wxDCPenChanger(wxDC
& dc
, const wxPen
& pen
);
1664 Restores the pen originally selected in the DC passed to the ctor.
1672 @class wxDCTextColourChanger
1674 wxDCTextColourChanger is a small helper class for setting a foreground
1675 text colour on a wxDC and unsetting it automatically in the destructor,
1676 restoring the previous one.
1681 @see wxDC::SetTextForeground(), wxDCFontChanger, wxDCPenChanger, wxDCBrushChanger,
1684 class wxDCTextColourChanger
1688 Trivial constructor not changing anything.
1690 This constructor is useful if you don't know beforehand if the colour
1691 needs to be changed or not. It simply creates the object which won't do
1692 anything in its destructor unless Set() is called -- in which case it
1693 would reset the previous colour.
1695 wxDCTextColourChanger(wxDC
& dc
);
1698 Sets @a col on the given @a dc, storing the old one.
1701 The DC where the colour must be temporary set.
1705 wxDCTextColourChanger(wxDC
& dc
, const wxColour
& col
);
1708 Set the colour to use.
1710 This method is meant to be called once only and only on the objects
1711 created with the constructor overload not taking wxColour argument and
1712 has the same effect as the other constructor, i.e. sets the colour to
1713 the given @a col and ensures that the old value is restored when this
1714 object is destroyed.
1716 void Set(const wxColour
& col
);
1719 Restores the colour originally selected in the DC passed to the ctor.
1721 ~wxDCTextColourChanger();
1727 @class wxDCFontChanger
1729 wxDCFontChanger is a small helper class for setting a font on a wxDC and
1730 unsetting it automatically in the destructor, restoring the previous one.
1737 @see wxDC::SetFont(), wxDCTextColourChanger, wxDCPenChanger, wxDCBrushChanger,
1740 class wxDCFontChanger
1744 Trivial constructor not changing anything.
1746 This constructor is useful if you don't know beforehand if the font
1747 needs to be changed or not. It simply creates the object which won't do
1748 anything in its destructor unless Set() is called -- in which case it
1749 would reset the previous font.
1753 wxDCFontChanger(wxDC
& dc
);
1756 Sets @a font on the given @a dc, storing the old one.
1759 The DC where the font must be temporary set.
1763 wxDCFontChanger(wxDC
& dc
, const wxFont
& font
);
1766 Set the font to use.
1768 This method is meant to be called once only and only on the objects
1769 created with the constructor overload not taking wxColour argument and
1770 has the same effect as the other constructor, i.e. sets the font to
1771 the given @a font and ensures that the old value is restored when this
1772 object is destroyed.
1774 void Set(const wxFont
& font
);
1777 Restores the font originally selected in the DC passed to the ctor.