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.
169 @see @ref overview_dc, wxGraphicsContext, wxDCFontChanger, wxDCTextColourChanger,
170 wxDCPenChanger, wxDCBrushChanger, wxDCClipper
172 @todo Precise definition of default/initial state.
173 @todo Pixelwise definition of operations (e.g. last point of a line not
176 class wxDC
: public wxObject
180 @name Coordinate conversion functions
185 Convert @e device X coordinate to logical coordinate, using the current
186 mapping mode, user scale factor, device origin and axis orientation.
188 wxCoord
DeviceToLogicalX(wxCoord x
) const;
191 Convert @e device X coordinate to relative logical coordinate, using the
192 current mapping mode and user scale factor but ignoring the
193 axis orientation. Use this for converting a width, for example.
195 wxCoord
DeviceToLogicalXRel(wxCoord x
) const;
198 Converts @e device Y coordinate to logical coordinate, using the current
199 mapping mode, user scale factor, device origin and axis orientation.
201 wxCoord
DeviceToLogicalY(wxCoord y
) const;
204 Convert @e device Y coordinate to relative logical coordinate, using the
205 current mapping mode and user scale factor but ignoring the
206 axis orientation. Use this for converting a height, for example.
208 wxCoord
DeviceToLogicalYRel(wxCoord y
) const;
211 Converts logical X coordinate to device coordinate, using the current
212 mapping mode, user scale factor, device origin and axis orientation.
214 wxCoord
LogicalToDeviceX(wxCoord x
) const;
217 Converts logical X coordinate to relative device coordinate, using the
218 current mapping mode and user scale factor but ignoring the
219 axis orientation. Use this for converting a width, for example.
221 wxCoord
LogicalToDeviceXRel(wxCoord x
) const;
224 Converts logical Y coordinate to device coordinate, using the current
225 mapping mode, user scale factor, device origin and axis orientation.
227 wxCoord
LogicalToDeviceY(wxCoord y
) const;
230 Converts logical Y coordinate to relative device coordinate, using the
231 current mapping mode and user scale factor but ignoring the
232 axis orientation. Use this for converting a height, for example.
234 wxCoord
LogicalToDeviceYRel(wxCoord y
) const;
241 @name Drawing functions
246 Clears the device context using the current background brush.
251 Draws an arc of a circle, centred on (@a xc, @a yc), with starting
252 point (@a xStart, @a yStart) and ending at (@a xEnd, @a yEnd).
253 The current pen is used for the outline and the current brush for
256 The arc is drawn in a counter-clockwise direction from the start point
259 void DrawArc(wxCoord xStart
, wxCoord yStart
, wxCoord xEnd
, wxCoord yEnd
,
260 wxCoord xc
, wxCoord yc
);
265 void DrawArc(const wxPoint
& ptStart
, const wxPoint
& ptEnd
, const wxPoint
& centre
);
268 Draw a bitmap on the device context at the specified point. If
269 @a transparent is @true and the bitmap has a transparency mask, the
270 bitmap will be drawn transparently.
272 When drawing a mono-bitmap, the current text foreground colour will be
273 used to draw the foreground of the bitmap (all bits set to 1), and the
274 current text background colour to draw the background (all bits set to
277 @see SetTextForeground(), SetTextBackground(), wxMemoryDC
279 void DrawBitmap(const wxBitmap
& bitmap
, wxCoord x
, wxCoord y
,
280 bool useMask
= false);
285 void DrawBitmap(const wxBitmap
&bmp
, const wxPoint
& pt
,
286 bool useMask
= false);
289 Draws a check mark inside the given rectangle.
291 void DrawCheckMark(wxCoord x
, wxCoord y
, wxCoord width
, wxCoord height
);
296 void DrawCheckMark(const wxRect
& rect
);
299 Draws a circle with the given centre and radius.
303 void DrawCircle(wxCoord x
, wxCoord y
, wxCoord radius
);
308 void DrawCircle(const wxPoint
& pt
, wxCoord radius
);
311 Draws an ellipse contained in the rectangle specified either with the
312 given top left corner and the given size or directly. The current pen
313 is used for the outline and the current brush for filling the shape.
317 void DrawEllipse(wxCoord x
, wxCoord y
, wxCoord width
, wxCoord height
);
322 void DrawEllipse(const wxPoint
& pt
, const wxSize
& size
);
327 void DrawEllipse(const wxRect
& rect
);
330 Draws an arc of an ellipse. The current pen is used for drawing the arc
331 and the current brush is used for drawing the pie.
333 @a x and @a y specify the x and y coordinates of the upper-left corner
334 of the rectangle that contains the ellipse.
336 @a width and @a height specify the width and height of the rectangle
337 that contains the ellipse.
339 @a start and @a end specify the start and end of the arc relative to
340 the three-o'clock position from the center of the rectangle. Angles are
341 specified in degrees (360 is a complete circle). Positive values mean
342 counter-clockwise motion. If @a start is equal to @e end, a complete
343 ellipse will be drawn.
345 void DrawEllipticArc(wxCoord x
, wxCoord y
, wxCoord width
, wxCoord height
,
346 double start
, double end
);
351 void DrawEllipticArc(const wxPoint
& pt
, const wxSize
& sz
,
352 double sa
, double ea
);
355 Draw an icon on the display (does nothing if the device context is
356 PostScript). This can be the simplest way of drawing bitmaps on a
359 void DrawIcon(const wxIcon
& icon
, wxCoord x
, wxCoord y
);
364 void DrawIcon(const wxIcon
& icon
, const wxPoint
& pt
);
367 Draw optional bitmap and the text into the given rectangle and aligns
368 it as specified by alignment parameter; it also will emphasize the
369 character with the given index if it is != -1 and return the bounding
370 rectangle if required.
372 void DrawLabel(const wxString
& text
, const wxBitmap
& image
,
374 int alignment
= wxALIGN_LEFT
| wxALIGN_TOP
,
375 int indexAccel
= -1, wxRect
* rectBounding
= NULL
);
380 void DrawLabel(const wxString
& text
, const wxRect
& rect
,
381 int alignment
= wxALIGN_LEFT
| wxALIGN_TOP
,
382 int indexAccel
= -1);
385 Draws a line from the first point to the second. The current pen is
386 used for drawing the line. Note that the point (@a x2, @a y2) is not
387 part of the line and is not drawn by this function (this is consistent
388 with the behaviour of many other toolkits).
390 void DrawLine(wxCoord x1
, wxCoord y1
, wxCoord x2
, wxCoord y2
);
395 void DrawLine(const wxPoint
& pt1
, const wxPoint
& pt2
);
398 Draws lines using an array of points of size @a n adding the optional
399 offset coordinate. The current pen is used for drawing the lines.
402 The wxPython version of this method accepts a Python list of wxPoint
407 Not supported by wxPerl.
410 void DrawLines(int n
, wxPoint points
[], wxCoord xoffset
= 0,
411 wxCoord yoffset
= 0);
413 This method uses a list of wxPoints, adding the optional offset
414 coordinate. The programmer is responsible for deleting the list of
418 The wxPython version of this method accepts a Python list of wxPoint
423 The wxPerl version of this method accepts
424 as its first parameter a reference to an array
428 void DrawLines(const wxPointList
* points
,
429 wxCoord xoffset
= 0, wxCoord yoffset
= 0);
432 Draws a point using the color of the current pen. Note that the other
433 properties of the pen are not used, such as width.
435 void DrawPoint(wxCoord x
, wxCoord y
);
440 void DrawPoint(const wxPoint
& pt
);
443 Draws a filled polygon using an array of points of size @a n, adding
444 the optional offset coordinate. The first and last points are
445 automatically closed.
447 The last argument specifies the fill rule: @b wxODDEVEN_RULE (the
448 default) or @b wxWINDING_RULE.
450 The current pen is used for drawing the outline, and the current brush
451 for filling the shape. Using a transparent brush suppresses filling.
454 Not supported by wxPerl.
457 void DrawPolygon(int n
, wxPoint points
[], wxCoord xoffset
= 0,
459 wxPolygonFillMode fill_style
= wxODDEVEN_RULE
);
461 This method draws a filled polygon using a list of wxPoints, adding the
462 optional offset coordinate. The first and last points are automatically
465 The last argument specifies the fill rule: @b wxODDEVEN_RULE (the
466 default) or @b wxWINDING_RULE.
468 The current pen is used for drawing the outline, and the current brush
469 for filling the shape. Using a transparent brush suppresses filling.
471 The programmer is responsible for deleting the list of points.
474 The wxPython version of this method accepts a Python list of wxPoint
479 The wxPerl version of this method accepts
480 as its first parameter a reference to an array
484 void DrawPolygon(const wxPointList
* points
,
485 wxCoord xoffset
= 0, wxCoord yoffset
= 0,
486 wxPolygonFillMode fill_style
= wxODDEVEN_RULE
);
489 Draws two or more filled polygons using an array of @a points, adding
490 the optional offset coordinates.
492 Notice that for the platforms providing a native implementation of this
493 function (Windows and PostScript-based wxDC currently), this is more
494 efficient than using DrawPolygon() in a loop.
496 @a n specifies the number of polygons to draw, the array @e count of
497 size @a n specifies the number of points in each of the polygons in the
500 The last argument specifies the fill rule: @b wxODDEVEN_RULE (the
501 default) or @b wxWINDING_RULE.
503 The current pen is used for drawing the outline, and the current brush
504 for filling the shape. Using a transparent brush suppresses filling.
506 The polygons maybe disjoint or overlapping. Each polygon specified in a
507 call to DrawPolyPolygon() must be closed. Unlike polygons created by
508 the DrawPolygon() member function, the polygons created by this
509 method are not closed automatically.
515 void DrawPolyPolygon(int n
, int count
[], wxPoint points
[],
516 wxCoord xoffset
= 0, wxCoord yoffset
= 0,
517 wxPolygonFillMode fill_style
= wxODDEVEN_RULE
);
520 Draws a rectangle with the given top left corner, and with the given
521 size. The current pen is used for the outline and the current brush
522 for filling the shape.
524 void DrawRectangle(wxCoord x
, wxCoord y
, wxCoord width
, wxCoord height
);
529 void DrawRectangle(const wxPoint
& pt
, const wxSize
& sz
);
534 void DrawRectangle(const wxRect
& rect
);
537 Draws the text rotated by @a angle degrees
538 (positive angles are counterclockwise; the full angle is 360 degrees).
540 @note Under Win9x only TrueType fonts can be drawn by this function. In
541 particular, a font different from @c wxNORMAL_FONT should be used
542 as the latter is not a TrueType font. @c wxSWISS_FONT is an
543 example of a font which is.
547 void DrawRotatedText(const wxString
& text
, wxCoord x
, wxCoord y
,
553 void DrawRotatedText(const wxString
& text
, const wxPoint
&,
557 Draws a rectangle with the given top left corner, and with the given
558 size. The corners are quarter-circles using the given radius. The
559 current pen is used for the outline and the current brush for filling
562 If @a radius is positive, the value is assumed to be the radius of the
563 rounded corner. If @a radius is negative, the absolute value is assumed
564 to be the @e proportion of the smallest dimension of the rectangle.
565 This means that the corner can be a sensible size relative to the size
566 of the rectangle, and also avoids the strange effects X produces when
567 the corners are too big for the rectangle.
569 void DrawRoundedRectangle(wxCoord x
, wxCoord y
, wxCoord width
,
570 wxCoord height
, double radius
);
575 void DrawRoundedRectangle(const wxPoint
& pt
, const wxSize
& sz
,
581 void DrawRoundedRectangle(const wxRect
& rect
, double radius
);
584 Draws a spline between all given points using the current pen.
587 The wxPython version of this method accepts a Python list of wxPoint
592 Not supported by wxPerl.
595 void DrawSpline(int n
, wxPoint points
[]);
602 The wxPerl version of this method accepts
603 as its first parameter a reference to an array
607 void DrawSpline(const wxPointList
* points
);
614 Not supported by wxPerl.
617 void DrawSpline(wxCoord x1
, wxCoord y1
, wxCoord x2
, wxCoord y2
,
618 wxCoord x3
, wxCoord y3
);
621 Draws a text string at the specified point, using the current text
622 font, and the current text foreground and background colours.
624 The coordinates refer to the top-left corner of the rectangle bounding
625 the string. See GetTextExtent() for how to get the dimensions of a text
626 string, which can be used to position the text more precisely and
627 DrawLabel() if you need to align the string differently.
629 Starting from wxWidgets 2.9.2 @a text parameter can be a multi-line
630 string, i.e. contain new line characters, and will be rendered
633 @note The current @ref GetLogicalFunction() "logical function" is
634 ignored by this function.
636 void DrawText(const wxString
& text
, wxCoord x
, wxCoord y
);
641 void DrawText(const wxString
& text
, const wxPoint
& pt
);
644 Fill the area specified by rect with a radial gradient, starting from
645 @a initialColour at the centre of the circle and fading to
646 @a destColour on the circle outside.
648 The circle is placed at the centre of @a rect.
650 @note Currently this function is very slow, don't use it for real-time
653 void GradientFillConcentric(const wxRect
& rect
,
654 const wxColour
& initialColour
,
655 const wxColour
& destColour
);
658 Fill the area specified by rect with a radial gradient, starting from
659 @a initialColour at the centre of the circle and fading to
660 @a destColour on the circle outside.
662 @a circleCenter are the relative coordinates of centre of the circle in
663 the specified @a rect.
665 @note Currently this function is very slow, don't use it for real-time
668 void GradientFillConcentric(const wxRect
& rect
,
669 const wxColour
& initialColour
,
670 const wxColour
& destColour
,
671 const wxPoint
& circleCenter
);
674 Fill the area specified by @a rect with a linear gradient, starting
675 from @a initialColour and eventually fading to @e destColour.
677 The @a nDirection specifies the direction of the colour change, default is
678 to use @a initialColour on the left part of the rectangle and
679 @a destColour on the right one.
681 void GradientFillLinear(const wxRect
& rect
, const wxColour
& initialColour
,
682 const wxColour
& destColour
,
683 wxDirection nDirection
= wxRIGHT
);
686 Flood fills the device context starting from the given point, using
687 the current brush colour, and using a style:
689 - wxFLOOD_SURFACE: The flooding occurs until a colour other than the
690 given colour is encountered.
691 - wxFLOOD_BORDER: The area to be flooded is bounded by the given
694 @return @false if the operation failed.
696 @note The present implementation for non-Windows platforms may fail to
697 find colour borders if the pixels do not match the colour
698 exactly. However the function will still return @true.
700 bool FloodFill(wxCoord x
, wxCoord y
, const wxColour
& colour
,
701 wxFloodFillStyle style
= wxFLOOD_SURFACE
);
706 bool FloodFill(const wxPoint
& pt
, const wxColour
& col
,
707 int style
= wxFLOOD_SURFACE
);
710 Displays a cross hair using the current pen. This is a vertical and
711 horizontal line the height and width of the window, centred on the
714 void CrossHair(wxCoord x
, wxCoord y
);
719 void CrossHair(const wxPoint
& pt
);
725 @name Clipping region functions
730 Destroys the current clipping region so that none of the DC is clipped.
732 @see SetClippingRegion()
734 void DestroyClippingRegion();
737 Gets the rectangle surrounding the current clipping region.
740 No arguments are required and the four values defining the rectangle
741 are returned as a tuple.
744 void GetClippingBox(wxCoord
*x
, wxCoord
*y
, wxCoord
*width
, wxCoord
*height
) const;
747 Sets the clipping region for this device context to the intersection of
748 the given region described by the parameters of this method and the
749 previously set clipping region.
751 The clipping region is an area to which drawing is restricted. Possible
752 uses for the clipping region are for clipping text or for speeding up
753 window redraws when only a known area of the screen is damaged.
755 Notice that you need to call DestroyClippingRegion() if you want to set
756 the clipping region exactly to the region specified.
758 Also note that if the clipping region is empty, any previously set
759 clipping region is destroyed, i.e. it is equivalent to calling
760 DestroyClippingRegion(), and not to clipping out all drawing on the DC
761 as might be expected.
763 @see DestroyClippingRegion(), wxRegion
765 void SetClippingRegion(wxCoord x
, wxCoord y
, wxCoord width
, wxCoord height
);
770 void SetClippingRegion(const wxPoint
& pt
, const wxSize
& sz
);
775 void SetClippingRegion(const wxRect
& rect
);
778 Sets the clipping region for this device context.
780 Unlike SetClippingRegion(), this function works with physical
781 coordinates and not with the logical ones.
783 void SetDeviceClippingRegion(const wxRegion
& region
);
789 @name Text/character extent functions
794 Gets the character height of the currently set font.
796 wxCoord
GetCharHeight() const;
799 Gets the average character width of the currently set font.
801 wxCoord
GetCharWidth() const;
804 Returns the various font characteristics.
806 This method allows to retrieve some of the font characteristics not
807 returned by GetTextExtent(), notably internal leading and average
810 Currently this method returns correct results only under wxMSW, in the
811 other ports the internal leading will always be 0 and the average
812 character width will be computed as the width of the character 'x'.
816 wxFontMetrics
GetFontMetrics() const;
819 Gets the dimensions of the string using the currently selected font.
820 @a string is the text string to measure, @e heightLine, if non @NULL,
821 is where to store the height of a single line.
823 The text extent is set in the given @a w and @a h pointers.
825 If the optional parameter @a font is specified and valid, then it is
826 used for the text extent calculation, otherwise the currently selected
829 @note This function works with both single-line and multi-line strings.
832 In wxPerl this method is implemented as
833 GetMultiLineTextExtent(string, font = undef) returning a
834 3-element list (width, height, line_height)
837 @see wxFont, SetFont(), GetPartialTextExtents(), GetTextExtent()
839 void GetMultiLineTextExtent(const wxString
& string
, wxCoord
* w
,
841 wxCoord
* heightLine
= NULL
,
842 const wxFont
* font
= NULL
) const;
844 Gets the dimensions of the string using the currently selected font.
845 @a string is the text string to measure, @e heightLine, if non @NULL,
846 is where to store the height of a single line.
848 @return The text extent as a wxSize object.
850 @note This function works with both single-line and multi-line strings.
853 Not supported by wxPerl.
856 @see wxFont, SetFont(), GetPartialTextExtents(), GetTextExtent()
858 wxSize
GetMultiLineTextExtent(const wxString
& string
) const;
861 Fills the @a widths array with the widths from the beginning of @a text
862 to the corresponding character of @a text. The generic version simply
863 builds a running total of the widths of each character using
864 GetTextExtent(), however if the various platforms have a native API
865 function that is faster or more accurate than the generic
866 implementation then it should be used instead.
869 This method only takes the @a text parameter and returns a Python list
874 In wxPerl this method only takes the @a text parameter and
875 returns the widths as a list of integers.
878 @see GetMultiLineTextExtent(), GetTextExtent()
880 bool GetPartialTextExtents(const wxString
& text
,
881 wxArrayInt
& widths
) const;
884 Gets the dimensions of the string using the currently selected font.
885 @a string is the text string to measure, @a descent is the dimension
886 from the baseline of the font to the bottom of the descender, and
887 @a externalLeading is any extra vertical space added to the font by the
888 font designer (usually is zero).
890 The text extent is returned in @a w and @a h pointers or as a wxSize
891 object depending on which version of this function is used.
893 If the optional parameter @a font is specified and valid, then it is
894 used for the text extent calculation. Otherwise the currently selected
897 @note This function only works with single-line strings.
900 The following methods are implemented in wxPython:
901 - GetTextExtent(string) - Returns a 2-tuple, (width, height).
902 - GetFullTextExtent(string, font=NULL) -
903 Returns a 4-tuple, (width, height, descent, externalLeading).
907 In wxPerl this method is implemented as GetTextExtent(string,
908 font = undef) returning a 4-element list (width, height,
909 descent, externalLeading)
912 @see wxFont, SetFont(), GetPartialTextExtents(),
913 GetMultiLineTextExtent()
915 void GetTextExtent(const wxString
& string
, wxCoord
* w
, wxCoord
* h
,
916 wxCoord
* descent
= NULL
,
917 wxCoord
* externalLeading
= NULL
,
918 const wxFont
* font
= NULL
) const;
925 Not supported by wxPerl.
928 wxSize
GetTextExtent(const wxString
& string
) const;
934 @name Text properties functions
939 Returns the current background mode: @c wxSOLID or @c wxTRANSPARENT.
941 @see SetBackgroundMode()
943 int GetBackgroundMode() const;
946 Gets the current font.
948 Notice that even although each device context object has some default font
949 after creation, this method would return a ::wxNullFont initially and only
950 after calling SetFont() a valid font is returned.
952 const wxFont
& GetFont() const;
955 Gets the current layout direction of the device context. On platforms
956 where RTL layout is supported, the return value will either be
957 @c wxLayout_LeftToRight or @c wxLayout_RightToLeft. If RTL layout is
958 not supported, the return value will be @c wxLayout_Default.
960 @see SetLayoutDirection()
962 wxLayoutDirection
GetLayoutDirection() const;
965 Gets the current text background colour.
967 @see SetTextBackground()
969 const wxColour
& GetTextBackground() const;
972 Gets the current text foreground colour.
974 @see SetTextForeground()
976 const wxColour
& GetTextForeground() const;
979 @a mode may be one of @c wxSOLID and @c wxTRANSPARENT.
981 This setting determines whether text will be drawn with a background
984 void SetBackgroundMode(int mode
);
987 Sets the current font for the DC.
989 If the argument is ::wxNullFont (or another invalid font; see wxFont::IsOk),
990 the current font is selected out of the device context (leaving wxDC without
991 any valid font), allowing the current font to be destroyed safely.
995 void SetFont(const wxFont
& font
);
998 Sets the current text background colour for the DC.
1000 void SetTextBackground(const wxColour
& colour
);
1003 Sets the current text foreground colour for the DC.
1005 @see wxMemoryDC for the interpretation of colours when drawing into a
1008 void SetTextForeground(const wxColour
& colour
);
1011 Sets the current layout direction for the device context.
1014 May be either @c wxLayout_Default, @c wxLayout_LeftToRight or
1015 @c wxLayout_RightToLeft.
1017 @see GetLayoutDirection()
1019 void SetLayoutDirection(wxLayoutDirection dir
);
1025 @name Bounding box functions
1030 Adds the specified point to the bounding box which can be retrieved
1031 with MinX(), MaxX() and MinY(), MaxY() functions.
1033 @see ResetBoundingBox()
1035 void CalcBoundingBox(wxCoord x
, wxCoord y
);
1038 Gets the maximum horizontal extent used in drawing commands so far.
1040 wxCoord
MaxX() const;
1043 Gets the maximum vertical extent used in drawing commands so far.
1045 wxCoord
MaxY() const;
1048 Gets the minimum horizontal extent used in drawing commands so far.
1050 wxCoord
MinX() const;
1053 Gets the minimum vertical extent used in drawing commands so far.
1055 wxCoord
MinY() const;
1058 Resets the bounding box: after a call to this function, the bounding
1059 box doesn't contain anything.
1061 @see CalcBoundingBox()
1063 void ResetBoundingBox();
1069 @name Page and document start/end functions
1074 Starts a document (only relevant when outputting to a printer).
1075 @a message is a message to show while printing.
1077 bool StartDoc(const wxString
& message
);
1080 Starts a document page (only relevant when outputting to a printer).
1085 Ends a document (only relevant when outputting to a printer).
1090 Ends a document page (only relevant when outputting to a printer).
1098 @name Bit-Block Transfer operations (blit)
1103 Copy from a source DC to this DC, specifying the destination
1104 coordinates, size of area to copy, source DC, source coordinates,
1105 logical function, whether to use a bitmap mask, and mask source
1109 Destination device context x position.
1111 Destination device context y position.
1113 Width of source area to be copied.
1115 Height of source area to be copied.
1117 Source device context.
1119 Source device context x position.
1121 Source device context y position.
1123 Logical function to use, see SetLogicalFunction().
1125 If @true, Blit does a transparent blit using the mask that is
1126 associated with the bitmap selected into the source device context.
1127 The Windows implementation does the following if MaskBlt cannot be
1130 <li>Creates a temporary bitmap and copies the destination area into
1132 <li>Copies the source area into the temporary bitmap using the
1133 specified logical function.</li>
1134 <li>Sets the masked area in the temporary bitmap to BLACK by ANDing
1135 the mask bitmap with the temp bitmap with the foreground colour
1136 set to WHITE and the bg colour set to BLACK.</li>
1137 <li>Sets the unmasked area in the destination area to BLACK by
1138 ANDing the mask bitmap with the destination area with the
1139 foreground colour set to BLACK and the background colour set to
1141 <li>ORs the temporary bitmap with the destination area.</li>
1142 <li>Deletes the temporary bitmap.</li>
1144 This sequence of operations ensures that the source's transparent
1145 area need not be black, and logical functions are supported.
1146 @n @b Note: on Windows, blitting with masks can be speeded up
1147 considerably by compiling wxWidgets with the wxUSE_DC_CACHEING option
1148 enabled. You can also influence whether MaskBlt or the explicit
1149 mask blitting code above is used, by using wxSystemOptions and
1150 setting the @c no-maskblt option to 1.
1152 Source x position on the mask. If both xsrcMask and ysrcMask are
1153 @c -1, xsrc and ysrc will be assumed for the mask source position.
1154 Currently only implemented on Windows.
1156 Source y position on the mask. If both xsrcMask and ysrcMask are
1157 @c -1, xsrc and ysrc will be assumed for the mask source position.
1158 Currently only implemented on Windows.
1160 @remarks There is partial support for Blit() in wxPostScriptDC, under X.
1162 @see StretchBlit(), wxMemoryDC, wxBitmap, wxMask
1164 bool Blit(wxCoord xdest
, wxCoord ydest
, wxCoord width
,
1165 wxCoord height
, wxDC
* source
, wxCoord xsrc
, wxCoord ysrc
,
1166 wxRasterOperationMode logicalFunc
= wxCOPY
, bool useMask
= false,
1167 wxCoord xsrcMask
= wxDefaultCoord
, wxCoord ysrcMask
= wxDefaultCoord
);
1170 Copy from a source DC to this DC, specifying the destination
1171 coordinates, destination size, source DC, source coordinates, size of
1172 source area to copy, logical function, whether to use a bitmap mask,
1173 and mask source position.
1176 Destination device context x position.
1178 Destination device context y position.
1180 Width of destination area.
1182 Height of destination area.
1184 Source device context.
1186 Source device context x position.
1188 Source device context y position.
1190 Width of source area to be copied.
1192 Height of source area to be copied.
1194 Logical function to use, see SetLogicalFunction().
1196 If @true, Blit does a transparent blit using the mask that is
1197 associated with the bitmap selected into the source device context.
1198 The Windows implementation does the following if MaskBlt cannot be
1201 <li>Creates a temporary bitmap and copies the destination area into
1203 <li>Copies the source area into the temporary bitmap using the
1204 specified logical function.</li>
1205 <li>Sets the masked area in the temporary bitmap to BLACK by ANDing
1206 the mask bitmap with the temp bitmap with the foreground colour
1207 set to WHITE and the bg colour set to BLACK.</li>
1208 <li>Sets the unmasked area in the destination area to BLACK by
1209 ANDing the mask bitmap with the destination area with the
1210 foreground colour set to BLACK and the background colour set to
1212 <li>ORs the temporary bitmap with the destination area.</li>
1213 <li>Deletes the temporary bitmap.</li>
1215 This sequence of operations ensures that the source's transparent
1216 area need not be black, and logical functions are supported.
1217 @n @b Note: on Windows, blitting with masks can be speeded up
1218 considerably by compiling wxWidgets with the wxUSE_DC_CACHEING option
1219 enabled. You can also influence whether MaskBlt or the explicit
1220 mask blitting code above is used, by using wxSystemOptions and
1221 setting the @c no-maskblt option to 1.
1223 Source x position on the mask. If both xsrcMask and ysrcMask are
1224 wxDefaultCoord, @a xsrc and @a ysrc will be assumed for the mask
1225 source position. Currently only implemented on Windows.
1227 Source y position on the mask. If both xsrcMask and ysrcMask are
1228 wxDefaultCoord, @a xsrc and @a ysrc will be assumed for the mask
1229 source position. Currently only implemented on Windows.
1231 There is partial support for Blit() in wxPostScriptDC, under X.
1233 StretchBlit() is only implemented under wxMAC and wxMSW.
1235 See wxMemoryDC for typical usage.
1239 @see Blit(), wxMemoryDC, wxBitmap, wxMask
1241 bool StretchBlit(wxCoord xdest
, wxCoord ydest
,
1242 wxCoord dstWidth
, wxCoord dstHeight
,
1243 wxDC
* source
, wxCoord xsrc
, wxCoord ysrc
,
1244 wxCoord srcWidth
, wxCoord srcHeight
,
1245 wxRasterOperationMode logicalFunc
= wxCOPY
,
1246 bool useMask
= false,
1247 wxCoord xsrcMask
= wxDefaultCoord
,
1248 wxCoord ysrcMask
= wxDefaultCoord
);
1253 @name Background/foreground brush and pen
1258 Gets the brush used for painting the background.
1260 @see wxDC::SetBackground()
1262 const wxBrush
& GetBackground() const;
1265 Gets the current brush.
1267 @see wxDC::SetBrush()
1269 const wxBrush
& GetBrush() const;
1272 Gets the current pen.
1276 const wxPen
& GetPen() const;
1279 Sets the current background brush for the DC.
1281 void SetBackground(const wxBrush
& brush
);
1284 Sets the current brush for the DC.
1286 If the argument is ::wxNullBrush (or another invalid brush; see wxBrush::IsOk),
1287 the current brush is selected out of the device context (leaving wxDC without
1288 any valid brush), allowing the current brush to be destroyed safely.
1290 @see wxBrush, wxMemoryDC (for the interpretation of colours when
1291 drawing into a monochrome bitmap)
1293 void SetBrush(const wxBrush
& brush
);
1296 Sets the current pen for the DC.
1298 If the argument is ::wxNullPen (or another invalid pen; see wxPen::IsOk),
1299 the current pen is selected out of the device context (leaving wxDC without any
1300 valid pen), allowing the current pen to be destroyed safely.
1302 @see wxMemoryDC for the interpretation of colours when drawing into a
1305 void SetPen(const wxPen
& pen
);
1311 Copy attributes from another DC.
1313 The copied attributes currently are:
1315 - Text foreground and background colours
1320 A valid (i.e. its IsOk() must return @true) source device context.
1322 void CopyAttributes(const wxDC
& dc
);
1325 Returns the depth (number of bits/pixel) of this DC.
1327 @see wxDisplayDepth()
1329 int GetDepth() const;
1332 Returns the current device origin.
1334 @see SetDeviceOrigin()
1336 wxPoint
GetDeviceOrigin() const;
1339 Gets the current logical function.
1341 @see SetLogicalFunction()
1343 wxRasterOperationMode
GetLogicalFunction() const;
1346 Gets the current mapping mode for the device context.
1350 wxMappingMode
GetMapMode() const;
1353 Gets in @a colour the colour at the specified location. Not available
1354 for wxPostScriptDC or wxMetafileDC.
1356 @note Setting a pixel can be done using DrawPoint().
1359 The wxColour value is returned and is not required as a parameter.
1362 bool GetPixel(wxCoord x
, wxCoord y
, wxColour
* colour
) const;
1365 Returns the resolution of the device in pixels per inch.
1367 wxSize
GetPPI() const;
1370 Gets the horizontal and vertical extent of this device context in @e device units.
1371 It can be used to scale graphics to fit the page.
1373 For example, if @e maxX and @e maxY represent the maximum horizontal
1374 and vertical 'pixel' values used in your application, the following
1375 code will scale the graphic to fit on the printer page:
1380 double scaleX = (double)(maxX / w);
1381 double scaleY = (double)(maxY / h);
1382 dc.SetUserScale(min(scaleX, scaleY),min(scaleX, scaleY));
1386 In place of a single overloaded method name, wxPython implements the
1388 - GetSize() - Returns a wxSize.
1389 - GetSizeWH() - Returns a 2-tuple (width, height).
1393 In wxPerl there are two methods instead of a single overloaded
1395 - GetSize(): returns a Wx::Size object.
1396 - GetSizeWH(): returns a 2-element list (width, height).
1399 void GetSize(wxCoord
* width
, wxCoord
* height
) const;
1404 wxSize
GetSize() const;
1407 Returns the horizontal and vertical resolution in millimetres.
1409 void GetSizeMM(wxCoord
* width
, wxCoord
* height
) const;
1414 wxSize
GetSizeMM() const;
1417 Gets the current user scale factor.
1420 In wxPerl this method takes no arguments and return a two
1421 element array (x, y).
1426 void GetUserScale(double* x
, double* y
) const;
1429 Returns @true if the DC is ok to use.
1434 Sets the x and y axis orientation (i.e., the direction from lowest to
1435 highest values on the axis). The default orientation is x axis from
1436 left to right and y axis from top down.
1439 True to set the x axis orientation to the natural left to right
1440 orientation, @false to invert it.
1442 True to set the y axis orientation to the natural bottom up
1443 orientation, @false to invert it.
1445 void SetAxisOrientation(bool xLeftRight
, bool yBottomUp
);
1448 Sets the device origin (i.e., the origin in pixels after scaling has
1449 been applied). This function may be useful in Windows printing
1450 operations for placing a graphic on a page.
1452 void SetDeviceOrigin(wxCoord x
, wxCoord y
);
1455 Sets the current logical function for the device context.
1456 It determines how a @e source pixel (from a pen or brush colour, or source
1457 device context if using Blit()) combines with a @e destination pixel in
1458 the current device context.
1459 Text drawing is not affected by this function.
1461 See ::wxRasterOperationMode enumeration values for more info.
1463 The default is @c wxCOPY, which simply draws with the current colour.
1464 The others combine the current colour and the background using a logical
1465 operation. @c wxINVERT is commonly used for drawing rubber bands or moving
1466 outlines, since drawing twice reverts to the original colour.
1468 void SetLogicalFunction(wxRasterOperationMode function
);
1471 The mapping mode of the device context defines the unit of measurement
1472 used to convert @e logical units to @e device units.
1474 Note that in X, text drawing isn't handled consistently with the mapping mode;
1475 a font is always specified in point size. However, setting the user scale (see
1476 SetUserScale()) scales the text appropriately. In Windows, scalable
1477 TrueType fonts are always used; in X, results depend on availability of
1478 fonts, but usually a reasonable match is found.
1480 The coordinate origin is always at the top left of the screen/printer.
1482 Drawing to a Windows printer device context uses the current mapping
1483 mode, but mapping mode is currently ignored for PostScript output.
1485 void SetMapMode(wxMappingMode mode
);
1488 If this is a window DC or memory DC, assigns the given palette to the
1489 window or bitmap associated with the DC. If the argument is
1490 ::wxNullPalette, the current palette is selected out of the device
1491 context, and the original palette restored.
1495 void SetPalette(const wxPalette
& palette
);
1498 Sets the user scaling factor, useful for applications which require
1501 void SetUserScale(double xScale
, double yScale
);
1509 wxDCClipper is a small helper class for setting a clipping region on a wxDC
1510 and unsetting it automatically. An object of wxDCClipper class is typically
1511 created on the stack so that it is automatically destroyed when the object
1512 goes out of scope. A typical usage example:
1515 void MyFunction(wxDC& dc)
1517 wxDCClipper clip(dc, rect);
1518 // ... drawing functions here are affected by clipping rect ...
1521 void OtherFunction()
1525 // ... drawing functions here are not affected by clipping rect ...
1532 @see wxDC::SetClippingRegion(), wxDCFontChanger, wxDCTextColourChanger, wxDCPenChanger,
1540 Sets the clipping region to the specified region/coordinates.
1542 The clipping region is automatically unset when this object is destroyed.
1544 wxDCClipper(wxDC
& dc
, const wxRegion
& r
);
1545 wxDCClipper(wxDC
& dc
, const wxRect
& rect
);
1546 wxDCClipper(wxDC
& dc
, wxCoord x
, wxCoord y
, wxCoord w
, wxCoord h
);
1550 Destroys the clipping region associated with the DC passed to the ctor.
1557 @class wxDCBrushChanger
1559 wxDCBrushChanger is a small helper class for setting a brush on a wxDC
1560 and unsetting it automatically in the destructor, restoring the previous one.
1565 @see wxDC::SetBrush(), wxDCFontChanger, wxDCTextColourChanger, wxDCPenChanger,
1568 class wxDCBrushChanger
1572 Sets @a brush on the given @a dc, storing the old one.
1575 The DC where the brush must be temporary set.
1579 wxDCBrushChanger(wxDC
& dc
, const wxBrush
& brush
);
1582 Restores the brush originally selected in the DC passed to the ctor.
1584 ~wxDCBrushChanger();
1589 @class wxDCPenChanger
1591 wxDCPenChanger is a small helper class for setting a pen on a wxDC
1592 and unsetting it automatically in the destructor, restoring the previous one.
1597 @see wxDC::SetPen(), wxDCFontChanger, wxDCTextColourChanger, wxDCBrushChanger,
1600 class wxDCPenChanger
1604 Sets @a pen on the given @a dc, storing the old one.
1607 The DC where the pen must be temporary set.
1611 wxDCPenChanger(wxDC
& dc
, const wxPen
& pen
);
1614 Restores the pen originally selected in the DC passed to the ctor.
1622 @class wxDCTextColourChanger
1624 wxDCTextColourChanger is a small helper class for setting a foreground
1625 text colour on a wxDC and unsetting it automatically in the destructor,
1626 restoring the previous one.
1631 @see wxDC::SetTextForeground(), wxDCFontChanger, wxDCPenChanger, wxDCBrushChanger,
1634 class wxDCTextColourChanger
1638 Trivial constructor not changing anything.
1640 This constructor is useful if you don't know beforehand if the colour
1641 needs to be changed or not. It simply creates the object which won't do
1642 anything in its destructor unless Set() is called -- in which case it
1643 would reset the previous colour.
1645 wxDCTextColourChanger(wxDC
& dc
);
1648 Sets @a col on the given @a dc, storing the old one.
1651 The DC where the colour must be temporary set.
1655 wxDCTextColourChanger(wxDC
& dc
, const wxColour
& col
);
1658 Set the colour to use.
1660 This method is meant to be called once only and only on the objects
1661 created with the constructor overload not taking wxColour argument and
1662 has the same effect as the other constructor, i.e. sets the colour to
1663 the given @a col and ensures that the old value is restored when this
1664 object is destroyed.
1666 void Set(const wxColour
& col
);
1669 Restores the colour originally selected in the DC passed to the ctor.
1671 ~wxDCTextColourChanger();
1677 @class wxDCFontChanger
1679 wxDCFontChanger is a small helper class for setting a font on a wxDC and
1680 unsetting it automatically in the destructor, restoring the previous one.
1687 @see wxDC::SetFont(), wxDCTextColourChanger, wxDCPenChanger, wxDCBrushChanger,
1690 class wxDCFontChanger
1694 Trivial constructor not changing anything.
1696 This constructor is useful if you don't know beforehand if the font
1697 needs to be changed or not. It simply creates the object which won't do
1698 anything in its destructor unless Set() is called -- in which case it
1699 would reset the previous font.
1703 wxDCFontChanger(wxDC
& dc
);
1706 Sets @a font on the given @a dc, storing the old one.
1709 The DC where the font must be temporary set.
1713 wxDCFontChanger(wxDC
& dc
, const wxFont
& font
);
1716 Set the font to use.
1718 This method is meant to be called once only and only on the objects
1719 created with the constructor overload not taking wxColour argument and
1720 has the same effect as the other constructor, i.e. sets the font to
1721 the given @a font and ensures that the old value is restored when this
1722 object is destroyed.
1724 void Set(const wxFont
& font
);
1727 Restores the font originally selected in the DC passed to the ctor.