///////////////////////////////////////////////////////////////////////////// // Name: dc.h // Purpose: interface of wxDC // Author: wxWidgets team // Licence: wxWindows licence ///////////////////////////////////////////////////////////////////////////// /** Logical raster operations which can be used with wxDC::SetLogicalFunction and some other wxDC functions (e.g. wxDC::Blit and wxDC::StretchBlit). The description of the values below refer to how a generic @e src source pixel and the corresponding @e dst destination pixel gets combined together to produce the final pixel. E.g. @c wxCLEAR and @c wxSET completely ignore the source and the destination pixel and always put zeroes or ones in the final surface. */ enum wxRasterOperationMode { wxCLEAR, //!< 0 wxXOR, //!< @e src XOR @e dst wxINVERT, //!< NOT @e dst wxOR_REVERSE, //!< @e src OR (NOT @e dst) wxAND_REVERSE, //!< @e src AND (NOT @e dst) wxCOPY, //!< @e src wxAND, //!< @e src AND @e dst wxAND_INVERT, //!< (NOT @e src) AND @e dst wxNO_OP, //!< @e dst wxNOR, //!< (NOT @e src) AND (NOT @e dst) wxEQUIV, //!< (NOT @e src) XOR @e dst wxSRC_INVERT, //!< (NOT @e src) wxOR_INVERT, //!< (NOT @e src) OR @e dst wxNAND, //!< (NOT @e src) OR (NOT @e dst) wxOR, //!< @e src OR @e dst wxSET //!< 1 }; /** Flood styles used by wxDC::FloodFill. */ enum wxFloodFillStyle { /** The flooding occurs until a colour other than the given colour is encountered. */ wxFLOOD_SURFACE = 1, /** The area to be flooded is bounded by the given colour. */ wxFLOOD_BORDER }; /** The mapping used to transform @e logical units to @e device units. See wxDC::SetMapMode. */ enum wxMappingMode { /** Each logical unit is 1 device pixel. This is the default mapping mode for all wxDC-derived classes. */ wxMM_TEXT = 1, /** Each logical unit is 1 millimeter. */ wxMM_METRIC, /** Each logical unit is 1/10 of a millimeter. */ wxMM_LOMETRIC, /** Each logical unit is 1/20 of a @e "printer point", or 1/1440 of an inch (also known as "twip"). Equivalent to about 17.64 micrometers. */ wxMM_TWIPS, /** Each logical unit is a @e "printer point" i.e.\ 1/72 of an inch. Equivalent to about 353 micrometers. */ wxMM_POINTS }; /** Simple collection of various font metrics. This object is returned by wxDC::GetFontMetrics(). @since 2.9.2 @library{wxcore} @category{dc,gdi} */ struct wxFontMetrics { /// Constructor initializes all fields to 0. wxFontMetrics(); int height, ///< Total character height. ascent, ///< Part of the height above the baseline. descent, ///< Part of the height below the baseline. internalLeading, ///< Intra-line spacing. externalLeading, ///< Inter-line spacing. averageWidth; ///< Average font width, a.k.a. "x-width". }; /** @class wxDC A wxDC is a @e "device context" onto which graphics and text can be drawn. It is intended to represent different output devices and offers a common abstract API for drawing on any of them. wxWidgets offers an alternative drawing API based on the modern drawing backends GDI+, CoreGraphics, Cairo and Direct2D. See wxGraphicsContext, wxGraphicsRenderer and related classes. There is also a wxGCDC linking the APIs by offering the wxDC API on top of a wxGraphicsContext. wxDC is an abstract base class and cannot be created directly. Use wxPaintDC, wxClientDC, wxWindowDC, wxScreenDC, wxMemoryDC or wxPrinterDC. Notice that device contexts which are associated with windows (i.e. wxClientDC, wxWindowDC and wxPaintDC) use the window font and colours by default (starting with wxWidgets 2.9.0) but the other device context classes use system-default values so you always must set the appropriate fonts and colours before using them. In addition to the versions of the methods documented below, there are also versions which accept single wxPoint parameter instead of the two wxCoord ones or wxPoint and wxSize instead of the four wxCoord parameters. Beginning with wxWidgets 2.9.0 the entire wxDC code has been reorganized. All platform dependent code (actually all drawing code) has been moved into backend classes which derive from a common wxDCImpl class. The user-visible classes such as wxClientDC and wxPaintDC merely forward all calls to the backend implementation. @section dc_units Device and logical units In the wxDC context there is a distinction between @e logical units and @e device units. @b Device units are the units native to the particular device; e.g. for a screen, a device unit is a @e pixel. For a printer, the device unit is defined by the resolution of the printer (usually given in @c DPI: dot-per-inch). All wxDC functions use instead @b logical units, unless where explicitly stated. Logical units are arbitrary units mapped to device units using the current mapping mode (see wxDC::SetMapMode). This mechanism allows reusing the same code which prints on e.g. a window on the screen to print on e.g. a paper. @section dc_alpha_support Support for Transparency / Alpha Channel In general wxDC methods don't support alpha transparency and the alpha component of wxColour is simply ignored and you need to use wxGraphicsContext for full transparency support. There are, however, a few exceptions: first, under OS X and GTK+ 3 colours with alpha channel are supported in all the normal wxDC-derived classes as they use wxGraphicsContext internally. Second, under all platforms wxSVGFileDC also fully supports alpha channel. In both of these cases the instances of wxPen or wxBrush that are built from wxColour use the colour's alpha values when stroking or filling. @section dc_transform_support Support for Transformation Matrix On some platforms (currently under MSW, GTK+ 3, OS X) wxDC has support for applying an arbitrary affine transformation matrix to its coordinate system (since 3.1.1 this feature is also supported by wxGCDC in all ports). Call CanUseTransformMatrix() to check if this support is available and then call SetTransformMatrix() if it is. If the transformation matrix is not supported, SetTransformMatrix() always simply returns @c false and doesn't do anything. This feature is only available when @c wxUSE_DC_TRANSFORM_MATRIX build option is enabled. @library{wxcore} @category{dc,gdi} @see @ref overview_dc, wxGraphicsContext, wxDCFontChanger, wxDCTextColourChanger, wxDCPenChanger, wxDCBrushChanger, wxDCClipper @todo Precise definition of default/initial state. @todo Pixelwise definition of operations (e.g. last point of a line not drawn). */ class wxDC : public wxObject { public: /** @name Coordinate conversion functions */ //@{ /** Convert @e device X coordinate to logical coordinate, using the current mapping mode, user scale factor, device origin and axis orientation. */ wxCoord DeviceToLogicalX(wxCoord x) const; /** Convert @e device X coordinate to relative logical coordinate, using the current mapping mode and user scale factor but ignoring the axis orientation. Use this for converting a width, for example. */ wxCoord DeviceToLogicalXRel(wxCoord x) const; /** Converts @e device Y coordinate to logical coordinate, using the current mapping mode, user scale factor, device origin and axis orientation. */ wxCoord DeviceToLogicalY(wxCoord y) const; /** Convert @e device Y coordinate to relative logical coordinate, using the current mapping mode and user scale factor but ignoring the axis orientation. Use this for converting a height, for example. */ wxCoord DeviceToLogicalYRel(wxCoord y) const; /** Converts logical X coordinate to device coordinate, using the current mapping mode, user scale factor, device origin and axis orientation. */ wxCoord LogicalToDeviceX(wxCoord x) const; /** Converts logical X coordinate to relative device coordinate, using the current mapping mode and user scale factor but ignoring the axis orientation. Use this for converting a width, for example. */ wxCoord LogicalToDeviceXRel(wxCoord x) const; /** Converts logical Y coordinate to device coordinate, using the current mapping mode, user scale factor, device origin and axis orientation. */ wxCoord LogicalToDeviceY(wxCoord y) const; /** Converts logical Y coordinate to relative device coordinate, using the current mapping mode and user scale factor but ignoring the axis orientation. Use this for converting a height, for example. */ wxCoord LogicalToDeviceYRel(wxCoord y) const; //@} /** @name Drawing functions */ //@{ /** Clears the device context using the current background brush. Note that SetBackground() method must be used to set the brush used by Clear(), the brush used for filling the shapes set by SetBrush() is ignored by it. If no background brush was set, solid white brush is used to clear the device context. */ void Clear(); /** Draws an arc from the given start to the given end point. @note DrawEllipticArc() has more clear semantics and it is recommended to use it instead of this function. The arc drawn is an arc of the circle centered at (@a xc, @a yc). Its start point is (@a xStart, @a yStart) whereas its end point is the point of intersection of the line passing by (@a xc, @a yc) and (@a xEnd, @a yEnd) with the circle passing by (@a xStart, @a yStart). The arc is drawn in a counter-clockwise direction between the start and the end points. The current pen is used for the outline and the current brush for filling the shape. Notice that unless the brush is transparent, the lines connecting the centre of the circle to the end points of the arc are drawn as well. */ void DrawArc(wxCoord xStart, wxCoord yStart, wxCoord xEnd, wxCoord yEnd, wxCoord xc, wxCoord yc); /** @overload */ void DrawArc(const wxPoint& ptStart, const wxPoint& ptEnd, const wxPoint& centre); /** Draw a bitmap on the device context at the specified point. If @a transparent is @true and the bitmap has a transparency mask, the bitmap will be drawn transparently. When drawing a mono-bitmap, the current text foreground colour will be used to draw the foreground of the bitmap (all bits set to 1), and the current text background colour to draw the background (all bits set to 0). @see SetTextForeground(), SetTextBackground(), wxMemoryDC */ void DrawBitmap(const wxBitmap& bitmap, wxCoord x, wxCoord y, bool useMask = false); /** @overload */ void DrawBitmap(const wxBitmap &bmp, const wxPoint& pt, bool useMask = false); /** Draws a check mark inside the given rectangle. */ void DrawCheckMark(wxCoord x, wxCoord y, wxCoord width, wxCoord height); /** @overload */ void DrawCheckMark(const wxRect& rect); /** Draws a circle with the given centre and radius. @see DrawEllipse() */ void DrawCircle(wxCoord x, wxCoord y, wxCoord radius); /** @overload */ void DrawCircle(const wxPoint& pt, wxCoord radius); /** Draws an ellipse contained in the rectangle specified either with the given top left corner and the given size or directly. The current pen is used for the outline and the current brush for filling the shape. @see DrawCircle() */ void DrawEllipse(wxCoord x, wxCoord y, wxCoord width, wxCoord height); /** @overload */ void DrawEllipse(const wxPoint& pt, const wxSize& size); /** @overload */ void DrawEllipse(const wxRect& rect); /** Draws an arc of an ellipse. The current pen is used for drawing the arc and the current brush is used for drawing the pie. @a x and @a y specify the x and y coordinates of the upper-left corner of the rectangle that contains the ellipse. @a width and @a height specify the width and height of the rectangle that contains the ellipse. @a start and @a end specify the end points of the arc relative to the three-o'clock position from the center of the rectangle. Angles are specified in degrees with 0 degree angle corresponding to the positive horizontal axis (3 o'clock) direction. Independently of whether @a start is greater than or less than @a end, the arc is drawn in the counter-clockwise direction. Also, if @a start is equal to @e end, a complete ellipse is drawn. Notice that unlike DrawArc(), this function does not draw the lines to the arc ends, even when using non-transparent brush. */ void DrawEllipticArc(wxCoord x, wxCoord y, wxCoord width, wxCoord height, double start, double end); /** @overload */ void DrawEllipticArc(const wxPoint& pt, const wxSize& sz, double sa, double ea); /** Draw an icon on the display (does nothing if the device context is PostScript). This can be the simplest way of drawing bitmaps on a window. */ void DrawIcon(const wxIcon& icon, wxCoord x, wxCoord y); /** @overload */ void DrawIcon(const wxIcon& icon, const wxPoint& pt); /** Draw optional bitmap and the text into the given rectangle and aligns it as specified by alignment parameter; it also will emphasize the character with the given index if it is != -1 and return the bounding rectangle if required. */ void DrawLabel(const wxString& text, const wxBitmap& bitmap, const wxRect& rect, int alignment = wxALIGN_LEFT | wxALIGN_TOP, int indexAccel = -1, wxRect* rectBounding = NULL); /** @overload */ void DrawLabel(const wxString& text, const wxRect& rect, int alignment = wxALIGN_LEFT | wxALIGN_TOP, int indexAccel = -1); /** Draws a line from the first point to the second. The current pen is used for drawing the line. Note that the point (@a x2, @a y2) is not part of the line and is not drawn by this function (this is consistent with the behaviour of many other toolkits). */ void DrawLine(wxCoord x1, wxCoord y1, wxCoord x2, wxCoord y2); /** @overload */ void DrawLine(const wxPoint& pt1, const wxPoint& pt2); /** Draws lines using an array of points of size @a n adding the optional offset coordinate. The current pen is used for drawing the lines. @beginWxPerlOnly Not supported by wxPerl. @endWxPerlOnly */ void DrawLines(int n, const wxPoint points[], wxCoord xoffset = 0, wxCoord yoffset = 0); /** This method uses a list of wxPoints, adding the optional offset coordinate. The programmer is responsible for deleting the list of points. @beginWxPerlOnly The wxPerl version of this method accepts as its first parameter a reference to an array of wxPoint objects. @endWxPerlOnly */ void DrawLines(const wxPointList* points, wxCoord xoffset = 0, wxCoord yoffset = 0); /** Draws a point using the color of the current pen. Note that the other properties of the pen are not used, such as width. */ void DrawPoint(wxCoord x, wxCoord y); /** @overload */ void DrawPoint(const wxPoint& pt); /** Draws a filled polygon using an array of points of size @a n, adding the optional offset coordinate. The first and last points are automatically closed. The last argument specifies the fill rule: @b wxODDEVEN_RULE (the default) or @b wxWINDING_RULE. The current pen is used for drawing the outline, and the current brush for filling the shape. Using a transparent brush suppresses filling. @beginWxPerlOnly Not supported by wxPerl. @endWxPerlOnly */ void DrawPolygon(int n, const wxPoint points[], wxCoord xoffset = 0, wxCoord yoffset = 0, wxPolygonFillMode fill_style = wxODDEVEN_RULE); /** This method draws a filled polygon using a list of wxPoints, adding the optional offset coordinate. The first and last points are automatically closed. The last argument specifies the fill rule: @b wxODDEVEN_RULE (the default) or @b wxWINDING_RULE. The current pen is used for drawing the outline, and the current brush for filling the shape. Using a transparent brush suppresses filling. The programmer is responsible for deleting the list of points. @beginWxPerlOnly The wxPerl version of this method accepts as its first parameter a reference to an array of wxPoint objects. @endWxPerlOnly */ void DrawPolygon(const wxPointList* points, wxCoord xoffset = 0, wxCoord yoffset = 0, wxPolygonFillMode fill_style = wxODDEVEN_RULE); /** Draws two or more filled polygons using an array of @a points, adding the optional offset coordinates. Notice that for the platforms providing a native implementation of this function (Windows and PostScript-based wxDC currently), this is more efficient than using DrawPolygon() in a loop. @a n specifies the number of polygons to draw, the array @e count of size @a n specifies the number of points in each of the polygons in the @a points array. The last argument specifies the fill rule: @b wxODDEVEN_RULE (the default) or @b wxWINDING_RULE. The current pen is used for drawing the outline, and the current brush for filling the shape. Using a transparent brush suppresses filling. The polygons maybe disjoint or overlapping. Each polygon specified in a call to DrawPolyPolygon() must be closed. Unlike polygons created by the DrawPolygon() member function, the polygons created by this method are not closed automatically. */ void DrawPolyPolygon(int n, const int count[], const wxPoint points[], wxCoord xoffset = 0, wxCoord yoffset = 0, wxPolygonFillMode fill_style = wxODDEVEN_RULE); /** Draws a rectangle with the given corner coordinate and size. Normally, @a x and @a y specify the top left corner coordinates and both @a width and @a height are positive, however they are also allowed to be negative, in which case the corresponding corner coordinate refers to the right or bottom corner instead. The current pen is used for the outline and the current brush for filling the shape. */ void DrawRectangle(wxCoord x, wxCoord y, wxCoord width, wxCoord height); /** @overload */ void DrawRectangle(const wxPoint& pt, const wxSize& sz); /** @overload */ void DrawRectangle(const wxRect& rect); /** Draws the text rotated by @a angle degrees (positive angles are counterclockwise; the full angle is 360 degrees). Notice that, as with DrawText(), the @a text can contain multiple lines separated by the new line (@c '\\n') characters. @note Under MSW only TrueType fonts can be drawn by this function. In particular, a font different from @c wxNORMAL_FONT should be used as the latter is not a TrueType font. @c wxSWISS_FONT is an example of a font which is. @see DrawText() */ void DrawRotatedText(const wxString& text, wxCoord x, wxCoord y, double angle); /** @overload */ void DrawRotatedText(const wxString& text, const wxPoint& point, double angle); /** Draws a rectangle with the given top left corner, and with the given size. The corners are quarter-circles using the given radius. The current pen is used for the outline and the current brush for filling the shape. If @a radius is positive, the value is assumed to be the radius of the rounded corner. If @a radius is negative, the absolute value is assumed to be the @e proportion of the smallest dimension of the rectangle. This means that the corner can be a sensible size relative to the size of the rectangle, and also avoids the strange effects X produces when the corners are too big for the rectangle. */ void DrawRoundedRectangle(wxCoord x, wxCoord y, wxCoord width, wxCoord height, double radius); /** @overload */ void DrawRoundedRectangle(const wxPoint& pt, const wxSize& sz, double radius); /** @overload */ void DrawRoundedRectangle(const wxRect& rect, double radius); /** Draws a spline between all given points using the current pen. @beginWxPerlOnly Not supported by wxPerl. @endWxPerlOnly */ void DrawSpline(int n, const wxPoint points[]); /** @overload @beginWxPerlOnly The wxPerl version of this method accepts as its first parameter a reference to an array of wxPoint objects. @endWxPerlOnly */ void DrawSpline(const wxPointList* points); /** @overload @beginWxPerlOnly Not supported by wxPerl. @endWxPerlOnly */ void DrawSpline(wxCoord x1, wxCoord y1, wxCoord x2, wxCoord y2, wxCoord x3, wxCoord y3); /** Draws a text string at the specified point, using the current text font, and the current text foreground and background colours. The coordinates refer to the top-left corner of the rectangle bounding the string. See GetTextExtent() for how to get the dimensions of a text string, which can be used to position the text more precisely and DrawLabel() if you need to align the string differently. Starting from wxWidgets 2.9.2 @a text parameter can be a multi-line string, i.e. contain new line characters, and will be rendered correctly. @note The current @ref GetLogicalFunction() "logical function" is ignored by this function. */ void DrawText(const wxString& text, wxCoord x, wxCoord y); /** @overload */ void DrawText(const wxString& text, const wxPoint& pt); /** Fill the area specified by rect with a radial gradient, starting from @a initialColour at the centre of the circle and fading to @a destColour on the circle outside. The circle is placed at the centre of @a rect. @note Currently this function is very slow, don't use it for real-time drawing. */ void GradientFillConcentric(const wxRect& rect, const wxColour& initialColour, const wxColour& destColour); /** Fill the area specified by rect with a radial gradient, starting from @a initialColour at the centre of the circle and fading to @a destColour on the circle outside. @a circleCenter are the relative coordinates of centre of the circle in the specified @a rect. @note Currently this function is very slow, don't use it for real-time drawing. */ void GradientFillConcentric(const wxRect& rect, const wxColour& initialColour, const wxColour& destColour, const wxPoint& circleCenter); /** Fill the area specified by @a rect with a linear gradient, starting from @a initialColour and eventually fading to @e destColour. The @a nDirection specifies the direction of the colour change, default is to use @a initialColour on the left part of the rectangle and @a destColour on the right one. */ void GradientFillLinear(const wxRect& rect, const wxColour& initialColour, const wxColour& destColour, wxDirection nDirection = wxRIGHT); /** Flood fills the device context starting from the given point, using the current brush colour, and using a style: - wxFLOOD_SURFACE: The flooding occurs until a colour other than the given colour is encountered. - wxFLOOD_BORDER: The area to be flooded is bounded by the given colour. Currently this method is not implemented in wxOSX and does nothing there. @return @false if the operation failed. @note The present implementation for non-Windows platforms may fail to find colour borders if the pixels do not match the colour exactly. However the function will still return @true. @note This method shouldn't be used with wxPaintDC under non-Windows platforms as it uses GetPixel() internally and this may give wrong results, notably in wxGTK. If you need to flood fill wxPaintDC, create a temporary wxMemoryDC, flood fill it and then blit it to, or draw as a bitmap on, wxPaintDC. See the example of doing this in the drawing sample and wxBufferedPaintDC class. */ bool FloodFill(wxCoord x, wxCoord y, const wxColour& colour, wxFloodFillStyle style = wxFLOOD_SURFACE); /** @overload */ bool FloodFill(const wxPoint& pt, const wxColour& col, wxFloodFillStyle style = wxFLOOD_SURFACE); /** Displays a cross hair using the current pen. This is a vertical and horizontal line the height and width of the window, centred on the given point. */ void CrossHair(wxCoord x, wxCoord y); /** @overload */ void CrossHair(const wxPoint& pt); //@} /** @name Clipping region functions */ //@{ /** Destroys the current clipping region so that none of the DC is clipped. @see SetClippingRegion() */ void DestroyClippingRegion(); /** Gets the rectangle surrounding the current clipping region. If no clipping region is set this function returns the extent of the device context. @remarks Clipping region is given in logical coordinates. @param x If non-@NULL, filled in with the logical horizontal coordinate of the top left corner of the clipping region if the function returns true or 0 otherwise. @param y If non-@NULL, filled in with the logical vertical coordinate of the top left corner of the clipping region if the function returns true or 0 otherwise. @param width If non-@NULL, filled in with the width of the clipping region if the function returns true or the device context width otherwise. @param height If non-@NULL, filled in with the height of the clipping region if the function returns true or the device context height otherwise. @return @true if there is a clipping region or @false if there is no active clipping region (note that this return value is available only since wxWidgets 3.1.2, this function didn't return anything in the previous versions). */ bool GetClippingBox(wxCoord *x, wxCoord *y, wxCoord *width, wxCoord *height) const; /** @overload */ bool GetClippingBox(wxRect& rect) const; /** Sets the clipping region for this device context to the intersection of the given region described by the parameters of this method and the previously set clipping region. The clipping region is an area to which drawing is restricted. Possible uses for the clipping region are for clipping text or for speeding up window redraws when only a known area of the screen is damaged. @remarks - Clipping region should be given in logical coordinates. - Calling this function can only make the clipping region smaller, never larger. - You need to call DestroyClippingRegion() first if you want to set the clipping region exactly to the region specified. - If resulting clipping region is empty, then all drawing on the DC is clipped out (all changes made by drawing operations are masked out). @see DestroyClippingRegion(), wxRegion */ void SetClippingRegion(wxCoord x, wxCoord y, wxCoord width, wxCoord height); /** @overload */ void SetClippingRegion(const wxPoint& pt, const wxSize& sz); /** @overload */ void SetClippingRegion(const wxRect& rect); /** Sets the clipping region for this device context. Unlike SetClippingRegion(), this function works with physical coordinates and not with the logical ones. */ void SetDeviceClippingRegion(const wxRegion& region); //@} /** @name Text/character extent functions */ //@{ /** Gets the character height of the currently set font. */ wxCoord GetCharHeight() const; /** Gets the average character width of the currently set font. */ wxCoord GetCharWidth() const; /** Returns the various font characteristics. This method allows retrieving some of the font characteristics not returned by GetTextExtent(), notably internal leading and average character width. Currently this method returns correct results only under wxMSW, in the other ports the internal leading will always be 0 and the average character width will be computed as the width of the character 'x'. @since 2.9.2 */ wxFontMetrics GetFontMetrics() const; /** Gets the dimensions of the string using the currently selected font. @a string is the text string to measure, @e heightLine, if non @NULL, is where to store the height of a single line. The text extent is set in the given @a w and @a h pointers. If the optional parameter @a font is specified and valid, then it is used for the text extent calculation, otherwise the currently selected font is used. @note This function works with both single-line and multi-line strings. @beginWxPerlOnly In wxPerl this method is implemented as GetMultiLineTextExtent(string, font = undef) returning a 3-element list (width, height, line_height) @endWxPerlOnly @see wxFont, SetFont(), GetPartialTextExtents(), GetTextExtent() */ void GetMultiLineTextExtent(const wxString& string, wxCoord* w, wxCoord* h, wxCoord* heightLine = NULL, const wxFont* font = NULL) const; /** Gets the dimensions of the string using the currently selected font. @a string is the text string to measure. @return The text extent as a wxSize object. @note This function works with both single-line and multi-line strings. @beginWxPerlOnly Not supported by wxPerl. @endWxPerlOnly @see wxFont, SetFont(), GetPartialTextExtents(), GetTextExtent() */ wxSize GetMultiLineTextExtent(const wxString& string) const; /** Fills the @a widths array with the widths from the beginning of @a text to the corresponding character of @a text. The generic version simply builds a running total of the widths of each character using GetTextExtent(), however if the various platforms have a native API function that is faster or more accurate than the generic implementation then it should be used instead. @beginWxPerlOnly In wxPerl this method only takes the @a text parameter and returns the widths as a list of integers. @endWxPerlOnly @see GetMultiLineTextExtent(), GetTextExtent() */ bool GetPartialTextExtents(const wxString& text, wxArrayInt& widths) const; /** Gets the dimensions of the string using the currently selected font. @a string is the text string to measure, @a descent is the dimension from the baseline of the font to the bottom of the descender, and @a externalLeading is any extra vertical space added to the font by the font designer (usually is zero). The text extent is returned in @a w and @a h pointers or as a wxSize object depending on which version of this function is used. If the optional parameter @a font is specified and valid, then it is used for the text extent calculation. Otherwise the currently selected font is. @note This function only works with single-line strings. @beginWxPerlOnly In wxPerl this method is implemented as GetTextExtent(string, font = undef) returning a 4-element list (width, height, descent, externalLeading) @endWxPerlOnly @see wxFont, SetFont(), GetPartialTextExtents(), GetMultiLineTextExtent() */ void GetTextExtent(const wxString& string, wxCoord* w, wxCoord* h, wxCoord* descent = NULL, wxCoord* externalLeading = NULL, const wxFont* font = NULL) const; /** @overload @beginWxPerlOnly Not supported by wxPerl. @endWxPerlOnly */ wxSize GetTextExtent(const wxString& string) const; //@} /** @name Text properties functions */ //@{ /** Returns the current background mode: @c wxPENSTYLE_SOLID or @c wxPENSTYLE_TRANSPARENT. @see SetBackgroundMode() */ int GetBackgroundMode() const; /** Gets the current font. Notice that even although each device context object has some default font after creation, this method would return a ::wxNullFont initially and only after calling SetFont() a valid font is returned. */ const wxFont& GetFont() const; /** Gets the current layout direction of the device context. On platforms where RTL layout is supported, the return value will either be @c wxLayout_LeftToRight or @c wxLayout_RightToLeft. If RTL layout is not supported, the return value will be @c wxLayout_Default. @see SetLayoutDirection() */ wxLayoutDirection GetLayoutDirection() const; /** Gets the current text background colour. @see SetTextBackground() */ const wxColour& GetTextBackground() const; /** Gets the current text foreground colour. @see SetTextForeground() */ const wxColour& GetTextForeground() const; /** @a mode may be one of @c wxPENSTYLE_SOLID and @c wxPENSTYLE_TRANSPARENT. This setting determines whether text will be drawn with a background colour or not. */ void SetBackgroundMode(int mode); /** Sets the current font for the DC. If the argument is ::wxNullFont (or another invalid font; see wxFont::IsOk), the current font is selected out of the device context (leaving wxDC without any valid font), allowing the current font to be destroyed safely. @see wxFont */ void SetFont(const wxFont& font); /** Sets the current text background colour for the DC. */ void SetTextBackground(const wxColour& colour); /** Sets the current text foreground colour for the DC. @see wxMemoryDC for the interpretation of colours when drawing into a monochrome bitmap. */ void SetTextForeground(const wxColour& colour); /** Sets the current layout direction for the device context. @param dir May be either @c wxLayout_Default, @c wxLayout_LeftToRight or @c wxLayout_RightToLeft. @see GetLayoutDirection() */ void SetLayoutDirection(wxLayoutDirection dir); //@} /** @name Bounding box functions */ //@{ /** Adds the specified point to the bounding box which can be retrieved with MinX(), MaxX() and MinY(), MaxY() functions. @see ResetBoundingBox() */ void CalcBoundingBox(wxCoord x, wxCoord y); /** Gets the maximum horizontal extent used in drawing commands so far. */ wxCoord MaxX() const; /** Gets the maximum vertical extent used in drawing commands so far. */ wxCoord MaxY() const; /** Gets the minimum horizontal extent used in drawing commands so far. */ wxCoord MinX() const; /** Gets the minimum vertical extent used in drawing commands so far. */ wxCoord MinY() const; /** Resets the bounding box: after a call to this function, the bounding box doesn't contain anything. @see CalcBoundingBox() */ void ResetBoundingBox(); //@} /** @name Page and document start/end functions */ //@{ /** Starts a document (only relevant when outputting to a printer). @a message is a message to show while printing. */ bool StartDoc(const wxString& message); /** Starts a document page (only relevant when outputting to a printer). */ void StartPage(); /** Ends a document (only relevant when outputting to a printer). */ void EndDoc(); /** Ends a document page (only relevant when outputting to a printer). */ void EndPage(); //@} /** @name Bit-Block Transfer operations (blit) */ //@{ /** Copy from a source DC to this DC. With this method you can specify the destination coordinates and the size of area to copy which will be the same for both the source and target DCs. If you need to apply scaling while copying, use StretchBlit(). Notice that source DC coordinates @a xsrc and @a ysrc are interpreted using the current source DC coordinate system, i.e. the scale, origin position and axis directions are taken into account when transforming them to physical (pixel) coordinates. @param xdest Destination device context x position. @param ydest Destination device context y position. @param width Width of source area to be copied. @param height Height of source area to be copied. @param source Source device context. @param xsrc Source device context x position. @param ysrc Source device context y position. @param logicalFunc Logical function to use, see SetLogicalFunction(). @param useMask If @true, Blit does a transparent blit using the mask that is associated with the bitmap selected into the source device context. The Windows implementation does the following if MaskBlt cannot be used:
  1. Creates a temporary bitmap and copies the destination area into it.
  2. Copies the source area into the temporary bitmap using the specified logical function.
  3. Sets the masked area in the temporary bitmap to BLACK by ANDing the mask bitmap with the temp bitmap with the foreground colour set to WHITE and the bg colour set to BLACK.
  4. Sets the unmasked area in the destination area to BLACK by ANDing the mask bitmap with the destination area with the foreground colour set to BLACK and the background colour set to WHITE.
  5. ORs the temporary bitmap with the destination area.
  6. Deletes the temporary bitmap.
This sequence of operations ensures that the source's transparent area need not be black, and logical functions are supported. @n @b Note: on Windows, blitting with masks can be speeded up considerably by compiling wxWidgets with the wxUSE_DC_CACHEING option enabled. You can also influence whether MaskBlt or the explicit mask blitting code above is used, by using wxSystemOptions and setting the @c no-maskblt option to 1. @param xsrcMask Source x position on the mask. If both xsrcMask and ysrcMask are @c -1, xsrc and ysrc will be assumed for the mask source position. Currently only implemented on Windows. @param ysrcMask Source y position on the mask. If both xsrcMask and ysrcMask are @c -1, xsrc and ysrc will be assumed for the mask source position. Currently only implemented on Windows. @remarks There is partial support for Blit() in wxPostScriptDC, under X. @see StretchBlit(), wxMemoryDC, wxBitmap, wxMask */ bool Blit(wxCoord xdest, wxCoord ydest, wxCoord width, wxCoord height, wxDC* source, wxCoord xsrc, wxCoord ysrc, wxRasterOperationMode logicalFunc = wxCOPY, bool useMask = false, wxCoord xsrcMask = wxDefaultCoord, wxCoord ysrcMask = wxDefaultCoord); /** Copy from a source DC to this DC possibly changing the scale. Unlike Blit(), this method allows specifying different source and destination region sizes, meaning that it can stretch or shrink it while copying. The same can be achieved by changing the scale of the source or target DC but calling this method is simpler and can also be more efficient if the platform provides a native implementation of it. The meaning of its other parameters is the same as with Blit(), in particular all source coordinates are interpreted using the source DC coordinate system, i.e. are affected by its scale, origin translation and axis direction. @param xdest Destination device context x position. @param ydest Destination device context y position. @param dstWidth Width of destination area. @param dstHeight Height of destination area. @param source Source device context. @param xsrc Source device context x position. @param ysrc Source device context y position. @param srcWidth Width of source area to be copied. @param srcHeight Height of source area to be copied. @param logicalFunc Logical function to use, see SetLogicalFunction(). @param useMask If @true, Blit does a transparent blit using the mask that is associated with the bitmap selected into the source device context. The Windows implementation does the following if MaskBlt cannot be used:
  1. Creates a temporary bitmap and copies the destination area into it.
  2. Copies the source area into the temporary bitmap using the specified logical function.
  3. Sets the masked area in the temporary bitmap to BLACK by ANDing the mask bitmap with the temp bitmap with the foreground colour set to WHITE and the bg colour set to BLACK.
  4. Sets the unmasked area in the destination area to BLACK by ANDing the mask bitmap with the destination area with the foreground colour set to BLACK and the background colour set to WHITE.
  5. ORs the temporary bitmap with the destination area.
  6. Deletes the temporary bitmap.
This sequence of operations ensures that the source's transparent area need not be black, and logical functions are supported. @n @b Note: on Windows, blitting with masks can be speeded up considerably by compiling wxWidgets with the wxUSE_DC_CACHEING option enabled. You can also influence whether MaskBlt or the explicit mask blitting code above is used, by using wxSystemOptions and setting the @c no-maskblt option to 1. @param xsrcMask Source x position on the mask. If both xsrcMask and ysrcMask are wxDefaultCoord, @a xsrc and @a ysrc will be assumed for the mask source position. Currently only implemented on Windows. @param ysrcMask Source y position on the mask. If both xsrcMask and ysrcMask are wxDefaultCoord, @a xsrc and @a ysrc will be assumed for the mask source position. Currently only implemented on Windows. There is partial support for Blit() in wxPostScriptDC, under X. See wxMemoryDC for typical usage. @since 2.9.0 @see Blit(), wxMemoryDC, wxBitmap, wxMask */ bool StretchBlit(wxCoord xdest, wxCoord ydest, wxCoord dstWidth, wxCoord dstHeight, wxDC* source, wxCoord xsrc, wxCoord ysrc, wxCoord srcWidth, wxCoord srcHeight, wxRasterOperationMode logicalFunc = wxCOPY, bool useMask = false, wxCoord xsrcMask = wxDefaultCoord, wxCoord ysrcMask = wxDefaultCoord); //@} /** @name Background/foreground brush and pen */ //@{ /** Gets the brush used for painting the background. @see wxDC::SetBackground() */ const wxBrush& GetBackground() const; /** Gets the current brush. @see wxDC::SetBrush() */ const wxBrush& GetBrush() const; /** Gets the current pen. @see SetPen() */ const wxPen& GetPen() const; /** Sets the current background brush for the DC. */ void SetBackground(const wxBrush& brush); /** Sets the current brush for the DC. If the argument is ::wxNullBrush (or another invalid brush; see wxBrush::IsOk), the current brush is selected out of the device context (leaving wxDC without any valid brush), allowing the current brush to be destroyed safely. @see wxBrush, wxMemoryDC (for the interpretation of colours when drawing into a monochrome bitmap) */ void SetBrush(const wxBrush& brush); /** Sets the current pen for the DC. If the argument is ::wxNullPen (or another invalid pen; see wxPen::IsOk), the current pen is selected out of the device context (leaving wxDC without any valid pen), allowing the current pen to be destroyed safely. @see wxMemoryDC for the interpretation of colours when drawing into a monochrome bitmap. */ void SetPen(const wxPen& pen); //@} /** Copy attributes from another DC. The copied attributes currently are: - Font - Text foreground and background colours - Background brush - Layout direction @param dc A valid (i.e. its IsOk() must return @true) source device context. */ void CopyAttributes(const wxDC& dc); /** Returns the depth (number of bits/pixel) of this DC. @see wxDisplayDepth() */ int GetDepth() const; /** Returns the current device origin. @see SetDeviceOrigin() */ wxPoint GetDeviceOrigin() const; /** Gets the current logical function. @see SetLogicalFunction() */ wxRasterOperationMode GetLogicalFunction() const; /** Gets the current mapping mode for the device context. @see SetMapMode() */ wxMappingMode GetMapMode() const; /** Gets in @a colour the colour at the specified location. This method isn't available for wxPostScriptDC or wxMetafileDC nor for any DC in wxOSX port and simply returns @false there. @note Setting a pixel can be done using DrawPoint(). @note This method shouldn't be used with wxPaintDC as accessing the DC while drawing can result in unexpected results, notably in wxGTK. */ bool GetPixel(wxCoord x, wxCoord y, wxColour* colour) const; /** Returns the resolution of the device in pixels per inch. */ wxSize GetPPI() const; /** Gets the horizontal and vertical extent of this device context in @e device units. It can be used to scale graphics to fit the page. For example, if @e maxX and @e maxY represent the maximum horizontal and vertical 'pixel' values used in your application, the following code will scale the graphic to fit on the printer page: @code wxCoord w, h; dc.GetSize(&w, &h); double scaleX = (double)(maxX / w); double scaleY = (double)(maxY / h); dc.SetUserScale(min(scaleX, scaleY),min(scaleX, scaleY)); @endcode @beginWxPerlOnly In wxPerl there are two methods instead of a single overloaded method: - GetSize(): returns a Wx::Size object. - GetSizeWH(): returns a 2-element list (width, height). @endWxPerlOnly */ void GetSize(wxCoord* width, wxCoord* height) const; /** @overload */ wxSize GetSize() const; /** Returns the horizontal and vertical resolution in millimetres. */ void GetSizeMM(wxCoord* width, wxCoord* height) const; /** @overload */ wxSize GetSizeMM() const; /** Gets the current user scale factor. @beginWxPerlOnly In wxPerl this method takes no arguments and return a two element array (x, y). @endWxPerlOnly @see SetUserScale() */ void GetUserScale(double* x, double* y) const; /** Returns @true if the DC is ok to use. */ bool IsOk() const; /** Sets the x and y axis orientation (i.e.\ the direction from lowest to highest values on the axis). The default orientation is x axis from left to right and y axis from top down. @param xLeftRight True to set the x axis orientation to the natural left to right orientation, @false to invert it. @param yBottomUp True to set the y axis orientation to the natural bottom up orientation, @false to invert it. */ void SetAxisOrientation(bool xLeftRight, bool yBottomUp); /** Sets the device origin (i.e.\ the origin in pixels after scaling has been applied). This function may be useful in Windows printing operations for placing a graphic on a page. */ void SetDeviceOrigin(wxCoord x, wxCoord y); /** Sets the current logical function for the device context. It determines how a @e source pixel (from a pen or brush colour, or source device context if using Blit()) combines with a @e destination pixel in the current device context. Text drawing is not affected by this function. See ::wxRasterOperationMode enumeration values for more info. The default is @c wxCOPY, which simply draws with the current colour. The others combine the current colour and the background using a logical operation. @c wxINVERT is commonly used for drawing rubber bands or moving outlines, since drawing twice reverts to the original colour. */ void SetLogicalFunction(wxRasterOperationMode function); /** The mapping mode of the device context defines the unit of measurement used to convert @e logical units to @e device units. Note that in X, text drawing isn't handled consistently with the mapping mode; a font is always specified in point size. However, setting the user scale (see SetUserScale()) scales the text appropriately. In Windows, scalable TrueType fonts are always used; in X, results depend on availability of fonts, but usually a reasonable match is found. The coordinate origin is always at the top left of the screen/printer. Drawing to a Windows printer device context uses the current mapping mode, but mapping mode is currently ignored for PostScript output. */ void SetMapMode(wxMappingMode mode); /** If this is a window DC or memory DC, assigns the given palette to the window or bitmap associated with the DC. If the argument is ::wxNullPalette, the current palette is selected out of the device context, and the original palette restored. @see wxPalette */ void SetPalette(const wxPalette& palette); /** Sets the user scaling factor, useful for applications which require 'zooming'. */ void SetUserScale(double xScale, double yScale); /** @name Transformation matrix See the notes about the availability of these functions in the class documentation. */ //@{ /** Check if the use of transformation matrix is supported by the current system. This function returns @true for MSW and GTK+ 3 platforms and since 3.1.1 also for wxGCDC in all ports. @since 2.9.2 */ bool CanUseTransformMatrix() const; /** Set the transformation matrix. If transformation matrix is supported on the current system, the specified @a matrix will be used to transform between wxDC and physical coordinates. Otherwise the function returns @false and doesn't change the coordinate mapping. @since 2.9.2 */ bool SetTransformMatrix(const wxAffineMatrix2D& matrix); /** Return the transformation matrix used by this device context. By default the transformation matrix is the identity matrix. @since 2.9.2 */ wxAffineMatrix2D GetTransformMatrix() const; /** Revert the transformation matrix to identity matrix. @since 2.9.2 */ void ResetTransformMatrix(); //@} /** @name query capabilities */ //@{ /** Does the DC support drawing bitmaps? */ bool CanDrawBitmap() const; /** Does the DC support calculating the size required to draw text? */ bool CanGetTextExtent() const; //@} /** Returns a value that can be used as a handle to the native drawing context, if this wxDC has something that could be thought of in that way. (Not all of them do.) For example, on Windows the return value is an HDC, on OS X it is a CGContextRef and on wxGTK it will be a GdkDrawable. If the DC is a wxGCDC then the return value will be the value returned from wxGraphicsContext::GetNativeContext. A value of NULL is returned if the DC does not have anything that fits the handle concept. @since 2.9.5 */ void* GetHandle() const; /** If supported by the platform and the type of DC, fetch the contents of the DC, or a subset of it, as a bitmap. */ wxBitmap GetAsBitmap(const wxRect *subrect = NULL) const; /** Set the scale to use for translating wxDC coordinates to the physical pixels. The effect of calling this function is similar to that of calling SetUserScale(). */ void SetLogicalScale(double x, double y); /** Return the scale set by the last call to SetLogicalScale(). */ void GetLogicalScale(double *x, double *y) const; /** Change the offset used for translating wxDC coordinates. @see SetLogicalOrigin(), SetDeviceOrigin() */ void SetLogicalOrigin(wxCoord x, wxCoord y); //@{ /** Return the coordinates of the logical point (0, 0). @see SetLogicalOrigin() */ void GetLogicalOrigin(wxCoord *x, wxCoord *y) const; wxPoint GetLogicalOrigin() const; //@} }; /** @class wxDCClipper wxDCClipper is a helper class for setting a clipping region on a wxDC during its lifetime. An object of wxDCClipper class is typically created on the stack so that it is automatically destroyed when the object goes out of scope. A typical usage example: @code void MyFunction(wxDC& dc) { wxDCClipper clip(dc, rect); // ... drawing functions here are affected by clipping rect ... } void OtherFunction() { wxDC dc; MyFunction(dc); // ... drawing functions here are not affected by clipping rect ... } @endcode @note Since 3.1.1 wxDCClipper restores the previously active clipping region when it is destroyed. Previously it reset clipping on the associated wxDC and this has to be taken into account explicitly in previous wxWidgets versions. @library{wxcore} @category{gdi} @see wxDC::SetClippingRegion(), wxDCFontChanger, wxDCTextColourChanger, wxDCPenChanger, wxDCBrushChanger */ class wxDCClipper { public: //@{ /** Sets the clipping region to the specified region/coordinates. The clipping region is automatically unset when this object is destroyed. */ wxDCClipper(wxDC& dc, const wxRegion& region); wxDCClipper(wxDC& dc, const wxRect& rect); wxDCClipper(wxDC& dc, wxCoord x, wxCoord y, wxCoord w, wxCoord h); //@} /** Destroys the clipping region associated with the DC passed to the ctor. */ ~wxDCClipper(); }; /** @class wxDCBrushChanger wxDCBrushChanger is a small helper class for setting a brush on a wxDC and unsetting it automatically in the destructor, restoring the previous one. @library{wxcore} @category{gdi} @see wxDC::SetBrush(), wxDCFontChanger, wxDCTextColourChanger, wxDCPenChanger, wxDCClipper */ class wxDCBrushChanger { public: /** Sets @a brush on the given @a dc, storing the old one. @param dc The DC where the brush must be temporary set. @param brush The brush to set. */ wxDCBrushChanger(wxDC& dc, const wxBrush& brush); /** Restores the brush originally selected in the DC passed to the ctor. */ ~wxDCBrushChanger(); }; /** @class wxDCPenChanger wxDCPenChanger is a small helper class for setting a pen on a wxDC and unsetting it automatically in the destructor, restoring the previous one. @library{wxcore} @category{gdi} @see wxDC::SetPen(), wxDCFontChanger, wxDCTextColourChanger, wxDCBrushChanger, wxDCClipper */ class wxDCPenChanger { public: /** Sets @a pen on the given @a dc, storing the old one. @param dc The DC where the pen must be temporary set. @param pen The pen to set. */ wxDCPenChanger(wxDC& dc, const wxPen& pen); /** Restores the pen originally selected in the DC passed to the ctor. */ ~wxDCPenChanger(); }; /** @class wxDCTextColourChanger wxDCTextColourChanger is a small helper class for setting a foreground text colour on a wxDC and unsetting it automatically in the destructor, restoring the previous one. @library{wxcore} @category{gdi} @see wxDC::SetTextForeground(), wxDCFontChanger, wxDCPenChanger, wxDCBrushChanger, wxDCClipper, wxDCTextBgColourChanger, wxDCBgModeChanger */ class wxDCTextColourChanger { public: /** Trivial constructor not changing anything. This constructor is useful if you don't know beforehand if the colour needs to be changed or not. It simply creates the object which won't do anything in its destructor unless Set() is called -- in which case it would reset the previous colour. */ wxDCTextColourChanger(wxDC& dc); /** Sets @a col on the given @a dc, storing the old one. @param dc The DC where the colour must be temporary set. @param col The colour to set. */ wxDCTextColourChanger(wxDC& dc, const wxColour& col); /** Set the colour to use. This method is meant to be called once only and only on the objects created with the constructor overload not taking wxColour argument and has the same effect as the other constructor, i.e. sets the colour to the given @a col and ensures that the old value is restored when this object is destroyed. */ void Set(const wxColour& col); /** Restores the colour originally selected in the DC passed to the ctor. */ ~wxDCTextColourChanger(); }; /** @class wxDCTextBgColourChanger wxDCTextBgColourChanger is a small helper class for setting a background text colour on a wxDC and unsetting it automatically in the destructor, restoring the previous one. @library{wxcore} @category{gdi} @see wxDC::SetTextBackground(), wxDCFontChanger, wxDCPenChanger, wxDCBrushChanger, wxDCClipper, wxDCTextColourChanger, wxDCBgModeChanger @since 3.1.3 */ class wxDCTextBgColourChanger { public: /** Trivial constructor not changing anything. This constructor is useful if you don't know beforehand if the colour needs to be changed or not. It simply creates the object which won't do anything in its destructor unless Set() is called -- in which case it would reset the previous colour. */ wxDCTextBgColourChanger(wxDC& dc); /** Sets @a col on the given @a dc, storing the old one. @param dc The DC where the colour must be temporary set. @param col The text background colour to set. */ wxDCTextBgColourChanger(wxDC& dc, const wxColour& col); /** Set the background colour to use. This method is meant to be called once only and only on the objects created with the constructor overload not taking wxColour argument and has the same effect as the other constructor, i.e. sets the background colour to the given @a col and ensures that the old value is restored when this object is destroyed. */ void Set(const wxColour& col); /** Restores the background colour originally selected in the DC passed to the ctor. */ ~wxDCTextBgColourChanger(); }; /** @class wxDCTextBgModeChanger wxDCTextBgModeChanger is a small helper class for setting a background text mode on a wxDC and unsetting it automatically in the destructor, restoring the previous one. @library{wxcore} @category{gdi} @see wxDC::SetBackgroundMode(), wxDCFontChanger, wxDCPenChanger, wxDCBrushChanger, wxDCClipper, wxDCTextColourChanger, wxDCTextBgColourChanger @since 3.1.3 */ class wxDCBgModeChanger { public: /** Trivial constructor not changing anything. This constructor is useful if you don't know beforehand if the background mode needs to be changed or not. It simply creates the object which won't do anything in its destructor unless Set() is called -- in which case it would reset the previous mode. */ wxDCBgModeChanger(wxDC& dc); /** Sets @a mode on the given @a dc, storing the old one. @param dc The DC where the mode must be temporary set. @param mode The background mode to set. */ wxDCBgModeChanger(wxDC& dc, int mode); /** Set the text background mode to use. This method is meant to be called once only and only on the objects created with the constructor overload not taking mode argument and has the same effect as the other constructor, i.e. sets the background mode to the given @a one, and ensures that the old value is restored when this object is destroyed. */ void Set(int mode); /** Restores the text background mode originally selected in the DC passed to the ctor. */ ~wxDCBgModeChanger(); }; /** @class wxDCFontChanger wxDCFontChanger is a small helper class for setting a font on a wxDC and unsetting it automatically in the destructor, restoring the previous one. @since 2.9.0 @library{wxcore} @category{gdi} @see wxDC::SetFont(), wxDCTextColourChanger, wxDCPenChanger, wxDCBrushChanger, wxDCClipper */ class wxDCFontChanger { public: /** Trivial constructor not changing anything. This constructor is useful if you don't know beforehand if the font needs to be changed or not. It simply creates the object which won't do anything in its destructor unless Set() is called -- in which case it would reset the previous font. @since 2.9.1 */ wxDCFontChanger(wxDC& dc); /** Sets @a font on the given @a dc, storing the old one. @param dc The DC where the font must be temporary set. @param font The font to set. */ wxDCFontChanger(wxDC& dc, const wxFont& font); /** Set the font to use. This method is meant to be called once only and only on the objects created with the constructor overload not taking wxFont argument and has the same effect as the other constructor, i.e. sets the font to the given @a font and ensures that the old value is restored when this object is destroyed. */ void Set(const wxFont& font); /** Restores the font originally selected in the DC passed to the ctor. */ ~wxDCFontChanger(); };