///////////////////////////////////////////////////////////////////////////// // 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. Note that not all modes are supported under all platforms. Notably wxGTK3 and wxMac only support the following modes: - wxCOPY - wxOR - wxNO_OP - wxCLEAR - wxXOR and, in particular, do @em not support the commonly used @c wxINVERT. */ 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 macOS 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, macOS) 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. @note Affine transformation applied to the coordinate system with SetTransformMatrix() is not taken into account. */ 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 horizontal distance like for example a width. @note Affine transformation applied to the coordinate system with SetTransformMatrix() is not taken into account. */ 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. @note Affine transformation applied to the coordinate system with SetTransformMatrix() is not taken into account. */ 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 vertical distance like for example a height. @note Affine transformation applied to the coordinate system with SetTransformMatrix() is not taken into account. */ 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. @note Affine transformation applied to the coordinate system with SetTransformMatrix() is not taken into account. */ 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 horizontal distance like for example a width. @note Affine transformation applied to the coordinate system with SetTransformMatrix() is not taken into account. */ 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. @note Affine transformation applied to the coordinate system with SetTransformMatrix() is not taken into account. */ 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 vertical distance like for example a height. @note Affine transformation applied to the coordinate system with SetTransformMatrix() is not taken into account. */ wxCoord LogicalToDeviceYRel(wxCoord y) const; /** Converts device (@a x, @a y) coordinates to logical coordinates taking into account all applied transformations like the current mapping mode, scale factors, device origin, axes orientation, affine transformation. @since 3.1.5 */ wxPoint DeviceToLogical(wxCoord x, wxCoord y) const; /** @overload @since 3.1.5 */ wxPoint DeviceToLogical(const wxPoint& pt) const; /** Converts device @a x, @a y coordinates to relative logical coordinates taking into account all applied transformations like the current mapping mode, scale factors, affine transformation. Use this for converting distances like e.g. width and height. @since 3.1.5 */ wxSize DeviceToLogicalRel(int x, int y) const; /** @overload @since 3.1.5 */ wxSize DeviceToLogicalRel(const wxSize& dim) const; /** Converts logical (@a x, @a y) coordinates to device coordinates taking into account all applied transformations like the current mapping mode, scale factors, device origin, axes orientation, affine transformation. @since 3.1.5 */ wxPoint LogicalToDevice(wxCoord x, wxCoord y) const; /** @overload @since 3.1.5 */ wxPoint LogicalToDevice(const wxPoint& pt) const; /** Converts logical @a x, @a y coordinates to relative device coordinates taking into account all applied transformations like the current mapping mode, scale factors, affine transformation. Use this for converting distances like e.g. width and height. @since 3.1.5 */ wxSize LogicalToDeviceRel(int x, int y) const; /** @overload @since 3.1.5 */ wxSize LogicalToDeviceRel(const wxSize& dim) 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 useMask 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. The number of points must be at least 2 for the spline to be drawn. @note Drawn curve is not an interpolating curve - it does not go through all points. It may be considered a smoothing curve. @beginWxPerlOnly Not supported by wxPerl. @endWxPerlOnly @image html drawing-spline.png */ 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. If @a string is empty, its horizontal extent is 0 but, for convenience when using this function for allocating enough space for a possibly multi-line string, its vertical extent is the same as the height of an empty line of text. Please note that this behaviour differs from that of GetTextExtent(). @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. If @a string is empty, its extent is 0 in both directions, as expected. @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 wxBRUSHSTYLE_SOLID or @c wxBRUSHSTYLE_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; /** Change the current background mode. This setting determines whether text will be drawn with a background colour or not. Default is @c wxBRUSHSTYLE_TRANSPARENT, i.e. text background is not drawn. @param mode one of @c wxBRUSHSTYLE_SOLID and @c wxBRUSHSTYLE_TRANSPARENT. */ 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: