X-Git-Url: https://git.saurik.com/wxWidgets.git/blobdiff_plain/ea76a6a5ca75f8e623982de97f7f7b2746b5ee50..a607d8d633e055fc5cea22c0b829cd65b5c3dbfb:/docs/latex/wx/dc.tex diff --git a/docs/latex/wx/dc.tex b/docs/latex/wx/dc.tex index c2f28ef4b0..0c7b36cc80 100644 --- a/docs/latex/wx/dc.tex +++ b/docs/latex/wx/dc.tex @@ -6,8 +6,10 @@ so a window can have a device context associated with it, and a printer also has In this way, the same piece of code may write to a number of different devices, if the device context is used as a parameter. -Derived types of wxDC have documentation for specific features -only, so refer to this section for most device context information. +Notice that wxDC is an abstract base class and can't be created directly, +please use \helpref{wxPaintDC}{wxpaintdc}, \helpref{wxClientDC}{wxclientdc}, +\helpref{wxWindowDC}{wxwindowdc}, \helpref{wxScreenDC}{wxscreendc}, +\helpref{wxMemoryDC}{wxmemorydc} or \helpref{wxPrinterDC}{wxprinterdc}. % VZ: we should really document them instead of this lame excuse, but I don't % have time for it now, when it is done please remove this @@ -16,6 +18,12 @@ there are also versions which accept single {\tt wxPoint} parameter instead of two {\tt wxCoord} ones or {\tt wxPoint} and {\tt wxSize} instead of four of them. +\wxheading{Support for Transparency / Alpha Channel} + +On Mac OS X when using Core Graphics (wx\_MAC\_USE\_CORE\_GRAPHICS set to 1) +colors with alpha are supported, so instances {\tt wxPen} or {\tt wxBrush} that are built from {\tt wxColour} use +the color's alpha values when stroking or filling. + \wxheading{Derived from} \helpref{wxObject}{wxobject} @@ -24,6 +32,10 @@ them. +\wxheading{Library} + +\helpref{wxCore}{librarieslist} + \wxheading{See also} \helpref{Overview}{dcoverview} @@ -31,36 +43,6 @@ them. \latexignore{\rtfignore{\wxheading{Members}}} -\membersection{wxDC::wxDC}\label{wxdcctor} - -\func{}{wxDC}{\void} - -Constructor. - - -\membersection{wxDC::\destruct{wxDC}}\label{wxdcdtor} - -\func{}{\destruct{wxDC}}{\void} - -Destructor. - - -\membersection{wxDC::BeginDrawing}\label{wxdcbegindrawing} - -\func{void}{BeginDrawing}{\void} - -Allows optimization of drawing code under MS Windows. Enclose -drawing primitives between {\bf BeginDrawing} and {\bf EndDrawing}\rtfsp -calls. - -Drawing to a wxDialog panel device context outside of a -system-generated OnPaint event {\it requires} this pair of calls to -enclose drawing code. This is because a Windows dialog box does not have -a retained device context associated with it, and selections such as pen -and brush settings would be lost if the device context were obtained and -released for each drawing operation. - - \membersection{wxDC::Blit}\label{wxdcblit} \func{bool}{Blit}{\param{wxCoord}{ xdest}, \param{wxCoord}{ ydest}, \param{wxCoord}{ width}, \param{wxCoord}{ height}, @@ -130,7 +112,7 @@ See \helpref{wxMemoryDC}{wxmemorydc} for typical usage. \wxheading{See also} -\helpref{wxMemoryDC}{wxmemorydc}, \helpref{wxBitmap}{wxbitmap}, \helpref{wxMask}{wxmask} +\helpref{wxDC::StretchBlit}{wxdcstretchblit}, \helpref{wxMemoryDC}{wxmemorydc}, \helpref{wxBitmap}{wxbitmap}, \helpref{wxMask}{wxmask} \begin{comment} @@ -193,6 +175,15 @@ wxUSE\_DC\_CACHEING preprocessor symbol for portability. \end{comment} +\membersection{wxDC::ComputeScaleAndOrigin}\label{wxdccomputescaleandorigin} + +\func{virtual void}{ComputeScaleAndOrigin}{\void} + +Performs all necessary computations for given platform and context type +after each change of scale and origin parameters. Usually called automatically +internally after such changes. + + \membersection{wxDC::CrossHair}\label{wxdccrosshair} \func{void}{CrossHair}{\param{wxCoord}{ x}, \param{wxCoord}{ y}} @@ -212,7 +203,7 @@ See also \helpref{wxDC::SetClippingRegion}{wxdcsetclippingregion}. \membersection{wxDC::DeviceToLogicalX}\label{wxdcdevicetologicalx} -\func{wxCoord}{DeviceToLogicalX}{\param{wxCoord}{ x}} +\func{virtual wxCoord}{DeviceToLogicalX}{\param{wxCoord}{ x}} Convert device X coordinate to logical coordinate, using the current mapping mode. @@ -220,7 +211,7 @@ mapping mode. \membersection{wxDC::DeviceToLogicalXRel}\label{wxdcdevicetologicalxrel} -\func{wxCoord}{DeviceToLogicalXRel}{\param{wxCoord}{ x}} +\func{virtual wxCoord}{DeviceToLogicalXRel}{\param{wxCoord}{ x}} Convert device X coordinate to relative logical coordinate, using the current mapping mode but ignoring the x axis orientation. @@ -229,7 +220,7 @@ Use this function for converting a width, for example. \membersection{wxDC::DeviceToLogicalY}\label{wxdcdevicetologicaly} -\func{wxCoord}{DeviceToLogicalY}{\param{wxCoord}{ y}} +\func{virtual wxCoord}{DeviceToLogicalY}{\param{wxCoord}{ y}} Converts device Y coordinate to logical coordinate, using the current mapping mode. @@ -237,7 +228,7 @@ mapping mode. \membersection{wxDC::DeviceToLogicalYRel}\label{wxdcdevicetologicalyrel} -\func{wxCoord}{DeviceToLogicalYRel}{\param{wxCoord}{ y}} +\func{virtual wxCoord}{DeviceToLogicalYRel}{\param{wxCoord}{ y}} Convert device Y coordinate to relative logical coordinate, using the current mapping mode but ignoring the y axis orientation. @@ -477,7 +468,7 @@ which is. \membersection{wxDC::DrawRoundedRectangle}\label{wxdcdrawroundedrectangle} -\func{void}{DrawRoundedRectangle}{\param{wxCoord}{ x}, \param{wxCoord}{ y}, \param{wxCoord}{ width}, \param{wxCoord}{ height}, \param{double}{ radius = 20}} +\func{void}{DrawRoundedRectangle}{\param{wxCoord}{ x}, \param{wxCoord}{ y}, \param{wxCoord}{ width}, \param{wxCoord}{ height}, \param{double}{ radius}} Draws a rectangle with the given top left corner, and with the given size. The corners are quarter-circles using the given radius. The @@ -495,12 +486,15 @@ the rectangle. \membersection{wxDC::DrawSpline}\label{wxdcdrawspline} +\func{void}{DrawSpline}{\param{int }{n}, \param{wxPoint }{points[]}} + +Draws a spline between all given control points, using the current +pen. + \func{void}{DrawSpline}{\param{wxList *}{points}} Draws a spline between all given control points, using the current -pen. Doesn't delete the wxList and contents. The spline is drawn -using a series of lines, using an algorithm taken from the X drawing -program `XFIG'. +pen. Doesn't delete the wxList and contents. \func{void}{DrawSpline}{\param{wxCoord}{ x1}, \param{wxCoord}{ y1}, \param{wxCoord}{ x2}, \param{wxCoord}{ y2}, \param{wxCoord}{ x3}, \param{wxCoord}{ y3}} @@ -556,15 +550,6 @@ wxUSE\_DC\_CACHEING preprocessor symbol for portability. Ends a document (only relevant when outputting to a printer). -\membersection{wxDC::EndDrawing}\label{wxdcenddrawing} - -\func{void}{EndDrawing}{\void} - -Allows optimization of drawing code under MS Windows. Enclose -drawing primitives between {\bf BeginDrawing} and {\bf EndDrawing}\rtfsp -calls. - - \membersection{wxDC::EndPage}\label{wxdcendpage} \func{void}{EndPage}{\void} @@ -647,7 +632,24 @@ rectangle are returned as a tuple.} \constfunc{const wxFont\&}{GetFont}{\void} -Gets the current font (see \helpref{wxDC::SetFont}{wxdcsetfont}). +Gets the current font. Notice that even although each device context object has +some default font after creation, this method would return a \texttt{wxNullFont} +initially and only after calling \helpref{wxDC::SetFont}{wxdcsetfont} a valid +font is returned. + + +\membersection{wxDC::GetLayoutDirection}\label{wxdcgetlayoutdirection} + +\constfunc{wxLayoutDirection}{GetLayoutDirection}{\void} + +Gets the current layout direction of the device context. On platforms where RTL layout +is supported, the return value will either be \texttt{wxLayout\_LeftToRight} or +\texttt{wxLayout\_RightToLeft}. If RTL layout is not supported, the return value will +be \texttt{wxLayout\_Default}. + +\wxheading{See also} + +\helpref{SetLayoutDirection}{wxdcsetlayoutdirection} \membersection{wxDC::GetLogicalFunction}\label{wxdcgetlogicalfunction} @@ -664,19 +666,51 @@ Gets the current logical function (see \helpref{wxDC::SetLogicalFunction}{wxdcse Gets the {\it mapping mode} for the device context (see \helpref{wxDC::SetMapMode}{wxdcsetmapmode}). +\membersection{wxDC::GetMultiLineTextExtent}\label{wxdcgetmultilinetextextent} + +\constfunc{void}{GetMultiLineTextExtent}{\param{const wxString\& }{string}, \param{wxCoord *}{w},\\ + \param{wxCoord *}{h}, \param{wxCoord *}{heightLine = NULL}, \param{wxFont *}{font = NULL}} + +\constfunc{wxSize}{GetMultiLineTextExtent}{\param{const wxString\& }{string}} + +Gets the dimensions of the string using the currently selected font. +\rtfsp{\it string} is the text string to measure, {\it heightLine}, if non NULL, +is where to store the height of a single line. + +The text extent is returned in {\it w} and {\it h} pointers (first form) or as +a \helpref{wxSize}{wxsize} object (second form). + +If the optional parameter {\it font} is specified and valid, then it is used +for the text extent calculation. Otherwise the currently selected font is. + +Note that this function works both with single-line and multi-line strings. + +\wxheading{See also} + +\helpref{wxFont}{wxfont},\rtfsp +\helpref{wxDC::SetFont}{wxdcsetfont},\rtfsp +\helpref{wxDC::GetPartialTextExtents}{wxdcgetpartialtextextents},\rtfsp +\helpref{wxDC::GetTextExtent}{wxdcgettextextent} + + \membersection{wxDC::GetPartialTextExtents}\label{wxdcgetpartialtextextents} \constfunc{bool}{GetPartialTextExtents}{\param{const wxString\& }{text}, \param{wxArrayInt\& }{widths}} -Fills the {\it widths} array with the widths from the begining of -{\it text} to the coresponding character of {\it text}. The generic +Fills the {\it widths} array with the widths from the beginning of +{\it text} to the corresponding character of {\it text}. The generic version simply builds a running total of the widths of each character using \helpref{GetTextExtent}{wxdcgettextextent}, however if the various platforms have a native API function that is faster or more -accurate than the generic implementaiton then it should be used +accurate than the generic implementation then it should be used instead. +\wxheading{See also} + +\helpref{wxDC::GetMultiLineTextExtent}{wxdcgetmultilinetextextent},\rtfsp +\helpref{wxDC::GetTextExtent}{wxdcgettextextent} + \pythonnote{This method only takes the {\it text} parameter and returns a Python list of integers.} @@ -692,9 +726,11 @@ Gets the current pen (see \helpref{wxDC::SetPen}{wxdcsetpen}). \func{bool}{GetPixel}{\param{wxCoord}{ x}, \param{wxCoord}{ y}, \param{wxColour *}{colour}} -Sets {\it colour} to the colour at the specified location. +Gets in {\it colour} the colour at the specified location. Not available for wxPostScriptDC or wxMetafileDC. +Note that setting a pixel can be done using \helpref{DrawPoint}{wxdcdrawpoint}. + \pythonnote{For wxPython the wxColour value is returned and is not required as a parameter.} @@ -760,22 +796,31 @@ Gets the current text background colour (see \helpref{wxDC::SetTextBackground}{w \membersection{wxDC::GetTextExtent}\label{wxdcgettextextent} -\func{void}{GetTextExtent}{\param{const wxString\& }{string}, \param{wxCoord *}{w}, \param{wxCoord *}{h},\\ - \param{wxCoord *}{descent = NULL}, \param{wxCoord *}{externalLeading = NULL}, \param{wxFont *}{font = NULL}} +\constfunc{void}{GetTextExtent}{\param{const wxString\& }{string}, \param{wxCoord *}{w}, \param{wxCoord *}{h},\\ + \param{wxCoord *}{descent = NULL}, \param{wxCoord *}{externalLeading = NULL}, \param{const wxFont *}{font = NULL}} + +\constfunc{wxSize}{GetTextExtent}{\param{const wxString\& }{string}} Gets the dimensions of the string using the currently selected font. -\rtfsp{\it string} is the text string to measure, {\it w} and {\it h} are -the total width and height respectively, {\it descent} is the +\rtfsp{\it string} is the text string to measure, {\it descent} is the dimension from the baseline of the font to the bottom of the descender, and {\it externalLeading} is any extra vertical space added to the font by the font designer (usually is zero). -The optional parameter {\it font} specifies an alternative -to the currently selected font: but note that this does not -yet work under Windows, so you need to set a font for -the device context first. +The text extent is returned in {\it w} and {\it h} pointers (first form) or as +a \helpref{wxSize}{wxsize} object (second form). + +If the optional parameter {\it font} is specified and valid, then it is used +for the text extent calculation. Otherwise the currently selected font is. + +Note that this function only works with single-line strings. + +\wxheading{See also} -See also \helpref{wxFont}{wxfont}, \helpref{wxDC::SetFont}{wxdcsetfont}. +\helpref{wxFont}{wxfont},\rtfsp +\helpref{wxDC::SetFont}{wxdcsetfont},\rtfsp +\helpref{wxDC::GetPartialTextExtents}{wxdcgetpartialtextextents},\rtfsp +\helpref{wxDC::GetMultiLineTextExtent}{wxdcgetmultilinetextextent} \pythonnote{The following methods are implemented in wxPython:\par \indented{2cm}{\begin{twocollist} @@ -808,9 +853,38 @@ Gets the current user scale factor (set by \helpref{SetUserScale}{wxdcsetusersca array {\tt ( x, y )}} +\membersection{wxDC::GradientFillConcentric}\label{wxdcgradientfillconcentric} + +\func{void}{GradientFillConcentric}{\param{const wxRect\&}{ rect}, \param{const wxColour\&}{ initialColour}, \param{const wxColour\&}{ destColour}} + +\func{void}{GradientFillConcentric}{\param{const wxRect\&}{ rect}, \param{const wxColour\&}{ initialColour}, \param{const wxColour\&}{ destColour}, \param{const wxPoint\& }{circleCenter}} + +Fill the area specified by rect with a radial gradient, starting from +\arg{initialColour} at the centre of the circle and fading to \arg{destColour} +on the circle outside. + +\arg{circleCenter} are the relative coordinates of centre of the circle in +the specified \arg{rect}. If not specified, the cercle is placed at the +centre of rect. + +\textbf{Note: } Currently this function is very slow, don't use it for +real-time drawing. + + +\membersection{wxDC::GradientFillLinear}\label{wxdcgradientfilllinear} + +\func{void}{GradientFillLinear}{\param{const wxRect\&}{ rect}, \param{const wxColour\&}{ initialColour}, \param{const wxColour\&}{ destColour}, \param{wxDirection}{ nDirection = wxEAST}} + +Fill the area specified by \arg{rect} with a linear gradient, starting from +\arg{initialColour} and eventually fading to \arg{destColour}. The +\arg{nDirection} specifies the direction of the colour change, default is to +use \arg{initialColour} on the left part of the rectangle and +\arg{destColour} on the right one. + + \membersection{wxDC::LogicalToDeviceX}\label{wxdclogicaltodevicex} -\func{wxCoord}{LogicalToDeviceX}{\param{wxCoord}{ x}} +\func{virtual wxCoord}{LogicalToDeviceX}{\param{wxCoord}{ x}} Converts logical X coordinate to device coordinate, using the current mapping mode. @@ -818,7 +892,7 @@ mapping mode. \membersection{wxDC::LogicalToDeviceXRel}\label{wxdclogicaltodevicexrel} -\func{wxCoord}{LogicalToDeviceXRel}{\param{wxCoord}{ x}} +\func{virtual wxCoord}{LogicalToDeviceXRel}{\param{wxCoord}{ x}} Converts logical X coordinate to relative device coordinate, using the current mapping mode but ignoring the x axis orientation. @@ -827,7 +901,7 @@ Use this for converting a width, for example. \membersection{wxDC::LogicalToDeviceY}\label{wxdclogicaltodevicey} -\func{wxCoord}{LogicalToDeviceY}{\param{wxCoord}{ y}} +\func{virtual wxCoord}{LogicalToDeviceY}{\param{wxCoord}{ y}} Converts logical Y coordinate to device coordinate, using the current mapping mode. @@ -835,7 +909,7 @@ mapping mode. \membersection{wxDC::LogicalToDeviceYRel}\label{wxdclogicaltodeviceyrel} -\func{wxCoord}{LogicalToDeviceYRel}{\param{wxCoord}{ y}} +\func{virtual wxCoord}{LogicalToDeviceYRel}{\param{wxCoord}{ y}} Converts logical Y coordinate to relative device coordinate, using the current mapping mode but ignoring the y axis orientation. @@ -870,7 +944,7 @@ Gets the minimum horizontal extent used in drawing commands so far. Gets the minimum vertical extent used in drawing commands so far. -\membersection{wxDC::Ok}\label{wxdcok} +\membersection{wxDC::IsOk}\label{wxdcisok} \func{bool}{Ok}{\void} @@ -895,8 +969,8 @@ doesn't contain anything. \param{bool}{ yBottomUp}} Sets the x and y axis orientation (i.e., the direction from lowest to -highest values on the axis). The default orientation is the natural -orientation, e.g. x axis from left to right and y axis from bottom up. +highest values on the axis). The default orientation is +x axis from left to right and y axis from top down. \wxheading{Parameters} @@ -929,7 +1003,7 @@ whether text will be drawn with a background colour or not. Sets the current brush for the DC. If the argument is wxNullBrush, the current brush is selected out of the device -context, and the original brush restored, allowing the current brush to +context (leaving wxDC without any valid brush), allowing the current brush to be destroyed safely. See also \helpref{wxBrush}{wxbrush}. @@ -984,6 +1058,18 @@ should not pass {\tt wxNullFont} to this method. See also \helpref{wxFont}{wxfont}. +\membersection{wxDC::SetLayoutDirection}\label{wxdcsetlayoutdirection} + +\func{void}{SetLayoutDirection}{\param{wxLayoutDirection}{ dir}} + +Sets the current layout direction for the device context. \arg{dir} may be either +\texttt{wxLayout\_Default}, \texttt{wxLayout\_LeftToRight} or \texttt{wxLayout\_RightToLeft}. + +\wxheading{See also} + +\helpref{GetLayoutDirection}{wxdcgetlayoutdirection} + + \membersection{wxDC::SetLogicalFunction}\label{wxdcsetlogicalfunction} \func{void}{SetLogicalFunction}{\param{int}{ function}} @@ -1070,7 +1156,8 @@ See \helpref{wxPalette}{wxpalette} for further details. Sets the current pen for the DC. If the argument is wxNullPen, the current pen is selected out of the device -context, and the original pen restored. +context (leaving wxDC without any valid pen), allowing the current brush to +be destroyed safely. See also \helpref{wxMemoryDC}{wxmemorydc} for the interpretation of colours when drawing into a monochrome bitmap. @@ -1106,7 +1193,7 @@ Sets the user scaling factor, useful for applications which require \func{bool}{StartDoc}{\param{const wxString\& }{message}} Starts a document (only relevant when outputting to a printer). -Message is a message to show whilst printing. +Message is a message to show while printing. \membersection{wxDC::StartPage}\label{wxdcstartpage} @@ -1115,40 +1202,84 @@ Message is a message to show whilst printing. Starts a document page (only relevant when outputting to a printer). -\section{\class{wxDCClipper}}\label{wxdcclipper} -This is a small helper class which sets the specified to its constructor -clipping region and then automatically destroys it in its destructor. Using -it ensures that unwanted clipping region is not left set on the DC. +\membersection{wxDC::StretchBlit}\label{wxdcstretchblit} -\wxheading{Derived from} +\func{bool}{StretchBlit}{\param{wxCoord}{ xdest}, \param{wxCoord}{ ydest}, \param{wxCoord}{ dstWidth}, \param{wxCoord}{ dstHeight}, + \param{wxDC* }{source}, \param{wxCoord}{ xsrc}, \param{wxCoord}{ ysrc}, \param{wxCoord}{ srcWidth}, \param{wxCoord}{ srcHeight}, + \param{int}{ logicalFunc = wxCOPY}, \param{bool }{useMask = false}, \param{wxCoord}{ xsrcMask = -1}, \param{wxCoord}{ ysrcMask = -1}} -No base class +Copy from a source DC to this DC, specifying the destination +coordinates, destination size, source DC, source coordinates, +size of source area to copy, logical function, whether to use a bitmap mask, +and mask source position. -\wxheading{Include files} +\wxheading{Parameters} - +\docparam{xdest}{Destination device context x position.} -\wxheading{See also} +\docparam{ydest}{Destination device context y position.} -\helpref{wxDC}{wxdc} +\docparam{dstWidth}{Width of destination area.} -\latexignore{\rtfignore{\wxheading{Members}}} +\docparam{dstHeight}{Height of destination area.} +\docparam{source}{Source device context.} -\membersection{wxDCClipper::wxDCClipper}\label{wxdcclipperctor} +\docparam{xsrc}{Source device context x position.} -\func{}{wxDCClipper}{\param{wxDC\& }{dc}, \param{wxCoord }{x},\param{wxCoord }{y},\param{wxCoord }{w},\param{wxCoord }{h},} +\docparam{ysrc}{Source device context y position.} -\func{}{wxDCClipper}{\param{wxDC\& }{dc}, \param{const wxRect\&}{ rect}} +\docparam{srcWidth}{Width of source area to be copied.} -Constructor: sets the the clipping region for the given device context to the -specified rectangle. +\docparam{srcHeight}{Height of source area to be copied.} +\docparam{logicalFunc}{Logical function to use: see \helpref{wxDC::SetLogicalFunction}{wxdcsetlogicalfunction}.} -\membersection{wxDCClipper::\destruct{wxDCClipper}}\label{wxdcclipperdtor} +\docparam{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 \texttt{MaskBlt} cannot be used: -\func{}{\destruct{wxDCClipper}}{\void} +\begin{enumerate} +\item Creates a temporary bitmap and copies the destination area into it. +\item Copies the source area into the temporary bitmap using the specified logical function. +\item 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 background colour set to BLACK. +\item 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. +\item ORs the temporary bitmap with the destination area. +\item Deletes the temporary bitmap. +\end{enumerate} + +This sequence of operations ensures that the source's transparent area need not be black, +and logical functions are supported. + +{\bf Note:} on Windows, blitting with masks can be speeded up considerably by compiling +wxWidgets with the \texttt{wxUSE\_DC\_CACHE} option enabled. You can also influence whether \texttt{MaskBlt} +or the explicit mask blitting code above is used, by using \helpref{wxSystemOptions}{wxsystemoptions} and +setting the {\bf no-maskblt} option to 1. + +} + +\docparam{xsrcMask}{Source x position on the mask. If both xsrcMask and ysrcMask are -1, xsrc and ysrc +will be assumed for the mask source position. Currently only implemented on Windows.} + +\docparam{ysrcMask}{Source y position on the mask. If both xsrcMask and ysrcMask are -1, xsrc and ysrc +will be assumed for the mask source position. Currently only implemented on Windows.} + + +\wxheading{Remarks} + +There is partial support for Blit in wxPostScriptDC, under X. + +wxDC::StretchBlit is only implemented under wxMAC and wxMSW. + +See \helpref{wxMemoryDC}{wxmemorydc} for typical usage. + +\newsince{2.9.0} + +\wxheading{See also} -Destructor: destroys the clipping region set in the constructor. +\helpref{wxDC::Blit}{wxdcblit}, \helpref{wxMemoryDC}{wxmemorydc}, \helpref{wxBitmap}{wxbitmap}, \helpref{wxMask}{wxmask}