X-Git-Url: https://git.saurik.com/wxWidgets.git/blobdiff_plain/a660d684eda27638bca0384b2058911a31c8e845..c266eff98c5e44012647f54f38a1e29ecabd8759:/docs/latex/wx/memorydc.tex?ds=sidebyside diff --git a/docs/latex/wx/memorydc.tex b/docs/latex/wx/memorydc.tex index 5237bb765a..0f36054aca 100644 --- a/docs/latex/wx/memorydc.tex +++ b/docs/latex/wx/memorydc.tex @@ -1,12 +1,24 @@ \section{\class{wxMemoryDC}}\label{wxmemorydc} -A memory device context provides a means to draw graphics onto a bitmap. +A memory device context provides a means to draw graphics onto a bitmap. When +drawing in to a mono-bitmap, using {\tt wxWHITE}, {\tt wxWHITE\_PEN} and +{\tt wxWHITE\_BRUSH} +will draw the background colour (i.e. 0) whereas all other colours will draw the +foreground colour (i.e. 1). \wxheading{Derived from} \helpref{wxDC}{wxdc}\\ \helpref{wxObject}{wxobject} +\wxheading{Include files} + + + +\wxheading{Library} + +\helpref{wxCore}{librarieslist} + \wxheading{Remarks} A bitmap must be selected into the new memory DC before it may be used @@ -31,27 +43,58 @@ can be reselected into another memory DC. \latexignore{\rtfignore{\wxheading{Members}}} -\membersection{wxMemoryDC::wxMemoryDC} +\membersection{wxMemoryDC::wxMemoryDC}\label{wxmemorydcctor} \func{}{wxMemoryDC}{\void} Constructs a new memory device context. -Use the {\it Ok} member to test whether the constructor was successful -in creating a useable device context. Don't forget to select a bitmap -into the DC before drawing on it. +Use the \helpref{IsOk}{wxdcisok} member to test whether the constructor was successful +in creating a usable device context. +Don't forget to select a bitmap into the DC before drawing on it. + +\func{}{wxMemoryDC}{\param{wxBitmap\& }{bitmap}} -\membersection{wxMemoryDC::SelectObject} +Constructs a new memory device context and calls \helpref{SelectObject}{wxmemorydcselectobject} +with the given bitmap. +Use the \helpref{IsOk}{wxdcisok} member to test whether the constructor was successful +in creating a usable device context. -\func{}{SelectObject}{\param{const wxBitmap\& }{bitmap}} + +\membersection{wxMemoryDC::SelectObject}\label{wxmemorydcselectobject} + +\func{void}{SelectObject}{\param{wxBitmap\& }{bitmap}} + +Works exactly like \helpref{SelectObjectAsSource}{wxmemorydcselectobjectassource} but +this is the function you should use when you select a bitmap because you want to modify +it, e.g. drawing on this DC. + +Be careful to use this function and not \helpref{SelectObjectAsSource}{wxmemorydcselectobjectassource} +when you want to modify the bitmap you are selecting otherwise you may incurr in some +problems related to wxBitmap being a reference counted object +(see \helpref{reference counting overview}{trefcount}). + +\wxheading{See also} + +\helpref{wxDC::DrawBitmap}{wxdcdrawbitmap} + + + +\membersection{wxMemoryDC::SelectObjectAsSource}\label{wxmemorydcselectobjectassource} + +\func{void}{SelectObjectAsSource}{\param{const wxBitmap\& }{bitmap}} Selects the given bitmap into the device context, to use as the memory bitmap. Selecting the bitmap into a memory DC allows you to draw into -the DC (and therefore the bitmap) and also to use {\bf Blit} to copy -the bitmap to a canvas. For this purpose, you may find \helpref{wxDC::DrawIcon}{wxdcdrawicon}\rtfsp +the DC (and therefore the bitmap) and also to use \helpref{wxDC::Blit}{wxdcblit} to copy +the bitmap to a window. For this purpose, you may find \helpref{wxDC::DrawIcon}{wxdcdrawicon}\rtfsp easier to use instead. -If the argument is wxNullBitmap (or some other uninitialised wxBitmap) the current bitmap is selected out of the device -context, and the original bitmap restored, allowing the current bitmap to +If the argument is wxNullBitmap (or some other uninitialised wxBitmap) the current bitmap is +selected out of the device context, and the original bitmap restored, allowing the current bitmap to be destroyed safely. +\wxheading{See also} + +\helpref{wxMemoryDC::SelectObject}{wxmemorydcselectobject} +