added wxMessageQueue class for inter-thread communications

[wxWidgets.git] / docs / latex / wx / memorydc.tex

diff --git a/docs/latex/wx/memorydc.tex b/docs/latex/wx/memorydc.tex
index 39a8fbbbcacf4e48099f2c6568b0f86a595b89cc..e71262b954304a2cdea653263c94e76784989fa1 100644 (file)
--- a/docs/latex/wx/memorydc.tex
+++ b/docs/latex/wx/memorydc.tex
@@ -15,6 +15,10 @@ foreground colour (i.e. 1).
 
 <wx/dcmemory.h>
 
+\wxheading{Library}
+
+\helpref{wxCore}{librarieslist}
+
 \wxheading{Remarks}
 
 A bitmap must be selected into the new memory DC before it may be used
@@ -33,33 +37,76 @@ for anything.  Typical usage is as follows:
 Note that the memory DC {\it must} be deleted (or the bitmap selected out of it) before a bitmap
 can be reselected into another memory DC.
 
+And, before performing any other operations on the bitmap data, the bitmap must
+be selected out of the memory DC:
+
+\begin{verbatim}
+    temp_dc.SelectObject(wxNullBitmap)
+\end{verbatim}
+
+(this happens automatically when wxMemoryDC object goes out of scope).
+
+
 \wxheading{See also}
 
 \helpref{wxBitmap}{wxbitmap}, \helpref{wxDC}{wxdc}
 
 \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}}
+
+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.
+
+
+\membersection{wxMemoryDC::SelectObject}\label{wxmemorydcselectobject}
 
-\membersection{wxMemoryDC::SelectObject}
+\func{void}{SelectObject}{\param{wxBitmap\& }{bitmap}}
 
-\func{}{SelectObject}{\param{const 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.
+
+Using \helpref{SelectObjectAsSource}{wxmemorydcselectobjectassource} when modifying
+the bitmap may incurr some problems related to wxBitmap being a reference counted object
+(see \helpref{reference counting overview}{trefcount}).
+
+Also, before using the updated bitmap data, make sure to select it out of context first
+(for example by selecting wxNullBitmap into the device context).
+
+\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 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}
+