added wxDC::ResetBoundingBox(), documented it and CalcBoundingBox() too

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/branches/WX_2_2_BRANCH@7496 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

docs/latex/wx/dc.tex

@@ -108,6 +108,18 @@ See \helpref{wxMemoryDC}{wxmemorydc} for typical usage.
 
 \helpref{wxMemoryDC}{wxmemorydc}, \helpref{wxBitmap}{wxbitmap}, \helpref{wxMask}{wxmask}
 
+\membersection{wxDC::CalcBoundingBox}\label{wxdccalcboundingbox}
+
+\func{void}{CalcBoundingBox}{\param{wxCoord }{x}, \param{wxCoord }{y}}
+
+Adds the specified point to the bounding box which can be retrieved with 
+\helpref{MinX}{wxdcminx}, \helpref{MaxX}{wxdcmaxx} and 
+\helpref{MinY}{wxdcminy}, \helpref{MaxY}{wxdcmaxy} functions.
+
+\wxheading{See also}
+
+\helpref{ResetBoundingBox}{wxdcresetboundingbox}
+
 \membersection{wxDC::Clear}\label{wxdcclear}
 
 \func{void}{Clear}{\void}
@@ -579,6 +591,17 @@ Gets the minimum vertical extent used in drawing commands so far.
 
 Returns TRUE if the DC is ok to use.
 
+\membersection{wxDC::ResetBoundingBox}\label{wxdcresetboundingbox}
+
+\func{void}{ResetBoundingBox}{\void}
+
+Resets the bounding box: after a call to this function, the bounding box
+doesn't contain anything.
+
+\wxheading{See also}
+
+\helpref{CalcBoundingBox}{wxdccalcboundingbox}
+
 \membersection{wxDC::SetDeviceOrigin}\label{wxdcsetdeviceorigin}
 
 \func{void}{SetDeviceOrigin}{\param{wxCoord}{ x}, \param{wxCoord}{ y}}

include/wx/dc.h

@@ -48,9 +48,8 @@ public:
     {
         m_clipping = FALSE;
         m_ok = TRUE;
-        m_isBBoxValid = FALSE;
 
-        m_minX = m_minY = m_maxX = m_maxY = 0;
+        ResetBoundingBox();
 
         m_signX = m_signY = 1;
 
@@ -419,6 +418,13 @@ public:
       }
     }
 
+    void ResetBoundingBox()
+    {
+        m_isBBoxValid = FALSE;
+
+        m_minX = m_maxX = m_minY = m_maxY = 0;
+    }
+
     // Get the final bounding box of the PostScript or Metafile picture.
     wxCoord MinX() const { return m_minX; }
     wxCoord MaxX() const { return m_maxX; }