src/msw/dcmemory.cpp

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        dcmemory.cpp
   3 // Purpose:     wxMemoryDC class
   4 // Author:      Julian Smart
   5 // Modified by:
   6 // Created:     01/02/97
   7 // RCS-ID:      $Id$
   8 // Copyright:   (c) Julian Smart and Markus Holzem
   9 // Licence:     wxWindows licence
  10 /////////////////////////////////////////////////////////////////////////////
  11
  12 // ============================================================================
  13 // declarations
  14 // ============================================================================
  15
  16 // ----------------------------------------------------------------------------
  17 // headers
  18 // ----------------------------------------------------------------------------
  19
  20 #ifdef __GNUG__
  21     #pragma implementation "dcmemory.h"
  22 #endif
  23
  24 // For compilers that support precompilation, includes "wx.h".
  25 #include "wx/wxprec.h"
  26
  27 #ifdef __BORLANDC__
  28     #pragma hdrstop
  29 #endif
  30
  31 #ifndef WX_PRECOMP
  32     #include "wx/utils.h"
  33 #endif
  34
  35 #include "wx/msw/private.h"
  36
  37 #include "wx/dcmemory.h"
  38
  39 // ----------------------------------------------------------------------------
  40 // wxWin macros
  41 // ----------------------------------------------------------------------------
  42
  43 #if !USE_SHARED_LIBRARY
  44     IMPLEMENT_DYNAMIC_CLASS(wxMemoryDC, wxDC)
  45 #endif
  46
  47 // ============================================================================
  48 // implementation
  49 // ============================================================================
  50
  51 // ----------------------------------------------------------------------------
  52 // wxMemoryDC
  53 // ----------------------------------------------------------------------------
  54
  55 wxMemoryDC::wxMemoryDC()
  56 {
  57     m_hDC = (WXHDC) ::CreateCompatibleDC((HDC) NULL);
  58     m_ok = (m_hDC != 0);
  59     m_bOwnsDC = TRUE;
  60
  61     SetBrush(*wxWHITE_BRUSH);
  62     SetPen(*wxBLACK_PEN);
  63
  64     // the background mode is only used for text background and is set in
  65     // DrawText() to OPAQUE as required, otherwise always TRANSPARENT
  66     ::SetBkMode( GetHdc(), TRANSPARENT );
  67 }
  68
  69 wxMemoryDC::wxMemoryDC(wxDC *old_dc)
  70 {
  71     old_dc->BeginDrawing();
  72
  73     m_hDC = (WXHDC) ::CreateCompatibleDC(GetHdcOf(*old_dc));
  74     m_ok = (m_hDC != 0);
  75
  76     old_dc->EndDrawing();
  77
  78     SetBrush(*wxWHITE_BRUSH);
  79     SetPen(*wxBLACK_PEN);
  80
  81     // the background mode is only used for text background and is set in
  82     // DrawText() to OPAQUE as required, otherwise always TRANSPARENT
  83     ::SetBkMode( GetHdc(), TRANSPARENT );
  84 }
  85
  86 wxMemoryDC::~wxMemoryDC()
  87 {
  88 }
  89
  90 void wxMemoryDC::SelectObject(const wxBitmap& bitmap)
  91 {
  92     // select old bitmap out of the device context
  93     if ( m_oldBitmap )
  94     {
  95         ::SelectObject(GetHdc(), (HBITMAP) m_oldBitmap);
  96         if ( m_selectedBitmap.Ok() )
  97         {
  98             m_selectedBitmap.SetSelectedInto(NULL);
  99             m_selectedBitmap = wxNullBitmap;
 100         }
 101     }
 102
 103     // check for whether the bitmap is already selected into a device context
 104     wxCHECK_RET( !bitmap.GetSelectedInto() ||
 105                  (bitmap.GetSelectedInto() == this),
 106                  wxT("Bitmap is selected in another wxMemoryDC, delete the "
 107                      "first wxMemoryDC or use SelectObject(NULL)") );
 108
 109     m_selectedBitmap = bitmap;
 110     WXHBITMAP hBmp = m_selectedBitmap.GetHBITMAP();
 111     if ( !hBmp )
 112         return;
 113
 114     m_selectedBitmap.SetSelectedInto(this);
 115     hBmp = (WXHBITMAP)::SelectObject(GetHdc(), (HBITMAP)hBmp);
 116
 117     if ( !hBmp )
 118     {
 119         wxLogLastError("SelectObject(memDC, bitmap)");
 120
 121         wxFAIL_MSG(wxT("Couldn't select a bitmap into wxMemoryDC"));
 122     }
 123     else if ( !m_oldBitmap )
 124     {
 125         m_oldBitmap = hBmp;
 126     }
 127 }
 128
 129 void wxMemoryDC::DoGetSize(int *width, int *height) const
 130 {
 131     if ( m_selectedBitmap.Ok() )
 132     {
 133         *width = m_selectedBitmap.GetWidth();
 134         *height = m_selectedBitmap.GetHeight();
 135     }
 136     else
 137     {
 138         *width = 0;
 139         *height = 0;
 140     }
 141 }
 142