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     #include "wx/log.h"
  34 #endif
  35
  36 #include "wx/msw/private.h"
  37
  38 #include "wx/dcmemory.h"
  39
  40 // ----------------------------------------------------------------------------
  41 // wxWin macros
  42 // ----------------------------------------------------------------------------
  43
  44 #if !USE_SHARED_LIBRARY
  45     IMPLEMENT_DYNAMIC_CLASS(wxMemoryDC, wxDC)
  46 #endif
  47
  48 // ============================================================================
  49 // implementation
  50 // ============================================================================
  51
  52 // ----------------------------------------------------------------------------
  53 // wxMemoryDC
  54 // ----------------------------------------------------------------------------
  55
  56 wxMemoryDC::wxMemoryDC()
  57 {
  58     m_hDC = (WXHDC) ::CreateCompatibleDC((HDC) NULL);
  59     m_ok = (m_hDC != 0);
  60     m_bOwnsDC = TRUE;
  61
  62     SetBrush(*wxWHITE_BRUSH);
  63     SetPen(*wxBLACK_PEN);
  64
  65     // the background mode is only used for text background and is set in
  66     // DrawText() to OPAQUE as required, otherwise always TRANSPARENT
  67     ::SetBkMode( GetHdc(), TRANSPARENT );
  68 }
  69
  70 wxMemoryDC::wxMemoryDC(wxDC *old_dc)
  71 {
  72     old_dc->BeginDrawing();
  73
  74     m_hDC = (WXHDC) ::CreateCompatibleDC(GetHdcOf(*old_dc));
  75     m_ok = (m_hDC != 0);
  76
  77     old_dc->EndDrawing();
  78
  79     SetBrush(*wxWHITE_BRUSH);
  80     SetPen(*wxBLACK_PEN);
  81
  82     // the background mode is only used for text background and is set in
  83     // DrawText() to OPAQUE as required, otherwise always TRANSPARENT
  84     ::SetBkMode( GetHdc(), TRANSPARENT );
  85 }
  86
  87 wxMemoryDC::~wxMemoryDC()
  88 {
  89 }
  90
  91 void wxMemoryDC::SelectObject(const wxBitmap& bitmap)
  92 {
  93     // select old bitmap out of the device context
  94     if ( m_oldBitmap )
  95     {
  96         ::SelectObject(GetHdc(), (HBITMAP) m_oldBitmap);
  97         if ( m_selectedBitmap.Ok() )
  98         {
  99             m_selectedBitmap.SetSelectedInto(NULL);
 100             m_selectedBitmap = wxNullBitmap;
 101         }
 102     }
 103
 104     // check for whether the bitmap is already selected into a device context
 105     wxCHECK_RET( !bitmap.GetSelectedInto() ||
 106                  (bitmap.GetSelectedInto() == this),
 107                  wxT("Bitmap is selected in another wxMemoryDC, delete the "
 108                      "first wxMemoryDC or use SelectObject(NULL)") );
 109
 110     m_selectedBitmap = bitmap;
 111     WXHBITMAP hBmp = m_selectedBitmap.GetHBITMAP();
 112     if ( !hBmp )
 113         return;
 114
 115     m_selectedBitmap.SetSelectedInto(this);
 116     hBmp = (WXHBITMAP)::SelectObject(GetHdc(), (HBITMAP)hBmp);
 117
 118     if ( !hBmp )
 119     {
 120         wxLogLastError("SelectObject(memDC, bitmap)");
 121
 122         wxFAIL_MSG(wxT("Couldn't select a bitmap into wxMemoryDC"));
 123     }
 124     else if ( !m_oldBitmap )
 125     {
 126         m_oldBitmap = hBmp;
 127     }
 128 }
 129
 130 void wxMemoryDC::DoGetSize(int *width, int *height) const
 131 {
 132     if ( m_selectedBitmap.Ok() )
 133     {
 134         *width = m_selectedBitmap.GetWidth();
 135         *height = m_selectedBitmap.GetHeight();
 136     }
 137     else
 138     {
 139         *width = 0;
 140         *height = 0;
 141     }
 142 }
 143