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
   9 // Licence:     wxWindows licence
  10 /////////////////////////////////////////////////////////////////////////////
  11
  12 // ============================================================================
  13 // declarations
  14 // ============================================================================
  15
  16 // ----------------------------------------------------------------------------
  17 // headers
  18 // ----------------------------------------------------------------------------
  19
  20 // For compilers that support precompilation, includes "wx.h".
  21 #include "wx/wxprec.h"
  22
  23 #ifdef __BORLANDC__
  24     #pragma hdrstop
  25 #endif
  26
  27 #ifndef WX_PRECOMP
  28     #include "wx/utils.h"
  29     #include "wx/log.h"
  30 #endif
  31
  32 #include "wx/msw/private.h"
  33
  34 #include "wx/dcmemory.h"
  35
  36 // ----------------------------------------------------------------------------
  37 // wxWin macros
  38 // ----------------------------------------------------------------------------
  39
  40 IMPLEMENT_DYNAMIC_CLASS(wxMemoryDC, wxDC)
  41
  42 // ============================================================================
  43 // implementation
  44 // ============================================================================
  45
  46 // ----------------------------------------------------------------------------
  47 // wxMemoryDC
  48 // ----------------------------------------------------------------------------
  49
  50 wxMemoryDC::wxMemoryDC()
  51 {
  52     CreateCompatible(NULL);
  53
  54     Init();
  55 }
  56
  57 wxMemoryDC::wxMemoryDC(wxDC *dc)
  58 {
  59     wxCHECK_RET( dc, _T("NULL dc in wxMemoryDC ctor") );
  60
  61     CreateCompatible(dc);
  62
  63     Init();
  64 }
  65
  66 void wxMemoryDC::Init()
  67 {
  68     if ( m_ok )
  69     {
  70         SetBrush(*wxWHITE_BRUSH);
  71         SetPen(*wxBLACK_PEN);
  72
  73         // the background mode is only used for text background and is set in
  74         // DrawText() to OPAQUE as required, otherwise always TRANSPARENT
  75         ::SetBkMode( GetHdc(), TRANSPARENT );
  76     }
  77 }
  78
  79 bool wxMemoryDC::CreateCompatible(wxDC *dc)
  80 {
  81     m_hDC = (WXHDC)::CreateCompatibleDC(dc ? GetHdcOf(*dc) : NULL);
  82
  83     // as we created the DC, we must delete it in the dtor
  84     m_bOwnsDC = true;
  85
  86     m_ok = m_hDC != 0;
  87
  88     return m_ok;
  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 #ifdef __WXDEBUG__
 100             m_selectedBitmap.SetSelectedInto(NULL);
 101 #endif
 102             m_selectedBitmap = wxNullBitmap;
 103         }
 104     }
 105
 106     // check for whether the bitmap is already selected into a device context
 107     wxASSERT_MSG( !bitmap.GetSelectedInto() ||
 108                   (bitmap.GetSelectedInto() == this),
 109                   wxT("Bitmap is selected in another wxMemoryDC, delete the first wxMemoryDC or use SelectObject(NULL)") );
 110
 111     m_selectedBitmap = bitmap;
 112     WXHBITMAP hBmp = m_selectedBitmap.GetHBITMAP();
 113     if ( !hBmp )
 114         return;
 115
 116 #ifdef __WXDEBUG__
 117     m_selectedBitmap.SetSelectedInto(this);
 118 #endif
 119     hBmp = (WXHBITMAP)::SelectObject(GetHdc(), (HBITMAP)hBmp);
 120
 121     if ( !hBmp )
 122     {
 123         wxLogLastError(wxT("SelectObject(memDC, bitmap)"));
 124
 125         wxFAIL_MSG(wxT("Couldn't select a bitmap into wxMemoryDC"));
 126     }
 127     else if ( !m_oldBitmap )
 128     {
 129         m_oldBitmap = hBmp;
 130     }
 131 }
 132
 133 void wxMemoryDC::DoGetSize(int *width, int *height) const
 134 {
 135     if ( m_selectedBitmap.Ok() )
 136     {
 137         *width = m_selectedBitmap.GetWidth();
 138         *height = m_selectedBitmap.GetHeight();
 139     }
 140     else
 141     {
 142         *width = 0;
 143         *height = 0;
 144     }
 145 }
 146
 147 // the rest of this file deals with drawing rectangles workaround, disabled by
 148 // default
 149
 150 #define wxUSE_MEMORY_DC_DRAW_RECTANGLE 0
 151
 152 #if wxUSE_MEMORY_DC_DRAW_RECTANGLE
 153
 154 // For some reason, drawing a rectangle on a memory DC has problems.
 155 // Use this substitute if we can.
 156 static void wxDrawRectangle(wxDC& dc, wxCoord x, wxCoord y, wxCoord width, wxCoord height)
 157 {
 158     wxBrush brush(dc.GetBrush());
 159     wxPen pen(dc.GetPen());
 160     if (brush.Ok() && brush.GetStyle() != wxTRANSPARENT)
 161     {
 162         HBRUSH hBrush = (HBRUSH) brush.GetResourceHandle() ;
 163         if (hBrush)
 164         {
 165             RECT rect;
 166             rect.left = x; rect.top = y;
 167             rect.right = x + width - 1;
 168             rect.bottom = y + height - 1;
 169             ::FillRect((HDC) dc.GetHDC(), &rect, hBrush);
 170         }
 171     }
 172     width --; height --;
 173     if (pen.Ok() && pen.GetStyle() != wxTRANSPARENT)
 174     {
 175         dc.DrawLine(x, y, x + width, y);
 176         dc.DrawLine(x, y, x, y + height);
 177         dc.DrawLine(x, y+height, x+width, y + height);
 178         dc.DrawLine(x+width, y+height, x+width, y);
 179     }
 180 }
 181
 182 #endif // wxUSE_MEMORY_DC_DRAW_RECTANGLE
 183
 184 void wxMemoryDC::DoDrawRectangle(wxCoord x, wxCoord y, wxCoord width, wxCoord height)
 185 {
 186     // Set this to 1 to work around an apparent video driver bug
 187     // (visible with e.g. 70x70 rectangle on a memory DC; see Drawing sample)
 188 #if wxUSE_MEMORY_DC_DRAW_RECTANGLE
 189     if (m_brush.Ok() && m_pen.Ok() &&
 190         (m_brush.GetStyle() == wxSOLID || m_brush.GetStyle() == wxTRANSPARENT) &&
 191         (m_pen.GetStyle() == wxSOLID || m_pen.GetStyle() == wxTRANSPARENT) &&
 192         (GetLogicalFunction() == wxCOPY))
 193     {
 194         wxDrawRectangle(* this, x, y, width, height);
 195     }
 196     else
 197 #endif // wxUSE_MEMORY_DC_DRAW_RECTANGLE
 198     {
 199         wxDC::DoDrawRectangle(x, y, width, height);
 200     }
 201 }
 202