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 #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 IMPLEMENT_DYNAMIC_CLASS(wxMemoryDC, wxDC)
  45
  46 // ============================================================================
  47 // implementation
  48 // ============================================================================
  49
  50 // ----------------------------------------------------------------------------
  51 // wxMemoryDC
  52 // ----------------------------------------------------------------------------
  53
  54 wxMemoryDC::wxMemoryDC()
  55 {
  56     CreateCompatible(NULL);
  57
  58     Init();
  59 }
  60
  61 wxMemoryDC::wxMemoryDC(wxDC *dc)
  62 {
  63     wxCHECK_RET( dc, _T("NULL dc in wxMemoryDC ctor") );
  64
  65     dc->BeginDrawing();
  66
  67     CreateCompatible(dc);
  68
  69     dc->EndDrawing();
  70
  71     Init();
  72 }
  73
  74 void wxMemoryDC::Init()
  75 {
  76     if ( m_ok )
  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
  87 bool wxMemoryDC::CreateCompatible(wxDC *dc)
  88 {
  89     m_hDC = (WXHDC)::CreateCompatibleDC(dc ? GetHdcOf(*dc) : NULL);
  90
  91     // as we created the DC, we must delete it in the dtor
  92     m_bOwnsDC = TRUE;
  93
  94     m_ok = m_hDC != 0;
  95
  96     return m_ok;
  97 }
  98
  99 void wxMemoryDC::SelectObject(const wxBitmap& bitmap)
 100 {
 101     // select old bitmap out of the device context
 102     if ( m_oldBitmap )
 103     {
 104         ::SelectObject(GetHdc(), (HBITMAP) m_oldBitmap);
 105         if ( m_selectedBitmap.Ok() )
 106         {
 107 #ifdef __WXDEBUG__
 108             m_selectedBitmap.SetSelectedInto(NULL);
 109 #endif
 110             m_selectedBitmap = wxNullBitmap;
 111         }
 112     }
 113
 114     // check for whether the bitmap is already selected into a device context
 115     wxASSERT_MSG( !bitmap.GetSelectedInto() ||
 116                   (bitmap.GetSelectedInto() == this),
 117                   wxT("Bitmap is selected in another wxMemoryDC, delete the first wxMemoryDC or use SelectObject(NULL)") );
 118
 119     m_selectedBitmap = bitmap;
 120     WXHBITMAP hBmp = m_selectedBitmap.GetHBITMAP();
 121     if ( !hBmp )
 122         return;
 123
 124 #ifdef __WXDEBUG__
 125     m_selectedBitmap.SetSelectedInto(this);
 126 #endif
 127     hBmp = (WXHBITMAP)::SelectObject(GetHdc(), (HBITMAP)hBmp);
 128
 129     if ( !hBmp )
 130     {
 131         wxLogLastError(wxT("SelectObject(memDC, bitmap)"));
 132
 133         wxFAIL_MSG(wxT("Couldn't select a bitmap into wxMemoryDC"));
 134     }
 135     else if ( !m_oldBitmap )
 136     {
 137         m_oldBitmap = hBmp;
 138     }
 139 }
 140
 141 void wxMemoryDC::DoGetSize(int *width, int *height) const
 142 {
 143     if ( m_selectedBitmap.Ok() )
 144     {
 145         *width = m_selectedBitmap.GetWidth();
 146         *height = m_selectedBitmap.GetHeight();
 147     }
 148     else
 149     {
 150         *width = 0;
 151         *height = 0;
 152     }
 153 }
 154
 155 // the rest of this file deals with drawing rectangles workaround, disabled by
 156 // default
 157
 158 #define wxUSE_MEMORY_DC_DRAW_RECTANGLE 0
 159
 160 #if wxUSE_MEMORY_DC_DRAW_RECTANGLE
 161
 162 // For some reason, drawing a rectangle on a memory DC has problems.
 163 // Use this substitute if we can.
 164 static void wxDrawRectangle(wxDC& dc, wxCoord x, wxCoord y, wxCoord width, wxCoord height)
 165 {
 166     wxBrush brush(dc.GetBrush());
 167     wxPen pen(dc.GetPen());
 168     if (brush.Ok() && brush.GetStyle() != wxTRANSPARENT)
 169     {
 170         HBRUSH hBrush = (HBRUSH) brush.GetResourceHandle() ;
 171         if (hBrush)
 172         {
 173             RECT rect;
 174             rect.left = x; rect.top = y;
 175             rect.right = x + width - 1;
 176             rect.bottom = y + height - 1;
 177             ::FillRect((HDC) dc.GetHDC(), &rect, hBrush);
 178         }
 179     }
 180     width --; height --;
 181     if (pen.Ok() && pen.GetStyle() != wxTRANSPARENT)
 182     {
 183         dc.DrawLine(x, y, x + width, y);
 184         dc.DrawLine(x, y, x, y + height);
 185         dc.DrawLine(x, y+height, x+width, y + height);
 186         dc.DrawLine(x+width, y+height, x+width, y);
 187     }
 188 }
 189
 190 #endif // wxUSE_MEMORY_DC_DRAW_RECTANGLE
 191
 192 void wxMemoryDC::DoDrawRectangle(wxCoord x, wxCoord y, wxCoord width, wxCoord height)
 193 {
 194     // Set this to 1 to work around an apparent video driver bug
 195     // (visible with e.g. 70x70 rectangle on a memory DC; see Drawing sample)
 196 #if wxUSE_MEMORY_DC_DRAW_RECTANGLE
 197     if (m_brush.Ok() && m_pen.Ok() &&
 198         (m_brush.GetStyle() == wxSOLID || m_brush.GetStyle() == wxTRANSPARENT) &&
 199         (m_pen.GetStyle() == wxSOLID || m_pen.GetStyle() == wxTRANSPARENT) &&
 200         (GetLogicalFunction() == wxCOPY))
 201     {
 202         wxDrawRectangle(* this, x, y, width, height);
 203     }
 204     else
 205 #endif // wxUSE_MEMORY_DC_DRAW_RECTANGLE
 206     {
 207         wxDC::DoDrawRectangle(x, y, width, height);
 208     }
 209 }
 210