1 /////////////////////////////////////////////////////////////////////////////
2 // Name: src/common/dcbufcmn.cpp
3 // Purpose: Buffered DC implementation
4 // Author: Ron Lee, Jaakko Salli
5 // Modified by:
6 // Created: Sep-20-2006
7 // Copyright: (c) wxWidgets team
8 // Licence: wxWindows licence
9 /////////////////////////////////////////////////////////////////////////////
10
11 // ============================================================================
12 // declarations
13 // ============================================================================
14
15 // ----------------------------------------------------------------------------
16 // headers
17 // ----------------------------------------------------------------------------
18
19 // For compilers that support precompilation, includes "wx.h".
20 #include "wx/wxprec.h"
21
22 #ifdef __BORLANDC__
23 #pragma hdrstop
24 #endif
25
26 #include "wx/dcbuffer.h"
27
28 #ifndef WX_PRECOMP
29 #include "wx/module.h"
30 #endif
31
32 // ============================================================================
33 // implementation
34 // ============================================================================
35
36 IMPLEMENT_DYNAMIC_CLASS(wxBufferedDC,wxMemoryDC)
37 IMPLEMENT_ABSTRACT_CLASS(wxBufferedPaintDC,wxBufferedDC)
38
39 // ----------------------------------------------------------------------------
40 // wxSharedDCBufferManager: helper class maintaining backing store bitmap
41 // ----------------------------------------------------------------------------
42
43 class wxSharedDCBufferManager : public wxModule
44 {
45 public:
wxSharedDCBufferManager()46 wxSharedDCBufferManager() { }
47
OnInit()48 virtual bool OnInit() { return true; }
OnExit()49 virtual void OnExit() { wxDELETE(ms_buffer); }
50
GetBuffer(int w,int h)51 static wxBitmap* GetBuffer(int w, int h)
52 {
53 if ( ms_usingSharedBuffer )
54 return new wxBitmap(w, h);
55
56 if ( !ms_buffer ||
57 w > ms_buffer->GetWidth() ||
58 h > ms_buffer->GetHeight() )
59 {
60 delete ms_buffer;
61
62 // we must always return a valid bitmap but creating a bitmap of
63 // size 0 would fail, so create a 1*1 bitmap in this case
64 if ( !w )
65 w = 1;
66 if ( !h )
67 h = 1;
68
69 ms_buffer = new wxBitmap(w, h);
70 }
71
72 ms_usingSharedBuffer = true;
73 return ms_buffer;
74 }
75
ReleaseBuffer(wxBitmap * buffer)76 static void ReleaseBuffer(wxBitmap* buffer)
77 {
78 if ( buffer == ms_buffer )
79 {
80 wxASSERT_MSG( ms_usingSharedBuffer, wxT("shared buffer already released") );
81 ms_usingSharedBuffer = false;
82 }
83 else
84 {
85 delete buffer;
86 }
87 }
88
89 private:
90 static wxBitmap *ms_buffer;
91 static bool ms_usingSharedBuffer;
92
93 DECLARE_DYNAMIC_CLASS(wxSharedDCBufferManager)
94 };
95
96 wxBitmap* wxSharedDCBufferManager::ms_buffer = NULL;
97 bool wxSharedDCBufferManager::ms_usingSharedBuffer = false;
98
IMPLEMENT_DYNAMIC_CLASS(wxSharedDCBufferManager,wxModule)99 IMPLEMENT_DYNAMIC_CLASS(wxSharedDCBufferManager, wxModule)
100
101 // ============================================================================
102 // wxBufferedDC
103 // ============================================================================
104
105 void wxBufferedDC::UseBuffer(wxCoord w, wxCoord h)
106 {
107 wxCHECK_RET( w >= -1 && h >= -1, "Invalid buffer size" );
108
109 if ( !m_buffer || !m_buffer->IsOk() )
110 {
111 if ( w == -1 || h == -1 )
112 m_dc->GetSize(&w, &h);
113
114 m_buffer = wxSharedDCBufferManager::GetBuffer(w, h);
115 m_style |= wxBUFFER_USES_SHARED_BUFFER;
116 m_area.Set(w,h);
117 }
118 else
119 m_area = m_buffer->GetSize();
120
121 SelectObject(*m_buffer);
122
123 // now that the DC is valid we can inherit the attributes (fonts, colours,
124 // layout direction, ...) from the original DC
125 if ( m_dc && m_dc->IsOk() )
126 CopyAttributes(*m_dc);
127 }
128
UnMask()129 void wxBufferedDC::UnMask()
130 {
131 wxCHECK_RET( m_dc, wxT("no underlying wxDC?") );
132 wxASSERT_MSG( m_buffer && m_buffer->IsOk(), wxT("invalid backing store") );
133
134 wxCoord x = 0,
135 y = 0;
136
137 // Ensure the scale matches the device
138 SetUserScale(1.0, 1.0);
139
140 if ( m_style & wxBUFFER_CLIENT_AREA )
141 GetDeviceOrigin(&x, &y);
142
143 // It's possible that the buffer may be bigger than the area that needs to
144 // be drawn (the client size of the window is smaller than the bitmap, or
145 // a shared bitmap has been reused for a smaller area, etc.) so avoid
146 // blitting too much if possible, but only use the real DC size if the
147 // wxBUFFER_VIRTUAL_AREA style is not set.
148 int width = m_area.GetWidth(),
149 height = m_area.GetHeight();
150
151 if (!(m_style & wxBUFFER_VIRTUAL_AREA))
152 {
153 int widthDC,
154 heightDC;
155 m_dc->GetSize(&widthDC, &heightDC);
156 width = wxMin(width, widthDC);
157 height = wxMin(height, heightDC);
158 }
159
160 const wxPoint origin = GetLogicalOrigin();
161 m_dc->Blit(-origin.x, -origin.y, width, height, this, -x, -y);
162 m_dc = NULL;
163
164 if ( m_style & wxBUFFER_USES_SHARED_BUFFER )
165 wxSharedDCBufferManager::ReleaseBuffer(m_buffer);
166 }
167