samples/erase/erase.cpp

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        samples/erase/erase.cpp
   3 // Purpose:     Erase wxWidgets sample
   4 // Author:      Robert Roebling, Vadim Zeitlin
   5 // Created:     04/01/98
   6 // RCS-ID:      $Id$
   7 // Copyright:   (c) 1998 Robert Roebling
   8 //              (c) 2009 Vadim Zeitlin
   9 // Licence:     wxWindows licence
  10 /////////////////////////////////////////////////////////////////////////////
  11
  12 // ============================================================================
  13 // declarations
  14 // ============================================================================
  15
  16 // ----------------------------------------------------------------------------
  17 // headers
  18 // ----------------------------------------------------------------------------
  19
  20 // For compilers that support precompilation, includes "wx/wx.h".
  21 #include "wx/wxprec.h"
  22
  23 #ifdef __BORLANDC__
  24     #pragma hdrstop
  25 #endif
  26
  27 // for all others, include the necessary headers (this file is usually all you
  28 // need because it includes almost all "standard" wxWidgets headers)
  29 #ifndef WX_PRECOMP
  30     #include "wx/wx.h"
  31 #endif
  32
  33 #include "wx/dcbuffer.h"
  34
  35 // ----------------------------------------------------------------------------
  36 // resources
  37 // ----------------------------------------------------------------------------
  38 // the application icon
  39 #if defined(__WXGTK__) || defined(__WXMOTIF__) || defined(__WXMAC__) || defined(__WXMGL__) || defined(__WXX11__)
  40     #include "mondrian.xpm"
  41 #endif
  42
  43 // ----------------------------------------------------------------------------
  44 // private classes
  45 // ----------------------------------------------------------------------------
  46
  47 class MyApp : public wxApp
  48 {
  49 public:
  50     virtual bool OnInit();
  51 };
  52
  53
  54 class MyCanvas : public wxScrolledWindow
  55 {
  56 public:
  57     MyCanvas(wxFrame *parent);
  58
  59     void UseBuffer(bool useBuffer) { m_useBuffer = useBuffer; Refresh(); }
  60     bool UsesBuffer() const { return m_useBuffer; }
  61
  62 private:
  63     void OnPaint( wxPaintEvent &event );
  64     void OnChar( wxKeyEvent &event );
  65     void OnEraseBackground( wxEraseEvent &event );
  66
  67     void DoPaint(wxDC& dc);
  68
  69
  70     wxBitmap    m_bitmap;
  71     wxString    m_text;
  72
  73     // use wxMemoryDC in OnPaint()?
  74     bool m_useBuffer;
  75
  76
  77     DECLARE_EVENT_TABLE()
  78 };
  79
  80 class MyFrame : public wxFrame
  81 {
  82 public:
  83     MyFrame();
  84
  85 private:
  86     void OnUseBuffer(wxCommandEvent& event);
  87     void OnChangeBgStyle(wxCommandEvent& event);
  88     void OnQuit(wxCommandEvent& event);
  89     void OnAbout(wxCommandEvent& event);
  90
  91     // we can only use double-buffering with wxBG_STYLE_PAINT
  92     void OnUpdateUIUseBuffer(wxUpdateUIEvent& event)
  93     {
  94         event.Enable( m_canvas->GetBackgroundStyle() == wxBG_STYLE_PAINT );
  95     }
  96
  97     void OnUpdateUIChangeBgStyle(wxUpdateUIEvent& event)
  98     {
  99         event.Enable( !m_canvas->UsesBuffer() );
 100     }
 101
 102     MyCanvas *m_canvas;
 103
 104     DECLARE_EVENT_TABLE()
 105 };
 106
 107
 108 // ----------------------------------------------------------------------------
 109 // constants
 110 // ----------------------------------------------------------------------------
 111
 112 enum
 113 {
 114     // menu items
 115     Erase_Menu_UseBuffer = 100,
 116     Erase_Menu_BgStyleErase,
 117     Erase_Menu_BgStyleSystem,
 118     Erase_Menu_BgStylePaint,
 119     Erase_Menu_Exit = wxID_EXIT,
 120     Erase_Menu_About = wxID_ABOUT
 121 };
 122
 123
 124 // ----------------------------------------------------------------------------
 125 // the application class
 126 // ----------------------------------------------------------------------------
 127
 128 IMPLEMENT_APP(MyApp)
 129
 130 bool MyApp::OnInit()
 131 {
 132     if ( !wxApp::OnInit() )
 133         return false;
 134
 135     MyFrame *frame = new MyFrame;
 136
 137     frame->Show(true);
 138
 139     return true;
 140 }
 141
 142 // ----------------------------------------------------------------------------
 143 // main frame
 144 // ----------------------------------------------------------------------------
 145
 146 BEGIN_EVENT_TABLE(MyFrame, wxFrame)
 147     EVT_MENU(Erase_Menu_UseBuffer,  MyFrame::OnUseBuffer)
 148     EVT_MENU_RANGE(Erase_Menu_BgStyleErase, Erase_Menu_BgStylePaint,
 149                    MyFrame::OnChangeBgStyle)
 150
 151     EVT_MENU(Erase_Menu_Exit,  MyFrame::OnQuit)
 152     EVT_MENU(Erase_Menu_About, MyFrame::OnAbout)
 153
 154     EVT_UPDATE_UI(Erase_Menu_UseBuffer, MyFrame::OnUpdateUIUseBuffer)
 155     EVT_UPDATE_UI_RANGE(Erase_Menu_BgStyleErase, Erase_Menu_BgStylePaint,
 156                         MyFrame::OnUpdateUIChangeBgStyle)
 157 END_EVENT_TABLE()
 158
 159 // frame constructor
 160 MyFrame::MyFrame()
 161        : wxFrame(NULL, wxID_ANY, "Erase sample",
 162                  wxPoint(50, 50), wxSize(450, 340))
 163 {
 164     SetIcon(wxICON(mondrian));
 165
 166     wxMenu *menuFile = new wxMenu("", wxMENU_TEAROFF);
 167     menuFile->AppendCheckItem(Erase_Menu_UseBuffer, "&Use memory DC\tCtrl-M");
 168     menuFile->AppendSeparator();
 169     menuFile->AppendRadioItem(Erase_Menu_BgStyleErase,
 170                               "Use wxBG_STYLE_&ERASE\tCtrl-E");
 171     menuFile->AppendRadioItem(Erase_Menu_BgStyleSystem,
 172                               "Use wxBG_STYLE_&SYSTEM\tCtrl-S");
 173     menuFile->AppendRadioItem(Erase_Menu_BgStylePaint,
 174                               "Use wxBG_STYLE_&PAINT\tCtrl-P");
 175     menuFile->AppendSeparator();
 176     menuFile->Append(Erase_Menu_Exit, "E&xit\tAlt-X", "Quit this program");
 177
 178
 179     wxMenu *helpMenu = new wxMenu;
 180     helpMenu->Append(Erase_Menu_About, "&About...\tCtrl-A", "Show about dialog");
 181
 182     wxMenuBar *menuBar = new wxMenuBar();
 183     menuBar->Append(menuFile, "&File");
 184     menuBar->Append(helpMenu, "&Help");
 185
 186     SetMenuBar(menuBar);
 187
 188     m_canvas = new MyCanvas( this );
 189 }
 190
 191
 192 void MyFrame::OnUseBuffer(wxCommandEvent& event)
 193 {
 194     m_canvas->UseBuffer(event.IsChecked());
 195 }
 196
 197 void MyFrame::OnChangeBgStyle(wxCommandEvent& event)
 198 {
 199     int style = wxBG_STYLE_ERASE + event.GetId() - Erase_Menu_BgStyleErase;
 200     m_canvas->SetBackgroundStyle(static_cast<wxBackgroundStyle>(style));
 201
 202     m_canvas->Refresh();
 203 }
 204
 205 void MyFrame::OnQuit(wxCommandEvent& WXUNUSED(event))
 206 {
 207     Close(true);
 208 }
 209
 210 void MyFrame::OnAbout(wxCommandEvent& WXUNUSED(event))
 211 {
 212     wxMessageBox
 213     (
 214         "This sample shows differences between different background styles "
 215         "and how you may draw custom background.\n"
 216         "\n"
 217         "(c) 1998 Robert Roebling\n"
 218         "(c) 2009 Vadim Zeitlin\n",
 219         "About Erase Sample",
 220         wxOK | wxICON_INFORMATION,
 221         this
 222     );
 223 }
 224
 225
 226 BEGIN_EVENT_TABLE(MyCanvas, wxScrolledWindow)
 227     EVT_PAINT(MyCanvas::OnPaint)
 228     EVT_CHAR(MyCanvas::OnChar)
 229     EVT_ERASE_BACKGROUND(MyCanvas::OnEraseBackground)
 230 END_EVENT_TABLE()
 231
 232 MyCanvas::MyCanvas(wxFrame *parent)
 233         : wxScrolledWindow(parent, wxID_ANY)
 234 {
 235     m_useBuffer = false;
 236
 237     SetScrollbars( 10, 10, 40, 100, 0, 0 );
 238
 239     m_bitmap = wxBitmap( wxICON(mondrian) );
 240
 241     new wxStaticBitmap( this, wxID_ANY, m_bitmap, wxPoint(80,20) );
 242
 243     SetFocusIgnoringChildren();
 244     SetBackgroundColour(*wxBLUE);
 245 }
 246
 247 void MyCanvas::OnChar( wxKeyEvent &event )
 248 {
 249 #if wxUSE_UNICODE
 250     if (event.m_uniChar)
 251     {
 252         m_text += event.m_uniChar;
 253         Refresh();
 254         return;
 255     }
 256 #endif
 257
 258     // some test cases
 259     switch (event.m_keyCode)
 260     {
 261         case WXK_UP: m_text += wxT( "<UP>" ); break;
 262         case WXK_LEFT: m_text += wxT( "<LEFT>" ); break;
 263         case WXK_RIGHT: m_text += wxT( "<RIGHT>" ); break;
 264         case WXK_DOWN: m_text += wxT( "<DOWN>" ); break;
 265         case WXK_RETURN: m_text += wxT( "<ENTER>" ); break;
 266         default: m_text += (wxChar)event.m_keyCode; break;
 267     }
 268 }
 269
 270 void MyCanvas::DoPaint(wxDC& dc)
 271 {
 272     dc.SetBrush( *wxBLACK_BRUSH );
 273     dc.DrawRectangle( 10,10,60,50 );
 274
 275     dc.DrawBitmap( m_bitmap, 20, 20, true );
 276
 277     dc.SetTextForeground(*wxWHITE);
 278     dc.DrawText("This text is drawn from OnPaint", 65, 65);
 279
 280     wxString tmp;
 281     tmp.Printf("Hit any key to display more text: %s", m_text);
 282
 283     int w,h;
 284     dc.GetTextExtent( tmp, &w, &h );
 285     dc.DrawRectangle( 65, 85, w, h );
 286     dc.DrawText( tmp, 65, 85 );
 287 }
 288
 289 void MyCanvas::OnPaint( wxPaintEvent &WXUNUSED(event) )
 290 {
 291     if ( m_useBuffer )
 292     {
 293         wxAutoBufferedPaintDC dc(this);
 294         PrepareDC(dc);
 295
 296         DoPaint(dc);
 297     }
 298     else
 299     {
 300         wxPaintDC dc(this);
 301         PrepareDC(dc);
 302
 303         DoPaint(dc);
 304     }
 305 }
 306
 307 void MyCanvas::OnEraseBackground( wxEraseEvent& event )
 308 {
 309     wxASSERT_MSG
 310     (
 311         GetBackgroundStyle() == wxBG_STYLE_ERASE,
 312         "shouldn't be called unless background style is \"erase\""
 313     );
 314
 315     wxDC& dc = *event.GetDC();
 316     dc.SetPen(*wxGREEN_PEN);
 317
 318     PrepareDC( dc );
 319
 320     // clear any junk currently displayed
 321     dc.Clear();
 322
 323     const wxSize size = GetClientSize();
 324     for ( int x = 0; x < size.x; x += 15 )
 325     {
 326         dc.DrawLine(x, 0, x, size.y);
 327     }
 328
 329     for ( int y = 0; y < size.y; y += 15 )
 330     {
 331         dc.DrawLine(0, y, size.x, y);
 332     }
 333
 334     dc.SetTextForeground(*wxRED);
 335     dc.SetBackgroundMode(wxSOLID);
 336     dc.DrawText("This text is drawn from OnEraseBackground", 60, 160);
 337 }
 338