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     void EraseBgInPaint(bool erase) { m_eraseBgInPaint = erase; Refresh(); }
  63
  64 private:
  65     void OnPaint( wxPaintEvent &event );
  66     void OnChar( wxKeyEvent &event );
  67     void OnEraseBackground( wxEraseEvent &event );
  68
  69     void DoPaint(wxDC& dc);
  70
  71
  72     wxBitmap    m_bitmap;
  73     wxString    m_text;
  74
  75     // use wxMemoryDC in OnPaint()?
  76     bool m_useBuffer;
  77
  78     // erase background in OnPaint()?
  79     bool m_eraseBgInPaint;
  80
  81
  82     DECLARE_EVENT_TABLE()
  83 };
  84
  85 class MyFrame : public wxFrame
  86 {
  87 public:
  88     MyFrame();
  89
  90 private:
  91     void OnUseBuffer(wxCommandEvent& event);
  92     void OnEraseBgInPaint(wxCommandEvent& event);
  93     void OnChangeBgStyle(wxCommandEvent& event);
  94     void OnQuit(wxCommandEvent& event);
  95     void OnAbout(wxCommandEvent& event);
  96
  97     // we can only use double-buffering with wxBG_STYLE_PAINT
  98     void OnUpdateUIUseBuffer(wxUpdateUIEvent& event)
  99     {
 100         event.Enable( m_canvas->GetBackgroundStyle() == wxBG_STYLE_PAINT );
 101     }
 102
 103     void OnUpdateUIChangeBgStyle(wxUpdateUIEvent& event)
 104     {
 105         event.Enable( !m_canvas->UsesBuffer() );
 106     }
 107
 108     MyCanvas *m_canvas;
 109
 110     DECLARE_EVENT_TABLE()
 111 };
 112
 113
 114 // ----------------------------------------------------------------------------
 115 // constants
 116 // ----------------------------------------------------------------------------
 117
 118 enum
 119 {
 120     // menu items
 121     Erase_Menu_UseBuffer = 100,
 122     Erase_Menu_EraseBgInPaint,
 123     Erase_Menu_BgStyleErase,
 124     Erase_Menu_BgStyleSystem,
 125     Erase_Menu_BgStylePaint,
 126     Erase_Menu_Exit = wxID_EXIT,
 127     Erase_Menu_About = wxID_ABOUT
 128 };
 129
 130
 131 // ----------------------------------------------------------------------------
 132 // the application class
 133 // ----------------------------------------------------------------------------
 134
 135 IMPLEMENT_APP(MyApp)
 136
 137 bool MyApp::OnInit()
 138 {
 139     if ( !wxApp::OnInit() )
 140         return false;
 141
 142     MyFrame *frame = new MyFrame;
 143
 144     frame->Show(true);
 145
 146     return true;
 147 }
 148
 149 // ----------------------------------------------------------------------------
 150 // main frame
 151 // ----------------------------------------------------------------------------
 152
 153 BEGIN_EVENT_TABLE(MyFrame, wxFrame)
 154     EVT_MENU(Erase_Menu_UseBuffer, MyFrame::OnUseBuffer)
 155     EVT_MENU(Erase_Menu_EraseBgInPaint, MyFrame::OnEraseBgInPaint)
 156     EVT_MENU_RANGE(Erase_Menu_BgStyleErase, Erase_Menu_BgStylePaint,
 157                    MyFrame::OnChangeBgStyle)
 158
 159     EVT_MENU(Erase_Menu_Exit,  MyFrame::OnQuit)
 160     EVT_MENU(Erase_Menu_About, MyFrame::OnAbout)
 161
 162     EVT_UPDATE_UI(Erase_Menu_UseBuffer, MyFrame::OnUpdateUIUseBuffer)
 163     EVT_UPDATE_UI_RANGE(Erase_Menu_BgStyleErase, Erase_Menu_BgStylePaint,
 164                         MyFrame::OnUpdateUIChangeBgStyle)
 165 END_EVENT_TABLE()
 166
 167 // frame constructor
 168 MyFrame::MyFrame()
 169        : wxFrame(NULL, wxID_ANY, "Erase sample",
 170                  wxPoint(50, 50), wxSize(450, 340))
 171 {
 172     SetIcon(wxICON(mondrian));
 173
 174     wxMenu *menuFile = new wxMenu("", wxMENU_TEAROFF);
 175     menuFile->AppendCheckItem(Erase_Menu_UseBuffer, "&Use memory DC\tCtrl-M");
 176     menuFile->AppendCheckItem(Erase_Menu_EraseBgInPaint,
 177                               "&Erase background in EVT_PAINT\tCtrl-R");
 178     menuFile->AppendSeparator();
 179     menuFile->AppendRadioItem(Erase_Menu_BgStyleErase,
 180                               "Use wxBG_STYLE_&ERASE\tCtrl-E");
 181     menuFile->AppendRadioItem(Erase_Menu_BgStyleSystem,
 182                               "Use wxBG_STYLE_&SYSTEM\tCtrl-S");
 183     menuFile->AppendRadioItem(Erase_Menu_BgStylePaint,
 184                               "Use wxBG_STYLE_&PAINT\tCtrl-P");
 185     menuFile->AppendSeparator();
 186     menuFile->Append(Erase_Menu_Exit, "E&xit\tAlt-X", "Quit this program");
 187
 188
 189     wxMenu *helpMenu = new wxMenu;
 190     helpMenu->Append(Erase_Menu_About, "&About...\tCtrl-A", "Show about dialog");
 191
 192     wxMenuBar *menuBar = new wxMenuBar();
 193     menuBar->Append(menuFile, "&File");
 194     menuBar->Append(helpMenu, "&Help");
 195
 196     SetMenuBar(menuBar);
 197
 198     m_canvas = new MyCanvas( this );
 199 }
 200
 201
 202 void MyFrame::OnUseBuffer(wxCommandEvent& event)
 203 {
 204     m_canvas->UseBuffer(event.IsChecked());
 205 }
 206
 207 void MyFrame::OnEraseBgInPaint(wxCommandEvent& event)
 208 {
 209     m_canvas->EraseBgInPaint(event.IsChecked());
 210 }
 211
 212 void MyFrame::OnChangeBgStyle(wxCommandEvent& event)
 213 {
 214     int style = wxBG_STYLE_ERASE + event.GetId() - Erase_Menu_BgStyleErase;
 215     m_canvas->SetBackgroundStyle(static_cast<wxBackgroundStyle>(style));
 216
 217     m_canvas->Refresh();
 218 }
 219
 220 void MyFrame::OnQuit(wxCommandEvent& WXUNUSED(event))
 221 {
 222     Close(true);
 223 }
 224
 225 void MyFrame::OnAbout(wxCommandEvent& WXUNUSED(event))
 226 {
 227     wxMessageBox
 228     (
 229         "This sample shows differences between different background styles "
 230         "and how you may draw custom background.\n"
 231         "\n"
 232         "(c) 1998 Robert Roebling\n"
 233         "(c) 2009 Vadim Zeitlin\n",
 234         "About Erase Sample",
 235         wxOK | wxICON_INFORMATION,
 236         this
 237     );
 238 }
 239
 240
 241 BEGIN_EVENT_TABLE(MyCanvas, wxScrolledWindow)
 242     EVT_PAINT(MyCanvas::OnPaint)
 243     EVT_CHAR(MyCanvas::OnChar)
 244     EVT_ERASE_BACKGROUND(MyCanvas::OnEraseBackground)
 245 END_EVENT_TABLE()
 246
 247 MyCanvas::MyCanvas(wxFrame *parent)
 248         : wxScrolledWindow(parent, wxID_ANY)
 249 {
 250     m_useBuffer = false;
 251     m_eraseBgInPaint = false;
 252
 253     SetScrollbars( 10, 10, 40, 100, 0, 0 );
 254
 255     m_bitmap = wxBitmap( wxICON(mondrian) );
 256
 257     new wxStaticBitmap( this, wxID_ANY, m_bitmap, wxPoint(80,20) );
 258
 259     SetFocusIgnoringChildren();
 260     SetBackgroundColour(*wxBLUE);
 261 }
 262
 263 void MyCanvas::OnChar( wxKeyEvent &event )
 264 {
 265 #if wxUSE_UNICODE
 266     if (event.m_uniChar)
 267     {
 268         m_text += event.m_uniChar;
 269         Refresh();
 270         return;
 271     }
 272 #endif
 273
 274     // some test cases
 275     switch (event.m_keyCode)
 276     {
 277         case WXK_UP: m_text += wxT( "<UP>" ); break;
 278         case WXK_LEFT: m_text += wxT( "<LEFT>" ); break;
 279         case WXK_RIGHT: m_text += wxT( "<RIGHT>" ); break;
 280         case WXK_DOWN: m_text += wxT( "<DOWN>" ); break;
 281         case WXK_RETURN: m_text += wxT( "<ENTER>" ); break;
 282         default: m_text += (wxChar)event.m_keyCode; break;
 283     }
 284 }
 285
 286 void MyCanvas::DoPaint(wxDC& dc)
 287 {
 288     if ( m_eraseBgInPaint )
 289     {
 290         dc.SetBackground(*wxLIGHT_GREY);
 291         dc.Clear();
 292
 293         dc.DrawText("Background erased in OnPaint", 65, 110);
 294     }
 295     else if ( GetBackgroundStyle() == wxBG_STYLE_PAINT )
 296     {
 297         dc.SetTextForeground(*wxRED);
 298         dc.DrawText("You must enable erasing background in OnPaint to avoid "
 299                     "display corruption", 65, 110);
 300     }
 301
 302     dc.SetBrush( *wxBLACK_BRUSH );
 303     dc.DrawRectangle( 10,10,60,50 );
 304
 305     dc.DrawBitmap( m_bitmap, 20, 20, true );
 306
 307     dc.SetTextForeground(*wxWHITE);
 308     dc.DrawText("This text is drawn from OnPaint", 65, 65);
 309
 310     wxString tmp;
 311     tmp.Printf("Hit any key to display more text: %s", m_text);
 312
 313     int w,h;
 314     dc.GetTextExtent( tmp, &w, &h );
 315     dc.DrawRectangle( 65, 85, w, h );
 316     dc.DrawText( tmp, 65, 85 );
 317 }
 318
 319 void MyCanvas::OnPaint( wxPaintEvent &WXUNUSED(event) )
 320 {
 321     if ( m_useBuffer )
 322     {
 323         wxAutoBufferedPaintDC dc(this);
 324         PrepareDC(dc);
 325
 326         DoPaint(dc);
 327     }
 328     else
 329     {
 330         wxPaintDC dc(this);
 331         PrepareDC(dc);
 332
 333         DoPaint(dc);
 334     }
 335 }
 336
 337 void MyCanvas::OnEraseBackground( wxEraseEvent& event )
 338 {
 339     wxASSERT_MSG
 340     (
 341         GetBackgroundStyle() == wxBG_STYLE_ERASE,
 342         "shouldn't be called unless background style is \"erase\""
 343     );
 344
 345     wxDC& dc = *event.GetDC();
 346     dc.SetPen(*wxGREEN_PEN);
 347
 348     PrepareDC( dc );
 349
 350     // clear any junk currently displayed
 351     dc.Clear();
 352
 353     const wxSize size = GetClientSize();
 354     for ( int x = 0; x < size.x; x += 15 )
 355     {
 356         dc.DrawLine(x, 0, x, size.y);
 357     }
 358
 359     for ( int y = 0; y < size.y; y += 15 )
 360     {
 361         dc.DrawLine(0, y, size.x, y);
 362     }
 363
 364     dc.SetTextForeground(*wxRED);
 365     dc.SetBackgroundMode(wxSOLID);
 366     dc.DrawText("This text is drawn from OnEraseBackground", 60, 160);
 367 }
 368