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
  39 // the application icon
  40 #if !defined(__WXMSW__) && !defined(__WXPM__)
  41     #include "../sample.xpm"
  42 #endif
  43
  44 // ----------------------------------------------------------------------------
  45 // private classes
  46 // ----------------------------------------------------------------------------
  47
  48 class MyApp : public wxApp
  49 {
  50 public:
  51     virtual bool OnInit();
  52 };
  53
  54
  55 class MyCanvas : public wxScrolledWindow
  56 {
  57 public:
  58     MyCanvas(wxFrame *parent);
  59
  60     void UseBuffer(bool useBuffer) { m_useBuffer = useBuffer; Refresh(); }
  61     bool UsesBuffer() const { return m_useBuffer; }
  62
  63     void EraseBgInPaint(bool erase) { m_eraseBgInPaint = erase; Refresh(); }
  64
  65 private:
  66     void OnPaint( wxPaintEvent &event );
  67     void OnChar( wxKeyEvent &event );
  68     void OnEraseBackground( wxEraseEvent &event );
  69
  70     void DoPaint(wxDC& dc);
  71
  72
  73     wxBitmap    m_bitmap;
  74     wxString    m_text;
  75
  76     // use wxMemoryDC in OnPaint()?
  77     bool m_useBuffer;
  78
  79     // erase background in OnPaint()?
  80     bool m_eraseBgInPaint;
  81
  82
  83     DECLARE_EVENT_TABLE()
  84 };
  85
  86 class MyFrame : public wxFrame
  87 {
  88 public:
  89     MyFrame();
  90
  91 private:
  92     void OnUseBuffer(wxCommandEvent& event);
  93     void OnEraseBgInPaint(wxCommandEvent& event);
  94     void OnChangeBgStyle(wxCommandEvent& event);
  95     void OnQuit(wxCommandEvent& event);
  96     void OnAbout(wxCommandEvent& event);
  97
  98     // we can only use double-buffering with wxBG_STYLE_PAINT
  99     void OnUpdateUIUseBuffer(wxUpdateUIEvent& event)
 100     {
 101         event.Enable( m_canvas->GetBackgroundStyle() == wxBG_STYLE_PAINT );
 102     }
 103
 104     void OnUpdateUIChangeBgStyle(wxUpdateUIEvent& event)
 105     {
 106         event.Enable( !m_canvas->UsesBuffer() );
 107     }
 108
 109     MyCanvas *m_canvas;
 110
 111     DECLARE_EVENT_TABLE()
 112 };
 113
 114
 115 // ----------------------------------------------------------------------------
 116 // constants
 117 // ----------------------------------------------------------------------------
 118
 119 enum
 120 {
 121     // menu items
 122     Erase_Menu_UseBuffer = 100,
 123     Erase_Menu_EraseBgInPaint,
 124     Erase_Menu_BgStyleErase,
 125     Erase_Menu_BgStyleSystem,
 126     Erase_Menu_BgStylePaint,
 127     Erase_Menu_Exit = wxID_EXIT,
 128     Erase_Menu_About = wxID_ABOUT
 129 };
 130
 131
 132 // ----------------------------------------------------------------------------
 133 // the application class
 134 // ----------------------------------------------------------------------------
 135
 136 IMPLEMENT_APP(MyApp)
 137
 138 bool MyApp::OnInit()
 139 {
 140     if ( !wxApp::OnInit() )
 141         return false;
 142
 143     MyFrame *frame = new MyFrame;
 144
 145     frame->Show(true);
 146
 147     return true;
 148 }
 149
 150 // ----------------------------------------------------------------------------
 151 // main frame
 152 // ----------------------------------------------------------------------------
 153
 154 BEGIN_EVENT_TABLE(MyFrame, wxFrame)
 155     EVT_MENU(Erase_Menu_UseBuffer, MyFrame::OnUseBuffer)
 156     EVT_MENU(Erase_Menu_EraseBgInPaint, MyFrame::OnEraseBgInPaint)
 157     EVT_MENU_RANGE(Erase_Menu_BgStyleErase, Erase_Menu_BgStylePaint,
 158                    MyFrame::OnChangeBgStyle)
 159
 160     EVT_MENU(Erase_Menu_Exit,  MyFrame::OnQuit)
 161     EVT_MENU(Erase_Menu_About, MyFrame::OnAbout)
 162
 163     EVT_UPDATE_UI(Erase_Menu_UseBuffer, MyFrame::OnUpdateUIUseBuffer)
 164     EVT_UPDATE_UI_RANGE(Erase_Menu_BgStyleErase, Erase_Menu_BgStylePaint,
 165                         MyFrame::OnUpdateUIChangeBgStyle)
 166 END_EVENT_TABLE()
 167
 168 // frame constructor
 169 MyFrame::MyFrame()
 170        : wxFrame(NULL, wxID_ANY, "Erase sample",
 171                  wxPoint(50, 50), wxSize(450, 340))
 172 {
 173     SetIcon(wxICON(sample));
 174
 175     wxMenu *menuFile = new wxMenu("", wxMENU_TEAROFF);
 176     menuFile->AppendCheckItem(Erase_Menu_UseBuffer, "&Use memory DC\tCtrl-M");
 177     menuFile->AppendCheckItem(Erase_Menu_EraseBgInPaint,
 178                               "&Erase background in EVT_PAINT\tCtrl-R");
 179     menuFile->AppendSeparator();
 180     menuFile->AppendRadioItem(Erase_Menu_BgStyleErase,
 181                               "Use wxBG_STYLE_&ERASE\tCtrl-E");
 182     menuFile->AppendRadioItem(Erase_Menu_BgStyleSystem,
 183                               "Use wxBG_STYLE_&SYSTEM\tCtrl-S");
 184     menuFile->AppendRadioItem(Erase_Menu_BgStylePaint,
 185                               "Use wxBG_STYLE_&PAINT\tCtrl-P");
 186     menuFile->AppendSeparator();
 187     menuFile->Append(Erase_Menu_Exit, "E&xit\tAlt-X", "Quit this program");
 188
 189
 190     wxMenu *helpMenu = new wxMenu;
 191     helpMenu->Append(Erase_Menu_About, "&About...\tCtrl-A", "Show about dialog");
 192
 193     wxMenuBar *menuBar = new wxMenuBar();
 194     menuBar->Append(menuFile, "&File");
 195     menuBar->Append(helpMenu, "&Help");
 196
 197     SetMenuBar(menuBar);
 198
 199     m_canvas = new MyCanvas( this );
 200 }
 201
 202
 203 void MyFrame::OnUseBuffer(wxCommandEvent& event)
 204 {
 205     m_canvas->UseBuffer(event.IsChecked());
 206 }
 207
 208 void MyFrame::OnEraseBgInPaint(wxCommandEvent& event)
 209 {
 210     m_canvas->EraseBgInPaint(event.IsChecked());
 211 }
 212
 213 void MyFrame::OnChangeBgStyle(wxCommandEvent& event)
 214 {
 215     int style = wxBG_STYLE_ERASE + event.GetId() - Erase_Menu_BgStyleErase;
 216     m_canvas->SetBackgroundStyle(static_cast<wxBackgroundStyle>(style));
 217
 218     m_canvas->Refresh();
 219 }
 220
 221 void MyFrame::OnQuit(wxCommandEvent& WXUNUSED(event))
 222 {
 223     Close(true);
 224 }
 225
 226 void MyFrame::OnAbout(wxCommandEvent& WXUNUSED(event))
 227 {
 228     wxMessageBox
 229     (
 230         "This sample shows differences between different background styles "
 231         "and how you may draw custom background.\n"
 232         "\n"
 233         "(c) 1998 Robert Roebling\n"
 234         "(c) 2009 Vadim Zeitlin\n",
 235         "About Erase Sample",
 236         wxOK | wxICON_INFORMATION,
 237         this
 238     );
 239 }
 240
 241
 242 BEGIN_EVENT_TABLE(MyCanvas, wxScrolledWindow)
 243     EVT_PAINT(MyCanvas::OnPaint)
 244     EVT_CHAR(MyCanvas::OnChar)
 245     EVT_ERASE_BACKGROUND(MyCanvas::OnEraseBackground)
 246 END_EVENT_TABLE()
 247
 248 MyCanvas::MyCanvas(wxFrame *parent)
 249         : wxScrolledWindow(parent, wxID_ANY)
 250 {
 251     m_useBuffer = false;
 252     m_eraseBgInPaint = false;
 253
 254     SetScrollbars( 10, 10, 40, 100, 0, 0 );
 255
 256     m_bitmap = wxBitmap( wxICON(sample) );
 257
 258     new wxStaticBitmap( this, wxID_ANY, m_bitmap, wxPoint(80,20) );
 259
 260     new wxStaticText(this, wxID_ANY,
 261                      "Left bitmap is a wxStaticBitmap,\n"
 262                      "right one drawn directly",
 263                      wxPoint(150, 20));
 264
 265     SetFocusIgnoringChildren();
 266     SetBackgroundColour(*wxCYAN);
 267 }
 268
 269 void MyCanvas::OnChar( wxKeyEvent &event )
 270 {
 271 #if wxUSE_UNICODE
 272     if (event.m_uniChar)
 273     {
 274         m_text += event.m_uniChar;
 275         Refresh();
 276         return;
 277     }
 278 #endif
 279
 280     // some test cases
 281     switch (event.m_keyCode)
 282     {
 283         case WXK_UP: m_text += wxT( "<UP>" ); break;
 284         case WXK_LEFT: m_text += wxT( "<LEFT>" ); break;
 285         case WXK_RIGHT: m_text += wxT( "<RIGHT>" ); break;
 286         case WXK_DOWN: m_text += wxT( "<DOWN>" ); break;
 287         case WXK_RETURN: m_text += wxT( "<ENTER>" ); break;
 288         default: m_text += (wxChar)event.m_keyCode; break;
 289     }
 290 }
 291
 292 void MyCanvas::DoPaint(wxDC& dc)
 293 {
 294     if ( m_eraseBgInPaint )
 295     {
 296         dc.SetBackground(*wxLIGHT_GREY);
 297         dc.Clear();
 298
 299         dc.DrawText("Background erased in OnPaint", 65, 110);
 300     }
 301     else if ( GetBackgroundStyle() == wxBG_STYLE_PAINT )
 302     {
 303         dc.SetTextForeground(*wxRED);
 304         dc.DrawText("You must enable erasing background in OnPaint to avoid "
 305                     "display corruption", 65, 110);
 306     }
 307
 308     dc.SetBrush( *wxBLACK_BRUSH );
 309     dc.DrawRectangle( 10,10,60,50 );
 310
 311     dc.DrawBitmap( m_bitmap, 20, 20, true );
 312
 313     dc.SetTextForeground(*wxWHITE);
 314     dc.DrawText("This text is drawn from OnPaint", 65, 65);
 315
 316     wxString tmp;
 317     tmp.Printf("Hit any key to display more text: %s", m_text);
 318
 319     int w,h;
 320     dc.GetTextExtent( tmp, &w, &h );
 321     dc.DrawRectangle( 65, 85, w, h );
 322     dc.DrawText( tmp, 65, 85 );
 323 }
 324
 325 void MyCanvas::OnPaint( wxPaintEvent &WXUNUSED(event) )
 326 {
 327     if ( m_useBuffer )
 328     {
 329         wxAutoBufferedPaintDC dc(this);
 330         PrepareDC(dc);
 331
 332         DoPaint(dc);
 333     }
 334     else
 335     {
 336         wxPaintDC dc(this);
 337         PrepareDC(dc);
 338
 339         DoPaint(dc);
 340     }
 341 }
 342
 343 void MyCanvas::OnEraseBackground( wxEraseEvent& event )
 344 {
 345     wxASSERT_MSG
 346     (
 347         GetBackgroundStyle() == wxBG_STYLE_ERASE,
 348         "shouldn't be called unless background style is \"erase\""
 349     );
 350
 351     wxDC& dc = *event.GetDC();
 352     dc.SetPen(*wxGREEN_PEN);
 353
 354     PrepareDC( dc );
 355
 356     // clear any junk currently displayed
 357     dc.Clear();
 358
 359     const wxSize size = GetClientSize();
 360     for ( int x = 0; x < size.x; x += 15 )
 361     {
 362         dc.DrawLine(x, 0, x, size.y);
 363     }
 364
 365     for ( int y = 0; y < size.y; y += 15 )
 366     {
 367         dc.DrawLine(0, y, size.x, y);
 368     }
 369
 370     dc.SetTextForeground(*wxRED);
 371     dc.SetBackgroundMode(wxSOLID);
 372     dc.DrawText("This text is drawn from OnEraseBackground", 60, 160);
 373 }
 374