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/custombgwin.h"
  34 #include "wx/dcbuffer.h"
  35
  36 // ----------------------------------------------------------------------------
  37 // resources
  38 // ----------------------------------------------------------------------------
  39
  40 // the application icon
  41 #if !defined(__WXMSW__) && !defined(__WXPM__)
  42     #include "../sample.xpm"
  43 #endif
  44
  45 // ----------------------------------------------------------------------------
  46 // private classes
  47 // ----------------------------------------------------------------------------
  48
  49 class MyApp : public wxApp
  50 {
  51 public:
  52     virtual bool OnInit();
  53 };
  54
  55
  56 class MyCanvas : public wxCustomBackgroundWindow<wxScrolledWindow>
  57 {
  58 public:
  59     MyCanvas(wxFrame *parent);
  60
  61     void UseBuffer(bool useBuffer) { m_useBuffer = useBuffer; Refresh(); }
  62     bool UsesBuffer() const { return m_useBuffer; }
  63
  64     void UseBgBitmap(bool useBgBmp)
  65     {
  66         m_useBgBmp = useBgBmp;
  67         SetBackgroundBitmap(m_useBgBmp ? GetBgBitmap() : wxBitmap());
  68
  69         Refresh();
  70     }
  71
  72     void EraseBgInPaint(bool erase) { m_eraseBgInPaint = erase; Refresh(); }
  73
  74 private:
  75     void OnPaint( wxPaintEvent &event );
  76     void OnEraseBackground( wxEraseEvent &event );
  77
  78     void DoPaint(wxDC& dc);
  79
  80     // Create an easily recognizable background bitmap.
  81     static wxBitmap GetBgBitmap()
  82     {
  83         static const int BMP_SIZE = 40;
  84
  85         wxBitmap bmp(BMP_SIZE, BMP_SIZE);
  86         wxMemoryDC dc(bmp);
  87         dc.SetBackground(*wxCYAN);
  88         dc.Clear();
  89
  90         dc.SetPen(*wxBLUE_PEN);
  91         dc.DrawLine(0, BMP_SIZE/2, BMP_SIZE/2, 0);
  92         dc.DrawLine(BMP_SIZE/2, 0, BMP_SIZE, BMP_SIZE/2);
  93         dc.DrawLine(BMP_SIZE, BMP_SIZE/2, BMP_SIZE/2, BMP_SIZE);
  94         dc.DrawLine(BMP_SIZE/2, BMP_SIZE, 0, BMP_SIZE/2);
  95
  96         return bmp;
  97     }
  98
  99     wxBitmap    m_bitmap;
 100
 101     // use wxMemoryDC in OnPaint()?
 102     bool m_useBuffer;
 103
 104     // use background bitmap?
 105     bool m_useBgBmp;
 106
 107     // erase background in OnPaint()?
 108     bool m_eraseBgInPaint;
 109
 110
 111     DECLARE_EVENT_TABLE()
 112 };
 113
 114 class MyFrame : public wxFrame
 115 {
 116 public:
 117     MyFrame();
 118
 119 private:
 120     void OnUseBuffer(wxCommandEvent& event);
 121     void OnUseBgBitmap(wxCommandEvent& event);
 122     void OnEraseBgInPaint(wxCommandEvent& event);
 123     void OnChangeBgStyle(wxCommandEvent& event);
 124     void OnQuit(wxCommandEvent& event);
 125     void OnAbout(wxCommandEvent& event);
 126
 127     // we can only use double-buffering with wxBG_STYLE_PAINT
 128     void OnUpdateUIUseBuffer(wxUpdateUIEvent& event)
 129     {
 130         event.Enable( m_canvas->GetBackgroundStyle() == wxBG_STYLE_PAINT );
 131     }
 132
 133     void OnUpdateUIChangeBgStyle(wxUpdateUIEvent& event)
 134     {
 135         event.Enable( !m_canvas->UsesBuffer() );
 136     }
 137
 138     MyCanvas *m_canvas;
 139
 140     DECLARE_EVENT_TABLE()
 141 };
 142
 143 class ControlWithTransparency : public wxWindow
 144 {
 145 public:
 146     ControlWithTransparency(wxWindow *parent,
 147                             const wxPoint& pos,
 148                             const wxSize& size)
 149         : wxWindow(parent, wxID_ANY, pos, size, wxBORDER_NONE)
 150     {
 151         Connect(wxEVT_PAINT,
 152                 wxPaintEventHandler(ControlWithTransparency::OnPaint));
 153     }
 154
 155     virtual bool HasTransparentBackground() { return true; }
 156
 157 private:
 158     void OnPaint( wxPaintEvent& WXUNUSED(event) )
 159     {
 160         wxPaintDC dc(this);
 161
 162         dc.SetPen(*wxRED_PEN);
 163         dc.SetBrush(*wxTRANSPARENT_BRUSH);
 164         dc.DrawRectangle(GetClientSize());
 165
 166         dc.SetTextForeground(*wxBLUE);
 167         dc.SetBackgroundMode(wxTRANSPARENT);
 168         dc.DrawText("This is custom control with transparency", 0, 2);
 169     }
 170 };
 171
 172 // ----------------------------------------------------------------------------
 173 // constants
 174 // ----------------------------------------------------------------------------
 175
 176 enum
 177 {
 178     // menu items
 179     Erase_Menu_UseBuffer = 100,
 180     Erase_Menu_UseBgBitmap,
 181     Erase_Menu_EraseBgInPaint,
 182     Erase_Menu_BgStyleErase,
 183     Erase_Menu_BgStyleSystem,
 184     Erase_Menu_BgStylePaint,
 185     Erase_Menu_Exit = wxID_EXIT,
 186     Erase_Menu_About = wxID_ABOUT
 187 };
 188
 189
 190 // ----------------------------------------------------------------------------
 191 // the application class
 192 // ----------------------------------------------------------------------------
 193
 194 IMPLEMENT_APP(MyApp)
 195
 196 bool MyApp::OnInit()
 197 {
 198     if ( !wxApp::OnInit() )
 199         return false;
 200
 201     MyFrame *frame = new MyFrame;
 202
 203     frame->Show(true);
 204
 205     return true;
 206 }
 207
 208 // ----------------------------------------------------------------------------
 209 // main frame
 210 // ----------------------------------------------------------------------------
 211
 212 BEGIN_EVENT_TABLE(MyFrame, wxFrame)
 213     EVT_MENU(Erase_Menu_UseBuffer, MyFrame::OnUseBuffer)
 214     EVT_MENU(Erase_Menu_UseBgBitmap, MyFrame::OnUseBgBitmap)
 215     EVT_MENU(Erase_Menu_EraseBgInPaint, MyFrame::OnEraseBgInPaint)
 216     EVT_MENU_RANGE(Erase_Menu_BgStyleErase, Erase_Menu_BgStylePaint,
 217                    MyFrame::OnChangeBgStyle)
 218
 219     EVT_MENU(Erase_Menu_Exit,  MyFrame::OnQuit)
 220     EVT_MENU(Erase_Menu_About, MyFrame::OnAbout)
 221
 222     EVT_UPDATE_UI(Erase_Menu_UseBuffer, MyFrame::OnUpdateUIUseBuffer)
 223     EVT_UPDATE_UI_RANGE(Erase_Menu_BgStyleErase, Erase_Menu_BgStylePaint,
 224                         MyFrame::OnUpdateUIChangeBgStyle)
 225 END_EVENT_TABLE()
 226
 227 // frame constructor
 228 MyFrame::MyFrame()
 229        : wxFrame(NULL, wxID_ANY, "Erase sample",
 230                  wxPoint(50, 50), wxSize(450, 340))
 231 {
 232     SetIcon(wxICON(sample));
 233
 234     wxMenu *menuFile = new wxMenu("", wxMENU_TEAROFF);
 235     menuFile->AppendCheckItem(Erase_Menu_UseBuffer, "&Use memory DC\tCtrl-M");
 236     menuFile->AppendCheckItem(Erase_Menu_UseBgBitmap,
 237                               "Use background &bitmap\tCtrl-B");
 238     menuFile->AppendCheckItem(Erase_Menu_EraseBgInPaint,
 239                               "&Erase background in EVT_PAINT\tCtrl-R");
 240     menuFile->AppendSeparator();
 241     menuFile->AppendRadioItem(Erase_Menu_BgStyleErase,
 242                               "Use wxBG_STYLE_&ERASE\tCtrl-E");
 243     menuFile->AppendRadioItem(Erase_Menu_BgStyleSystem,
 244                               "Use wxBG_STYLE_&SYSTEM\tCtrl-S");
 245     menuFile->AppendRadioItem(Erase_Menu_BgStylePaint,
 246                               "Use wxBG_STYLE_&PAINT\tCtrl-P");
 247     menuFile->AppendSeparator();
 248     menuFile->Append(Erase_Menu_Exit, "E&xit\tAlt-X", "Quit this program");
 249
 250
 251     wxMenu *helpMenu = new wxMenu;
 252     helpMenu->Append(Erase_Menu_About, "&About...\tCtrl-A", "Show about dialog");
 253
 254     wxMenuBar *menuBar = new wxMenuBar();
 255     menuBar->Append(menuFile, "&File");
 256     menuBar->Append(helpMenu, "&Help");
 257
 258     SetMenuBar(menuBar);
 259
 260     m_canvas = new MyCanvas( this );
 261 }
 262
 263
 264 void MyFrame::OnUseBuffer(wxCommandEvent& event)
 265 {
 266     m_canvas->UseBuffer(event.IsChecked());
 267 }
 268
 269 void MyFrame::OnUseBgBitmap(wxCommandEvent& event)
 270 {
 271     m_canvas->UseBgBitmap(event.IsChecked());
 272 }
 273
 274 void MyFrame::OnEraseBgInPaint(wxCommandEvent& event)
 275 {
 276     m_canvas->EraseBgInPaint(event.IsChecked());
 277 }
 278
 279 void MyFrame::OnChangeBgStyle(wxCommandEvent& event)
 280 {
 281     int style = wxBG_STYLE_ERASE + event.GetId() - Erase_Menu_BgStyleErase;
 282     m_canvas->SetBackgroundStyle(static_cast<wxBackgroundStyle>(style));
 283
 284     m_canvas->Refresh();
 285 }
 286
 287 void MyFrame::OnQuit(wxCommandEvent& WXUNUSED(event))
 288 {
 289     Close(true);
 290 }
 291
 292 void MyFrame::OnAbout(wxCommandEvent& WXUNUSED(event))
 293 {
 294     wxMessageBox
 295     (
 296         "This sample shows differences between different background styles "
 297         "and how you may draw custom background.\n"
 298         "\n"
 299         "(c) 1998 Robert Roebling\n"
 300         "(c) 2009 Vadim Zeitlin\n",
 301         "About Erase Sample",
 302         wxOK | wxICON_INFORMATION,
 303         this
 304     );
 305 }
 306
 307
 308 BEGIN_EVENT_TABLE(MyCanvas, wxScrolledWindow)
 309     EVT_PAINT(MyCanvas::OnPaint)
 310     EVT_ERASE_BACKGROUND(MyCanvas::OnEraseBackground)
 311 END_EVENT_TABLE()
 312
 313 MyCanvas::MyCanvas(wxFrame *parent)
 314 {
 315     Create(parent, wxID_ANY);
 316
 317     m_useBuffer = false;
 318     m_useBgBmp = false;
 319     m_eraseBgInPaint = false;
 320
 321     SetScrollbars( 10, 10, 40, 100, 0, 0 );
 322
 323     m_bitmap = wxBitmap( wxICON(sample) );
 324
 325     new wxStaticBitmap( this, wxID_ANY, m_bitmap, wxPoint(80,20) );
 326
 327     new wxStaticText(this, wxID_ANY,
 328                      "Left bitmap is a wxStaticBitmap,\n"
 329                      "right one drawn directly",
 330                      wxPoint(150, 20));
 331
 332     new ControlWithTransparency(this, wxPoint(65, 125), wxSize(300, 22));
 333
 334     SetFocusIgnoringChildren();
 335     SetBackgroundColour(*wxCYAN);
 336 }
 337
 338 void MyCanvas::DoPaint(wxDC& dc)
 339 {
 340     if ( m_eraseBgInPaint )
 341     {
 342         dc.SetBackground(*wxLIGHT_GREY);
 343         dc.Clear();
 344
 345         dc.DrawText("Background erased in OnPaint", 65, 110);
 346     }
 347     else if ( GetBackgroundStyle() == wxBG_STYLE_PAINT )
 348     {
 349         dc.SetTextForeground(*wxRED);
 350         dc.DrawText("You must enable erasing background in OnPaint to avoid "
 351                     "display corruption", 65, 110);
 352     }
 353
 354     dc.DrawBitmap( m_bitmap, 20, 20, true );
 355
 356     dc.SetTextForeground(*wxRED);
 357     dc.DrawText("This text is drawn from OnPaint", 65, 65);
 358 }
 359
 360 void MyCanvas::OnPaint( wxPaintEvent &WXUNUSED(event) )
 361 {
 362     if ( m_useBuffer )
 363     {
 364         wxAutoBufferedPaintDC dc(this);
 365         PrepareDC(dc);
 366
 367         DoPaint(dc);
 368     }
 369     else
 370     {
 371         wxPaintDC dc(this);
 372         PrepareDC(dc);
 373
 374         DoPaint(dc);
 375     }
 376 }
 377
 378 void MyCanvas::OnEraseBackground( wxEraseEvent& event )
 379 {
 380     // We must not erase the background ourselves if we asked wxPanel to erase
 381     // it using a background bitmap.
 382     if ( m_useBgBmp )
 383     {
 384         event.Skip();
 385         return;
 386     }
 387
 388     wxASSERT_MSG
 389     (
 390         GetBackgroundStyle() == wxBG_STYLE_ERASE,
 391         "shouldn't be called unless background style is \"erase\""
 392     );
 393
 394     wxDC& dc = *event.GetDC();
 395     dc.SetPen(*wxGREEN_PEN);
 396
 397     PrepareDC( dc );
 398
 399     // clear any junk currently displayed
 400     dc.Clear();
 401
 402     const wxSize size = GetClientSize();
 403     for ( int x = 0; x < size.x; x += 15 )
 404     {
 405         dc.DrawLine(x, 0, x, size.y);
 406     }
 407
 408     for ( int y = 0; y < size.y; y += 15 )
 409     {
 410         dc.DrawLine(0, y, size.x, y);
 411     }
 412
 413     dc.SetTextForeground(*wxRED);
 414     dc.SetBackgroundMode(wxSOLID);
 415     dc.DrawText("This text is drawn from OnEraseBackground", 60, 160);
 416 }
 417