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