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 // Copyright:   (c) 1998 Robert Roebling
   7 //              (c) 2009 Vadim Zeitlin
   8 // Licence:     wxWindows licence
   9 /////////////////////////////////////////////////////////////////////////////
  10
  11 // ============================================================================
  12 // declarations
  13 // ============================================================================
  14
  15 // ----------------------------------------------------------------------------
  16 // headers
  17 // ----------------------------------------------------------------------------
  18
  19 // For compilers that support precompilation, includes "wx/wx.h".
  20 #include "wx/wxprec.h"
  21
  22 #ifdef __BORLANDC__
  23     #pragma hdrstop
  24 #endif
  25
  26 // for all others, include the necessary headers (this file is usually all you
  27 // need because it includes almost all "standard" wxWidgets headers)
  28 #ifndef WX_PRECOMP
  29     #include "wx/wx.h"
  30 #endif
  31
  32 #include "wx/custombgwin.h"
  33 #include "wx/dcbuffer.h"
  34 #include "wx/artprov.h"
  35
  36 // ----------------------------------------------------------------------------
  37 // resources
  38 // ----------------------------------------------------------------------------
  39
  40 // the application icon
  41 #ifndef wxHAS_IMAGES_IN_RESOURCES
  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     {
 150         wxString reason;
 151         if ( parent->IsTransparentBackgroundSupported(&reason) )
 152         {
 153             SetBackgroundStyle (wxBG_STYLE_TRANSPARENT);
 154             m_message = "This is custom control with transparency";
 155         }
 156         else
 157         {
 158             m_message = "Transparency not supported, check tooltip.";
 159         }
 160
 161         Create (parent, wxID_ANY, pos, size, wxBORDER_NONE);
 162         Connect(wxEVT_PAINT,
 163                 wxPaintEventHandler(ControlWithTransparency::OnPaint));
 164
 165         if ( !reason.empty() )
 166         {
 167             // This can be only done now, after creating the window.
 168             SetToolTip(reason);
 169         }
 170     }
 171
 172 private:
 173     void OnPaint( wxPaintEvent& WXUNUSED(event) )
 174     {
 175         wxPaintDC dc(this);
 176
 177         dc.SetPen(*wxRED_PEN);
 178         dc.SetBrush(*wxTRANSPARENT_BRUSH);
 179         dc.DrawRectangle(GetClientSize());
 180
 181         dc.SetTextForeground(*wxBLUE);
 182         dc.SetBackgroundMode(wxTRANSPARENT);
 183         dc.DrawText(m_message, 0, 2);
 184
 185         // Draw some bitmap/icon to ensure transparent bitmaps are indeed
 186         //  transparent on transparent windows
 187         wxBitmap bmp(wxArtProvider::GetBitmap(wxART_WARNING, wxART_MENU));
 188         wxIcon icon(wxArtProvider::GetIcon(wxART_GOTO_LAST, wxART_MENU));
 189         dc.DrawBitmap (bmp, GetSize().x - 1 - bmp.GetWidth(), 2);
 190         dc.DrawIcon(icon, GetSize().x - 1 - bmp.GetWidth()-icon.GetWidth(), 2);
 191     }
 192
 193     wxString m_message;
 194 };
 195
 196 // ----------------------------------------------------------------------------
 197 // constants
 198 // ----------------------------------------------------------------------------
 199
 200 enum
 201 {
 202     // menu items
 203     Erase_Menu_UseBuffer = 100,
 204     Erase_Menu_UseBgBitmap,
 205     Erase_Menu_EraseBgInPaint,
 206     Erase_Menu_BgStyleErase,
 207     Erase_Menu_BgStyleSystem,
 208     Erase_Menu_BgStylePaint,
 209     Erase_Menu_Exit = wxID_EXIT,
 210     Erase_Menu_About = wxID_ABOUT
 211 };
 212
 213
 214 // ----------------------------------------------------------------------------
 215 // the application class
 216 // ----------------------------------------------------------------------------
 217
 218 IMPLEMENT_APP(MyApp)
 219
 220 bool MyApp::OnInit()
 221 {
 222     if ( !wxApp::OnInit() )
 223         return false;
 224
 225     MyFrame *frame = new MyFrame;
 226
 227     frame->Show(true);
 228
 229     return true;
 230 }
 231
 232 // ----------------------------------------------------------------------------
 233 // main frame
 234 // ----------------------------------------------------------------------------
 235
 236 BEGIN_EVENT_TABLE(MyFrame, wxFrame)
 237     EVT_MENU(Erase_Menu_UseBuffer, MyFrame::OnUseBuffer)
 238     EVT_MENU(Erase_Menu_UseBgBitmap, MyFrame::OnUseBgBitmap)
 239     EVT_MENU(Erase_Menu_EraseBgInPaint, MyFrame::OnEraseBgInPaint)
 240     EVT_MENU_RANGE(Erase_Menu_BgStyleErase, Erase_Menu_BgStylePaint,
 241                    MyFrame::OnChangeBgStyle)
 242
 243     EVT_MENU(Erase_Menu_Exit,  MyFrame::OnQuit)
 244     EVT_MENU(Erase_Menu_About, MyFrame::OnAbout)
 245
 246     EVT_UPDATE_UI(Erase_Menu_UseBuffer, MyFrame::OnUpdateUIUseBuffer)
 247     EVT_UPDATE_UI_RANGE(Erase_Menu_BgStyleErase, Erase_Menu_BgStylePaint,
 248                         MyFrame::OnUpdateUIChangeBgStyle)
 249 END_EVENT_TABLE()
 250
 251 // frame constructor
 252 MyFrame::MyFrame()
 253        : wxFrame(NULL, wxID_ANY, "Erase sample",
 254                  wxPoint(50, 50), wxSize(450, 340))
 255 {
 256     SetIcon(wxICON(sample));
 257
 258     wxMenu *menuFile = new wxMenu("", wxMENU_TEAROFF);
 259     menuFile->AppendCheckItem(Erase_Menu_UseBuffer, "&Use memory DC\tCtrl-M");
 260     menuFile->AppendCheckItem(Erase_Menu_UseBgBitmap,
 261                               "Use background &bitmap\tCtrl-B");
 262     menuFile->AppendCheckItem(Erase_Menu_EraseBgInPaint,
 263                               "&Erase background in EVT_PAINT\tCtrl-R");
 264     menuFile->AppendSeparator();
 265     menuFile->AppendRadioItem(Erase_Menu_BgStyleErase,
 266                               "Use wxBG_STYLE_&ERASE\tCtrl-E");
 267     menuFile->AppendRadioItem(Erase_Menu_BgStyleSystem,
 268                               "Use wxBG_STYLE_&SYSTEM\tCtrl-S");
 269     menuFile->AppendRadioItem(Erase_Menu_BgStylePaint,
 270                               "Use wxBG_STYLE_&PAINT\tCtrl-P");
 271     menuFile->AppendSeparator();
 272     menuFile->Append(Erase_Menu_Exit, "E&xit\tAlt-X", "Quit this program");
 273
 274
 275     wxMenu *helpMenu = new wxMenu;
 276     helpMenu->Append(Erase_Menu_About, "&About\tCtrl-A", "Show about dialog");
 277
 278     wxMenuBar *menuBar = new wxMenuBar();
 279     menuBar->Append(menuFile, "&File");
 280     menuBar->Append(helpMenu, "&Help");
 281
 282     SetMenuBar(menuBar);
 283
 284     m_canvas = new MyCanvas( this );
 285 }
 286
 287
 288 void MyFrame::OnUseBuffer(wxCommandEvent& event)
 289 {
 290     m_canvas->UseBuffer(event.IsChecked());
 291 }
 292
 293 void MyFrame::OnUseBgBitmap(wxCommandEvent& event)
 294 {
 295     m_canvas->UseBgBitmap(event.IsChecked());
 296 }
 297
 298 void MyFrame::OnEraseBgInPaint(wxCommandEvent& event)
 299 {
 300     m_canvas->EraseBgInPaint(event.IsChecked());
 301 }
 302
 303 void MyFrame::OnChangeBgStyle(wxCommandEvent& event)
 304 {
 305     int style = wxBG_STYLE_ERASE + event.GetId() - Erase_Menu_BgStyleErase;
 306     m_canvas->SetBackgroundStyle(static_cast<wxBackgroundStyle>(style));
 307
 308     m_canvas->Refresh();
 309 }
 310
 311 void MyFrame::OnQuit(wxCommandEvent& WXUNUSED(event))
 312 {
 313     Close(true);
 314 }
 315
 316 void MyFrame::OnAbout(wxCommandEvent& WXUNUSED(event))
 317 {
 318     wxMessageBox
 319     (
 320         "This sample shows differences between different background styles "
 321         "and how you may draw custom background.\n"
 322         "\n"
 323         "(c) 1998 Robert Roebling\n"
 324         "(c) 2009 Vadim Zeitlin\n",
 325         "About Erase Sample",
 326         wxOK | wxICON_INFORMATION,
 327         this
 328     );
 329 }
 330
 331
 332 BEGIN_EVENT_TABLE(MyCanvas, wxScrolledWindow)
 333     EVT_PAINT(MyCanvas::OnPaint)
 334     EVT_ERASE_BACKGROUND(MyCanvas::OnEraseBackground)
 335 END_EVENT_TABLE()
 336
 337 MyCanvas::MyCanvas(wxFrame *parent)
 338 {
 339     Create(parent, wxID_ANY);
 340
 341     m_useBuffer = false;
 342     m_useBgBmp = false;
 343     m_eraseBgInPaint = false;
 344
 345     SetScrollbars( 10, 10, 40, 100, 0, 0 );
 346
 347     m_bitmap = wxBitmap( wxICON(sample) );
 348
 349     new wxStaticBitmap( this, wxID_ANY, m_bitmap, wxPoint(80,20) );
 350
 351     new wxStaticText(this, wxID_ANY,
 352                      "Left bitmap is a wxStaticBitmap,\n"
 353                      "right one drawn directly",
 354                      wxPoint(150, 20));
 355
 356     new ControlWithTransparency(this, wxPoint(65, 125), wxSize(350, 22));
 357
 358     SetFocusIgnoringChildren();
 359     SetBackgroundColour(*wxCYAN);
 360 }
 361
 362 void MyCanvas::DoPaint(wxDC& dc)
 363 {
 364     PrepareDC(dc);
 365
 366     if ( m_eraseBgInPaint )
 367     {
 368         dc.SetBackground(*wxLIGHT_GREY);
 369
 370         // Erase the entire virtual area, not just the client area.
 371         dc.SetPen(*wxTRANSPARENT_PEN);
 372         dc.SetBrush(GetBackgroundColour());
 373         dc.DrawRectangle(GetVirtualSize());
 374
 375         dc.DrawText("Background erased in OnPaint", 65, 110);
 376     }
 377     else if ( GetBackgroundStyle() == wxBG_STYLE_PAINT )
 378     {
 379         dc.SetTextForeground(*wxRED);
 380         dc.DrawText("You must enable erasing background in OnPaint to avoid "
 381                     "display corruption", 65, 110);
 382     }
 383
 384     dc.DrawBitmap( m_bitmap, 20, 20, true );
 385
 386     dc.SetTextForeground(*wxRED);
 387     dc.DrawText("This text is drawn from OnPaint", 65, 65);
 388 }
 389
 390 void MyCanvas::OnPaint( wxPaintEvent &WXUNUSED(event) )
 391 {
 392     if ( m_useBuffer )
 393     {
 394         wxAutoBufferedPaintDC dc(this);
 395         DoPaint(dc);
 396     }
 397     else
 398     {
 399         wxPaintDC dc(this);
 400         DoPaint(dc);
 401     }
 402 }
 403
 404 void MyCanvas::OnEraseBackground( wxEraseEvent& event )
 405 {
 406     // We must not erase the background ourselves if we asked wxPanel to erase
 407     // it using a background bitmap.
 408     if ( m_useBgBmp )
 409     {
 410         event.Skip();
 411         return;
 412     }
 413
 414     wxASSERT_MSG
 415     (
 416         GetBackgroundStyle() == wxBG_STYLE_ERASE,
 417         "shouldn't be called unless background style is \"erase\""
 418     );
 419
 420     wxDC& dc = *event.GetDC();
 421     dc.SetPen(*wxGREEN_PEN);
 422
 423     // clear any junk currently displayed
 424     dc.Clear();
 425
 426     PrepareDC( dc );
 427
 428     const wxSize size = GetVirtualSize();
 429     for ( int x = 0; x < size.x; x += 15 )
 430     {
 431         dc.DrawLine(x, 0, x, size.y);
 432     }
 433
 434     for ( int y = 0; y < size.y; y += 15 )
 435     {
 436         dc.DrawLine(0, y, size.x, y);
 437     }
 438
 439     dc.SetTextForeground(*wxRED);
 440     dc.SetBackgroundMode(wxSOLID);
 441     dc.DrawText("This text is drawn from OnEraseBackground", 60, 160);
 442 }
 443