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 #include "wx/artprov.h"
  36
  37 // ----------------------------------------------------------------------------
  38 // resources
  39 // ----------------------------------------------------------------------------
  40
  41 // the application icon
  42 #ifndef wxHAS_IMAGES_IN_RESOURCES
  43     #include "../sample.xpm"
  44 #endif
  45
  46 // ----------------------------------------------------------------------------
  47 // private classes
  48 // ----------------------------------------------------------------------------
  49
  50 class MyApp : public wxApp
  51 {
  52 public:
  53     virtual bool OnInit();
  54 };
  55
  56
  57 class MyCanvas : public wxCustomBackgroundWindow<wxScrolledWindow>
  58 {
  59 public:
  60     MyCanvas(wxFrame *parent);
  61
  62     void UseBuffer(bool useBuffer) { m_useBuffer = useBuffer; Refresh(); }
  63     bool UsesBuffer() const { return m_useBuffer; }
  64
  65     void UseBgBitmap(bool useBgBmp)
  66     {
  67         m_useBgBmp = useBgBmp;
  68         SetBackgroundBitmap(m_useBgBmp ? GetBgBitmap() : wxBitmap());
  69
  70         Refresh();
  71     }
  72
  73     void EraseBgInPaint(bool erase) { m_eraseBgInPaint = erase; Refresh(); }
  74
  75 private:
  76     void OnPaint( wxPaintEvent &event );
  77     void OnEraseBackground( wxEraseEvent &event );
  78
  79     void DoPaint(wxDC& dc);
  80
  81     // Create an easily recognizable background bitmap.
  82     static wxBitmap GetBgBitmap()
  83     {
  84         static const int BMP_SIZE = 40;
  85
  86         wxBitmap bmp(BMP_SIZE, BMP_SIZE);
  87         wxMemoryDC dc(bmp);
  88         dc.SetBackground(*wxCYAN);
  89         dc.Clear();
  90
  91         dc.SetPen(*wxBLUE_PEN);
  92         dc.DrawLine(0, BMP_SIZE/2, BMP_SIZE/2, 0);
  93         dc.DrawLine(BMP_SIZE/2, 0, BMP_SIZE, BMP_SIZE/2);
  94         dc.DrawLine(BMP_SIZE, BMP_SIZE/2, BMP_SIZE/2, BMP_SIZE);
  95         dc.DrawLine(BMP_SIZE/2, BMP_SIZE, 0, BMP_SIZE/2);
  96
  97         return bmp;
  98     }
  99
 100     wxBitmap    m_bitmap;
 101
 102     // use wxMemoryDC in OnPaint()?
 103     bool m_useBuffer;
 104
 105     // use background bitmap?
 106     bool m_useBgBmp;
 107
 108     // erase background in OnPaint()?
 109     bool m_eraseBgInPaint;
 110
 111
 112     DECLARE_EVENT_TABLE()
 113 };
 114
 115 class MyFrame : public wxFrame
 116 {
 117 public:
 118     MyFrame();
 119
 120 private:
 121     void OnUseBuffer(wxCommandEvent& event);
 122     void OnUseBgBitmap(wxCommandEvent& event);
 123     void OnEraseBgInPaint(wxCommandEvent& event);
 124     void OnChangeBgStyle(wxCommandEvent& event);
 125     void OnQuit(wxCommandEvent& event);
 126     void OnAbout(wxCommandEvent& event);
 127
 128     // we can only use double-buffering with wxBG_STYLE_PAINT
 129     void OnUpdateUIUseBuffer(wxUpdateUIEvent& event)
 130     {
 131         event.Enable( m_canvas->GetBackgroundStyle() == wxBG_STYLE_PAINT );
 132     }
 133
 134     void OnUpdateUIChangeBgStyle(wxUpdateUIEvent& event)
 135     {
 136         event.Enable( !m_canvas->UsesBuffer() );
 137     }
 138
 139     MyCanvas *m_canvas;
 140
 141     DECLARE_EVENT_TABLE()
 142 };
 143
 144 class ControlWithTransparency : public wxWindow
 145 {
 146 public:
 147     ControlWithTransparency(wxWindow *parent,
 148                             const wxPoint& pos,
 149                             const wxSize& size)
 150     {
 151         wxString reason;
 152         if ( parent->IsTransparentBackgroundSupported(&reason) )
 153         {
 154             SetBackgroundStyle (wxBG_STYLE_TRANSPARENT);
 155             m_message = "This is custom control with transparency";
 156         }
 157         else
 158         {
 159             m_message = "Transparency not supported, check tooltip.";
 160         }
 161
 162         Create (parent, wxID_ANY, pos, size, wxBORDER_NONE);
 163         Connect(wxEVT_PAINT,
 164                 wxPaintEventHandler(ControlWithTransparency::OnPaint));
 165
 166         if ( !reason.empty() )
 167         {
 168             // This can be only done now, after creating the window.
 169             SetToolTip(reason);
 170         }
 171     }
 172
 173 private:
 174     void OnPaint( wxPaintEvent& WXUNUSED(event) )
 175     {
 176         wxPaintDC dc(this);
 177
 178         dc.SetPen(*wxRED_PEN);
 179         dc.SetBrush(*wxTRANSPARENT_BRUSH);
 180         dc.DrawRectangle(GetClientSize());
 181
 182         dc.SetTextForeground(*wxBLUE);
 183         dc.SetBackgroundMode(wxTRANSPARENT);
 184         dc.DrawText(m_message, 0, 2);
 185
 186         // Draw some bitmap/icon to ensure transparent bitmaps are indeed
 187         //  transparent on transparent windows
 188         wxBitmap bmp(wxArtProvider::GetBitmap(wxART_WARNING, wxART_MENU));
 189         wxIcon icon(wxArtProvider::GetIcon(wxART_GOTO_LAST, wxART_MENU));
 190         dc.DrawBitmap (bmp, GetSize().x - 1 - bmp.GetWidth(), 2);
 191         dc.DrawIcon(icon, GetSize().x - 1 - bmp.GetWidth()-icon.GetWidth(), 2);
 192     }
 193
 194     wxString m_message;
 195 };
 196
 197 // ----------------------------------------------------------------------------
 198 // constants
 199 // ----------------------------------------------------------------------------
 200
 201 enum
 202 {
 203     // menu items
 204     Erase_Menu_UseBuffer = 100,
 205     Erase_Menu_UseBgBitmap,
 206     Erase_Menu_EraseBgInPaint,
 207     Erase_Menu_BgStyleErase,
 208     Erase_Menu_BgStyleSystem,
 209     Erase_Menu_BgStylePaint,
 210     Erase_Menu_Exit = wxID_EXIT,
 211     Erase_Menu_About = wxID_ABOUT
 212 };
 213
 214
 215 // ----------------------------------------------------------------------------
 216 // the application class
 217 // ----------------------------------------------------------------------------
 218
 219 IMPLEMENT_APP(MyApp)
 220
 221 bool MyApp::OnInit()
 222 {
 223     if ( !wxApp::OnInit() )
 224         return false;
 225
 226     MyFrame *frame = new MyFrame;
 227
 228     frame->Show(true);
 229
 230     return true;
 231 }
 232
 233 // ----------------------------------------------------------------------------
 234 // main frame
 235 // ----------------------------------------------------------------------------
 236
 237 BEGIN_EVENT_TABLE(MyFrame, wxFrame)
 238     EVT_MENU(Erase_Menu_UseBuffer, MyFrame::OnUseBuffer)
 239     EVT_MENU(Erase_Menu_UseBgBitmap, MyFrame::OnUseBgBitmap)
 240     EVT_MENU(Erase_Menu_EraseBgInPaint, MyFrame::OnEraseBgInPaint)
 241     EVT_MENU_RANGE(Erase_Menu_BgStyleErase, Erase_Menu_BgStylePaint,
 242                    MyFrame::OnChangeBgStyle)
 243
 244     EVT_MENU(Erase_Menu_Exit,  MyFrame::OnQuit)
 245     EVT_MENU(Erase_Menu_About, MyFrame::OnAbout)
 246
 247     EVT_UPDATE_UI(Erase_Menu_UseBuffer, MyFrame::OnUpdateUIUseBuffer)
 248     EVT_UPDATE_UI_RANGE(Erase_Menu_BgStyleErase, Erase_Menu_BgStylePaint,
 249                         MyFrame::OnUpdateUIChangeBgStyle)
 250 END_EVENT_TABLE()
 251
 252 // frame constructor
 253 MyFrame::MyFrame()
 254        : wxFrame(NULL, wxID_ANY, "Erase sample",
 255                  wxPoint(50, 50), wxSize(450, 340))
 256 {
 257     SetIcon(wxICON(sample));
 258
 259     wxMenu *menuFile = new wxMenu("", wxMENU_TEAROFF);
 260     menuFile->AppendCheckItem(Erase_Menu_UseBuffer, "&Use memory DC\tCtrl-M");
 261     menuFile->AppendCheckItem(Erase_Menu_UseBgBitmap,
 262                               "Use background &bitmap\tCtrl-B");
 263     menuFile->AppendCheckItem(Erase_Menu_EraseBgInPaint,
 264                               "&Erase background in EVT_PAINT\tCtrl-R");
 265     menuFile->AppendSeparator();
 266     menuFile->AppendRadioItem(Erase_Menu_BgStyleErase,
 267                               "Use wxBG_STYLE_&ERASE\tCtrl-E");
 268     menuFile->AppendRadioItem(Erase_Menu_BgStyleSystem,
 269                               "Use wxBG_STYLE_&SYSTEM\tCtrl-S");
 270     menuFile->AppendRadioItem(Erase_Menu_BgStylePaint,
 271                               "Use wxBG_STYLE_&PAINT\tCtrl-P");
 272     menuFile->AppendSeparator();
 273     menuFile->Append(Erase_Menu_Exit, "E&xit\tAlt-X", "Quit this program");
 274
 275
 276     wxMenu *helpMenu = new wxMenu;
 277     helpMenu->Append(Erase_Menu_About, "&About\tCtrl-A", "Show about dialog");
 278
 279     wxMenuBar *menuBar = new wxMenuBar();
 280     menuBar->Append(menuFile, "&File");
 281     menuBar->Append(helpMenu, "&Help");
 282
 283     SetMenuBar(menuBar);
 284
 285     m_canvas = new MyCanvas( this );
 286 }
 287
 288
 289 void MyFrame::OnUseBuffer(wxCommandEvent& event)
 290 {
 291     m_canvas->UseBuffer(event.IsChecked());
 292 }
 293
 294 void MyFrame::OnUseBgBitmap(wxCommandEvent& event)
 295 {
 296     m_canvas->UseBgBitmap(event.IsChecked());
 297 }
 298
 299 void MyFrame::OnEraseBgInPaint(wxCommandEvent& event)
 300 {
 301     m_canvas->EraseBgInPaint(event.IsChecked());
 302 }
 303
 304 void MyFrame::OnChangeBgStyle(wxCommandEvent& event)
 305 {
 306     int style = wxBG_STYLE_ERASE + event.GetId() - Erase_Menu_BgStyleErase;
 307     m_canvas->SetBackgroundStyle(static_cast<wxBackgroundStyle>(style));
 308
 309     m_canvas->Refresh();
 310 }
 311
 312 void MyFrame::OnQuit(wxCommandEvent& WXUNUSED(event))
 313 {
 314     Close(true);
 315 }
 316
 317 void MyFrame::OnAbout(wxCommandEvent& WXUNUSED(event))
 318 {
 319     wxMessageBox
 320     (
 321         "This sample shows differences between different background styles "
 322         "and how you may draw custom background.\n"
 323         "\n"
 324         "(c) 1998 Robert Roebling\n"
 325         "(c) 2009 Vadim Zeitlin\n",
 326         "About Erase Sample",
 327         wxOK | wxICON_INFORMATION,
 328         this
 329     );
 330 }
 331
 332
 333 BEGIN_EVENT_TABLE(MyCanvas, wxScrolledWindow)
 334     EVT_PAINT(MyCanvas::OnPaint)
 335     EVT_ERASE_BACKGROUND(MyCanvas::OnEraseBackground)
 336 END_EVENT_TABLE()
 337
 338 MyCanvas::MyCanvas(wxFrame *parent)
 339 {
 340     Create(parent, wxID_ANY);
 341
 342     m_useBuffer = false;
 343     m_useBgBmp = false;
 344     m_eraseBgInPaint = false;
 345
 346     SetScrollbars( 10, 10, 40, 100, 0, 0 );
 347
 348     m_bitmap = wxBitmap( wxICON(sample) );
 349
 350     new wxStaticBitmap( this, wxID_ANY, m_bitmap, wxPoint(80,20) );
 351
 352     new wxStaticText(this, wxID_ANY,
 353                      "Left bitmap is a wxStaticBitmap,\n"
 354                      "right one drawn directly",
 355                      wxPoint(150, 20));
 356
 357     new ControlWithTransparency(this, wxPoint(65, 125), wxSize(350, 22));
 358
 359     SetFocusIgnoringChildren();
 360     SetBackgroundColour(*wxCYAN);
 361 }
 362
 363 void MyCanvas::DoPaint(wxDC& dc)
 364 {
 365     PrepareDC(dc);
 366
 367     if ( m_eraseBgInPaint )
 368     {
 369         dc.SetBackground(*wxLIGHT_GREY);
 370
 371         // Erase the entire virtual area, not just the client area.
 372         dc.SetPen(*wxTRANSPARENT_PEN);
 373         dc.SetBrush(GetBackgroundColour());
 374         dc.DrawRectangle(GetVirtualSize());
 375
 376         dc.DrawText("Background erased in OnPaint", 65, 110);
 377     }
 378     else if ( GetBackgroundStyle() == wxBG_STYLE_PAINT )
 379     {
 380         dc.SetTextForeground(*wxRED);
 381         dc.DrawText("You must enable erasing background in OnPaint to avoid "
 382                     "display corruption", 65, 110);
 383     }
 384
 385     dc.DrawBitmap( m_bitmap, 20, 20, true );
 386
 387     dc.SetTextForeground(*wxRED);
 388     dc.DrawText("This text is drawn from OnPaint", 65, 65);
 389 }
 390
 391 void MyCanvas::OnPaint( wxPaintEvent &WXUNUSED(event) )
 392 {
 393     if ( m_useBuffer )
 394     {
 395         wxAutoBufferedPaintDC dc(this);
 396         DoPaint(dc);
 397     }
 398     else
 399     {
 400         wxPaintDC dc(this);
 401         DoPaint(dc);
 402     }
 403 }
 404
 405 void MyCanvas::OnEraseBackground( wxEraseEvent& event )
 406 {
 407     // We must not erase the background ourselves if we asked wxPanel to erase
 408     // it using a background bitmap.
 409     if ( m_useBgBmp )
 410     {
 411         event.Skip();
 412         return;
 413     }
 414
 415     wxASSERT_MSG
 416     (
 417         GetBackgroundStyle() == wxBG_STYLE_ERASE,
 418         "shouldn't be called unless background style is \"erase\""
 419     );
 420
 421     wxDC& dc = *event.GetDC();
 422     dc.SetPen(*wxGREEN_PEN);
 423
 424     // clear any junk currently displayed
 425     dc.Clear();
 426
 427     PrepareDC( dc );
 428
 429     const wxSize size = GetVirtualSize();
 430     for ( int x = 0; x < size.x; x += 15 )
 431     {
 432         dc.DrawLine(x, 0, x, size.y);
 433     }
 434
 435     for ( int y = 0; y < size.y; y += 15 )
 436     {
 437         dc.DrawLine(0, y, size.x, y);
 438     }
 439
 440     dc.SetTextForeground(*wxRED);
 441     dc.SetBackgroundMode(wxSOLID);
 442     dc.DrawText("This text is drawn from OnEraseBackground", 60, 160);
 443 }
 444