1/////////////////////////////////////////////////////////////////////////////
2// Name:        erase.cpp
3// Purpose:     Erase wxWidgets sample
4// Author:      Robert Roebling
5// Modified by:
6// Created:     04/01/98
7// RCS-ID:      $Id: erase.cpp 35650 2005-09-23 12:56:45Z MR $
8// Copyright:   (c) Robert Roebling
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// ----------------------------------------------------------------------------
34// resources
35// ----------------------------------------------------------------------------
36// the application icon
37#if defined(__WXGTK__) || defined(__WXMOTIF__) || defined(__WXMAC__) || defined(__WXMGL__) || defined(__WXX11__)
38    #include "mondrian.xpm"
39#endif
40
41// ----------------------------------------------------------------------------
42// private classes
43// ----------------------------------------------------------------------------
44
45class MyApp : public wxApp
46{
47public:
48    virtual bool OnInit();
49};
50
51
52class MyCanvas : public wxScrolledWindow
53{
54public:
55    MyCanvas( wxFrame *parent );
56
57    void UseBuffer(bool useBuffer) { m_useBuffer = useBuffer; Refresh(); }
58    void EraseBg(bool eraseBg) { m_eraseBg = eraseBg; Refresh(); }
59
60private:
61    void OnPaint( wxPaintEvent &event );
62    void OnChar( wxKeyEvent &event );
63    void OnEraseBackground( wxEraseEvent &event );
64
65    void DoPaint(wxDC& dc);
66
67
68    wxBitmap    m_bitmap;
69    wxString    m_text;
70
71    // use wxMemoryDC in OnPaint()?
72    bool m_useBuffer;
73
74    // paint custom background in OnEraseBackground()?
75    bool m_eraseBg;
76
77
78    DECLARE_EVENT_TABLE()
79};
80
81class MyFrame : public wxFrame
82{
83public:
84    MyFrame();
85
86    void OnUseBuffer(wxCommandEvent& event);
87    void OnEraseBg(wxCommandEvent& event);
88    void OnQuit(wxCommandEvent& event);
89    void OnAbout(wxCommandEvent& event);
90
91private:
92    MyCanvas *m_canvas;
93
94    DECLARE_EVENT_TABLE()
95};
96
97
98// ----------------------------------------------------------------------------
99// constants
100// ----------------------------------------------------------------------------
101
102enum
103{
104    // menu items
105    Erase_Menu_UseBuffer = 100,
106    Erase_Menu_EraseBg,
107    Erase_Menu_Exit = wxID_EXIT,
108    Erase_Menu_About = wxID_ABOUT
109};
110
111
112// ----------------------------------------------------------------------------
113// the application class
114// ----------------------------------------------------------------------------
115
116IMPLEMENT_APP(MyApp)
117
118bool MyApp::OnInit()
119{
120    MyFrame *frame = new MyFrame;
121
122    frame->Show(true);
123
124    return true;
125}
126
127// ----------------------------------------------------------------------------
128// main frame
129// ----------------------------------------------------------------------------
130
131BEGIN_EVENT_TABLE(MyFrame, wxFrame)
132    EVT_MENU(Erase_Menu_UseBuffer,  MyFrame::OnUseBuffer)
133    EVT_MENU(Erase_Menu_EraseBg,  MyFrame::OnEraseBg)
134    EVT_MENU(Erase_Menu_Exit,  MyFrame::OnQuit)
135    EVT_MENU(Erase_Menu_About, MyFrame::OnAbout)
136END_EVENT_TABLE()
137
138// frame constructor
139MyFrame::MyFrame()
140       : wxFrame(NULL, wxID_ANY, _T("Erase sample"),
141                 wxPoint(50, 50), wxSize(450, 340))
142{
143    SetIcon(wxICON(mondrian));
144
145    wxMenu *menuFile = new wxMenu(_T(""), wxMENU_TEAROFF);
146    menuFile->AppendCheckItem(Erase_Menu_UseBuffer, _T("&Use memory DC\tCtrl-M"));
147    menuFile->AppendCheckItem(Erase_Menu_EraseBg, _T("Custom &background\tCtrl-B"));
148    menuFile->AppendSeparator();
149    menuFile->Append(Erase_Menu_Exit, _T("E&xit\tAlt-X"), _T("Quit this program"));
150
151
152    wxMenu *helpMenu = new wxMenu;
153    helpMenu->Append(Erase_Menu_About, _T("&About...\tCtrl-A"), _T("Show about dialog"));
154
155    wxMenuBar *menuBar = new wxMenuBar();
156    menuBar->Append(menuFile, _T("&File"));
157    menuBar->Append(helpMenu, _T("&Help"));
158
159    SetMenuBar(menuBar);
160
161#if wxUSE_STATUSBAR
162    // create a status bar just for fun (by default with 1 pane only)
163    CreateStatusBar(2);
164    SetStatusText(_T("Welcome to wxWidgets erase sample!"));
165#endif // wxUSE_STATUSBAR
166
167    m_canvas = new MyCanvas( this );
168}
169
170
171void MyFrame::OnUseBuffer(wxCommandEvent& event)
172{
173    m_canvas->UseBuffer(event.IsChecked());
174}
175
176void MyFrame::OnEraseBg(wxCommandEvent& event)
177{
178    m_canvas->EraseBg(event.IsChecked());
179}
180
181void MyFrame::OnQuit(wxCommandEvent& WXUNUSED(event))
182{
183    Close(true);
184}
185
186void MyFrame::OnAbout(wxCommandEvent& WXUNUSED(event))
187{
188    wxMessageBox(_T("This sample shows how you can draw custom background."),
189                 _T("About Erase Sample"), wxOK | wxICON_INFORMATION, this);
190}
191
192
193BEGIN_EVENT_TABLE(MyCanvas, wxScrolledWindow)
194    EVT_PAINT(  MyCanvas::OnPaint)
195    EVT_CHAR(  MyCanvas::OnChar)
196    EVT_ERASE_BACKGROUND(  MyCanvas::OnEraseBackground)
197END_EVENT_TABLE()
198
199MyCanvas::MyCanvas( wxFrame *parent )
200        : wxScrolledWindow( parent, wxID_ANY, wxDefaultPosition, wxDefaultSize,
201                            wxScrolledWindowStyle | wxSUNKEN_BORDER )
202{
203    m_eraseBg =
204    m_useBuffer = false;
205
206    SetScrollbars( 10, 10, 40, 100, 0, 0 );
207
208    m_bitmap = wxBitmap( wxICON(mondrian) );
209
210    new wxStaticBitmap( this, wxID_ANY, m_bitmap, wxPoint(80,20) );
211
212    SetFocusIgnoringChildren();
213}
214
215void MyCanvas::OnChar( wxKeyEvent &event )
216{
217#if wxUSE_UNICODE
218    if (event.m_uniChar)
219    {
220        m_text += event.m_uniChar;
221        Refresh();
222        return;
223    }
224#endif
225
226    // some test cases
227    switch (event.m_keyCode)
228    {
229        case WXK_UP: m_text += wxT( "<UP>" ); break;
230        case WXK_LEFT: m_text += wxT( "<LEFT>" ); break;
231        case WXK_RIGHT: m_text += wxT( "<RIGHT>" ); break;
232        case WXK_DOWN: m_text += wxT( "<DOWN>" ); break;
233        case WXK_RETURN: m_text += wxT( "<ENTER>" ); break;
234        default: m_text += (wxChar)event.m_keyCode; break;
235    }
236}
237
238void MyCanvas::DoPaint(wxDC& dc)
239{
240    dc.SetBrush( *wxBLACK_BRUSH );
241    dc.DrawRectangle( 10,10,200,50 );
242
243    dc.DrawBitmap( m_bitmap, 10, 20, true );
244
245    dc.SetTextForeground(*wxBLUE);
246    dc.DrawText(_T("This text is drawn from OnPaint"), 65, 65);
247
248    wxString tmp;
249    tmp.Printf( _T("Hit any key to display more text: %s"), m_text.c_str() );
250    int w,h;
251    dc.GetTextExtent( tmp, &w, &h );
252    dc.SetBrush( *wxWHITE_BRUSH );
253    dc.DrawRectangle( 65, 85, w, h );
254    dc.DrawText( tmp, 65, 85 );
255
256#if 0
257    wxRegionIterator upd( GetUpdateRegion() );
258    while (upd)
259    {
260        wxLogDebug( _T("Paint: %d %d %d %d"), upd.GetX(), upd.GetY(), upd.GetWidth(), upd.GetHeight() );
261        upd ++;
262    }
263#endif
264
265#if 0
266    wxSize size = GetSize();
267    wxSize client_size = GetClientSize();
268    wxLogDebug( _T("size %d %d client_size %d %d"), size.x, size.y, client_size.x, client_size.y );
269#endif
270
271#if 0
272    int i;
273    dc.SetPen( *wxWHITE_PEN );
274    for (i = 0; i < 20; i += 2)
275       dc.DrawLine( i,i, i+100,i );
276
277    dc.SetPen( *wxWHITE_PEN );
278    for (i = 200; i < 220; i += 2)
279       dc.DrawLine( i-200,i, i-100,i );
280
281    wxRegion region( 110, 110, 80, 80 );
282    wxRegion hole( 130, 130, 40, 1 );
283    region.Intersect( hole );
284    dc.SetClippingRegion( region );
285
286    dc.SetBrush( *wxRED_BRUSH );
287    dc.DrawRectangle( 100, 100, 200, 200 );
288
289    dc.DestroyClippingRegion();
290
291    dc.SetPen( *wxTRANSPARENT_PEN );
292
293    wxRegion strip( 110, 200, 30, 1 );
294    wxRegionIterator it( strip );
295    while (it)
296    {
297        dc.DrawRectangle( it.GetX(), it.GetY(), it.GetWidth(), it.GetHeight() );
298        it ++;
299    }
300#endif // 0
301}
302
303void MyCanvas::OnPaint( wxPaintEvent &WXUNUSED(event) )
304{
305    wxPaintDC dcWin(this);
306    PrepareDC( dcWin );
307
308    if ( m_useBuffer )
309    {
310        const wxSize size = GetClientSize();
311        wxMemoryDC dc;
312        wxBitmap bmp(size.x, size.y);
313        dc.SelectObject(bmp);
314        dc.Blit(0, 0, size.x, size.y, &dcWin, 0, 0);
315        dc.DrawText(_T("(copy of background)"), 5, 120 );
316
317        DoPaint(dc);
318
319        dcWin.Blit(0, 0, size.x, size.y, &dc, 0, 0);
320    }
321    else
322    {
323        DoPaint(dcWin);
324    }
325}
326
327void MyCanvas::OnEraseBackground( wxEraseEvent& event )
328{
329    if ( !m_eraseBg )
330    {
331        event.Skip();
332        return;
333    }
334
335    wxDC& dc = *event.GetDC();
336    dc.SetPen(*wxGREEN_PEN);
337
338    PrepareDC( dc );
339
340    // clear any junk currently displayed
341    dc.Clear();
342
343    const wxSize size = GetClientSize();
344    for ( int x = 0; x < size.x; x += 15 )
345    {
346        dc.DrawLine(x, 0, x, size.y);
347    }
348
349    for ( int y = 0; y < size.y; y += 15 )
350    {
351        dc.DrawLine(0, y, size.x, y);
352    }
353
354    dc.SetTextForeground(*wxRED);
355    dc.DrawText(_T("This text is drawn from OnEraseBackground"), 60, 160);
356}
357
358