Fix crash by checking if icon is valid before drawing it, fixes #12376: PATCH for...

[wxWidgets.git] / samples / erase / erase.cpp

diff --git a/samples/erase/erase.cpp b/samples/erase/erase.cpp
index cd9c9f8ac29055f75c0aea6d530491144b1462ae..d603a93cefca80e56db8a84ff4d2a4756e36a5f3 100644 (file)
--- a/samples/erase/erase.cpp
+++ b/samples/erase/erase.cpp
@@ -1,11 +1,11 @@
 /////////////////////////////////////////////////////////////////////////////
 /////////////////////////////////////////////////////////////////////////////

-// Name:        erase.cpp
+// Name:        samples/erase/erase.cpp

 // Purpose:     Erase wxWidgets sample
 // Purpose:     Erase wxWidgets sample

-// Author:      Robert Roebling
-// Modified by:
+// Author:      Robert Roebling, Vadim Zeitlin

 // Created:     04/01/98
 // RCS-ID:      $Id$
 // Created:     04/01/98
 // RCS-ID:      $Id$

-// Copyright:   (c) Robert Roebling
+// Copyright:   (c) 1998 Robert Roebling
+//              (c) 2009 Vadim Zeitlin

 // Licence:     wxWindows licence
 /////////////////////////////////////////////////////////////////////////////
 
 // Licence:     wxWindows licence
 /////////////////////////////////////////////////////////////////////////////
 


@@ -17,11 +17,6 @@
 // headers
 // ----------------------------------------------------------------------------
 
 // headers
 // ----------------------------------------------------------------------------
 

-#if defined(__GNUG__) && !defined(__APPLE__)
-    #pragma implementation "erase.cpp"
-    #pragma interface "erase.cpp"
-#endif
-

 // For compilers that support precompilation, includes "wx/wx.h".
 #include "wx/wxprec.h"
 
 // For compilers that support precompilation, includes "wx/wx.h".
 #include "wx/wxprec.h"
 


@@ -35,12 +30,15 @@
     #include "wx/wx.h"
 #endif
 
     #include "wx/wx.h"
 #endif
 

+#include "wx/dcbuffer.h"
+

 // ----------------------------------------------------------------------------
 // resources
 // ----------------------------------------------------------------------------
 // ----------------------------------------------------------------------------
 // resources
 // ----------------------------------------------------------------------------

+

 // the application icon
 // the application icon

-#if defined(__WXGTK__) || defined(__WXMOTIF__) || defined(__WXMAC__) || defined(__WXMGL__) || defined(__WXX11__)
-    #include "mondrian.xpm"
+#if !defined(__WXMSW__) && !defined(__WXPM__)
+    #include "../sample.xpm"

 #endif
 
 // ----------------------------------------------------------------------------
 #endif
 
 // ----------------------------------------------------------------------------


@@ -54,35 +52,66 @@ public:
 };
 
 
 };
 
 

-class MyFrame : public wxFrame
+class MyCanvas : public wxScrolledWindow

 {
 public:
 {
 public:

-    MyFrame(const wxString& title, const wxPoint& pos, const wxSize& size);
+    MyCanvas(wxFrame *parent);

 
 

-    void OnQuit(wxCommandEvent& event);
-    void OnAbout(wxCommandEvent& event);
+    void UseBuffer(bool useBuffer) { m_useBuffer = useBuffer; Refresh(); }
+    bool UsesBuffer() const { return m_useBuffer; }

 
 

-private:
-    DECLARE_EVENT_TABLE()
-};
-
-
-class MyCanvas : public wxScrolledWindow
-{
-public:
-    MyCanvas( MyFrame *parent );
+    void EraseBgInPaint(bool erase) { m_eraseBgInPaint = erase; Refresh(); }

 
 

+private:

     void OnPaint( wxPaintEvent &event );
     void OnChar( wxKeyEvent &event );
     void OnEraseBackground( wxEraseEvent &event );
 
     void OnPaint( wxPaintEvent &event );
     void OnChar( wxKeyEvent &event );
     void OnEraseBackground( wxEraseEvent &event );
 

+    void DoPaint(wxDC& dc);
+
+

     wxBitmap    m_bitmap;
     wxString    m_text;
 
     wxBitmap    m_bitmap;
     wxString    m_text;
 

+    // use wxMemoryDC in OnPaint()?
+    bool m_useBuffer;
+
+    // erase background in OnPaint()?
+    bool m_eraseBgInPaint;
+
+
+    DECLARE_EVENT_TABLE()
+};
+
+class MyFrame : public wxFrame
+{
+public:
+    MyFrame();
+

 private:
 private:

+    void OnUseBuffer(wxCommandEvent& event);
+    void OnEraseBgInPaint(wxCommandEvent& event);
+    void OnChangeBgStyle(wxCommandEvent& event);
+    void OnQuit(wxCommandEvent& event);
+    void OnAbout(wxCommandEvent& event);
+
+    // we can only use double-buffering with wxBG_STYLE_PAINT
+    void OnUpdateUIUseBuffer(wxUpdateUIEvent& event)
+    {
+        event.Enable( m_canvas->GetBackgroundStyle() == wxBG_STYLE_PAINT );
+    }
+
+    void OnUpdateUIChangeBgStyle(wxUpdateUIEvent& event)
+    {
+        event.Enable( !m_canvas->UsesBuffer() );
+    }
+
+    MyCanvas *m_canvas;
+

     DECLARE_EVENT_TABLE()
 };
 
     DECLARE_EVENT_TABLE()
 };
 

+

 // ----------------------------------------------------------------------------
 // constants
 // ----------------------------------------------------------------------------
 // ----------------------------------------------------------------------------
 // constants
 // ----------------------------------------------------------------------------


@@ -90,7 +119,13 @@ private:
 enum
 {
     // menu items
 enum
 {
     // menu items

-    ID_MENU_QUIT = 1,
+    Erase_Menu_UseBuffer = 100,
+    Erase_Menu_EraseBgInPaint,
+    Erase_Menu_BgStyleErase,
+    Erase_Menu_BgStyleSystem,
+    Erase_Menu_BgStylePaint,
+    Erase_Menu_Exit = wxID_EXIT,
+    Erase_Menu_About = wxID_ABOUT

 };
 
 
 };
 
 


@@ -102,8 +137,10 @@ IMPLEMENT_APP(MyApp)
 
 bool MyApp::OnInit()
 {
 
 bool MyApp::OnInit()
 {

-    MyFrame *frame = new MyFrame(_T("Erase sample"),
-                                 wxPoint(50, 50), wxSize(450, 340));
+    if ( !wxApp::OnInit() )
+        return false;
+
+    MyFrame *frame = new MyFrame;

 
     frame->Show(true);
 
 
     frame->Show(true);
 


@@ -115,38 +152,71 @@ bool MyApp::OnInit()
 // ----------------------------------------------------------------------------
 
 BEGIN_EVENT_TABLE(MyFrame, wxFrame)
 // ----------------------------------------------------------------------------
 
 BEGIN_EVENT_TABLE(MyFrame, wxFrame)

-    EVT_MENU(ID_MENU_QUIT,  MyFrame::OnQuit)
-    EVT_MENU(wxID_ABOUT, MyFrame::OnAbout)
+    EVT_MENU(Erase_Menu_UseBuffer, MyFrame::OnUseBuffer)
+    EVT_MENU(Erase_Menu_EraseBgInPaint, MyFrame::OnEraseBgInPaint)
+    EVT_MENU_RANGE(Erase_Menu_BgStyleErase, Erase_Menu_BgStylePaint,
+                   MyFrame::OnChangeBgStyle)
+
+    EVT_MENU(Erase_Menu_Exit,  MyFrame::OnQuit)
+    EVT_MENU(Erase_Menu_About, MyFrame::OnAbout)
+
+    EVT_UPDATE_UI(Erase_Menu_UseBuffer, MyFrame::OnUpdateUIUseBuffer)
+    EVT_UPDATE_UI_RANGE(Erase_Menu_BgStyleErase, Erase_Menu_BgStylePaint,
+                        MyFrame::OnUpdateUIChangeBgStyle)

 END_EVENT_TABLE()
 
 // frame constructor
 END_EVENT_TABLE()
 
 // frame constructor

-MyFrame::MyFrame(const wxString& title, const wxPoint& pos, const wxSize& size)
-       : wxFrame((wxFrame *)NULL, wxID_ANY, title, pos, size)
+MyFrame::MyFrame()
+       : wxFrame(NULL, wxID_ANY, "Erase sample",
+                 wxPoint(50, 50), wxSize(450, 340))

 {
 {

-    SetIcon(wxICON(mondrian));
+    SetIcon(wxICON(sample));
+
+    wxMenu *menuFile = new wxMenu("", wxMENU_TEAROFF);
+    menuFile->AppendCheckItem(Erase_Menu_UseBuffer, "&Use memory DC\tCtrl-M");
+    menuFile->AppendCheckItem(Erase_Menu_EraseBgInPaint,
+                              "&Erase background in EVT_PAINT\tCtrl-R");
+    menuFile->AppendSeparator();
+    menuFile->AppendRadioItem(Erase_Menu_BgStyleErase,
+                              "Use wxBG_STYLE_&ERASE\tCtrl-E");
+    menuFile->AppendRadioItem(Erase_Menu_BgStyleSystem,
+                              "Use wxBG_STYLE_&SYSTEM\tCtrl-S");
+    menuFile->AppendRadioItem(Erase_Menu_BgStylePaint,
+                              "Use wxBG_STYLE_&PAINT\tCtrl-P");
+    menuFile->AppendSeparator();
+    menuFile->Append(Erase_Menu_Exit, "E&xit\tAlt-X", "Quit this program");

 
 

-    wxMenu *menuFile = new wxMenu(_T(""), wxMENU_TEAROFF);

 
     wxMenu *helpMenu = new wxMenu;
 
     wxMenu *helpMenu = new wxMenu;

-    helpMenu->Append(wxID_ABOUT, _T("&About...\tCtrl-A"), _T("Show about dialog"));
-
-    menuFile->Append(ID_MENU_QUIT, _T("E&xit\tAlt-X"), _T("Quit this program"));
+    helpMenu->Append(Erase_Menu_About, "&About...\tCtrl-A", "Show about dialog");

 
     wxMenuBar *menuBar = new wxMenuBar();
 
     wxMenuBar *menuBar = new wxMenuBar();

-    menuBar->Append(menuFile, _T("&File"));
-    menuBar->Append(helpMenu, _T("&Help"));
+    menuBar->Append(menuFile, "&File");
+    menuBar->Append(helpMenu, "&Help");

 
     SetMenuBar(menuBar);
 
 
     SetMenuBar(menuBar);
 

-#if wxUSE_STATUSBAR
-    // create a status bar just for fun (by default with 1 pane only)
-    CreateStatusBar(2);
-    SetStatusText(_T("Welcome to wxWidgets erase sample!"));
-#endif // wxUSE_STATUSBAR
+    m_canvas = new MyCanvas( this );
+}
+

 
 

-    (void)new MyCanvas( this );
+void MyFrame::OnUseBuffer(wxCommandEvent& event)
+{
+    m_canvas->UseBuffer(event.IsChecked());

 }
 
 }
 

+void MyFrame::OnEraseBgInPaint(wxCommandEvent& event)
+{
+    m_canvas->EraseBgInPaint(event.IsChecked());
+}
+
+void MyFrame::OnChangeBgStyle(wxCommandEvent& event)
+{
+    int style = wxBG_STYLE_ERASE + event.GetId() - Erase_Menu_BgStyleErase;
+    m_canvas->SetBackgroundStyle(static_cast<wxBackgroundStyle>(style));
+
+    m_canvas->Refresh();
+}

 
 void MyFrame::OnQuit(wxCommandEvent& WXUNUSED(event))
 {
 
 void MyFrame::OnQuit(wxCommandEvent& WXUNUSED(event))
 {


@@ -155,28 +225,40 @@ void MyFrame::OnQuit(wxCommandEvent& WXUNUSED(event))
 
 void MyFrame::OnAbout(wxCommandEvent& WXUNUSED(event))
 {
 
 void MyFrame::OnAbout(wxCommandEvent& WXUNUSED(event))
 {

-    wxMessageBox(_T("This sample shows how you can draw custom background."),
-                 _T("About Erase Sample"), wxOK | wxICON_INFORMATION, this);
+    wxMessageBox
+    (
+        "This sample shows differences between different background styles "
+        "and how you may draw custom background.\n"
+        "\n"
+        "(c) 1998 Robert Roebling\n"
+        "(c) 2009 Vadim Zeitlin\n",
+        "About Erase Sample",
+        wxOK | wxICON_INFORMATION,
+        this
+    );

 }
 
 
 BEGIN_EVENT_TABLE(MyCanvas, wxScrolledWindow)
 }
 
 
 BEGIN_EVENT_TABLE(MyCanvas, wxScrolledWindow)

-    EVT_PAINT(  MyCanvas::OnPaint)
-    EVT_CHAR(  MyCanvas::OnChar)
-    EVT_ERASE_BACKGROUND(  MyCanvas::OnEraseBackground)
+    EVT_PAINT(MyCanvas::OnPaint)
+    EVT_CHAR(MyCanvas::OnChar)
+    EVT_ERASE_BACKGROUND(MyCanvas::OnEraseBackground)

 END_EVENT_TABLE()
 
 END_EVENT_TABLE()
 

-MyCanvas::MyCanvas( MyFrame *parent )
-        : wxScrolledWindow( parent, wxID_ANY, wxDefaultPosition, wxDefaultSize,
-                            wxScrolledWindowStyle |
-                            wxNO_FULL_REPAINT_ON_RESIZE|
-                            wxSUNKEN_BORDER )
+MyCanvas::MyCanvas(wxFrame *parent)
+        : wxScrolledWindow(parent, wxID_ANY)

 {
 {

+    m_useBuffer = false;
+    m_eraseBgInPaint = false;
+

     SetScrollbars( 10, 10, 40, 100, 0, 0 );
 
     SetScrollbars( 10, 10, 40, 100, 0, 0 );
 

-    m_bitmap = wxBitmap( wxICON(mondrian) );
+    m_bitmap = wxBitmap( wxICON(sample) );

 
     new wxStaticBitmap( this, wxID_ANY, m_bitmap, wxPoint(80,20) );
 
     new wxStaticBitmap( this, wxID_ANY, m_bitmap, wxPoint(80,20) );

+
+    SetFocusIgnoringChildren();
+    SetBackgroundColour(*wxBLUE);

 }
 
 void MyCanvas::OnChar( wxKeyEvent &event )
 }
 
 void MyCanvas::OnChar( wxKeyEvent &event )


@@ -200,97 +282,88 @@ void MyCanvas::OnChar( wxKeyEvent &event )
         case WXK_RETURN: m_text += wxT( "<ENTER>" ); break;
         default: m_text += (wxChar)event.m_keyCode; break;
     }
         case WXK_RETURN: m_text += wxT( "<ENTER>" ); break;
         default: m_text += (wxChar)event.m_keyCode; break;
     }

-

 }
 
 }
 

-void MyCanvas::OnPaint( wxPaintEvent &WXUNUSED(event) )
+void MyCanvas::DoPaint(wxDC& dc)

 {
 {

-    wxPaintDC dc(this);
-    PrepareDC( dc );
+    if ( m_eraseBgInPaint )
+    {
+        dc.SetBackground(*wxLIGHT_GREY);
+        dc.Clear();
+
+        dc.DrawText("Background erased in OnPaint", 65, 110);
+    }
+    else if ( GetBackgroundStyle() == wxBG_STYLE_PAINT )
+    {
+        dc.SetTextForeground(*wxRED);
+        dc.DrawText("You must enable erasing background in OnPaint to avoid "
+                    "display corruption", 65, 110);
+    }

 
     dc.SetBrush( *wxBLACK_BRUSH );
 
     dc.SetBrush( *wxBLACK_BRUSH );

-    dc.DrawRectangle( 0,0,200,50 );
+    dc.DrawRectangle( 10,10,60,50 );

 
 

-    dc.DrawBitmap( m_bitmap, 10, 20, true );
+    dc.DrawBitmap( m_bitmap, 20, 20, true );

 
 

-    dc.SetTextForeground(*wxBLUE);
-    dc.DrawText(_T("This text is drawn from OnPaint"), 65, 65);
+    dc.SetTextForeground(*wxWHITE);
+    dc.DrawText("This text is drawn from OnPaint", 65, 65);

 
     wxString tmp;
 
     wxString tmp;

-    tmp.Printf( _T("Hit any key to display more text: %s"), m_text.c_str() );
+    tmp.Printf("Hit any key to display more text: %s", m_text);
+

     int w,h;
     dc.GetTextExtent( tmp, &w, &h );
     int w,h;
     dc.GetTextExtent( tmp, &w, &h );

-    dc.SetBrush( *wxWHITE_BRUSH );

     dc.DrawRectangle( 65, 85, w, h );
     dc.DrawText( tmp, 65, 85 );
     dc.DrawRectangle( 65, 85, w, h );
     dc.DrawText( tmp, 65, 85 );

+}

 
 

-#if 0
-    wxRegionIterator upd( GetUpdateRegion() );
-    while (upd)
+void MyCanvas::OnPaint( wxPaintEvent &WXUNUSED(event) )
+{
+    if ( m_useBuffer )

     {
     {

-        wxLogDebug( _T("Paint: %d %d %d %d"), upd.GetX(), upd.GetY(), upd.GetWidth(), upd.GetHeight() );
-        upd ++;
-    }
-#endif
-
-#if 0
-    wxSize size = GetSize();
-    wxSize client_size = GetClientSize();
-    wxLogDebug( _T("size %d %d client_size %d %d"), size.x, size.y, client_size.x, client_size.y );
-#endif
-
-#if 0
-    int i;
-    dc.SetPen( *wxWHITE_PEN );
-    for (i = 0; i < 20; i += 2)
-       dc.DrawLine( i,i, i+100,i );
+        wxAutoBufferedPaintDC dc(this);
+        PrepareDC(dc);

 
 

-    dc.SetPen( *wxWHITE_PEN );
-    for (i = 200; i < 220; i += 2)
-       dc.DrawLine( i-200,i, i-100,i );
-
-    wxRegion region( 110, 110, 80, 80 );
-    wxRegion hole( 130, 130, 40, 1 );
-    region.Intersect( hole );
-    dc.SetClippingRegion( region );
-
-    dc.SetBrush( *wxRED_BRUSH );
-    dc.DrawRectangle( 100, 100, 200, 200 );
-
-    dc.DestroyClippingRegion();
-
-    dc.SetPen( *wxTRANSPARENT_PEN );
-
-    wxRegion strip( 110, 200, 30, 1 );
-    wxRegionIterator it( strip );
-    while (it)
+        DoPaint(dc);
+    }
+    else

     {
     {

-        dc.DrawRectangle( it.GetX(), it.GetY(), it.GetWidth(), it.GetHeight() );
-        it ++;
+        wxPaintDC dc(this);
+        PrepareDC(dc);
+
+        DoPaint(dc);

     }
     }

-#endif // 0

 }
 
 void MyCanvas::OnEraseBackground( wxEraseEvent& event )
 {
 }
 
 void MyCanvas::OnEraseBackground( wxEraseEvent& event )
 {

+    wxASSERT_MSG
+    (
+        GetBackgroundStyle() == wxBG_STYLE_ERASE,
+        "shouldn't be called unless background style is \"erase\""
+    );
+

     wxDC& dc = *event.GetDC();
     dc.SetPen(*wxGREEN_PEN);
 
     wxDC& dc = *event.GetDC();
     dc.SetPen(*wxGREEN_PEN);
 

-    // this line is needed, otherwise the junk is left on win the background
+    PrepareDC( dc );
+
+    // clear any junk currently displayed

     dc.Clear();
 
     dc.Clear();
 

-    wxSize size = GetClientSize();
-    for ( int x = 0; x < size.x; x+= 10 )
+    const wxSize size = GetClientSize();
+    for ( int x = 0; x < size.x; x += 15 )

     {
         dc.DrawLine(x, 0, x, size.y);
     }
 
     {
         dc.DrawLine(x, 0, x, size.y);
     }
 

-    for ( int y = 0; y < size.y; y+= 10 )
+    for ( int y = 0; y < size.y; y += 15 )

     {
         dc.DrawLine(0, y, size.x, y);
     }
 
     dc.SetTextForeground(*wxRED);
     {
         dc.DrawLine(0, y, size.x, y);
     }
 
     dc.SetTextForeground(*wxRED);

-    dc.DrawText(_T("This text is drawn from OnEraseBackground"), 60, 60);
+    dc.SetBackgroundMode(wxSOLID);
+    dc.DrawText("This text is drawn from OnEraseBackground", 60, 160);

 }
 
 }