Fix best size computation for buttons without image and with empty label.

[wxWidgets.git] / src / msw / button.cpp

/////////////////////////////////////////////////////////////////////////////
// Name:        src/msw/button.cpp
// Purpose:     wxButton
// Author:      Julian Smart
// Modified by:
// Created:     04/01/98
// RCS-ID:      $Id$
// Copyright:   (c) Julian Smart
// Licence:     wxWindows licence
/////////////////////////////////////////////////////////////////////////////

// ============================================================================
// declarations
// ============================================================================

// ----------------------------------------------------------------------------
// headers
// ----------------------------------------------------------------------------

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

#ifdef __BORLANDC__
    #pragma hdrstop
#endif

#if wxUSE_BUTTON

#include "wx/button.h"

#ifndef WX_PRECOMP
    #include "wx/app.h"
    #include "wx/brush.h"
    #include "wx/panel.h"
    #include "wx/bmpbuttn.h"
    #include "wx/settings.h"
    #include "wx/dcscreen.h"
    #include "wx/dcclient.h"
    #include "wx/toplevel.h"
#endif

#include "wx/imaglist.h"
#include "wx/stockitem.h"
#include "wx/msw/private.h"
#include "wx/msw/private/button.h"
#include "wx/msw/private/dc.h"

using namespace wxMSWImpl;

#if wxUSE_UXTHEME
    #include "wx/msw/uxtheme.h"

    // no need to include tmschema.h
    #ifndef BP_PUSHBUTTON
        #define BP_PUSHBUTTON 1

        #define PBS_NORMAL    1
        #define PBS_HOT       2
        #define PBS_PRESSED   3
        #define PBS_DISABLED  4
        #define PBS_DEFAULTED 5

        #define TMT_CONTENTMARGINS 3602
    #endif

    // provide the necessary declarations ourselves if they're missing from
    // headers
    #ifndef BCM_SETIMAGELIST
        #define BCM_SETIMAGELIST    0x1602
        #define BCM_SETTEXTMARGIN   0x1604

        enum
        {
            BUTTON_IMAGELIST_ALIGN_LEFT,
            BUTTON_IMAGELIST_ALIGN_RIGHT,
            BUTTON_IMAGELIST_ALIGN_TOP,
            BUTTON_IMAGELIST_ALIGN_BOTTOM
        };

        struct BUTTON_IMAGELIST
        {
            HIMAGELIST himl;
            RECT margin;
            UINT uAlign;
        };
    #endif
#endif // wxUSE_UXTHEME

#ifndef WM_THEMECHANGED
    #define WM_THEMECHANGED     0x031A
#endif

#ifndef ODS_NOACCEL
    #define ODS_NOACCEL         0x0100
#endif

#ifndef ODS_NOFOCUSRECT
    #define ODS_NOFOCUSRECT     0x0200
#endif

#ifndef DT_HIDEPREFIX
    #define DT_HIDEPREFIX       0x00100000
#endif

// ----------------------------------------------------------------------------
// button image data
// ----------------------------------------------------------------------------

// we use different data classes for owner drawn buttons and for themed XP ones

class wxButtonImageData
{
public:
    wxButtonImageData() { }
    virtual ~wxButtonImageData() { }

    virtual wxBitmap GetBitmap(wxButton::State which) const = 0;
    virtual void SetBitmap(const wxBitmap& bitmap, wxButton::State which) = 0;

    virtual wxSize GetBitmapMargins() const = 0;
    virtual void SetBitmapMargins(wxCoord x, wxCoord y) = 0;

    virtual wxDirection GetBitmapPosition() const = 0;
    virtual void SetBitmapPosition(wxDirection dir) = 0;

private:
    wxDECLARE_NO_COPY_CLASS(wxButtonImageData);
};

namespace
{

// the gap between button edge and the interior area used by Windows for the
// standard buttons
const int OD_BUTTON_MARGIN = 4;

class wxODButtonImageData : public wxButtonImageData
{
public:
    wxODButtonImageData(wxButton *btn, const wxBitmap& bitmap)
    {
        SetBitmap(bitmap, wxButton::State_Normal);

        m_dir = wxLEFT;

        // we use margins when we have both bitmap and text, but when we have
        // only the bitmap it should take up the entire button area
        if ( btn->ShowsLabel() )
        {
            m_margin.x = btn->GetCharWidth();
            m_margin.y = btn->GetCharHeight() / 2;
        }
    }

    virtual wxBitmap GetBitmap(wxButton::State which) const
    {
        return m_bitmaps[which];
    }

    virtual void SetBitmap(const wxBitmap& bitmap, wxButton::State which)
    {
        m_bitmaps[which] = bitmap;
    }

    virtual wxSize GetBitmapMargins() const
    {
        return m_margin;
    }

    virtual void SetBitmapMargins(wxCoord x, wxCoord y)
    {
        m_margin = wxSize(x, y);
    }

    virtual wxDirection GetBitmapPosition() const
    {
        return m_dir;
    }

    virtual void SetBitmapPosition(wxDirection dir)
    {
        m_dir = dir;
    }

private:
    // just store the values passed to us to be able to retrieve them later
    // from the drawing code
    wxBitmap m_bitmaps[wxButton::State_Max];
    wxSize m_margin;
    wxDirection m_dir;

    wxDECLARE_NO_COPY_CLASS(wxODButtonImageData);
};

#if wxUSE_UXTHEME

// somehow the margin is one pixel greater than the value returned by
// GetThemeMargins() call
const int XP_BUTTON_EXTRA_MARGIN = 1;

class wxXPButtonImageData : public wxButtonImageData
{
public:
    // we must be constructed with the size of our images as we need to create
    // the image list
    wxXPButtonImageData(wxButton *btn, const wxBitmap& bitmap)
        : m_iml(bitmap.GetWidth(), bitmap.GetHeight(), true /* use mask */,
                wxButton::State_Max),
          m_hwndBtn(GetHwndOf(btn))
    {
        // initialize all bitmaps to normal state
        for ( int n = 0; n < wxButton::State_Max; n++ )
        {
            m_iml.Add(bitmap);
        }

        m_data.himl = GetHimagelistOf(&m_iml);

        // use default margins
        m_data.margin.left =
        m_data.margin.right = btn->GetCharWidth();
        m_data.margin.top =
        m_data.margin.bottom = btn->GetCharHeight() / 2;

        // and default alignment
        m_data.uAlign = BUTTON_IMAGELIST_ALIGN_LEFT;

        UpdateImageInfo();
    }

    virtual wxBitmap GetBitmap(wxButton::State which) const
    {
        return m_iml.GetBitmap(which);
    }

    virtual void SetBitmap(const wxBitmap& bitmap, wxButton::State which)
    {
        m_iml.Replace(which, bitmap);

        UpdateImageInfo();
    }

    virtual wxSize GetBitmapMargins() const
    {
        return wxSize(m_data.margin.left, m_data.margin.top);
    }

    virtual void SetBitmapMargins(wxCoord x, wxCoord y)
    {
        RECT& margin = m_data.margin;
        margin.left =
        margin.right = x;
        margin.top =
        margin.bottom = y;

        if ( !::SendMessage(m_hwndBtn, BCM_SETTEXTMARGIN, 0, (LPARAM)&margin) )
        {
            wxLogDebug("SendMessage(BCM_SETTEXTMARGIN) failed");
        }
    }

    virtual wxDirection GetBitmapPosition() const
    {
        switch ( m_data.uAlign )
        {
            default:
                wxFAIL_MSG( "invalid image alignment" );
                // fall through

            case BUTTON_IMAGELIST_ALIGN_LEFT:
                return wxLEFT;

            case BUTTON_IMAGELIST_ALIGN_RIGHT:
                return wxRIGHT;

            case BUTTON_IMAGELIST_ALIGN_TOP:
                return wxTOP;

            case BUTTON_IMAGELIST_ALIGN_BOTTOM:
                return wxBOTTOM;
        }
    }

    virtual void SetBitmapPosition(wxDirection dir)
    {
        UINT alignNew;
        switch ( dir )
        {
            default:
                wxFAIL_MSG( "invalid direction" );
                // fall through

            case wxLEFT:
                alignNew = BUTTON_IMAGELIST_ALIGN_LEFT;
                break;

            case wxRIGHT:
                alignNew = BUTTON_IMAGELIST_ALIGN_RIGHT;
                break;

            case wxTOP:
                alignNew = BUTTON_IMAGELIST_ALIGN_TOP;
                break;

            case wxBOTTOM:
                alignNew = BUTTON_IMAGELIST_ALIGN_BOTTOM;
                break;
        }

        if ( alignNew != m_data.uAlign )
        {
            m_data.uAlign = alignNew;
            UpdateImageInfo();
        }
    }

private:
    void UpdateImageInfo()
    {
        if ( !::SendMessage(m_hwndBtn, BCM_SETIMAGELIST, 0, (LPARAM)&m_data) )
        {
            wxLogDebug("SendMessage(BCM_SETIMAGELIST) failed");
        }
    }

    // we store image list separately to be able to use convenient wxImageList
    // methods instead of working with raw HIMAGELIST
    wxImageList m_iml;

    // store the rest of the data in BCM_SETIMAGELIST-friendly form
    BUTTON_IMAGELIST m_data;

    // the button we're associated with
    const HWND m_hwndBtn;


    wxDECLARE_NO_COPY_CLASS(wxXPButtonImageData);
};

#endif // wxUSE_UXTHEME

} // anonymous namespace

// ----------------------------------------------------------------------------
// macros
// ----------------------------------------------------------------------------

#if wxUSE_EXTENDED_RTTI

WX_DEFINE_FLAGS( wxButtonStyle )

wxBEGIN_FLAGS( wxButtonStyle )
    // new style border flags, we put them first to
    // use them for streaming out
    wxFLAGS_MEMBER(wxBORDER_SIMPLE)
    wxFLAGS_MEMBER(wxBORDER_SUNKEN)
    wxFLAGS_MEMBER(wxBORDER_DOUBLE)
    wxFLAGS_MEMBER(wxBORDER_RAISED)
    wxFLAGS_MEMBER(wxBORDER_STATIC)
    wxFLAGS_MEMBER(wxBORDER_NONE)

    // old style border flags
    wxFLAGS_MEMBER(wxSIMPLE_BORDER)
    wxFLAGS_MEMBER(wxSUNKEN_BORDER)
    wxFLAGS_MEMBER(wxDOUBLE_BORDER)
    wxFLAGS_MEMBER(wxRAISED_BORDER)
    wxFLAGS_MEMBER(wxSTATIC_BORDER)
    wxFLAGS_MEMBER(wxBORDER)

    // standard window styles
    wxFLAGS_MEMBER(wxTAB_TRAVERSAL)
    wxFLAGS_MEMBER(wxCLIP_CHILDREN)
    wxFLAGS_MEMBER(wxTRANSPARENT_WINDOW)
    wxFLAGS_MEMBER(wxWANTS_CHARS)
    wxFLAGS_MEMBER(wxFULL_REPAINT_ON_RESIZE)
    wxFLAGS_MEMBER(wxALWAYS_SHOW_SB )
    wxFLAGS_MEMBER(wxVSCROLL)
    wxFLAGS_MEMBER(wxHSCROLL)

    wxFLAGS_MEMBER(wxBU_LEFT)
    wxFLAGS_MEMBER(wxBU_RIGHT)
    wxFLAGS_MEMBER(wxBU_TOP)
    wxFLAGS_MEMBER(wxBU_BOTTOM)
    wxFLAGS_MEMBER(wxBU_EXACTFIT)
wxEND_FLAGS( wxButtonStyle )

IMPLEMENT_DYNAMIC_CLASS_XTI(wxButton, wxControl,"wx/button.h")

wxBEGIN_PROPERTIES_TABLE(wxButton)
    wxEVENT_PROPERTY( Click , wxEVT_COMMAND_BUTTON_CLICKED , wxCommandEvent)

    wxPROPERTY( Font , wxFont , SetFont , GetFont  , EMPTY_MACROVALUE, 0 /*flags*/ , wxT("Helpstring") , wxT("group"))
    wxPROPERTY( Label, wxString , SetLabel, GetLabel, wxString(), 0 /*flags*/ , wxT("Helpstring") , wxT("group") )

    wxPROPERTY_FLAGS( WindowStyle , wxButtonStyle , long , SetWindowStyleFlag , GetWindowStyleFlag , EMPTY_MACROVALUE , 0 /*flags*/ , wxT("Helpstring") , wxT("group")) // style

wxEND_PROPERTIES_TABLE()

wxBEGIN_HANDLERS_TABLE(wxButton)
wxEND_HANDLERS_TABLE()

wxCONSTRUCTOR_6( wxButton , wxWindow* , Parent , wxWindowID , Id , wxString , Label , wxPoint , Position , wxSize , Size , long , WindowStyle  )


#else
IMPLEMENT_DYNAMIC_CLASS(wxButton, wxControl)
#endif

// ============================================================================
// implementation
// ============================================================================

// ----------------------------------------------------------------------------
// helper functions from wx/msw/private/button.h
// ----------------------------------------------------------------------------

void wxMSWButton::UpdateMultilineStyle(HWND hwnd, const wxString& label)
{
    // update BS_MULTILINE style depending on the new label (resetting it
    // doesn't seem to do anything very useful but it shouldn't hurt and we do
    // have to set it whenever the label becomes multi line as otherwise it
    // wouldn't be shown correctly as we don't use BS_MULTILINE when creating
    // the control unless it already has new lines in its label)
    long styleOld = ::GetWindowLong(hwnd, GWL_STYLE),
         styleNew;
    if ( label.find(wxT('\n')) != wxString::npos )
        styleNew = styleOld | BS_MULTILINE;
    else
        styleNew = styleOld & ~BS_MULTILINE;

    if ( styleNew != styleOld )
        ::SetWindowLong(hwnd, GWL_STYLE, styleNew);
}

wxSize wxMSWButton::GetFittingSize(wxWindow *win, const wxSize& sizeLabel)
{
    // FIXME: this is pure guesswork, need to retrieve the real button margins
    wxSize sizeBtn = sizeLabel;

    sizeBtn.x += 3*win->GetCharWidth();
    sizeBtn.y = 11*EDIT_HEIGHT_FROM_CHAR_HEIGHT(sizeLabel.y)/10;

    return sizeBtn;
}

wxSize wxMSWButton::ComputeBestSize(wxControl *btn)
{
    wxClientDC dc(btn);

    wxSize sizeBtn;
    dc.GetMultiLineTextExtent(btn->GetLabelText(), &sizeBtn.x, &sizeBtn.y);

    sizeBtn = GetFittingSize(btn, sizeBtn);

    // all buttons have at least the standard size unless the user explicitly
    // wants them to be of smaller size and used wxBU_EXACTFIT style when
    // creating the button
    if ( !btn->HasFlag(wxBU_EXACTFIT) )
    {
        wxSize sizeDef = wxButton::GetDefaultSize();
        if ( sizeBtn.x < sizeDef.x )
            sizeBtn.x = sizeDef.x;
        if ( sizeBtn.y < sizeDef.y )
            sizeBtn.y = sizeDef.y;
    }

    btn->CacheBestSize(sizeBtn);

    return sizeBtn;
}

// ----------------------------------------------------------------------------
// creation/destruction
// ----------------------------------------------------------------------------

bool wxButton::Create(wxWindow *parent,
                      wxWindowID id,
                      const wxString& lbl,
                      const wxPoint& pos,
                      const wxSize& size,
                      long style,
                      const wxValidator& validator,
                      const wxString& name)
{
    wxString label(lbl);
    if (label.empty() && wxIsStockID(id))
    {
        // On Windows, some buttons aren't supposed to have mnemonics
        label = wxGetStockLabel
                (
                    id,
                    id == wxID_OK || id == wxID_CANCEL || id == wxID_CLOSE
                        ? wxSTOCK_NOFLAGS
                        : wxSTOCK_WITH_MNEMONIC
                );
    }

    if ( !CreateControl(parent, id, pos, size, style, validator, name) )
        return false;

    WXDWORD exstyle;
    WXDWORD msStyle = MSWGetStyle(style, &exstyle);

    // if the label contains several lines we must explicitly tell the button
    // about it or it wouldn't draw it correctly ("\n"s would just appear as
    // black boxes)
    //
    // NB: we do it here and not in MSWGetStyle() because we need the label
    //     value and the label is not set yet when MSWGetStyle() is called
    msStyle |= wxMSWButton::GetMultilineStyle(label);

    return MSWCreateControl(wxT("BUTTON"), msStyle, pos, size, label, exstyle);
}

wxButton::~wxButton()
{
    wxTopLevelWindow *tlw = wxDynamicCast(wxGetTopLevelParent(this), wxTopLevelWindow);
    if ( tlw && tlw->GetTmpDefaultItem() == this )
    {
        UnsetTmpDefault();
    }

    delete m_imageData;
}

// ----------------------------------------------------------------------------
// flags
// ----------------------------------------------------------------------------

WXDWORD wxButton::MSWGetStyle(long style, WXDWORD *exstyle) const
{
    // buttons never have an external border, they draw their own one
    WXDWORD msStyle = wxControl::MSWGetStyle
                      (
                        (style & ~wxBORDER_MASK) | wxBORDER_NONE, exstyle
                      );

    // we must use WS_CLIPSIBLINGS with the buttons or they would draw over
    // each other in any resizeable dialog which has more than one button in
    // the bottom
    msStyle |= WS_CLIPSIBLINGS;

    // don't use "else if" here: weird as it is, but you may combine wxBU_LEFT
    // and wxBU_RIGHT to get BS_CENTER!
    if ( style & wxBU_LEFT )
        msStyle |= BS_LEFT;
    if ( style & wxBU_RIGHT )
        msStyle |= BS_RIGHT;
    if ( style & wxBU_TOP )
        msStyle |= BS_TOP;
    if ( style & wxBU_BOTTOM )
        msStyle |= BS_BOTTOM;
#ifndef __WXWINCE__
    // flat 2d buttons
    if ( style & wxNO_BORDER )
        msStyle |= BS_FLAT;
#endif // __WXWINCE__

    return msStyle;
}

void wxButton::SetLabel(const wxString& label)
{
    wxMSWButton::UpdateMultilineStyle(GetHwnd(), label);

    wxButtonBase::SetLabel(label);
}

// ----------------------------------------------------------------------------
// size management including autosizing
// ----------------------------------------------------------------------------

wxSize wxButton::DoGetBestSize() const
{
    wxSize size;

    // account for the text part if we have it or if we don't have any image at
    // all (buttons initially created with empty label should still have a non
    // zero size)
    if ( ShowsLabel() || !m_imageData )
    {
        size = wxMSWButton::ComputeBestSize(const_cast<wxButton *>(this));
    }

    if ( m_imageData )
    {
        // account for the bitmap size
        const wxSize sizeBmp = m_imageData->GetBitmap(State_Normal).GetSize();
        const wxDirection dirBmp = m_imageData->GetBitmapPosition();
        if ( dirBmp == wxLEFT || dirBmp == wxRIGHT )
        {
            size.x += sizeBmp.x;
            if ( sizeBmp.y > size.y )
                size.y = sizeBmp.y;
        }
        else // bitmap on top/below the text
        {
            size.y += sizeBmp.y;
            if ( sizeBmp.x > size.x )
                size.x = sizeBmp.x;
        }

        // account for the user-specified margins
        size += 2*m_imageData->GetBitmapMargins();

        // and also for the margins we always add internally (unless we have no
        // border at all in which case the button has exactly the same size as
        // bitmap and so no margins should be used)
        if ( !HasFlag(wxBORDER_NONE) )
        {
            int marginH = 0,
                marginV = 0;
#if wxUSE_UXTHEME
            if ( wxUxThemeEngine::GetIfActive() )
            {
                wxUxThemeHandle theme(const_cast<wxButton *>(this), L"BUTTON");

                MARGINS margins;
                wxUxThemeEngine::Get()->GetThemeMargins(theme, NULL,
                                                        BP_PUSHBUTTON,
                                                        PBS_NORMAL,
                                                        TMT_CONTENTMARGINS,
                                                        NULL,
                                                        &margins);

                // XP doesn't draw themed buttons correctly when the client
                // area is smaller than 8x8 - enforce this minimum size for
                // small bitmaps
                size.IncTo(wxSize(8, 8));

                marginH = margins.cxLeftWidth + margins.cxRightWidth
                            + 2*XP_BUTTON_EXTRA_MARGIN;
                marginV = margins.cyTopHeight + margins.cyBottomHeight
                            + 2*XP_BUTTON_EXTRA_MARGIN;
            }
            else
#endif // wxUSE_UXTHEME
            {
                marginH =
                marginV = OD_BUTTON_MARGIN;
            }

            size.IncBy(marginH, marginV);
        }

        CacheBestSize(size);
    }

    return size;
}

/* static */
wxSize wxButtonBase::GetDefaultSize()
{
    static wxSize s_sizeBtn;

    if ( s_sizeBtn.x == 0 )
    {
        wxScreenDC dc;
        dc.SetFont(wxSystemSettings::GetFont(wxSYS_DEFAULT_GUI_FONT));

        // the size of a standard button in the dialog units is 50x14,
        // translate this to pixels
        // NB1: the multipliers come from the Windows convention
        // NB2: the extra +1/+2 were needed to get the size be the same as the
        //      size of the buttons in the standard dialog - I don't know how
        //      this happens, but on my system this size is 75x23 in pixels and
        //      23*8 isn't even divisible by 14... Would be nice to understand
        //      why these constants are needed though!
        s_sizeBtn.x = (50 * (dc.GetCharWidth() + 1))/4;
        s_sizeBtn.y = ((14 * dc.GetCharHeight()) + 2)/8;
    }

    return s_sizeBtn;
}

// ----------------------------------------------------------------------------
// default button handling
// ----------------------------------------------------------------------------

/*
   The comment below and all this code is probably due to not using WM_NEXTDLGCTL
   message when changing focus (but just SetFocus() which is not enough), see
   http://blogs.msdn.com/oldnewthing/archive/2004/08/02/205624.aspx for the
   full explanation.

   TODO: Do use WM_NEXTDLGCTL and get rid of all this code.


   "Everything you ever wanted to know about the default buttons" or "Why do we
   have to do all this?"

   In MSW the default button should be activated when the user presses Enter
   and the current control doesn't process Enter itself somehow. This is
   handled by ::DefWindowProc() (or maybe ::DefDialogProc()) using DM_SETDEFID
   Another aspect of "defaultness" is that the default button has different
   appearance: this is due to BS_DEFPUSHBUTTON style which is completely
   separate from DM_SETDEFID stuff (!). Also note that BS_DEFPUSHBUTTON should
   be unset if our parent window is not active so it should be unset whenever
   we lose activation and set back when we regain it.

   Final complication is that when a button is active, it should be the default
   one, i.e. pressing Enter on a button always activates it and not another
   one.

   We handle this by maintaining a permanent and a temporary default items in
   wxControlContainer (both may be NULL). When a button becomes the current
   control (i.e. gets focus) it sets itself as the temporary default which
   ensures that it has the right appearance and that Enter will be redirected
   to it. When the button loses focus, it unsets the temporary default and so
   the default item will be the permanent default -- that is the default button
   if any had been set or none otherwise, which is just what we want.

   NB: all this is quite complicated by now and the worst is that normally
       it shouldn't be necessary at all as for the normal Windows programs
       DefWindowProc() and IsDialogMessage() take care of all this
       automatically -- however in wxWidgets programs this doesn't work for
       nested hierarchies (i.e. a notebook inside a notebook) for unknown
       reason and so we have to reproduce all this code ourselves. It would be
       very nice if we could avoid doing it.
 */

// set this button as the (permanently) default one in its panel
wxWindow *wxButton::SetDefault()
{
    // set this one as the default button both for wxWidgets ...
    wxWindow *winOldDefault = wxButtonBase::SetDefault();

    // ... and Windows
    SetDefaultStyle(wxDynamicCast(winOldDefault, wxButton), false);
    SetDefaultStyle(this, true);

    return winOldDefault;
}

// return the top level parent window if it's not being deleted yet, otherwise
// return NULL
static wxTopLevelWindow *GetTLWParentIfNotBeingDeleted(wxWindow *win)
{
    for ( ;; )
    {
        // IsTopLevel() will return false for a wxTLW being deleted, so we also
        // need the parent test for this case
        wxWindow * const parent = win->GetParent();
        if ( !parent || win->IsTopLevel() )
        {
            if ( win->IsBeingDeleted() )
                return NULL;

            break;
        }

        win = parent;
    }

    wxASSERT_MSG( win, wxT("button without top level parent?") );

    wxTopLevelWindow * const tlw = wxDynamicCast(win, wxTopLevelWindow);
    wxASSERT_MSG( tlw, wxT("logic error in GetTLWParentIfNotBeingDeleted()") );

    return tlw;
}

// set this button as being currently default
void wxButton::SetTmpDefault()
{
    wxTopLevelWindow * const tlw = GetTLWParentIfNotBeingDeleted(GetParent());
    if ( !tlw )
        return;

    wxWindow *winOldDefault = tlw->GetDefaultItem();
    tlw->SetTmpDefaultItem(this);

    SetDefaultStyle(wxDynamicCast(winOldDefault, wxButton), false);
    SetDefaultStyle(this, true);
}

// unset this button as currently default, it may still stay permanent default
void wxButton::UnsetTmpDefault()
{
    wxTopLevelWindow * const tlw = GetTLWParentIfNotBeingDeleted(GetParent());
    if ( !tlw )
        return;

    tlw->SetTmpDefaultItem(NULL);

    wxWindow *winOldDefault = tlw->GetDefaultItem();

    SetDefaultStyle(this, false);
    SetDefaultStyle(wxDynamicCast(winOldDefault, wxButton), true);
}

/* static */
void
wxButton::SetDefaultStyle(wxButton *btn, bool on)
{
    // we may be called with NULL pointer -- simpler to do the check here than
    // in the caller which does wxDynamicCast()
    if ( !btn )
        return;

    // first, let DefDlgProc() know about the new default button
    if ( on )
    {
        // we shouldn't set BS_DEFPUSHBUTTON for any button if we don't have
        // focus at all any more
        if ( !wxTheApp->IsActive() )
            return;

        wxWindow * const tlw = wxGetTopLevelParent(btn);
        wxCHECK_RET( tlw, wxT("button without top level window?") );

        ::SendMessage(GetHwndOf(tlw), DM_SETDEFID, btn->GetId(), 0L);

        // sending DM_SETDEFID also changes the button style to
        // BS_DEFPUSHBUTTON so there is nothing more to do
    }

    // then also change the style as needed
    long style = ::GetWindowLong(GetHwndOf(btn), GWL_STYLE);
    if ( !(style & BS_DEFPUSHBUTTON) == on )
    {
        // don't do it with the owner drawn buttons because it will
        // reset BS_OWNERDRAW style bit too (as BS_OWNERDRAW &
        // BS_DEFPUSHBUTTON != 0)!
        if ( (style & BS_OWNERDRAW) != BS_OWNERDRAW )
        {
            ::SendMessage(GetHwndOf(btn), BM_SETSTYLE,
                          on ? style | BS_DEFPUSHBUTTON
                             : style & ~BS_DEFPUSHBUTTON,
                          1L /* redraw */);
        }
        else // owner drawn
        {
            // redraw the button - it will notice itself that it's
            // [not] the default one [any longer]
            btn->Refresh();
        }
    }
    //else: already has correct style
}

// ----------------------------------------------------------------------------
// helpers
// ----------------------------------------------------------------------------

bool wxButton::SendClickEvent()
{
    wxCommandEvent event(wxEVT_COMMAND_BUTTON_CLICKED, GetId());
    event.SetEventObject(this);

    return ProcessCommand(event);
}

void wxButton::Command(wxCommandEvent & event)
{
    ProcessCommand(event);
}

// ----------------------------------------------------------------------------
// event/message handlers
// ----------------------------------------------------------------------------

bool wxButton::MSWCommand(WXUINT param, WXWORD WXUNUSED(id))
{
    bool processed = false;
    switch ( param )
    {
        // NOTE: Apparently older versions (NT 4?) of the common controls send
        //       BN_DOUBLECLICKED but not a second BN_CLICKED for owner-drawn
        //       buttons, so in order to send two EVT_BUTTON events we should
        //       catch both types.  Currently (Feb 2003) up-to-date versions of
        //       win98, win2k and winXP all send two BN_CLICKED messages for
        //       all button types, so we don't catch BN_DOUBLECLICKED anymore
        //       in order to not get 3 EVT_BUTTON events.  If this is a problem
        //       then we need to figure out which version of the comctl32 changed
        //       this behaviour and test for it.

        case 1:                     // message came from an accelerator
        case BN_CLICKED:            // normal buttons send this
            processed = SendClickEvent();
            break;
    }

    return processed;
}

WXLRESULT wxButton::MSWWindowProc(WXUINT nMsg, WXWPARAM wParam, WXLPARAM lParam)
{
    // when we receive focus, we want to temporarily become the default button in
    // our parent panel so that pressing "Enter" would activate us -- and when
    // losing it we should restore the previous default button as well
    if ( nMsg == WM_SETFOCUS )
    {
        SetTmpDefault();

        // let the default processing take place too
    }
    else if ( nMsg == WM_KILLFOCUS )
    {
        UnsetTmpDefault();
    }
    else if ( nMsg == WM_LBUTTONDBLCLK )
    {
        // emulate a click event to force an owner-drawn button to change its
        // appearance - without this, it won't do it
        (void)wxControl::MSWWindowProc(WM_LBUTTONDOWN, wParam, lParam);

        // and continue with processing the message normally as well
    }
#if wxUSE_UXTHEME
    else if ( nMsg == WM_THEMECHANGED )
    {
        // need to recalculate the best size here
        // as the theme size might have changed
        InvalidateBestSize();
    }
#endif // wxUSE_UXTHEME
    // must use m_mouseInWindow here instead of IsMouseInWindow()
    // since we need to know the first time the mouse enters the window
    // and IsMouseInWindow() would return true in this case
    else if ( (nMsg == WM_MOUSEMOVE && !m_mouseInWindow) ||
                nMsg == WM_MOUSELEAVE )
    {
        if (
                IsEnabled() &&
                (
#if wxUSE_UXTHEME
                wxUxThemeEngine::GetIfActive() ||
#endif // wxUSE_UXTHEME
                m_imageData && m_imageData->GetBitmap(State_Current).IsOk()
                )
           )
        {
            Refresh();
        }
    }

    // let the base class do all real processing
    return wxControl::MSWWindowProc(nMsg, wParam, lParam);
}

// ----------------------------------------------------------------------------
// button images
// ----------------------------------------------------------------------------

wxBitmap wxButton::DoGetBitmap(State which) const
{
    return m_imageData ? m_imageData->GetBitmap(which) : wxBitmap();
}

void wxButton::DoSetBitmap(const wxBitmap& bitmap, State which)
{
    // allocate the image data when the first bitmap is set
    if ( !m_imageData )
    {
#if wxUSE_UXTHEME
        // using image list doesn't work correctly if we don't have any label
        // (even if we use BUTTON_IMAGELIST_ALIGN_CENTER alignment and
        // BS_BITMAP style), at least under Windows 2003 so use owner drawn
        // strategy for bitmap-only buttons
        if ( ShowsLabel() && wxUxThemeEngine::GetIfActive() )
        {
            m_imageData = new wxXPButtonImageData(this, bitmap);
        }
        else
#endif // wxUSE_UXTHEME
        {
            m_imageData = new wxODButtonImageData(this, bitmap);
            MakeOwnerDrawn();
        }
    }
    else
    {
        m_imageData->SetBitmap(bitmap, which);
    }

    // it should be enough to only invalidate the best size when the normal
    // bitmap changes as all bitmaps assigned to the button should be of the
    // same size anyhow
    if ( which == State_Normal )
        InvalidateBestSize();

    Refresh();
}

wxSize wxButton::DoGetBitmapMargins() const
{
    return m_imageData ? m_imageData->GetBitmapMargins() : wxSize(0, 0);
}

void wxButton::DoSetBitmapMargins(wxCoord x, wxCoord y)
{
    wxCHECK_RET( m_imageData, "SetBitmap() must be called first" );

    m_imageData->SetBitmapMargins(x, y);
}

void wxButton::DoSetBitmapPosition(wxDirection dir)
{
    wxCHECK_RET( m_imageData, "SetBitmap() must be called first" );

    m_imageData->SetBitmapPosition(dir);
}

// ----------------------------------------------------------------------------
// owner-drawn buttons support
// ----------------------------------------------------------------------------

// drawing helpers
namespace
{

// return the button state using both the ODS_XXX flags specified in state
// parameter and the current button state
wxButton::State GetButtonState(wxButton *btn, UINT state)
{
    if ( state & ODS_DISABLED )
        return wxButton::State_Disabled;

    if ( state & ODS_SELECTED )
        return wxButton::State_Pressed;

    if ( btn->HasCapture() || btn->IsMouseInWindow() )
        return wxButton::State_Current;

    if ( state & ODS_FOCUS )
        return wxButton::State_Focused;

    return wxButton::State_Normal;
}

void DrawButtonText(HDC hdc,
                    RECT *pRect,
                    const wxString& text,
                    COLORREF col,
                    int flags)
{
    wxTextColoursChanger changeFg(hdc, col, CLR_INVALID);
    wxBkModeChanger changeBkMode(hdc, wxBRUSHSTYLE_TRANSPARENT);

    // center text horizontally in any case
    flags |= DT_CENTER;

    if ( text.find(wxT('\n')) != wxString::npos )
    {
        // draw multiline label

        // first we need to compute its bounding rect
        RECT rc;
        ::CopyRect(&rc, pRect);
        ::DrawText(hdc, text.wx_str(), text.length(), &rc,
                   DT_CENTER | DT_CALCRECT);

        // now center this rect inside the entire button area
        const LONG w = rc.right - rc.left;
        const LONG h = rc.bottom - rc.top;
        rc.left = (pRect->right - pRect->left)/2 - w/2;
        rc.right = rc.left+w;
        rc.top = (pRect->bottom - pRect->top)/2 - h/2;
        rc.bottom = rc.top+h;

        ::DrawText(hdc, text.wx_str(), text.length(), &rc, flags);
    }
    else // single line label
    {
        // centre text vertically too (notice that we must have DT_SINGLELINE
        // for DT_VCENTER to work)
        ::DrawText(hdc, text.wx_str(), text.length(), pRect,
                   flags | DT_SINGLELINE | DT_VCENTER);
    }
}

void DrawRect(HDC hdc, const RECT& r)
{
    wxDrawLine(hdc, r.left, r.top, r.right, r.top);
    wxDrawLine(hdc, r.right, r.top, r.right, r.bottom);
    wxDrawLine(hdc, r.right, r.bottom, r.left, r.bottom);
    wxDrawLine(hdc, r.left, r.bottom, r.left, r.top);
}

/*
   The button frame looks like this normally:

   WWWWWWWWWWWWWWWWWWB
   WHHHHHHHHHHHHHHHHGB  W = white       (HILIGHT)
   WH               GB  H = light grey  (LIGHT)
   WH               GB  G = dark grey   (SHADOW)
   WH               GB  B = black       (DKSHADOW)
   WH               GB
   WGGGGGGGGGGGGGGGGGB
   BBBBBBBBBBBBBBBBBBB

   When the button is selected, the button becomes like this (the total button
   size doesn't change):

   BBBBBBBBBBBBBBBBBBB
   BWWWWWWWWWWWWWWWWBB
   BWHHHHHHHHHHHHHHGBB
   BWH             GBB
   BWH             GBB
   BWGGGGGGGGGGGGGGGBB
   BBBBBBBBBBBBBBBBBBB
   BBBBBBBBBBBBBBBBBBB

   When the button is pushed (while selected) it is like:

   BBBBBBBBBBBBBBBBBBB
   BGGGGGGGGGGGGGGGGGB
   BG               GB
   BG               GB
   BG               GB
   BG               GB
   BGGGGGGGGGGGGGGGGGB
   BBBBBBBBBBBBBBBBBBB
*/
void DrawButtonFrame(HDC hdc, RECT& rectBtn,
                     bool selected, bool pushed)
{
    RECT r;
    CopyRect(&r, &rectBtn);

    AutoHPEN hpenBlack(GetSysColor(COLOR_3DDKSHADOW)),
             hpenGrey(GetSysColor(COLOR_3DSHADOW)),
             hpenLightGr(GetSysColor(COLOR_3DLIGHT)),
             hpenWhite(GetSysColor(COLOR_3DHILIGHT));

    SelectInHDC selectPen(hdc, hpenBlack);

    r.right--;
    r.bottom--;

    if ( pushed )
    {
        DrawRect(hdc, r);

        (void)SelectObject(hdc, hpenGrey);
        ::InflateRect(&r, -1, -1);

        DrawRect(hdc, r);
    }
    else // !pushed
    {
        if ( selected )
        {
            DrawRect(hdc, r);

            ::InflateRect(&r, -1, -1);
        }

        wxDrawLine(hdc, r.left, r.bottom, r.right, r.bottom);
        wxDrawLine(hdc, r.right, r.bottom, r.right, r.top - 1);

        (void)SelectObject(hdc, hpenWhite);
        wxDrawLine(hdc, r.left, r.bottom - 1, r.left, r.top);
        wxDrawLine(hdc, r.left, r.top, r.right, r.top);

        (void)SelectObject(hdc, hpenLightGr);
        wxDrawLine(hdc, r.left + 1, r.bottom - 2, r.left + 1, r.top + 1);
        wxDrawLine(hdc, r.left + 1, r.top + 1, r.right - 1, r.top + 1);

        (void)SelectObject(hdc, hpenGrey);
        wxDrawLine(hdc, r.left + 1, r.bottom - 1, r.right - 1, r.bottom - 1);
        wxDrawLine(hdc, r.right - 1, r.bottom - 1, r.right - 1, r.top);
    }

    InflateRect(&rectBtn, -OD_BUTTON_MARGIN, -OD_BUTTON_MARGIN);
}

#if wxUSE_UXTHEME
void DrawXPBackground(wxButton *button, HDC hdc, RECT& rectBtn, UINT state)
{
    wxUxThemeHandle theme(button, L"BUTTON");

    // this array is indexed by wxButton::State values and so must be kept in
    // sync with it
    static const int uxStates[] =
    {
        PBS_NORMAL, PBS_HOT, PBS_PRESSED, PBS_DISABLED, PBS_DEFAULTED
    };

    int iState = uxStates[GetButtonState(button, state)];

    wxUxThemeEngine * const engine = wxUxThemeEngine::Get();

    // draw parent background if needed
    if ( engine->IsThemeBackgroundPartiallyTransparent
                 (
                    theme,
                    BP_PUSHBUTTON,
                    iState
                 ) )
    {
        engine->DrawThemeParentBackground(GetHwndOf(button), hdc, &rectBtn);
    }

    // draw background
    engine->DrawThemeBackground(theme, hdc, BP_PUSHBUTTON, iState,
                                &rectBtn, NULL);

    // calculate content area margins
    MARGINS margins;
    engine->GetThemeMargins(theme, hdc, BP_PUSHBUTTON, iState,
                            TMT_CONTENTMARGINS, &rectBtn, &margins);
    ::InflateRect(&rectBtn, -margins.cxLeftWidth, -margins.cyTopHeight);
    ::InflateRect(&rectBtn, -XP_BUTTON_EXTRA_MARGIN, -XP_BUTTON_EXTRA_MARGIN);

    if ( button->UseBgCol() )
    {
        COLORREF colBg = wxColourToRGB(button->GetBackgroundColour());
        AutoHBRUSH hbrushBackground(colBg);

        // don't overwrite the focus rect
        RECT rectClient;
        ::CopyRect(&rectClient, &rectBtn);
        ::InflateRect(&rectClient, -1, -1);
        FillRect(hdc, &rectClient, hbrushBackground);
    }
}
#endif // wxUSE_UXTHEME

} // anonymous namespace

// ----------------------------------------------------------------------------
// owner drawn buttons support
// ----------------------------------------------------------------------------

void wxButton::MakeOwnerDrawn()
{
    long style = GetWindowLong(GetHwnd(), GWL_STYLE);
    if ( (style & BS_OWNERDRAW) != BS_OWNERDRAW )
    {
        // make it so
        style |= BS_OWNERDRAW;
        SetWindowLong(GetHwnd(), GWL_STYLE, style);
    }
}

bool wxButton::SetBackgroundColour(const wxColour &colour)
{
    if ( !wxControl::SetBackgroundColour(colour) )
    {
        // nothing to do
        return false;
    }

    MakeOwnerDrawn();

    Refresh();

    return true;
}

bool wxButton::SetForegroundColour(const wxColour &colour)
{
    if ( !wxControl::SetForegroundColour(colour) )
    {
        // nothing to do
        return false;
    }

    MakeOwnerDrawn();

    Refresh();

    return true;
}

bool wxButton::MSWOnDraw(WXDRAWITEMSTRUCT *wxdis)
{
    LPDRAWITEMSTRUCT lpDIS = (LPDRAWITEMSTRUCT)wxdis;
    HDC hdc = lpDIS->hDC;

    UINT state = lpDIS->itemState;
    bool pushed = (SendMessage(GetHwnd(), BM_GETSTATE, 0, 0) & BST_PUSHED) != 0;

    RECT rectBtn;
    CopyRect(&rectBtn, &lpDIS->rcItem);

    // draw the button background
    if ( !HasFlag(wxBORDER_NONE) )
    {
#if wxUSE_UXTHEME
        if ( wxUxThemeEngine::GetIfActive() )
        {
            DrawXPBackground(this, hdc, rectBtn, state);
        }
        else
#endif // wxUSE_UXTHEME
        {
            COLORREF colBg = wxColourToRGB(GetBackgroundColour());

            // first, draw the background
            AutoHBRUSH hbrushBackground(colBg);
            FillRect(hdc, &rectBtn, hbrushBackground);

            // draw the border for the current state
            bool selected = (state & ODS_SELECTED) != 0;
            if ( !selected )
            {
                wxTopLevelWindow *
                    tlw = wxDynamicCast(wxGetTopLevelParent(this), wxTopLevelWindow);
                if ( tlw )
                {
                    selected = tlw->GetDefaultItem() == this;
                }
            }

            DrawButtonFrame(hdc, rectBtn, selected, pushed);
        }

        // draw the focus rectangle if we need it
        if ( (state & ODS_FOCUS) && !(state & ODS_NOFOCUSRECT) )
        {
            DrawFocusRect(hdc, &rectBtn);

#if wxUSE_UXTHEME
            if ( !wxUxThemeEngine::GetIfActive() )
#endif // wxUSE_UXTHEME
            {
                if ( pushed )
                {
                    // the label is shifted by 1 pixel to create "pushed" effect
                    OffsetRect(&rectBtn, 1, 1);
                }
            }
        }
    }


    // draw the image, if any
    if ( m_imageData )
    {
        wxBitmap bmp = m_imageData->GetBitmap(GetButtonState(this, state));
        if ( !bmp.IsOk() )
            bmp = m_imageData->GetBitmap(State_Normal);

        const wxSize sizeBmp = bmp.GetSize();
        const wxSize margin = m_imageData->GetBitmapMargins();
        const wxSize sizeBmpWithMargins(sizeBmp + 2*margin);
        wxRect rectButton(wxRectFromRECT(rectBtn));

        // for simplicity, we start with centred rectangle and then move it to
        // the appropriate edge
        wxRect rectBitmap = wxRect(sizeBmp).CentreIn(rectButton);
        switch ( m_imageData->GetBitmapPosition() )
        {
            default:
                wxFAIL_MSG( "invalid direction" );
                // fall through

            case wxLEFT:
                rectBitmap.x = rectButton.x + margin.x;
                rectButton.x += sizeBmpWithMargins.x;
                rectButton.width -= sizeBmpWithMargins.x;
                break;

            case wxRIGHT:
                rectBitmap.x = rectButton.GetRight() - sizeBmp.x - margin.x;
                rectButton.width -= sizeBmpWithMargins.x;
                break;

            case wxTOP:
                rectBitmap.y = rectButton.y + margin.y;
                rectButton.y += sizeBmpWithMargins.y;
                rectButton.height -= sizeBmpWithMargins.y;
                break;

            case wxBOTTOM:
                rectBitmap.y = rectButton.GetBottom() - sizeBmp.y - margin.y;
                rectButton.height -= sizeBmpWithMargins.y;
                break;
        }

        wxDCTemp dst((WXHDC)hdc);
        dst.DrawBitmap(bmp, rectBitmap.GetPosition(), true);

        wxCopyRectToRECT(rectButton, rectBtn);
    }


    // finally draw the label
    if ( ShowsLabel() )
    {
        COLORREF colFg = state & ODS_DISABLED
                            ? ::GetSysColor(COLOR_GRAYTEXT)
                            : wxColourToRGB(GetForegroundColour());

        // notice that DT_HIDEPREFIX doesn't work on old (pre-Windows 2000)
        // systems but by happy coincidence ODS_NOACCEL is not used under them
        // neither so DT_HIDEPREFIX should never be used there
        DrawButtonText(hdc, &rectBtn, GetLabel(), colFg,
                       state & ODS_NOACCEL ? DT_HIDEPREFIX : 0);
    }

    return true;
}

#endif // wxUSE_BUTTON