textctrlce.cpp

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    // edit controls mostly)
    if ( (value.length() > 0x400) || (value != GetValue()) )
    {
        DoWriteText(value, false);

        // for compatibility, don't move the cursor when doing SetValue()
        SetInsertionPoint(0);
    }
    else // same text
    {
        // still send an event for consistency
        SendUpdateEvent();
    }

    // we should reset the modified flag even if the value didn't really change

    // mark the control as being not dirty - we changed its text, not the
    // user
    DiscardEdits();
}

void wxTextCtrl::WriteText(const wxString& value)
{
    DoWriteText(value);
}

void wxTextCtrl::DoWriteText(const wxString& value, bool selectionOnly)
{
    wxString valueDos;
    if ( m_windowStyle & wxTE_MULTILINE )
        valueDos = wxTextFile::Translate(value, wxTextFileType_Dos);
    else
        valueDos = value;

    // in some cases we get 2 EN_CHANGE notifications after the SendMessage
    // call below which is confusing for the client code and so should be
    // avoided
    //
    if ( ( selectionOnly && HasSelection() ) )
    {
        m_suppressNextUpdate = true;
    }

    ::SendMessage(GetBuddyHwnd(), selectionOnly ? EM_REPLACESEL : WM_SETTEXT,
                  0, (LPARAM)valueDos.c_str());

    if ( !selectionOnly )
    {
        // Windows already sends an update event for single-line
        // controls.
        if ( m_windowStyle & wxTE_MULTILINE )
            SendUpdateEvent();
    }

    AdjustSpaceLimit();
}

void wxTextCtrl::AppendText(const wxString& text)
{
    SetInsertionPointEnd();

    WriteText(text);
}

void wxTextCtrl::Clear()
{
    ::SetWindowText(GetBuddyHwnd(), wxEmptyString);

    // Windows already sends an update event for single-line
    // controls.
    if ( m_windowStyle & wxTE_MULTILINE )
        SendUpdateEvent();
}

// ----------------------------------------------------------------------------
// Clipboard operations
// ----------------------------------------------------------------------------

void wxTextCtrl::Copy()
{
    if (CanCopy())
    {
        ::SendMessage(GetBuddyHwnd(), WM_COPY, 0, 0L);
    }
}

void wxTextCtrl::Cut()
{
    if (CanCut())
    {
        ::SendMessage(GetBuddyHwnd(), WM_CUT, 0, 0L);
    }
}

void wxTextCtrl::Paste()
{
    if (CanPaste())
    {
        ::SendMessage(GetBuddyHwnd(), WM_PASTE, 0, 0L);
    }
}

bool wxTextCtrl::HasSelection() const
{
    long from, to;
    GetSelection(&from, &to);
    return from != to;
}

bool wxTextCtrl::CanCopy() const
{
    // Can copy if there's a selection
    return HasSelection();
}

bool wxTextCtrl::CanCut() const
{
    return CanCopy() && IsEditable();
}

bool wxTextCtrl::CanPaste() const
{
    if ( !IsEditable() )
        return false;

    // Standard edit control: check for straight text on clipboard
    if ( !::OpenClipboard(GetHwndOf(wxTheApp->GetTopWindow())) )
        return false;

    bool isTextAvailable = ::IsClipboardFormatAvailable(CF_TEXT) != 0;
    ::CloseClipboard();

    return isTextAvailable;
}

// ----------------------------------------------------------------------------
// Accessors
// ----------------------------------------------------------------------------

void wxTextCtrl::SetEditable(bool editable)
{
    ::SendMessage(GetBuddyHwnd(), EM_SETREADONLY, (WPARAM)!editable, (LPARAM)0L);
}

void wxTextCtrl::SetInsertionPoint(long pos)
{
    DoSetSelection(pos, pos);
}

void wxTextCtrl::SetInsertionPointEnd()
{
    if ( GetInsertionPoint() != GetLastPosition() )
        SetInsertionPoint(GetLastPosition());
}

long wxTextCtrl::GetInsertionPoint() const
{
    DWORD Pos = (DWORD)::SendMessage(GetBuddyHwnd(), EM_GETSEL, 0, 0L);
    return Pos & 0xFFFF;
}

wxTextPos wxTextCtrl::GetLastPosition() const
{
    int numLines = GetNumberOfLines();
    long posStartLastLine = XYToPosition(0, numLines - 1);

    long lenLastLine = GetLengthOfLineContainingPos(posStartLastLine);

    return posStartLastLine + lenLastLine;
}

void wxTextCtrl::GetSelection(long* from, long* to) const
{
    DWORD dwStart, dwEnd;
    ::SendMessage(GetBuddyHwnd(), EM_GETSEL, (WPARAM)&dwStart, (LPARAM)&dwEnd);

    *from = dwStart;
    *to = dwEnd;
}

bool wxTextCtrl::IsEditable() const
{
    if ( !GetBuddyHwnd() )
        return true;

    long style = ::GetWindowLong(GetBuddyHwnd(), GWL_STYLE);

    return (style & ES_READONLY) == 0;
}

// ----------------------------------------------------------------------------
// selection
// ----------------------------------------------------------------------------

void wxTextCtrl::SetSelection(long from, long to)
{
    // if from and to are both -1, it means (in wxWidgets) that all text should
    // be selected - translate into Windows convention
    if ( (from == -1) && (to == -1) )
    {
        from = 0;
        to = -1;
    }

    DoSetSelection(from, to);
}

void wxTextCtrl::DoSetSelection(long from, long to, bool scrollCaret)
{
    ::SendMessage(GetBuddyHwnd(), EM_SETSEL, (WPARAM)from, (LPARAM)to);

    if ( scrollCaret )
    {
        ::SendMessage(GetBuddyHwnd(), EM_SCROLLCARET, (WPARAM)0, (LPARAM)0);
    }
}

// ----------------------------------------------------------------------------
// Working with files
// ----------------------------------------------------------------------------

bool wxTextCtrl::LoadFile(const wxString& file)
{
    if ( wxTextCtrlBase::LoadFile(file) )
    {
        // update the size limit if needed
        AdjustSpaceLimit();

        return true;
    }

    return false;
}

// ----------------------------------------------------------------------------
// Editing
// ----------------------------------------------------------------------------

void wxTextCtrl::Replace(long from, long to, const wxString& value)
{
    // Set selection and remove it
    DoSetSelection(from, to, false);

    DoWriteText(value, true);
}

void wxTextCtrl::Remove(long from, long to)
{
    Replace(from, to, wxEmptyString);
}

bool wxTextCtrl::IsModified() const
{
    return ::SendMessage(GetBuddyHwnd(), EM_GETMODIFY, 0, 0) != 0;
}

void wxTextCtrl::MarkDirty()
{
    ::SendMessage(GetBuddyHwnd(), EM_SETMODIFY, TRUE, 0L);
}

void wxTextCtrl::DiscardEdits()
{
    ::SendMessage(GetBuddyHwnd(), EM_SETMODIFY, FALSE, 0L);
}

int wxTextCtrl::GetNumberOfLines() const
{
    return (int)::SendMessage(GetBuddyHwnd(), EM_GETLINECOUNT, 0, 0L);
}

// ----------------------------------------------------------------------------
// Positions <-> coords
// ----------------------------------------------------------------------------

long wxTextCtrl::XYToPosition(long x, long y) const
{
    // This gets the char index for the _beginning_ of this line
    long charIndex = ::SendMessage(GetBuddyHwnd(), EM_LINEINDEX, (WPARAM)y, (LPARAM)0);

    return charIndex + x;
}

bool wxTextCtrl::PositionToXY(long pos, long *x, long *y) const
{
    // This gets the line number containing the character
    long lineNo = ::SendMessage(GetBuddyHwnd(), EM_LINEFROMCHAR, (WPARAM)pos, 0);

    if ( lineNo == -1 )
    {
        // no such line
        return false;
    }

    // This gets the char index for the _beginning_ of this line
    long charIndex = ::SendMessage(GetBuddyHwnd(), EM_LINEINDEX, (WPARAM)lineNo, (LPARAM)0);
    if ( charIndex == -1 )
    {
        return false;
    }

    // The X position must therefore be the different between pos and charIndex
    if ( x )
        *x = pos - charIndex;
    if ( y )
        *y = lineNo;

    return true;
}

wxTextCtrlHitTestResult
wxTextCtrl::HitTest(const wxPoint& pt, long *posOut) const
{
    // first get the position from Windows
    // for the plain ones, we are limited to 16 bit positions which are
    // combined in a single 32 bit value
    LPARAM lParam = MAKELPARAM(pt.x, pt.y);

    LRESULT pos = ::SendMessage(GetBuddyHwnd(), EM_CHARFROMPOS, 0, lParam);

    if ( pos == -1 )
    {
        // this seems to indicate an error...
        return wxTE_HT_UNKNOWN;
    }

    // for plain EDIT controls the higher word contains something else
    pos = LOWORD(pos);


    // next determine where it is relatively to our point: EM_CHARFROMPOS
    // always returns the closest character but we need to be more precise, so
    // double check that we really are where it pretends
    POINTL ptReal;

    LRESULT lRc = ::SendMessage(GetBuddyHwnd(), EM_POSFROMCHAR, pos, 0);

    if ( lRc == -1 )
    {
        // this is apparently returned when pos corresponds to the last
        // position
        ptReal.x =
        ptReal.y = 0;
    }
    else
    {
        ptReal.x = LOWORD(lRc);
        ptReal.y = HIWORD(lRc);
    }

    wxTextCtrlHitTestResult rc;

    if ( pt.y > ptReal.y + GetCharHeight() )
        rc = wxTE_HT_BELOW;
    else if ( pt.x > ptReal.x + GetCharWidth() )
        rc = wxTE_HT_BEYOND;
    else
        rc = wxTE_HT_ON_TEXT;

    if ( posOut )
        *posOut = pos;

    return rc;
}

void wxTextCtrl::ShowPosition(long pos)
{
    int currentLineLineNo = (int)::SendMessage(GetBuddyHwnd(), EM_GETFIRSTVISIBLELINE, 0, 0L);

    int specifiedLineLineNo = (int)::SendMessage(GetBuddyHwnd(), EM_LINEFROMCHAR, (WPARAM)pos, 0L);

    int linesToScroll = specifiedLineLineNo - currentLineLineNo;

    if (linesToScroll != 0)
        (void)::SendMessage(GetBuddyHwnd(), EM_LINESCROLL, 0, (LPARAM)linesToScroll);
}

long wxTextCtrl::GetLengthOfLineContainingPos(long pos) const
{
    return ::SendMessage(GetBuddyHwnd(), EM_LINELENGTH, (WPARAM)pos, 0L);
}

int wxTextCtrl::GetLineLength(long lineNo) const
{
    long pos = XYToPosition(0, lineNo);

    return GetLengthOfLineContainingPos(pos);
}

wxString wxTextCtrl::GetLineText(long lineNo) const
{
    size_t len = (size_t)GetLineLength(lineNo) + 1;

    // there must be at least enough place for the length WORD in the
    // buffer
    len += sizeof(WORD);

    wxString str;
    {
        wxStringBufferLength tmp(str, len);
        wxChar *buf = tmp;

        *(WORD *)buf = (WORD)len;
        len = (size_t)::SendMessage(GetBuddyHwnd(), EM_GETLINE, lineNo, (LPARAM)buf);

        // remove the '\n' at the end, if any (this is how this function is
        // supposed to work according to the docs)