//-----------------------------------------------------------------------------
// AppendToLogAndScroll()
///
/// \brief Add a string to the serial log window at the current position,
/// then scroll to the end of the text such that the last line of
/// the text is shown at the bottom of the CRichEditCtrl.
///
/// The string is added to the message log starting at the current position,
/// i.e. without starting a new line. Then the control scrolls down to show
/// as much text as possible, including the last line of text at the very
/// bottom.
/// The string is displayed in the specified text color.
/// The string may be a multiline string using carriage return/line feed
/// (i.e. newline) characters to indicate a line breaks.
///
/// \param [in] str The string to add to the message log.
/// \param [in] color The text color of the string. You may use the
/// RGB(r,g,b) macro to specify the color byte-wise.
/// \return An integer indicating sucess or failure:
/// - 0, if the function succeeded.
/// - (-1), if the function failed.
/// (This function always returns 0, because no
/// parameter or failure checking is done.)
///
/// \remark
/// The automatic scrolling function would be easy, if the MFC documentation
/// was correct. Unfortunetely, it is not as trivial as one might think.
/// If the CRichEditCtrl has the focus, it scrolls automatically if you
/// insert text programatically. If it does not have the focus, it does not
/// scroll automatically, so in that case you can use the LineScroll()
/// method and you get the results you would expect when reading the MFC docs.
/// This is true even if ES_AUTOxSCROLL style is NOT set.
///
/// So the point is to check in the AppendToLogAndScroll() method if the
/// affected CRichEditCtrl has the focus. If so, we must not call
/// LineScroll(). If not, it is safe to call LineSroll() to first scroll to
/// the very end, which means that the last line of text is shown at the top
/// of the CRichEditCtrl.
/// Then we call LineScroll() a second time, this time scrolling back by
/// the number of visible lines. This leads to having the last line of the
/// text being displayed at the bottom of CRichEditCtrl.
///
/// Please note that in this sample application, the CRichEditCtrl never has
/// the focus, because we always have to click a button in order to insert
/// text. However, if you are using the code in an application not based on
/// a dialog and that fills up the control where the user could have set focus
/// to the control first, this method would fail to scroll correctly without
/// checking the focus.
/// I used this code in an MDI application, and there the control claims
/// to have the focus if I click into the control before clicking a menu
/// command (whatever the reason might be why in that case the focus is
/// not lost to the menu command).
///
/// Please note that the code is written for maximum comprehension / good
/// readability, not for code or execution efficiency.
//-----------------------------------------------------------------------------
int CThreadTestDlg::AppendToLogAndScroll( CString str, COLORREF color )
{
long nVisible = 0;
long nInsertionPoint = 0;
CHARFORMAT cf;
// Initialize character format structure
cf.cbSize = sizeof( CHARFORMAT );
cf.dwMask = CFM_COLOR | CFM_SIZE;
cf.dwEffects = 0; // To disable CFE_AUTOCOLOR
cf.yHeight = 210; // 1twips = 15px, 近似使用五号字体
cf.crTextColor = color;
// Set insertion point to end of text
nInsertionPoint = m_ctrlLog.GetWindowTextLength();
m_ctrlLog.SetSel( nInsertionPoint, -1 );
// Set the character format
m_ctrlLog.SetSelectionCharFormat( cf );
// Replace selection. Because we have nothing
// selected, this will simply insert
// the string at the current caret position.
m_ctrlLog.ReplaceSel( str );
// Get number of currently visible lines or maximum number of visible lines
// (We must call GetNumVisibleLines() before the first call to LineScroll()!)
nVisible = GetNumVisibleLines( &m_ctrlLog );
// Now this is the fix of CRichEditCtrl's abnormal behaviour when used
// in an application not based on dialogs. Checking the focus prevents
// us from scrolling when the CRichEditCtrl does so automatically,
// even though ES_AUTOxSCROLL style is NOT set.
if ( &m_ctrlLog != m_ctrlLog.GetFocus() )
{
m_ctrlLog.LineScroll( INT_MAX );
m_ctrlLog.LineScroll( 1 - nVisible );
}
return 0;
}
void CLogPid::DisplayData (LPCTSTR pszData)
{
long nVisible = 0;
if (m_bPause)
return;
// Format the selection as default text
CHARFORMAT cf;
cf.cbSize = sizeof(cf);
cf.dwMask = CFM_COLOR;
m_ctrlLog.GetSelectionCharFormat(cf);
cf.dwEffects |= CFE_AUTOCOLOR;
cf.yHeight = 183;
strcpy( cf.szFaceName, FONT_NAME );
m_ctrlLog.SetSelectionCharFormat(cf);
// Add the event to the edit control
m_ctrlLog.SetSel(-1,-1);
m_ctrlLog.ReplaceSel(pszData);
// Get number of currently visible lines or maximum number of visible lines
// (We must call GetNumVisibleLines() before the first call to LineScroll()!)
nVisible = GetNumVisibleLines(&m_ctrlLog);
// Now this is the fix of CRichEditCtrl's abnormal behaviour when used
// in an application not based on dialogs. Checking the focus prevents
// us from scrolling when the CRichEditCtrl does so automatically,
// even though ES_AUTOxSCROLL style is NOT set.
if (&m_ctrlLog != m_ctrlLog.GetFocus())
{
m_ctrlLog.LineScroll(INT_MAX);
m_ctrlLog.LineScroll(1 - nVisible);
}
}
