Count logical liines in a text control

Question

Hi, ALL,

There is a EM_GETLINECOUNT, but it will count the number of text lines.

I'm looking for to count the displayed lines (or wrapped lines) in a text control.

Either using WinAPI or C++.

Thank you.

Answer 1

An edit control may not necessarily display integral lines of text. So its possible that the following code could return a visible line count that includes a partially displayed line.

Used in a Win32 dialog -

void CVisibleCountApp::OnCount()
{
    RECT rc{};
    int lastLine{};
    BOOL bVisible{ TRUE };

    Edit_GetRect(m_hEdit, &rc);
    int firstLine = Edit_GetFirstVisibleLine(m_hEdit);

    for (int i = firstLine; bVisible; i++)
    {
        int charIndex = Edit_LineIndex(m_hEdit, i);
        auto coord = SendMessage(m_hEdit, EM_POSFROMCHAR, charIndex, 0);
        POINT pt{ LOWORD(coord), HIWORD(coord) };
        bVisible = PtInRect(&rc, pt);
        if (bVisible)
            lastLine = i;
    }

    TCHAR szMsg[128]{};
    _stprintf_s(szMsg, _T("First line index: %d, Last line index: %d, No. Lines %d"), firstLine, lastLine, lastLine - firstLine + 1);
    MessageBox(m_hWnd, szMsg, _T("Visible Line Count"), MB_ICONINFORMATION);
}

Example output -

Answer 2

Hi,@Igor Korot. You could get the text first, and then count the number of \r\r\n which is the number of soft returns. For more details, you can check out EM_FMTLINES.
Here is an example of getting the number of soft returns.

int countSubstring(const std::string& str, const std::string& sub)

{

    if (sub.length() == 0) return 0;

    int count = 0;

    for (size_t offset = str.find(sub); offset != std::string::npos;

        offset = str.find(sub, offset + sub.length()))

    {

        ++count;

    }

    return count;

}

        SendMessage(m_hEdit, EM_FMTLINES, 1, 0);

        int lineCount = SendMessage(m_hEdit, EM_GETLINECOUNT, 0, 0);

        char buff[1024];

        GetWindowTextA(m_hEdit, buff, 1024);

        int result = countSubstring(buff, "\r\r\n");

        SendMessage(m_hEdit, EM_FMTLINES, 0, 0);

        MessageBoxA(hDlg, std::to_string(result).c_str(), " soft line-break Count", MB_ICONINFORMATION);
     
      

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Answer 3

@RLWA32 ,

In your little GIF at the end (before you started moving the cursor up) I should get the 4 as the number of logical lines. and 2 as the physical lines.

(In my case 2 is defines as number of hard CR/LF plus the last line and 4 is defined as number of soft AND hard CR/LF plus the last line).

Thank you.

P.S.: I think the 2 will be produced by the EM_GETLINECOUNT. The question is - how to get 4.