Method OnMouseWheel

ColorCop/ColorCopDlg.cpp:2948–3001

BOOL CColorCopDlg::OnMouseWheel(UINT nFlags, int16_t zDelta, CPoint pt) {
    // first check if we are magnifying...

    if (m_isEyedropping) {
        return TRUE;
    } else if (m_isMagnifying) {
        m_MagLevel += zDelta / WHEEL_DELTA;
        m_MagLevel = std::clamp<int>(m_MagLevel, kMinZoom, kMaxZoom);
        return TRUE;
    }

    // determine which edit control has the focus??

    CWnd* curfocus = GetFocus();  // handle to the window with focus

    if (curfocus == NULL)  // There is nothing with the focus
        return TRUE;       // jump out

    int offset = 1;  // default

    if (nFlags == MK_CONTROL)  // jump by 5 if control is down
        offset = 5;
    else if (nFlags == MK_SHIFT)  // jump by 2 if shift is down
        offset = 2;

    // if bSnaptoWebsafe is on then incrementing by 1, 5 or 2 won't do any good
    // because it will just snap lower.

    if (m_Appflags & SnaptoWebsafe) {
        // therefore, increment or decrement by 51
        offset = WEBSAFE_STEP;
    }

    if (curfocus == GetDlgItem(IDC_RED)) {  // red has focus
        m_Reddec += zDelta / WHEEL_DELTA * offset;
        m_Reddec = std::clamp(m_Reddec, RGB_MIN, RGB_MAX);

    } else if (curfocus == GetDlgItem(IDC_GREEN)) {  // green has focus
        m_Greendec += zDelta / WHEEL_DELTA * offset;
        m_Greendec = std::clamp(m_Greendec, RGB_MIN, RGB_MAX);
    } else if (curfocus == GetDlgItem(IDC_BLUE)) {  // blue has focus
        m_Bluedec += zDelta / WHEEL_DELTA * offset;
        m_Bluedec = std::clamp(m_Bluedec, RGB_MIN, RGB_MAX);
    } else {          // there is focus, but it's not on either the Red,
        return TRUE;  // Green, or Blue edit controls -> jump out
    }

    UpdateData(false);
    CalcColorPal();
    OnconvertRGB();
    OnCopytoclip();

    return CDialog::OnMouseWheel(nFlags, zDelta, pt);
}

void CColorCopDlg::OnTimer(UINT nIDEvent) {
    // this allows animations to be magnified and eyedropped