kernel/lib/Date.php
public static function getWeek(int $iWeek, int $iYear, string $sFormat = "Y-m-d") : Date
    {
        $iFirstDayInYear = date("N",mktime(0, 0, 0, 1, 1, $iYear));

        if ($iFirstDayInYear < 5) { $iShift = -($iFirstDayInYear - 1) * 86400; } else { $iShift = (8 - $iFirstDayInYear) * 86400; }

        if ($iWeek > 1) { $iWeekInSeconds = ($iWeek-1) * 604800; } else { $iWeekInSeconds = 0; }

        $iTimestamp = mktime(0, 0, 0, 1, 1, $iYear) + $iWeekInSeconds + $iShift;
        $iTimestampLastDay = mktime(0, 0, 0, 1, 6, $iYear) + $iWeekInSeconds + $iShift + 604800;

        return array(date($sFormat, $iTimestamp), date($sFormat, $iTimestampLastDay));
    }
public static function getWeek(int $iWeek, int $iYear, string $sFormat = "Y-m-d") : Date
    {
        $iFirstDayInYear = date("N",mktime(0, 0, 0, 1, 1, $iYear));

        if ($iFirstDayInYear < 5) { $iShift = -($iFirstDayInYear - 1) * 86400; } else { $iShift = (8 - $iFirstDayInYear) * 86400; }

        if ($iWeek > 1) { $iWeekInSeconds = ($iWeek-1) * 604800; } else { $iWeekInSeconds = 0; }

        $iTimestamp = mktime(0, 0, 0, 1, 1, $iYear) + $iWeekInSeconds + $iShift;
        $iTimestampLastDay = mktime(0, 0, 0, 1, 6, $iYear) + $iWeekInSeconds + $iShift + 604800;

        return array(date($sFormat, $iTimestamp), date($sFormat, $iTimestampLastDay));
    }
set name of image

@access public
@param  int $iWeek number of week
@param  int $iYear year
@param string $sFormat
@return Date