PHP GD库 生成图片时，对于英文的换行

摘要：前言最近开发遇到后端生成图片时英文的换行贴代码字符串相关处理英文字符串换行如果是字母，并且到了换行的地方，则需要看这个字符的下一个字符是否是字母，如果是的话就需要回到上一个不是字母的地方注意中文和英文上一次出现不是字母的索引位置将单个字符存

最近开发遇到后端生成图片时英文的换行

贴代码

/*
 * 字符串相关处理
 */
class StringUtils
{
    /**
     * 英文字符串换行
     * 如果是字母，并且到了换行的地方，则需要看这个字符的下一个字符是否是字母，如果是的话就需要回到上一个不是字母的地方
     * 注意：中文和英文
     */
    public static function wrap($str, $max_len) {
        $arr = [];
        $len = mb_strlen($str);
        if ($len == 0) {
            return $arr;
        }
        if ($len <= $max_len) {
            $arr[] = $str;
            return $arr;
        }
        $w_len = 0;
        $w_str = "";
        $last_index = 0; // 上一次出现不是字母的索引位置
        for ($i = 0; $i < $len; $i++) {
            $sub_str = mb_substr($str, $i, 1); //将单个字符存到数组当中
            $w_str .= $sub_str;
            $w_len++;
            if (!self::isWord($sub_str)) {
                // 记录最后一次出现不是字母的索引
                $last_index = $w_len;
            }
            // 需要换行
            if ($w_len >= $max_len) {
                if (self::isWord($sub_str)) {
                    $w_str_1 = mb_substr($w_str, 0, $last_index);
                    $w_str_2 = mb_substr($w_str, $last_index, $w_len);
                    $w_len = $w_len - $last_index;
                } else {
                    $w_str_1 = $w_str;
                    $w_str_2 = "";
                    $w_len = 0;
                }
                $arr[] = $w_str_1;
                $w_str = $w_str_2;
                $last_index = 0;
            }
        }
        $arr[] = $w_str;

        return $arr;

    }

    /**
     * 中文换行
     */
    public static function wrapCh($str, $max_len) {
        $arr = [];
        $len = mb_strlen($str);
        if ($len == 0) {
            return $arr;
        }
        if ($len <= $max_len) {
            $arr[] = $str;
            return $arr;
        }
        $page = ceil($len / $max_len);
        for ($i = 0; $i < $page; $i++) {
            $temp_str = mb_substr($str, $i * $max_len, $max_len);
            $arr[] = $temp_str;
        }
        return $arr;
    }

    /**
     * 判断是否单词
     */
    public static function isWord($chr) {
        $wordArr = ["a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z","A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z"];
        return in_array($chr, $wordArr);
    }

}

    // 字符串
    $str = "呵呵呵发链接The British Charles Babbage was the inventor of an analytical machine with附加费两款手机 punch发vvvvv个版本发vv cards, and of a difference engine, both forerunners of the computer, and his name is given to the mwei or picoether, 10 to the -12 ether.";
    $arr = StringUtils::wrapCh($str , 20);
    echo "
暴力换行

";
    foreach($arr as $k=>$v){
        echo $v . "
";
    }
    $arr = StringUtils::wrap($str , 20);
    echo "
正确的换行

";
    foreach($arr as $k=>$v){
        echo $v . "
";
    }

暴力换行

呵呵呵发链接The British Ch
arles Babbage was th
e inventor of an ana
lytical machine with
附加费两款手机 punch发vvvvv个
版本发vv cards, and of 
a difference engine,
both forerunners of
the computer, and h
is name is given to 
the mwei or picoethe
r, 10 to the -12 eth
er.

正确的换行

呵呵呵发链接The British 
Charles Babbage was 
the inventor of an 
analytical machine 
with附加费两款手机 punch发
vvvvv个版本发vv cards, 
and of a difference 
engine, both 
forerunners of the 
computer, and his 
name is given to 
the mwei or 
picoether, 10 to 
the -12 ether.