/**
 * PHP實現文字寫入圖片
 */
class wordsOnImg {
 
  public $config = null;
 
  /**
   * @param $config 傳入參數
   * @param $config['file'] 圖片文件
   * @param $config['size'] 文字大小
   * @param $config['angle'] 文字的水平角度
   * @param $config['fontfile'] 字體文件路徑
   * @param $config['width'] 預先設置的寬度
   * @param $config['x'] 開始寫入時的橫坐標
   * @param $config['y'] 開始寫入時的縱坐標
   */
  public function __construct($config=null){
    if(empty($config)){
      return 'must be config';
    }
    $fileArr = explode(".",$config['file']);
    $config['file_name'] = $fileArr[0];
    $config['file_ext'] = $fileArr[1];
    $this->config = $config;
  }
  /**
   * PHP實現圖片上寫入實現文字自動換行
   * @param $fontsize 字體大小
   * @param $angle 角度
   * @param $font 字體路徑
   * @param $string 要寫在圖片上的文字
   * @param $width 預先設置圖片上文字的寬度
   * @param $flag  換行時單詞不折行
   */
  public function wordWrap($fontsize,$angle,$font,$string,$width,$flag=true) {
    $content = "";
    if($flag){
      $words = explode(" ",$string);
      foreach ($words as $key=>$value) {
        $teststr = $content." ".$value;
        $testbox = imagettfbbox($fontsize, $angle, $font, $teststr);
        //判斷拼接后的字符串是否超過預設的寬度
        if(($testbox[2] > $width)) {
          $content .= "\n";
        }
        $content .= $value." ";
      }
    }else{
      //將字符串拆分成一個個單字 保存到數組 letter 中
      for ($i=0;$imb_strlen($string);$i++) {
        $letter[] = mb_substr($string, $i, 1);
      }
      foreach ($letter as $l) {
        $teststr = $content." ".$l;
        $testbox = imagettfbbox($fontsize, $angle, $font, $teststr);
        // 判斷拼接后的字符串是否超過預設的寬度
        if (($testbox[2] > $width)  ($content !== "")) {
          $content .= "\n";
        }
        $content .= $l;
      }
    }
    return $content;
  }
 
  /**
   * 實現寫入圖片
   * @param $text 要寫入的文字
   * @param $flag 是否直接輸出到瀏覽器，默認是
   */
  public function writeWordsToImg($text,$flag=true){
    if(empty($this->config)){
      return 'must be config';
    }
    //獲取圖片大小
    $img_pathWH = getimagesize($this->config['file']);
    //打開指定的圖片文件
    $im = imagecreatefrompng($this->config['file']);
    #設置水印字體顏色
    $color = imagecolorallocatealpha($im,0, 0, 255, 75);//藍色
    $have = false;
    if(stripos($text,"br/>")!== false){
      $have = true;
    }
    if($have){
      $words_text = explode("br/>",$text);
      $words_text[0] = $this->wordWrap($this->config['size'], $this->config['angle'], $this->config['fontfile'], $words_text[0], $this->config['width']); //自動換行處理
      $words_text[1] = $this->wordWrap($this->config['size'], $this->config['angle'], $this->config['fontfile'], $words_text[1], $this->config['width']); //自動換行處理
      $words_text[2] = $this->wordWrap($this->config['size'], $this->config['angle'], $this->config['fontfile'], $words_text[2], $this->config['width']); //自動換行處理
      imagettftext($im, $this->config['size'], $this->config['angle'], $this->config['x'], $this->config['y'], $color, $this->config['fontfile'], $words_text[0]);
      imagettftext($im, $this->config['size'], $this->config['angle'], $this->config['x'], $this->config['y']+30, $color, $this->config['fontfile'], "  ".$words_text[1]);
      imagettftext($im, $this->config['size'], $this->config['angle'], $img_pathWH[0]/2+70, $img_pathWH[1]-80, $color, $this->config['fontfile'], $words_text[2]);
      if($flag){
        header("content-type:image/png");
        imagepng($im);
        imagedestroy($im);
      }
      imagepng($im,$this->config['file_name'].'_1.'.$this->config['file_ext']);
      imagedestroy($im);
    }
    $words_text = $this->wordWrap($this->config['size'], $this->config['angle'], $this->config['fontfile'], $text, $this->config['width']); //自動換行處理
    imagettftext($im, $this->config['size'], $this->config['angle'], $this->config['x'], $this->config['y'], $color, $this->config['fontfile'], $words_text);
    if($flag){
      header("content-type:image/png");
      imagepng($im);
      imagedestroy($im);
    }
    imagepng($im,$this->config['file_name'].'_1.'.$this->config['file_ext']);
    imagedestroy($im);
  }
}
 
$text = "Dear Kangbr/>If you can hold something up and put it down, it is called weight lifting;if you can hold something up but can never put it down, it's called bueden bearing. Pitifully, most of people are bearing heavy burdens when they are in love.\n\nBeing nice to someone you dislike doesn't mean you're a hypocritical people. It means you're mature enough to tolerate your dislike towards them.br/>Mr. Kang";
 
$data = array(
  'file'=>'20171226152410.png',
  'size'=>12,
  'angle'=>0,
  'fontfile'=>'./Font/ChalkboardSE.ttc',
  'width'=>270,
  'x'=>20,
  'y'=>70
);
//使用
$wordsOnImgObj = new wordsOnImg($data);
$wordsOnImgObj->writeWordsToImg($text);